This document examines the thermal stability, antioxidant activity, and photo-oxidation of natural polyphenols. Specifically, it investigates standard polyphenol solutions (catechin, gallic acid, vanillic acid) and vegetal extracts from spruce bark and grape seeds. The key findings are:
1) Polyphenols showed relative thermal stability when exposed to temperatures from 60-100°C, with degradations ranging from 15-30% after 4 hours.
2) Gallic acid and catechin exhibited the highest antioxidant activity based on DPPH radical scavenging assays.
3) UV exposure caused significant degradation of polyphenols, removing around 40% of vanillic acid, 50%
Hepatoprotective and antioxidant effects of Azolla microphylla based gold nan...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Our present study sought to evaluate hepatoprotective and antioxidant effects of methanol extract of Azolla microphylla phytochemically synthesized gold nanoparticles (GNaP) in acetaminophen (APAP) - induced hepatotoxicity of fresh water common carp fish.
Materials and Methods:
GNaP were prepared by green synthesis method using methanol extract of Azolla microphylla. Twenty four fishes weighing 146 ± 2.5 g were used in this experiment and these were divided into four experimental groups, each comprising 6 fishes. Group 1 served as control. Group 2 fishes were exposed to APAP (500 mg/kg) for 24 h. Groups 3 and 4 fishes were exposed to APAP (500 mg/kg) + GNaP (2.5 mg/kg) and GNaP (2.5 mg/kg) for 24 h, respectively. The hepatoprotective and antioxidant potentials were assessed by measuring liver damage, biochemical parameters, ions status, and histological alterations.
Results:
APAP exposed fish showed significant elevated levels of metabolic enzymes (LDH, G6PDH and MDH), hepatotoxic markers (GPT, GOT and ALP), reduced hepatic glycogen, lipids, protein, albumin, globulin, increased levels of bilirubin, creatinine, and oxidative stress markers (TBRAS, LHP and protein carbonyl), altered the tissue enzymes (SOD, CAT, GSH-Px and GST) non-enzyme (GSH), cellular sulfhydryl (T-SH, P-SH and NP-SH) levels, reduced hepatic ions (Ca2+, Na+ and K+), and abnormal liver histology. It was observe that GNaP has reversal effects on the levels of above mentioned parameters in APAP hepatotoxicity.
Conclusion:
Azolla microphylla phytochemically synthesized GNaP protects liver against oxidative damage and tissue damaging enzyme activities and could be used as an effective protector against acetaminophen-induced hepatic damage in fresh water common carp fish.
Background: Dennentia tripetalla (Pepper Fruit) belongs to the Annonaceae family and is abundant in Nigeria. Its
fruit in folklore medicine is used for treatment of varying ailments. While ample research evidence exists on the
plants fruit and seed, no current study exists on the toxicological profile of the plant leaves.
Methods: qualitative and quantitative phytochemicals and In vitro antioxidant assays were carried out using
standard methods. The acute toxicity study indicates that the LD50 was higher than 2000 mg/Kg body weight. Subchronic
toxicity studies was carried out using five groups of rats. Group 1 served as control, 2–5 received 100 mg/
Kg, 200 mg/Kg, 500 mg/Kg and 1000 mg/Kg body weight orally for 28 days.
Results: Post-administration biochemical analysis indicates there was increased weight in rats administered 100
mg/kg and 200 mg/kg while it reduced in the 500 mg/kg group. Significant elevations of liver function markers
were reported for 200 mg/kg and 500 mg/kg respectively. Serum and hepatic protein profiles remained unaltered.
Renal function analysis revealed elevated serum urea and creatinine for 200 and 500 mg/kg groups, elevated serum
Na+ and Ca+ and reduced serum Cl− for the 500 mg/Kg group. Elevated Kidney K+ and Ca+ levels, reduced Cl−
were significantly observed in 500 mg/Kg group. Significant rise in hepatic and renal lipid peroxidation was
observed in 200 and 500 mg/Kg groups. There were observed disarmament of the antioxidant defense systems
occasioned by rise and drop in tissue (hepatic, renal, testes, heart) Superoxide dismutase (SOD), Catalase (Cat),
Glutathione-s-transferase (GST), Glutathione peroxidase (GPx) activities in the test groups relative to control.
Histopathological examination indicated architectural aberrations at 500 and 1000 mg/kg.
Conclusions: It concluded that the plant had significant phytochemical and antioxidant properties of medical
interest and possessed toxic properties in rats when administered at a dose above 200 mg/Kg over a prolonged
period of time.
Ecofriendly green biosynthesized of metallic nanoparticles:
Bio-reduction mechanism, characterization and
pharmaceutical applications in biotechnology industry
Hepatoprotective and antioxidant effects of Azolla microphylla based gold nan...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Our present study sought to evaluate hepatoprotective and antioxidant effects of methanol extract of Azolla microphylla phytochemically synthesized gold nanoparticles (GNaP) in acetaminophen (APAP) - induced hepatotoxicity of fresh water common carp fish.
Materials and Methods:
GNaP were prepared by green synthesis method using methanol extract of Azolla microphylla. Twenty four fishes weighing 146 ± 2.5 g were used in this experiment and these were divided into four experimental groups, each comprising 6 fishes. Group 1 served as control. Group 2 fishes were exposed to APAP (500 mg/kg) for 24 h. Groups 3 and 4 fishes were exposed to APAP (500 mg/kg) + GNaP (2.5 mg/kg) and GNaP (2.5 mg/kg) for 24 h, respectively. The hepatoprotective and antioxidant potentials were assessed by measuring liver damage, biochemical parameters, ions status, and histological alterations.
Results:
APAP exposed fish showed significant elevated levels of metabolic enzymes (LDH, G6PDH and MDH), hepatotoxic markers (GPT, GOT and ALP), reduced hepatic glycogen, lipids, protein, albumin, globulin, increased levels of bilirubin, creatinine, and oxidative stress markers (TBRAS, LHP and protein carbonyl), altered the tissue enzymes (SOD, CAT, GSH-Px and GST) non-enzyme (GSH), cellular sulfhydryl (T-SH, P-SH and NP-SH) levels, reduced hepatic ions (Ca2+, Na+ and K+), and abnormal liver histology. It was observe that GNaP has reversal effects on the levels of above mentioned parameters in APAP hepatotoxicity.
Conclusion:
Azolla microphylla phytochemically synthesized GNaP protects liver against oxidative damage and tissue damaging enzyme activities and could be used as an effective protector against acetaminophen-induced hepatic damage in fresh water common carp fish.
Background: Dennentia tripetalla (Pepper Fruit) belongs to the Annonaceae family and is abundant in Nigeria. Its
fruit in folklore medicine is used for treatment of varying ailments. While ample research evidence exists on the
plants fruit and seed, no current study exists on the toxicological profile of the plant leaves.
Methods: qualitative and quantitative phytochemicals and In vitro antioxidant assays were carried out using
standard methods. The acute toxicity study indicates that the LD50 was higher than 2000 mg/Kg body weight. Subchronic
toxicity studies was carried out using five groups of rats. Group 1 served as control, 2–5 received 100 mg/
Kg, 200 mg/Kg, 500 mg/Kg and 1000 mg/Kg body weight orally for 28 days.
Results: Post-administration biochemical analysis indicates there was increased weight in rats administered 100
mg/kg and 200 mg/kg while it reduced in the 500 mg/kg group. Significant elevations of liver function markers
were reported for 200 mg/kg and 500 mg/kg respectively. Serum and hepatic protein profiles remained unaltered.
Renal function analysis revealed elevated serum urea and creatinine for 200 and 500 mg/kg groups, elevated serum
Na+ and Ca+ and reduced serum Cl− for the 500 mg/Kg group. Elevated Kidney K+ and Ca+ levels, reduced Cl−
were significantly observed in 500 mg/Kg group. Significant rise in hepatic and renal lipid peroxidation was
observed in 200 and 500 mg/Kg groups. There were observed disarmament of the antioxidant defense systems
occasioned by rise and drop in tissue (hepatic, renal, testes, heart) Superoxide dismutase (SOD), Catalase (Cat),
Glutathione-s-transferase (GST), Glutathione peroxidase (GPx) activities in the test groups relative to control.
Histopathological examination indicated architectural aberrations at 500 and 1000 mg/kg.
Conclusions: It concluded that the plant had significant phytochemical and antioxidant properties of medical
interest and possessed toxic properties in rats when administered at a dose above 200 mg/Kg over a prolonged
period of time.
Ecofriendly green biosynthesized of metallic nanoparticles:
Bio-reduction mechanism, characterization and
pharmaceutical applications in biotechnology industry
Radical Scavenging Activities of a Novel Flavonoid (-)-Mesquitol Isolated fro...Premier Publishers
Radical scavenging activities of a novel flavonoid (-)-mesquitol isolated from Prosopis Juliflora heartwood was estimated by measuring methyl linoleate oxidation inhibition in a closed borosilicate glass reactor containing ((2, 2’-azobis (2-methylpropionitrile)) (AIBN) in 1-butanol as initiator and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) disappearance in UV Perkin Elmer spectrophotometer respectively. (-)-mesquitol like (+)-catechin was able to slow down oxidation of methyl linoleate induced by AIBN as well as inhibit the activities of DPPH radical. IC50 values for (-)-mesquitol were observed at approximately 23μg/ml while 50μg/ml, inhibited more than ninety percent of the DPPH radical. The IC50 value of well-known antioxidant compounds, (+)-catechin and butylated hydroxytoluene (BHT), used as reference controls in this study were approximately 29μg/ml and 268μg/ml respectively. Increasing (-)-mesquitol concentration from 0.009g/l to 0.09g/l decreased oxygen uptake from 70% to 20% respectively after 3hrs. (-)-mesquitol from P. juliflora heartwood could therefore be of valuable interest as potential source of antioxidant from renewable source.
Investigation of Total Phenolic Content and Antioxidant Activities of Spruce ...Michal Jablonsky
Extracts from spruce bark obtained using dierent deep eutectic solvents were screened for
their total phenolic content (TPC) and antioxidant activities. Water containing choline chloride-based
deep eutectic solvents (DESs) with lactic acid and 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and
1,5-pentanediol, with dierent molar ratios, were used as extractants. Basic characteristics of the DESs
(density, viscosity, conductivity, and refractive index) were determined. All the DESs used behave
as Newtonian liquids. The extractions were performed for 2 h at 60 C under continuous stirring.
TPC was determined spectrophotometrically, using the Folin-Ciocalteu reagent, and expressed as
gallic acid equivalent (GAE). The antioxidant activity was determined spectrophotometrically by
2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The TPC varied from 233.6 to
596.2 mg GAE/100 g dry bark; radical scavenging activity (RSA) ranged between 81.4% and 95%.
This study demonstrated that deep eutectic solvents are suitable solvents for extracting phenolic
compounds from spruce bark.
Phytochemical Studies on Linum Usitatissimum Seeds and the Nanoformulation of...Editor IJCATR
The phytochemical investigation of Linum usitatissimum, family Linaceae, resulted in the separation and
identification of a lignane, 8–5' neolignan 1 (dehydrodiconiferyl alcohol-4-β-D-glucoside), in addition to
identification of many compounds by the GC/MS technique. The antimicrobial activities of hexane, methylene
chloride and butanol fractions were comparable to ampicillin. The activities against E. coli were 29.2%, 37.5%,
and 66.7%, respectively; against S. aureus were 45.4%, 36.4% and 63.6%, respectively, and against C. albicans
were 26.9%, 46.1% and 73.1%, respectively. Antioxidant activity was assessed by ABTS method. It decreased
in the following order: ascorbic acid > butanol fraction > methylene chloride fraction > hexane fraction. The
cytotoxicity against HePG2 was found to be “moderate” for butanol and methylene chloride fractions, and
“weak” for the hexane fraction. The cytotoxicity against MCF-7 was found to be “strong” for butanol fraction,
and “weak” for both hexane and methylene chloride fractions. The lignane-rich subfraction, Lu 3d was
incorporated into pluronic nano-micelles using nanoprecipitation technique through a modified procedure.
The physicochemical characteristics of the developed Lu 3d-loaded nano-micelles such as particle size,
potential and morphology were determined using DLS and HR-TEM. The average diameters of the prepared
plain and Lu 3d-loaded pluronic nano-micelles were found to be 207 ± 12 and 225 ± 18 nm, respectively. The
encapsulation of Lu 3d into nano-sized particles has enhanced their aqueous dissolution and consequently
improved their bioavailability. Nanoformulation of Lu 3d led also to a stable colloidal dispersion with a strong
green color, indicating its homogenous distribution in the aqueous medium at a significantly higher
concentration than that obtained using other solvents.
The Comparative Study of Antioxidant Activity Of Monsoon Plant-Clerodendrum S...inventionjournals
ABSTRACT: The increasing demands of convenient food have led to rapid growth in the ready-to-eat product category. Many of the food ingredients contain unsaturated fatty acids that are quite susceptible to quality deterioration, especially under oxidative stress. To combat this, the best strategy is addition of antioxidants. Also, natural antioxidants in the daily diet need to be encouraged in order to improve human health and prevent degenerative diseases like Alzheimer’s, coronary heart disease, neurogenetic disorders, cancer, atherosclerosis and inflammations by oxidation of proteins, lipids, nucleic acids, DNA, etc. The DPPH method of free radical scavenging was carried out and the effect of the commercial, fresh, dried and cooked sample of Clerodendrum serratum were compared and calculated to check for its antioxidant activity. All samples showed antioxidant activity, highest being in cooked, followed by commercial, fresh and dried samples. Thus, it is advisable to consume the vegetable in cooked form at home as it shows highest radical scavenging power. The dried samples were over-heated, thereby showing minimum antioxidant activity.
Background: The probable mechanism of an earlier reported capacity of palm oil extracts to confer protection
against high dose cadmium poisoning in rats was reported in this study. Similar experimental design earlier reported
by us was retained. Rats therefore were sacrificed at intervals of twelve; twenty four and forty eight hours post CdCl2
insult.
Results: Oxidative stress and antioxidant status (malondialdehyde, superoxide dismutase, catalase and glutathione)
were assessed in tissues (liver, kidney, heart, brain, muscle) and serum. Oxidative stress indicators showed a significantly
(p < 0.05) increased lipid peroxidation and alterations in antioxidant defence systems occasioned by drop in
catalase and superoxide dismutase enzymes (serum, liver, heart, brain and kidneys) of the rats. Also observed were
significant (p < 0.05) reduction in the non-enzymatic antioxidant reduced glutathione over time. Pre-administration of
rats with the crude palm oil and its extracts modulated cadmium mediated depletion of the antioxidant capacities of
rats acutely exposed to cadmium and rising lipid peroxidation profile.
Conclusions: Regulation of stress and antioxidant response was the underlying mechanism by which the extracts
conferred protection against high dose cadmium insult thus suggesting its potential as a viable therapeutic target
against its deleterious effects.
COMPARSION OF ANTIOXIDANT POTENTIAL OF DIMOCARPUS LONGAN LOUR. EXTRACTS AND ...IJSIT Editor
The present study was carried out to evaluate antioxidant activity of Dimocarpus longan stems
extracts and also to investigate the main phytoconstituents in the bio-active extract. N-hexane,
dichloromethane, ethyl acetate and methanol 80% extract were tested for free radical scavenging activity on
model reaction with stable 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The results showed that ethyl
acetate was the most active one as antioxidant agent and phytochemical analysis of that extract revealed the
presence of triterpenes, flavonoids, tannins and carbohydrates. The results may help to discover new
chemical classes of natural antioxidant substances that could serve as selective agents for infectious diseases.
Why pick on pharmaceuticals as an environmental "problem"(setac basle 2014)David Taylor
Pharmaceuticals have been singled out for specific attention as environmental pollutants but this is irrational. Pharmaceuticals , once in the environment, are similar to other emerging pollutants and should be treated on a case by case basis Attempts to regulate pharmaceuticals as a class of pollutants are unwarrented.
The use of medicinal plants in the treatment of harmful impacts of xenobiotics in animals is attracting an increasing attention in recent times. The aim of the current study is to assess the preventive potential of Costus afer aqueous leaves extract (CAAE) in treating metabolic aberrations imposed by crude oil contaminated diet in Wistar albino rats. Six groups of rats were treated as follows: A = Normal diet; B= Normal diet + 100 mg/kg body weight of CAAE; C =Normal diet + 200 mg/kg body weight of CAAE; D= Crude oil contaminated diet; E= crude oil contaminated diet + 100 mg/kg body weight of CAAE, F = crude oil contaminated diet + 200 mg/kg body weight of CAAE. After thirty days of exposure to the diet and administration of the corresponding plant extracts, the rats were sacrificed with chloroform and the required organs were excised. The hematological indices, as well as function indicators and levels of drug metabolizing enzymes in the liver and kidney, were investigated with standard protocols. The results indicated that the hematological parameters and kidney and liver function indices were altered in rats fed with crude oil contaminated diet. However, the values came close to those in control rats when Costus afer aqueous extracts were administered. Similarly, the activities of oxidase enzymes (aldehyde oxidase, monoamine oxidase, xanthine oxidase, and sulphite oxidase), following their inhibition by the ingestion of crude oil contaminated diet, equally restored close to control values upon treatment with Costus afer aqueous extract. This study, therefore, was able to establish an aqueous extract of Costus afer leave as an antidote for crude oil intoxication.
Engineering escherichia coli to convert acetic acid to free fatty acidszhenhua82
Fatty acids (FAs) are promising precursors of advanced biofuels. This study investigated conversion of acetic acid (HAc) to FAs by an engineered Escherichia coli strain. We combined established genetic engineering strategies including overexpression of acs and tesA genes, and knockout of fadE in E. coli BL21, resulting in the production of similar to 1 g/L FAs from acetic acid. The microbial conversion of HAc to FAs was achieved with similar to 20% of the theoretical yield. We cultured the engineered strain with HAc-rich liquid wastes, which yielded similar to 0.43 g/L FAs using waste streams from dilute acid hydrolysis of lignocellulosic biomass and similar to 0.17 g/L FAs using effluent from anaerobic-digested sewage sludge. C-13-isotopic experiments showed that the metabolism in our engineered strain had high carbon fluxes toward FAs synthesis and TCA cycle in a complex HAc medium. This proof-of-concept work demonstrates the possibility for coupling the waste treatment with the biosynthesis of advanced biofuel via genetically engineered microbial species.
Radical Scavenging Activities of a Novel Flavonoid (-)-Mesquitol Isolated fro...Premier Publishers
Radical scavenging activities of a novel flavonoid (-)-mesquitol isolated from Prosopis Juliflora heartwood was estimated by measuring methyl linoleate oxidation inhibition in a closed borosilicate glass reactor containing ((2, 2’-azobis (2-methylpropionitrile)) (AIBN) in 1-butanol as initiator and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) disappearance in UV Perkin Elmer spectrophotometer respectively. (-)-mesquitol like (+)-catechin was able to slow down oxidation of methyl linoleate induced by AIBN as well as inhibit the activities of DPPH radical. IC50 values for (-)-mesquitol were observed at approximately 23μg/ml while 50μg/ml, inhibited more than ninety percent of the DPPH radical. The IC50 value of well-known antioxidant compounds, (+)-catechin and butylated hydroxytoluene (BHT), used as reference controls in this study were approximately 29μg/ml and 268μg/ml respectively. Increasing (-)-mesquitol concentration from 0.009g/l to 0.09g/l decreased oxygen uptake from 70% to 20% respectively after 3hrs. (-)-mesquitol from P. juliflora heartwood could therefore be of valuable interest as potential source of antioxidant from renewable source.
Investigation of Total Phenolic Content and Antioxidant Activities of Spruce ...Michal Jablonsky
Extracts from spruce bark obtained using dierent deep eutectic solvents were screened for
their total phenolic content (TPC) and antioxidant activities. Water containing choline chloride-based
deep eutectic solvents (DESs) with lactic acid and 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and
1,5-pentanediol, with dierent molar ratios, were used as extractants. Basic characteristics of the DESs
(density, viscosity, conductivity, and refractive index) were determined. All the DESs used behave
as Newtonian liquids. The extractions were performed for 2 h at 60 C under continuous stirring.
TPC was determined spectrophotometrically, using the Folin-Ciocalteu reagent, and expressed as
gallic acid equivalent (GAE). The antioxidant activity was determined spectrophotometrically by
2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The TPC varied from 233.6 to
596.2 mg GAE/100 g dry bark; radical scavenging activity (RSA) ranged between 81.4% and 95%.
This study demonstrated that deep eutectic solvents are suitable solvents for extracting phenolic
compounds from spruce bark.
Phytochemical Studies on Linum Usitatissimum Seeds and the Nanoformulation of...Editor IJCATR
The phytochemical investigation of Linum usitatissimum, family Linaceae, resulted in the separation and
identification of a lignane, 8–5' neolignan 1 (dehydrodiconiferyl alcohol-4-β-D-glucoside), in addition to
identification of many compounds by the GC/MS technique. The antimicrobial activities of hexane, methylene
chloride and butanol fractions were comparable to ampicillin. The activities against E. coli were 29.2%, 37.5%,
and 66.7%, respectively; against S. aureus were 45.4%, 36.4% and 63.6%, respectively, and against C. albicans
were 26.9%, 46.1% and 73.1%, respectively. Antioxidant activity was assessed by ABTS method. It decreased
in the following order: ascorbic acid > butanol fraction > methylene chloride fraction > hexane fraction. The
cytotoxicity against HePG2 was found to be “moderate” for butanol and methylene chloride fractions, and
“weak” for the hexane fraction. The cytotoxicity against MCF-7 was found to be “strong” for butanol fraction,
and “weak” for both hexane and methylene chloride fractions. The lignane-rich subfraction, Lu 3d was
incorporated into pluronic nano-micelles using nanoprecipitation technique through a modified procedure.
The physicochemical characteristics of the developed Lu 3d-loaded nano-micelles such as particle size,
potential and morphology were determined using DLS and HR-TEM. The average diameters of the prepared
plain and Lu 3d-loaded pluronic nano-micelles were found to be 207 ± 12 and 225 ± 18 nm, respectively. The
encapsulation of Lu 3d into nano-sized particles has enhanced their aqueous dissolution and consequently
improved their bioavailability. Nanoformulation of Lu 3d led also to a stable colloidal dispersion with a strong
green color, indicating its homogenous distribution in the aqueous medium at a significantly higher
concentration than that obtained using other solvents.
The Comparative Study of Antioxidant Activity Of Monsoon Plant-Clerodendrum S...inventionjournals
ABSTRACT: The increasing demands of convenient food have led to rapid growth in the ready-to-eat product category. Many of the food ingredients contain unsaturated fatty acids that are quite susceptible to quality deterioration, especially under oxidative stress. To combat this, the best strategy is addition of antioxidants. Also, natural antioxidants in the daily diet need to be encouraged in order to improve human health and prevent degenerative diseases like Alzheimer’s, coronary heart disease, neurogenetic disorders, cancer, atherosclerosis and inflammations by oxidation of proteins, lipids, nucleic acids, DNA, etc. The DPPH method of free radical scavenging was carried out and the effect of the commercial, fresh, dried and cooked sample of Clerodendrum serratum were compared and calculated to check for its antioxidant activity. All samples showed antioxidant activity, highest being in cooked, followed by commercial, fresh and dried samples. Thus, it is advisable to consume the vegetable in cooked form at home as it shows highest radical scavenging power. The dried samples were over-heated, thereby showing minimum antioxidant activity.
Background: The probable mechanism of an earlier reported capacity of palm oil extracts to confer protection
against high dose cadmium poisoning in rats was reported in this study. Similar experimental design earlier reported
by us was retained. Rats therefore were sacrificed at intervals of twelve; twenty four and forty eight hours post CdCl2
insult.
Results: Oxidative stress and antioxidant status (malondialdehyde, superoxide dismutase, catalase and glutathione)
were assessed in tissues (liver, kidney, heart, brain, muscle) and serum. Oxidative stress indicators showed a significantly
(p < 0.05) increased lipid peroxidation and alterations in antioxidant defence systems occasioned by drop in
catalase and superoxide dismutase enzymes (serum, liver, heart, brain and kidneys) of the rats. Also observed were
significant (p < 0.05) reduction in the non-enzymatic antioxidant reduced glutathione over time. Pre-administration of
rats with the crude palm oil and its extracts modulated cadmium mediated depletion of the antioxidant capacities of
rats acutely exposed to cadmium and rising lipid peroxidation profile.
Conclusions: Regulation of stress and antioxidant response was the underlying mechanism by which the extracts
conferred protection against high dose cadmium insult thus suggesting its potential as a viable therapeutic target
against its deleterious effects.
COMPARSION OF ANTIOXIDANT POTENTIAL OF DIMOCARPUS LONGAN LOUR. EXTRACTS AND ...IJSIT Editor
The present study was carried out to evaluate antioxidant activity of Dimocarpus longan stems
extracts and also to investigate the main phytoconstituents in the bio-active extract. N-hexane,
dichloromethane, ethyl acetate and methanol 80% extract were tested for free radical scavenging activity on
model reaction with stable 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The results showed that ethyl
acetate was the most active one as antioxidant agent and phytochemical analysis of that extract revealed the
presence of triterpenes, flavonoids, tannins and carbohydrates. The results may help to discover new
chemical classes of natural antioxidant substances that could serve as selective agents for infectious diseases.
Why pick on pharmaceuticals as an environmental "problem"(setac basle 2014)David Taylor
Pharmaceuticals have been singled out for specific attention as environmental pollutants but this is irrational. Pharmaceuticals , once in the environment, are similar to other emerging pollutants and should be treated on a case by case basis Attempts to regulate pharmaceuticals as a class of pollutants are unwarrented.
The use of medicinal plants in the treatment of harmful impacts of xenobiotics in animals is attracting an increasing attention in recent times. The aim of the current study is to assess the preventive potential of Costus afer aqueous leaves extract (CAAE) in treating metabolic aberrations imposed by crude oil contaminated diet in Wistar albino rats. Six groups of rats were treated as follows: A = Normal diet; B= Normal diet + 100 mg/kg body weight of CAAE; C =Normal diet + 200 mg/kg body weight of CAAE; D= Crude oil contaminated diet; E= crude oil contaminated diet + 100 mg/kg body weight of CAAE, F = crude oil contaminated diet + 200 mg/kg body weight of CAAE. After thirty days of exposure to the diet and administration of the corresponding plant extracts, the rats were sacrificed with chloroform and the required organs were excised. The hematological indices, as well as function indicators and levels of drug metabolizing enzymes in the liver and kidney, were investigated with standard protocols. The results indicated that the hematological parameters and kidney and liver function indices were altered in rats fed with crude oil contaminated diet. However, the values came close to those in control rats when Costus afer aqueous extracts were administered. Similarly, the activities of oxidase enzymes (aldehyde oxidase, monoamine oxidase, xanthine oxidase, and sulphite oxidase), following their inhibition by the ingestion of crude oil contaminated diet, equally restored close to control values upon treatment with Costus afer aqueous extract. This study, therefore, was able to establish an aqueous extract of Costus afer leave as an antidote for crude oil intoxication.
Engineering escherichia coli to convert acetic acid to free fatty acidszhenhua82
Fatty acids (FAs) are promising precursors of advanced biofuels. This study investigated conversion of acetic acid (HAc) to FAs by an engineered Escherichia coli strain. We combined established genetic engineering strategies including overexpression of acs and tesA genes, and knockout of fadE in E. coli BL21, resulting in the production of similar to 1 g/L FAs from acetic acid. The microbial conversion of HAc to FAs was achieved with similar to 20% of the theoretical yield. We cultured the engineered strain with HAc-rich liquid wastes, which yielded similar to 0.43 g/L FAs using waste streams from dilute acid hydrolysis of lignocellulosic biomass and similar to 0.17 g/L FAs using effluent from anaerobic-digested sewage sludge. C-13-isotopic experiments showed that the metabolism in our engineered strain had high carbon fluxes toward FAs synthesis and TCA cycle in a complex HAc medium. This proof-of-concept work demonstrates the possibility for coupling the waste treatment with the biosynthesis of advanced biofuel via genetically engineered microbial species.
Phytochemical composition and antiradical activity of Sakersia africana Hook....Open Access Research Paper
The valorization of the medicinal plants of our country and determination of their impact on health due to their abundance of substances with various pharmacological effects are our principal objective. This study was evaluated the phytochemical screening and radical 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of different extracts of Sakersia africana Hook. f.. The results revealed that Sakersia africana Hook. f. is rich in phenols compounds, sterols, triterpenes, alkaloids and reducing compound. The values in total phenols and proanthocyanidines are ranging respectively from 391.58 ± 0.04 to 777 ± 0.03 mg/100 g of drugs and 113.5 ± 3.17 to 653.5 ± 36.83 mg/100 g of drugs. Results also show that different extracts tested present antiradical activity with values of IC50 ranging from 164.21± 0.014 to 195.54± 0.012 % and abundance in bioactive compounds. This study could justify the use of Sakersia africana of some chronic diseases.
GC-MS Analysis and Evaluation of In-vitro Antioxidant Potential and Total Phe...Innspub Net
Wild hops (Flemingia strobilifera Linn.) is a shrub belonging to Fabaceae family. The leaves of F. strobilifera are commonly used by the Subanen, the indigenous group in Lapuyan, Zamboanga del Sur, Philippines to treat inflammation. In this study, the hydromethanolic (80%) and aqueous leaf extracts of F. strobilifera were evaluated for their antioxidant activity and total phenolics content. The active semi-volatile components of 80% methanol leaf extract were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). DPPH radical scavenging activity was used to determine the potential of this plant as anti-oxidant. Total phenolics content was determined using Folin-Ciocalteu reagent and calculated as gallic acid equivalence. GC-MS analysis revealed the presence of eight compounds. Both the 80% methanol and aqueous extracts of F. strobilifera showed significant scavenging activity with low IC50 values of 0.299 mg/mL and <0.25 mg/mL, respectively. There was positive correlation between the scavenging activity percentage and the total phenolics content only in the aqueous extract of F. strobilifera while 80% methanol extract showed negative correlation between inhibition percentage and total phenolics content which can be attributed to the solvent used and method used in quantification of phenolics. Nevertheless, the results suggest that these leaf extracts are potent source of antioxidant compounds and may serve as natural anti-inflammatory agents.
GC-MS Analysis and Evaluation of In-vitro Antioxidant Potential and Total Phe...Innspub Net
Wild hops (Flemingia strobilifera Linn.) is a shrub belonging to Fabaceae family. The leaves of F. strobilifera are commonly used by the Subanen, the indigenous group in Lapuyan, Zamboanga del Sur, Philippines to treat inflammation. In this study, the hydromethanolic (80%) and aqueous leaf extracts of F. strobilifera were evaluated for their antioxidant activity and total phenolics content. The active semi-volatile components of 80% methanol leaf extract were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). DPPH radical scavenging activity was used to determine the potential of this plant as anti-oxidant. Total phenolics content was determined using Folin-Ciocalteu reagent and calculated as gallic acid equivalence. GC-MS analysis revealed the presence of eight compounds. Both the 80% methanol and aqueous extracts of F. strobilifera showed significant scavenging activity with low IC50 values of 0.299 mg/mL and <0.25 mg/mL, respectively. There was positive correlation between the scavenging activity percentage and the total phenolics content only in the aqueous extract of F. strobilifera while 80% methanol extract showed negative correlation between inhibition percentage and total phenolics content which can be attributed to the solvent used and method used in quantification of phenolics. Nevertheless, the results suggest that these leaf extracts are potent source of antioxidant compounds and may serve as natural anti-inflammatory agents. Get the full articles at: http://www.innspub.net/ijb/gc-ms-analysis-and-evaluation-of-in-vitro-antioxidant-potential-and-total-phenolics-content-of-wild-hops-flemingia-strobilifera-l-w-t-aiton/
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Termal stab
1. Chemical Papers 68 (1) 121–129 (2014)
DOI: 10.2478/s11696-013-0417-6
ORIGINAL PAPER
Thermal stability, antioxidant activity, and photo-oxidation
of natural polyphenols
Irina Volf, Ioana Ignat*, Mariana Neamtu*, Valentin I. Popa
Faculty of Chemical Engineering and Environmental Protection, “Gheorghe Asachi” Technical University of Iasi,
73 Prof. dr. docent Dimitrie Mangeron Bd., 700050 Ia¸si, Romania
Received 12 January 2013; Revised 25 March 2013; Accepted 5 April 2013
The thermal stability (60◦
C, 80◦
C, 100◦
C), antioxidant activity, and ultraviolet C light (UV-C)
stability of standard polyphenols solutions (catechin, gallic acid, and vanillic acid) and of vegetal
extracts from spruce bark and grape seeds were investigated. Exposure of the standard solutions
and vegetal extracts to high temperatures revealed that phenolic compounds were also relatively
stable (degradations ranged from 15 % to 30 % after 4 h of exposure). The highest antioxidant
activity was obtained for ascorbic acid and gallic acid followed by catechin and caffeic acid and the
grape seeds. The results show that, after 3 h of UV-C exposure, approximately 40 % of vanillic acid,
50 % of gallic acid, and 83 % of catechin were removed. Similar degradation rates were observed
for vegetal extracts, with the exception of the degradation of catechin (40 %) from grape seeds. In
addition, the photo-oxidation of polyphenols in the presence of food constituents such as citric acid,
ascorbic acid, sodium chloride, and sodium nitrate was assessed.
c 2013 Institute of Chemistry, Slovak Academy of Sciences
Keywords: polyphenols, photo-oxidation, thermal stability, radical scavenging activity, food addi-
tives
Introduction
There has recently been a considerable increase in
interest in finding naturally occurring antioxidants to
replace synthetic antioxidants, some of which are be-
ing restricted due to their carcinogenicity. The use
of natural antioxidants also has great potential as a
result of consumers demanding additive-free, fresher,
and more natural-tasting food (Muanda et al., 2011;
Díaz-García et al., 2013).
Antioxidants are compounds that can delay or in-
hibit the oxidation of lipids or other molecules by
inhibiting the initiation or propagation of oxidising
chain reactions. These properties can play an impor-
tant role in adsorbing and neutralising free radicals,
quenching oxygen, or decomposing peroxides (Karou
et al., 2005). Phenolic compounds, one of the most
widely occurring groups of phytochemicals, are of con-
siderable physiological and morphological importance
in plants. Phenolics may act, among others, as phy-
toalexins, anti-feedants, contributors to plant pigmen-
tation, antioxidants, and protective agents against ul-
traviolet (UV) light (Ignat et al., 2011a). Polyphe-
nols have many industrial applications in fields such
as medicine, cosmetics, and the food industry. These
compounds may be used as natural colorants and
preservatives for foods, or as additives in the pro-
duction of paints, paper, cosmetics, and pharmaceu-
tical products (Naczk & Shahidi, 2006; Giusti &
Wrolstad, 2003). Most notably, the antioxidant ac-
tivities of polyphenols are presumed to exert vari-
ous pharmacological effects such as anti-carcinogenic,
anti-mutagenic, and cardio-protective effects, linked to
their free radical scavenging (Parr & Bolwell, 2000;
Casta˜neda-Ovando et al., 2009; Díaz-García et al.,
2013).
In recent years, special attention has been focused
on the isolation of phenolics from different raw materi-
als (medicinal plants, fruits, vegetables, industrial by-
products, and beverages) and on exploration of their
*Corresponding author, e-mail: mariana.neamtu1@yahoo.de, ioana.ignat@gmail.com
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2. 122 I. Volf et al./Chemical Papers 68 (1) 121–129 (2014)
potential benefits for human health.
Although these raw materials have been exten-
sively investigated for the isolation of polyphenols,
special attention continues to focus on their extrac-
tion from inexpensive or residual sources. It is well
known that the by-products from industrial processes
still contain a considerable amount of phenolic com-
pounds. Moreover, the large amounts of by-products
resulting annually from vineyards and pulp and paper
mills, along with the use of grape seeds and spruce
bark extracts as food supplements, and alternative
medical products, warrant evaluation of their prop-
erties.
Polyphenols are widely seen as very unstable and
highly susceptible to degradation (B˛akowska et al.,
2003). The stability of polyphenols under different
conditions is a very important aspect which has to be
taken into account to ensure that phenolic compounds
have the desired properties and maintain their activity
and structure during the different stages of processing,
which can involve high temperatures, light, oxygen,
solvents, the presence of enzymes, proteins, metal-
lic ions, or association with other food constituents
(Casta˜neda-Ovando et al., 2009).
UV holds considerable promise in relation to food
processing as an alternative to traditional thermal
processing; however, UV treatment has received less
attention than other non-thermal processing methods.
Applications include pasteurisation of juices, post-
lethality treatment for meats, treatment of food con-
tact surface, and ways to extend the shelf-life of fresh
produce (Koutchma, 2008, 2009; Tikekar et al., 2011a,
2012). Any approach to evaluating UV entails con-
sideration of the properties and composition of the
food product to be treated, the source of the UV ra-
diation, microbial effects, as well as the modelling,
commercial, and economic aspects (Koutchma, 2009).
The use of UV is well established for air, disinfection
of water, and wastewater treatment. The wavelength
of 253.7 nm used in this study is the most efficient
in terms of its germicidal effect, since photons are
most readily absorbed by the DNA of microorgan-
isms at this specific wavelength (Oppenlaender, 2003;
Koutchma, 2009). A significant reduction in the num-
ber of spoilage and human pathogenic microorganisms
has been demonstrated through the use of UV process-
ing (Koutchma, 2009; Tikekar et al., 2011a). Ultravi-
olet C (UV-C) light processing is relatively less costly,
has minimal effects on product flavour, and is adapt-
able to continuous processing methods (Tikekar et al.,
2011a). The Food and Drug Administration (2000)
regulations approved the use of low pressure mercury
(LPM) lamps for juice-processing (Koutchma, 2009).
Little is known about the interaction of UV with com-
plex food matrices. Moreover, the effect of some essen-
tial food additives such as vitamin C, nitrate ions and
salts on the absorption effects of antioxidants needs to
be taken into account during UV treatment.
To date, less attention has been paid to the stabil-
ity of polyphenolic compounds and their degradation
under different conditions. However, these aspects can
influence their potential applications substantially and
might elicit substantial interest in studying the photo-
oxidation and thermal degradation of phenolics.
In the present work, the antioxidant activity, ther-
mal stability, and photo-oxidation of standard solu-
tions of polyphenols (gallic acid, catechin, vanillic
acid) and natural polyphenols (spruce bark and grape
seeds extracts) were investigated. The effects of food
constituents such as citric acid, ascorbic acid, sodium
chloride, and sodium nitrate on the photo-oxidation
of polyphenols were also evaluated.
Experimental
General
Spruce wood bark was provided by a Romanian
pulp and paper company and Merlot grape seeds were
obtained from Panciu vineyard (Vrancea, Romania).
Standard polyphenols (gallic acid, catechin, vanil-
lic acid, siringic acid, p-cumaric acid, ferulic acid, and
sinapic acid) and methanol (HPLC grade) were pur-
chased from Sigma–Aldrich (UK). The other chem-
icals and solvents used were of analytical grade ob-
tained from Merck (Germany) and Sigma–Aldrich
and used without further purification. The mobile
phases for HPLC and aqueous solutions containing
100 mg L−1
standards were prepared with ultrapure
water (conductivity of 0.056 ΩS cm−1
) from a Milli-
pore Waters Milli Q purification unit (France).
Methods
Vegetal extracts were obtained from grape seeds
and spruce bark as raw materials. 50 g of dried ground
material was extracted using distilled water as extrac-
tion solvent, at 70◦
C in a water bath. The extrac-
tion was repeated three times, each time for approxi-
mately 2.5 h, and the extracts were combined and sub-
jected to UV degradation. The initial concentration of
polyphenols was determined by HPLC analysis.
The alcoholic extractions of the two raw materials
were carried out in a Soxhlet installation, over 8 h
at 70◦
C, using ethanol/water (ϕr = 7 : 3) as solvent.
Prior to the HPLC determinations, all the extracts
were concentrated under vacuum and fractioned by
successive liquid–liquid extractions with ethyl acetate.
The organic phases were evaporated to dryness and
diluted in methanol, prior to HPLC determination.
A previously developed reverse-phase high-perfor-
mance liquid chromatographic method (Ignat et al.,
2011b) was used to identify and quantify the phenolic
compounds. The HPLC analysis was performed using
a DionexUltiMate 3000 chromatograph (USA) cou-
pled to a PDA detector. Separations were carried out
A
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3. I. Volf et al./Chemical Papers 68 (1) 121–129 (2014) 123
on a Zorbax RX C18 (USA) (4.6 × 250 mm, particle
size 5 µm) column, operating at 30◦
C with a flow-rate
of 1.2 mL min−1
. The injection volume was 5 µL. The
mobile phase used was 1 vol. % acetic acid in water (A)
vs. methanol (B) for a total run-time of 40 min. The
elution conditions were as follows: the vol. % of sol-
vent B was increased linearly from 10 to 40 in 40 min
and then decreased to 10 and maintained for 10 min.
For quantification, standards for external calibration
were used.
Total phenolic content (TPC) was determined us-
ing the Folin–Ciocalteau reagent, with a protocol de-
veloped previously (Hainal et al., 2011). Gallic acid
was employed as a calibration standard and the re-
sults were expressed as gallic acid equivalents (mg of
GAE per 100 g of dried material).
The radical scavenging activity of the natural
extracts was evaluated using the reduction of the
di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (2,2-
diphenyl-1-picrylhydrazyl, DPPH) radical. The an-
tioxidant activity of the extracts was expressed as
EC50, an equivalent amount of an extract that neu-
tralises 50 % of the radical. The colorimetric assay was
performed using a modification of the method devel-
oped by Almela et al. (2006).
For the DPPH assay, the alcoholic and aqueous
extracts were concentrated and freeze-dried to avoid
interference from the solvents. Thereafter, different
dosages of a 0.5 mg mL−1
methanolic solution of ei-
ther aqueous or ethanolic freeze-dried extracts (25 µL,
50 µL, 100 µL, 200 µL, 300 µL, 400 µL, 500 µL
each) were added to screw-capped glass vials contain-
ing 2 mL of the DPPH. All the volumes were adjusted
to 3.1 mL with MeOH. After a reaction time of 30 min,
the absorbance was measured at 517 nm. The inhi-
bition percentage of the free radical DPPH (I ) was
calculated according to the following equation:
I =
A0 − A
A0
× 100 % (1)
Methanolic solutions of ascorbic acid, gallic acid,
caffeic acid, and catechin were tested as reference an-
tioxidants. The different quantities of the extracts
tested, expressed in micrograms, were plotted on a
dose-inhibition curve.
The photo-degradation experiments were carried
out in a stirred-batch photo-reactor (volume of irradi-
ated solution = 500 mL, optical path length = 4 cm) at
298 K. The lamp was located on the central axis of the
reactor, in a quartz sleeve. The aqueous solutions, pre-
pared as above, were irradiated with a UV-immersed
low-pressure Heraeus mercury lamp TN 15/32 (Her-
aeus Nobelight, Germany) with a nominal output of
15 W, attaining its spectrum at the 254 nm line. The
incident photonic flux (P0 = 1.013 × 10−5
E s−1
) was
measured by hydrogen peroxide actinometry.
The stability of standard solutions of polyphenols
and vegetal extracts was evaluated at three different
Fig. 1. Typical chromatogram at 280 nm of standard polyphe-
nols (a), of spruce bark ethanolic extract (b), of grape
seeds ethanolic extract (c). Identified compounds: 1 –
gallic acid; 2 – catechin; 3 – vanillic acid; 4 – syringic
acid; 5 – p-coumaric acid; 6 – ferulic acid; 7 – sinapic
acid.
temperatures (60◦
C, 80◦
C, and 100◦
C) for 4 h. Sam-
ples were taken first after 30 min and every hour sub-
sequently and analysed by HPLC in order to establish
the concentration of polyphenols previously exposed
to temperature treatment.
Analysis of variance or R2
values was used to ver-
ify the statistical significance between the treatments
using Microsoft Excel (version 2007). Each data point
represents the average of three measurements ± stan-
dard deviation (5 %).
Results and discussion
Identification and quantification of polyphe-
nols by HPLC
The chromatographic profiles of the standards and
vegetal extracts are shown in Fig. 1.
The analytical polyphenolic composition of the
samples is given in Table 1; it should be noted that
the major compounds identified in the aqueous and
ethanolic fractions for both vegetal materials were gal-
lic acid and catechin. Furthermore, in the spruce bark
extract, vanillic acid was also identified in relatively
A
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4. 124 I. Volf et al./Chemical Papers 68 (1) 121–129 (2014)
Table 1. Concentration of phenolic compounds (mg per 100 g of dried plant) in samplesa investigated
Raw material Type of extract Gallic acid Catechin Vanillic acid TPC/(mg of GAE per 100 g−1)
Grape seeds Aqueous extract 6.12 ± 0.20 44.36 ± 0.10 – 506 ± 5
Ethanolic extract 12.54 ± 0.80 63.60 ± 1.70 – 1368 ± 14
Spruce bark Aqueous extract – 31.00 ± 1.90 39.40 ± 0.20 517 ± 5
Ethanolic extract 10.20 ± 0.30 71.90 ± 2.70 71.90 ± 0.80 1355 ± 12
a) Results represent average values of triplicate determination (n = 3) ± standard deviation. Caffeic acid, siringic acid, p-cumaric
acid, ferulic acid, and sinapic acid were not detected in the studied samples.
high concentrations. As expected, the concentrations
of the compounds were considerably higher in the al-
coholic extracts. Table 1 also shows the total phenolic
content; the high concentration values (up to 1368 mg
GAE 100 g−1
) indicate that the identified compounds
represent only a small percentage (from 9.6 % to 11 %)
of the total phenolic compounds detected. Similar con-
centrations were reported by Neo et al. (2008) and
Kirca and Arslan (2008).
Radical scavenging activity
The radical scavenging activity of natural extracts
and pure compounds was evaluated by DPPH assay.
The antioxidants react with the stable free radical, i.e.,
1,1-diphenyl-2-picrylhydrazyl (deep violet colour) and
convert it to 1,1-diphenyl-2-picrylhydrazine accompa-
nied with discoloration. The degree of discoloration
indicates the free radical scavenging potentials of the
sample/antioxidant (Sarikurkcu et al., 2008).
Determination of an absolute value for the antioxi-
dant activity of an extract is problematic because it is
dependent on the actual concentration of the radical,
its degradation during the analysis or the matrix inter-
ference. Accordingly, the EC50 parameter was used,
which represents the equivalent amount of an extract
that neutralises 50 % of the radical.
The radical scavenging activity of alcoholic and
aqueous extracts was compared with that of some
standard polyphenols (gallic acid, catechin, caffeic
acid), as well as with ascorbic acid, one of the synthetic
antioxidants commonly used in the food industry.
The reduction in absorbance was measured at
517 nm for different quantities of standards and
extracts, and the results were plotted on a dose-
inhibition curve. The resulting linear calibration
curves were used to derive the EC50 value. The equiv-
alent amount of an extract that neutralises 50 % of the
radical is reported in Table 2.
Table 2 shows that the lowest values of EC50,
which indicates the highest antioxidant activity, were
obtained for ascorbic acid and gallic acid, followed by
catechin and caffeic acid. The linear regression shows
a good accord with the experimental data; high R2
values result for almost all the samples.
In the natural extracts, significant differences in
scavenging activity against the DPPH radical were
Table 2. EC50 values obtained for standard compounds and
vegetal extractsa
Samples EC50/µg R2
Ascorbic acid 4.60 ± 0.87 0.998
Gallic acid 1.70 ± 0.32 0.907
Caffeic acid 42.10 ± 1.02 0.993
Catechin 12.70 ± 0.98 0.999
Grape seeds alcoholic extract 45.75 ± 1.09 0.994
Spruce bark alcoholic extract 159.15 ± 3.21 0.983
Grape seeds aqueous extract 76.25 ± 1.12 0.995
Spruce bark aqueous extract 246.00 ± 5.56 0.997
a) Values are expressed as means ± SD of three replicate anal-
yses.
recorded. The antioxidant activity of the plant ex-
tracts is correlated with their phenolic content (Mon-
toro et al., 2006). The DPPH assay indicated that the
grape seeds’ alcoholic extracts had high radical scav-
enging activities, which could be attributed to high
levels of polyphenols (considerable amounts of gallic
acid and catechin). The results are strongly correlated
with the total phenolic content and the HPLC deter-
minations. The alcoholic extracts show a higher rad-
ical scavenging activity than the aqueous ones, but a
slightly lower one than the standard compounds.
Photo-oxidation
The experiments were carried out with solutions of
polyphenols (gallic acid, catechin, and vanillic acid) in
ultrapure water and also with spruce bark and grape
seeds extracts. The selected standards of polyphenols
used in this study correspond to the compounds iden-
tified and quantified in the plant extracts.
The results of the degradation of polyphenols in
the presence of citric acid, ascorbic acid, sodium ni-
trate, and sodium chloride are presented in Table 3
and Fig. 2. The UV-C exposure of standard polyphe-
nols (100 mg L−1
concentration) for 480 min led to
the complete degradation of catechin, whereas a re-
moval of 85 % of gallic acid and 50 % of vanillic
acid was achieved after the same irradiation time. The
degradation of catechin was seen to be complete after
8 h of irradiation, whereas a removal of 85 % of gal-
lic acid and only 50 % of vanillic acid was achieved
A
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5. I. Volf et al./Chemical Papers 68 (1) 121–129 (2014) 125
Table 3. Kinetic parameters for photo-degradation of polyphenols in standard solution and vegetal extracts using a low-pressure
mercury lamp
Gallic acid Catechin Vanillic acid
Experience 10−3 k 10−5 Pabs 10−3 k 10−6 Pabs 10−3 k 10−5 Pabs
min−1 E s−1 min−1 E s−1 min−1 E s−1
Standard solutions
Without additives 5.70 1.007 1.17 7.960 3.70 1.010
In presence of NaCl 4.10 1.007 8.40 8.830 2.60 1.001
In presence of NaNO3 5.80 1.007 9.60 9.496 2.00 1.007
In presence of ascorbic acid 3.40 1.010 1.01 8.400 3.60 1.010
In presence of citric acid 1.50 1.010 4.80 9.510 1.00 1.010
Vegetal Extracts
Grape seeds aqueous extract 5.40 – 2.10 – – –
Spruce bark aqueous extract – – – – 3.70 –
k – Pseudo-first order rate constant, −
d[M]
dt
= k1[M]; Pabs – photonic flux absorbed by components, Pabs = P0(1 − 10−Aλ ).
Fig. 2. Influence of different additives on catechin (a), gallic
acid (b), and vanillic acid (c) upon exposure to UV. Ini-
tial conditions: 100 mg L−1 of compound; × – 0.5 g L−1
NaCl; – 0.5 g L−1 NaNO−
3 ; – 0.5 g L−1 citric acid;
• – 0.5 g L−1 ascorbic acid; – without additives.
after the same irradiation time. The gallic and vanil-
lic acids presented a higher stability under UV ex-
posure, which is in agreement with their highest an-
tioxidant activity. The first order rate constant of
5.9 × 10−3
min−1
of gallic acid photolysis was reported
by Benitez et al. (2005), comparable with our result
(5.7 × 10−3
min−1
).
In order to evaluate the impact of preservatives
usually used in food products on the antioxidant com-
pounds under UV exposure for 90 min, citric acid,
ascorbic acid, sodium nitrate, and sodium chloride, in
ratios similar to those used in food, were employed as
additives to the polyphenol standard solutions.
After 90 min of irradiation, the removals of gallic
acid amounted to 27 % and 28 % in the presence of
sodium chloride and ascorbic acid and, respectively,
to 40 % in the presence of sodium nitrate and in the
absence of additives. The use of citric acid as additive
led to a lower degradation of the gallic acid (16 %).
A similar tendency was also observed in the case of
catechin and vanillic acid. The corresponding catechin
removals after 90 min of irradiation were 58 % in the
presence of sodium nitrate and ascorbic acid, 53 % in
the presence of sodium chloride and less than 40 %
when citric acid was used as an additive. In compari-
son, the removal rate constituted approximately 65 %
without additives. Vanillic acid presented a higher sta-
bility against UV exposure, even in the presence of
other compounds.
The effect of food additives on the UV stability
of polyphenols was rather low. Nitrate had a low ab-
sorption rate in the UV-C range (200–280 nm), while
the nitrate molar absorption coefficient at 254 nm
was only 4 L−1
M−1
cm−1
. The photolysis of nitrates
leads, in an overall reaction, to the formation of ni-
trite and oxygen. The photolysis of nitrite in the 200–
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6. 126 I. Volf et al./Chemical Papers 68 (1) 121–129 (2014)
400 nm region results in the generation of NO. and O..
At pH < 12 O.−
protonates, to form the OH radical
(Mack & Bolton, 1999). The photolysis proceeds via
complex reaction sequences, involving the formation
of intermediary hydroxyl radicals (Mack & Bolton,
1999; Neamtu & Frimmel, 2006; Schindelin & Frim-
mel, 2000; Warneck & Wurzinger, 1988). The yield of
hydroxyl radicals generated upon exposure to UV ra-
diation of nitrate at 253.7 nm is low.
In theory, dissolved chloride ions react with OH
radicals and lead to the generation of ClOH.−
. This
species can decompose to yield chlorine atoms. The
couple Cl./Cl−
has a reduction potential E from 2.2 V
to 2.6 V. Chlorine atoms can add to the C——C dou-
ble bonds of the compounds present, thus generating
chlorinated hydrocarbons (Openlaender, 2003). Sajiki
and Yonekubo (2004), reported chemical degradation
of bisphenol A (BPA) in the presence of chloride ions
by reactive oxygen species (ROS) such as hydroxyl
radicals. They also suggested that NaCl could enhance
the degradation in the presence of ROS.
Ascorbic acid, also known as vitamin C, is natu-
rally present in some fruit juices or is added as an
antioxidant to minimise losses in colour, flavour, and
nutrients during processing and storage (Koutchma,
2009; Tikekar et al., 2011b, 2012). It is a unique radical
scavenger and is known to enhance the oxygen uptake
(Φ−O2). When exposed to UV radiation, molecular ex-
citation is induced and the photochemical degrada-
tion reactions occurring include multiple free radical
reactions through the formation of ascorbyl radicals.
The ascorbyl radicals generated upon exposure to UV
radiation have a long half-life (≈ 50 s) and persist
even during storage in the dark for a certain period,
continuing to degrade the compounds (Tikekar et al.,
2011b, 2012). The present results are consistent with
this. The presence of ascorbic acid has been shown to
slightly accelerate the oxidation of catechin.
Fig. 3 shows the results obtained for the UV-C ex-
posure of vegetal extracts versus the standard com-
pounds aqueous solutions. Over 180 min of irradia-
tion, approximately 60 % of the gallic acid and more
than 50 % of the vanillic acid was degraded.
Some differences were observed for catechin. Af-
ter 3 h of irradiation, the removal of catechin from
the grape seeds extract was 40 % whereas, in the
case of the standard compound, it reached 90 %.
The results may be explained by the high ini-
tial concentrations of catechin in the analysed ex-
tract. The initial concentration of catechin in the
analysed grape seeds extract was 275 mg L−1
,
while the concentration in the standard solution was
100 mg L−1
.
The results show that the polyphenols’ standard
solutions degraded faster under UV than the vege-
tal extracts. This can be explained by the presence
of complex matrices in the plant extracts, such as
co-pigments. Similar results have been reported by
Fig. 3. Stability against UV irradiation of catechin (a), gallic
acid (b), and vanillic acid (c) from vegetal aqueous ex-
tracts: Initial conditions: 161.69 mg L−1 of gallic acid;
275.55 mg L−1 of catechin; and 149.11 mg L−1 of vanil-
lic acid; – spruce bark extract; – standard.
other authors. B˛akowska et al. (2003) previously in-
vestigated the influence of UV irradiation on the sta-
bility of cyanidin and anthocyanin (AC) – natural
polyphenol co-pigments responsible for some colours
of fruit, vegetables, and other plant tissues. They
found that the presence of co-pigments inhibited the
degradation effect of UV. The presence of co-pigments
in natural extracts prevented the UV degradation
and stabilised the polyphenols in the vegetal ex-
tracts.
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7. I. Volf et al./Chemical Papers 68 (1) 121–129 (2014) 127
Fig. 4. Thermal degradation of standard polyphenols; gallic
acid (•), catechin ( ), and vanillic acid ( ) at 60◦C (a),
80◦C (b), and 100◦C (c). Initial conditions: 100 mg L−1
of gallic acid; catechin; and vanillic acid.
Thermal degradation
The thermal stability of polyphenols is crucial and
may be correlated with both the extraction and char-
acterisation methods, and the recommendations on
their fields of use. Figs. 4 and 5 show the stability
of gallic acid, catechin, and vanillic acid at different
temperatures.
The data obtained showed a good correlation with
the UV stability. Thus, catechin was the most un-
Fig. 5. Thermal degradation of natural polyphenols; gallic
acid (•), catechin ( ), and vanillic acid ( ) at 60◦C
(a), 80◦C (b), and 100◦C (c). Initial conditions:
161.69 mg L−1 of gallic acid and 275.55 mg L−1 of
catechin from grape seeds extract; 149.11 mg L−1 of
vanillic acid from spruce bark extract.
stable compound, its degradation rate being approx-
imately 20 % at 60◦
C, increasing to 32 % at 100◦
C.
Gallic acid and vanillic acid exhibited a higher sta-
bility, their degradation rates being almost similar at
60◦
C and 80◦
C, with degradations of 15 % and 25 %,
respectively. On the other hand, at 100◦
C over 4 h of
exposure, the removal of gallic acid (30 %), catechin
(32 %), and vanillic acid (37 %) was more visible.
In the case of vegetal extracts, the degradation of
the phenolic compounds surveyed was lower for all the
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8. 128 I. Volf et al./Chemical Papers 68 (1) 121–129 (2014)
temperatures used. Similar results were reported by
Fischer et al. (2013) in investigation of the thermal
stability of ACs in three pomegranate juices. The re-
sult may be explained by the higher concentrations of
phenolics in the natural samples. However, their com-
plex chemical composition should not be disregarded.
Conclusions
The antioxidant activity, thermal and UV-C stabil-
ities of standard polyphenols solutions and of vegetal
extracts were investigated. The radical scavenging ac-
tivity of the alcoholic and aqueous extracts indicates
the highest antioxidant activity for the ascorbic and
gallic acids, followed by catechin and caffeic acid. The
stability of standard polyphenols and vegetal extracts
against UV irradiation is relatively high. The pure
compounds exhibited a good stability rate, even in
the presence of various common additives. The highest
stability under UV light was observed for gallic acid
and vanillic acid. These data correspond with similar
conclusions relating to their radicals-scavenging activ-
ity and thermal degradation.
The response to UV irradiation of the extracts in-
vestigated was analogous to that of the standard com-
pounds, which confirms the stability of polyphenols
against UV irradiation (and temperature treatment).
The effect on UV-C exposure of food additives such as
citric acid, ascorbic acid, sodium chloride, and sodium
nitrate was rather low.
The results reveal that the selected by-products re-
sulting from vineyards and pulp and paper industries
are rich sources of phenolic compounds with a high
radical scavenging activity. This outcome favours the
application of natural extracts as natural additives in
different fields. Further studies are needed to evaluate
the effect of UV light on complex liquid food matrices
and on the quality of foods.
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