Recent Advances in Phytochemicals Corrie Cox DTC 608 June 13, 2010
Introduction In the past twenty years, phytochemicals and their importance in various foods have beenrecognized and established (1). More recently, phytochemicals have been the focus of many researchstudies, and are now seen on the market as dietary supplements. Each phytochemical found in foodsources plays a different role in the human body. Carotenoids are known to reduce the risk of cancer andflavonoid molecules are potent antioxidants. Furthermore, anthocyanin compounds, which are found inberries, help to improve neuronal and cognitive brain functions. In addition, they help with ocular healthand protect DNA integrity. Phytochemicals such as phenolic acids and tannins naturally occur in coffeeand tea, and research has proven they may help in the prevention of chronic and degenerative disorders(2). The following studies discuss current literature that is published (or in press) in regards toadvancements in phytochemicals. In addition, Table 1 (found on pg. 6) lists phytochemicals, food sources,and their benefits. Also, see Figure 1 (found on pg. 7) for photomicrgraphed images of two commonphytochemicals. The factors that influence phytochemical content include: the weather (year-to-year),environmental conditions from one farm to the next, soil conditions, and farming methods. Thesefactors affect the nutritional content of crops, which can influence the amount of phytochemicals thatwill be in a crop (1). Sablani and colleagues (3) reviewed the effects of thermal treatments on phytochemicals inconventionally and organically grown raspberries and blueberries. They measured anthocyanins,phenolic compounds, and antioxidant activity. The berries were either steam blanched or non-blanchedthan placed into cans with sugar syrup. Then both blanched and non-blanched red raspberries andblueberries were stored in sterilized bottles in the form of processed fruit juice and pureed berries.Throughout each process any changes in phytochemicals were closely monitored. Prior to blanching,the berries showed no significant changes in anthocyanin and phenolic contents. The study showed
that during canning, anthocyanin decreased and phenolic content and antioxidant activities increased.Moreover, blanching improved the amount of phytochemicals held in blueberries prior to thepuree/juicing process. The agricultural production system used (i.e organic or conventional) for bothred raspberries and blueberries showed no significant influence on total anthocyanin, phenoliccompounds, and antioxidant activity during each process. Milbury and colleagues (4) conducted a study of anthocyanins in blueberries because numerousstudies have suggested that phytochemicals found in berries play a role in reversing age relatedcognitive impairment. Additionally, they have been know to protect against neurodegenerativedisorders. For an eight week duration, pigs were fed 2% whole freeze-dried, powered blueberry.Levels of anthocyanins were measured in the brain. Xenobiotic metabolism had taken place andanthocyanins were removed by the blood which cause a loss of the phytochemicals. The studyconcluded that the benefits of the phytochemicals found in berries were beneficial to the body throughgene expression and signal transduction in the human brain, not through direct phytochemical mega-doses. Ferruzzi (2) conducted a literature review on the two most commonly consumed beverages inthe world, coffee and tea. Epidemiological data suggests these beverages have provided evidence thatsupports its role in preventing chronic and degenerative diseases. Coffee and tea are both rich sourcesof bioactive phytochemicals such as: methylxanthines, amino acids, phenolic acids, and polyphenols.Recent attention is being drawn to the polyphenols and phenolic acids which are abundant in bothcoffee and tea. Their reported biological activities that have been shown include antioxidant activities,stimulation of NO production and vasolidation, regulation of xenobiotic-metabolizing enzymes,increased fatty acid oxidation and insulin sensitivity, and modulation of glucose absorption andutilization. Hayes and colleagues (5) evaluated the effects of selected phytochemicals on quality indicesand sensorial properties of raw and cooked pork stored in different packaging systems. They injected
raw and cooked pork with lutein, sesamol, ellagic acid and olive leaf extract and stored the pork pattiesaerobically or in modified atmosphere packs for up to twelve days. The results showed that in bothpackaging systems, sesamol, ellagic acid, and olive leaf extract exhibited significant lipid antioxidantactivity in raw and cooked pork. In addition, the study suggests these phytochemicals can be added toraw and cooked pork and may prove to be safe, natural, and functional ingredients for the pork industryto utilize in the development of novel functional pork products. Pellegrini and colleagues (6) studied the phytochemical content and total antioxidant content offresh or frozen broccoli, Brussel sprouts, and cauliflower during boiling, microwaving, and basket andoven steaming. The results showed that fresh broccoli, Brussel sprouts, and cauliflower were able toretain phytochemicals and total antioxidant content better than the frozen broccoli, Brussel sprouts, andcauliflower during each cooking method. Steaming preserved the phytochemicals in the freshvegetables better than microwaving and the basket and oven steaming method in both the fresh andfrozen vegetables. Hervert-Hernandez and colleagues (7) conducted studies on the bioactive compounds in hotpeppers. The peppers contain an abundance of phytochemicals that contain antioxidant properties. Thestudy measured the individual antioxidant, carotenoid, and phenolic content of four hot peppers. Inaddition, using an in vitro gastrointestinal model, the degree of intestinal bioaccessibility of carotenoids(with significance in human health), beta-carotene, beta-cryptoxanthin, and zeaxanthin were estimated.At ripe stage, all four hot peppers had a high content of bioactive compounds that exhibited significantantioxidant properties, such as polyphenols and carotenoids, which were partly bioaccessible. Theresults suggest 50 to 80% of these carotenoids could reach the colon to be potentially fermented orcould remain unavailable.Agriculture Research on Phytochemicals Research is also conducted to see if growers can increase the phytochemical content of lettucegrown in a greenhouse. Li and colleagues (8) studied the effects of exogenous abscisic acid (ABA) on
yield, antioxidant capacities, and phytochemical content of red and green loose leaf lettuce. On the 30thand 39th days after sowing, three concentrations of ABA in water were sprayed on the blocks, on the46th day the lettuce was harvested. The phenolic compounds in the red and green lettuce includedcaffeoyltartaric acid, 5-O-caffeoylquinic acid, dicaffeoyltartaric acid, 3,5-dicaffeoylquinic acid, andquercetin 3-(6-malonyl)-glucoside. In addition, cyanidin 3-glucoside, cyanidin 3-(3-malonoyl)-glucoside, and cyanidin 3-(6-malonoyl)-glucoside were seen in the red lettuce. Significant increasesof individual phytochemical content in red lettuce were measured in response to the ABA except for 5-O-caffeoylquinic acid; whereas no significant change was observed in the green lettuce. Significantincreases in antioxidant content were observed in both types of lettuce. Xu and colleagues (9) measured the nutritional and functional properties of immature corngrains, which are being used as a popular snack/vegetable. In the study, plants at multiple stages wereexamined to see if any changes occurred in nutrients, phytochemicals, and antioxidant activity in corngrains during different stages of growth. The results of the study revealed that during the growthperiod of corn grains, phytochemicals and antioxidant levels both decreased. Current research conducted by Zhang and colleagues (10) studied the phenolic profiles andantioxidant activity of black rice bran of differenct commercially available varieties. The objective ofthe study was to determine the phytochemical profiles and antioxidant activities from twelve varites ofblack rice in comparison to white rice. The results of the comparison showed the average values offree, bound, and total antioxidant activty of black rice was significantlly higher than that of white ricebran. In addition, all tweleve varities of black rice had higher content of total phenolics, totalflavonoids, and total anthocyans (specifically cyanidin-3-glucoside, cyanidin-3-rutinoside, andpeonidin-3-glucoside) when compared to white rice. The study suggest that knowing thephytochemical profile and antioxidant activity of black rice bran gives insights to its potentialapplication to promote health.
Conclusion In conclusion, the phytochemical content of foods is dependent on many variables includingcrop conditions, packaging systems used, cooking methods, etc. Phytochemicals are not essentialnutrients; however when consumed, they can help in the prevention of chronic and degenerativediseases. The future of phytochemicals is in educating consumers on actual health benefits.Additionally, further research needs to be conducted specifically in regards to actual health benefits, notjust assumed benefits.Table 1. Phytochemicals, food sources, and benefits ( from reference 11).Phytochemical Name Food Source BenefitsAllicin Garlic or onions May lower serum cholesterol and and protect against cardiovascular disease.Capsaicin Hot peppers May reduce blood clotting.Carotenoids Carrots, sweet potatoes, spinach, May have anti-cancer benefits. kale, etc.Flavinoids Blueberries, black raspberries, May help to improve memory. and cranberriesIndoles Cruciferous vegetables Appear to block carcinogens from damaging DNA.Isothiocyanates Cruciferous vegetables Inhibit enzymes that promote cancer activity.Lignans Whole grains and some seeds May help prevent cancers that (flax seeds) are estrogen positive from spreading or metastasizing.Limonene Citrus fruits May inhibit cancer growth.Lycopene Tomatoes, pink grapefuit, May retard the growth of watermelon, guava, and papaya cancers, particularly prostate cancer.Phenolic Acids Coffee and fruits May promote excretion of carcinogens.Phytic Acid Whole grain May inhibit free radical activity.Phytosterols Soybeans May slow rate of some cancers.Resveratrol Grapes, peanuts, and red wine. Inhibits cell growth and lowers risk of blood clotting.
Saponions Legumes and vegetables May slow DNA replication which affects growth rate of cancer cells.Tannins Tea, wine, and legumes Can inhibit cancer activity.Vitamin C Vegetables and fruit May help lower the risk of oral, throat, larynx, and esophageal cancer.Figure 1. Photomicrographs of common phytochemicals ( from reference 12).CapsaicinPhenethyl Isothiocyanate ( A Phenolic Acid)
References:1. Crinnion W. Organic foods contain higher levels of certain nutrients, lower levels of pesticides, andmay provide health benefits for the consumer. Altern Med Rev. 2010;15(1):4-12.2. Ferruzzi M. The influence of beverage composition on delivery of phenolic compounds from coffeeand tea. Physiol Behav. 2010;100(1):33-41.3. Sablani S., Andrews P., Davies N., Walters T., Saez H., Syamaladevi R., Mohekar P. Effect ofthermal treatments on phytochemicals in conventionally and organically grown berries. J Sci FoodAgric. 2010;90(5):769-78.4. Milbury P., Kalt W. Xenobiotic metabolism and berry flavonoid transport across the blood-brainbarrier. J Agric Food Chem. 2010;58(7):3950-6.5. Hayes J., Stepanyan V., OGrady M., Allen P., Kerry J. Evaluation of the effects of selectedphytochemicals on quality indices and sensorial properties of raw and cooked pork stored in differentpackaging systems. Meat Sci. 2010;85(2):289-96.6. Pellegrini N., Chiavaro E., Gardana C., Mazzeo T., Contino D., Gallo M., Riso P., Fogliano V.,Porrini M. Effect of different cooking methods on color, phytochemical concentration, and antioxidantcapacity of raw and frozen brassica vegetables. J Agric Food Chem. 2010;58(7):4310-21.7. Hervert-Hernandez D., Sayago-Ayerdi S., Goni I. Bioactive compounds of four hot pepper varieties(Capsicum annuum L.), antioxidant capacity, and intestinal bioaccessibility. J Agric Food Chem.2010;58(6):3399-4068. Li Z., Zhao X., Sandhu A., Gu L. Effects of Exogenous Abscisic Acid on Yield, AntioxidantCapacities, and Phytochemical Contents of Greenhouse Grown Lettuces. J Agric Food Chem. 2010; Inpress.9. Xu J., Hu Q., Wang X., Luo J., Liu Y., Tian C. Changes in the main nutrients, phytochemicals, andantioxidant activity in yellow corn grain during maturation. J Agric Food Chem. 2010;58(9):5751-6.
10. Zhang M., Zhang R., Zhang F., Liu R. Phenolic Profiles and Antioxidant Activity of Black RiceBran of Different Commercially Available Varieties. J Agric Food Chem. 2010; In press.11. Phytochemicals and Functional Foods. The Bellevue College Website.http://scidiv.bellevuecollege.edu/rkr/Biology130/lectures/pdfs/Phytochemicals130.pdf . Published April1999 and October 2003. Accessed June 6, 2010.12. Davidson M. The Phytochemical Collection. The Florida State University Website.http://micro.magnet.fsu.edu/micro/gallery/phytochemicals/phytochemical.html . Published September19, 1995. Updated March 8, 2004. Accessed Jun 6, 2010.