2. INTRODUCTION
Antinutritional factors (ANFs):
Naturally produced in plants
Don’t offer nourishment to the body
Act to reduce nutrient intake, digestion, absorption and
utilization
Usually harmful for humans but sometimes beneficial
(Soetan, 2008)
Effects depend upon the digestion process and
concentration in food material
Also known as “Plant’s secondary metabolites”
4. Classification of ANFs:
Two major categories-
Proteins Other substances
Protease inhibitors Tannins
Lectins Toxic amino acids
Avidin (egg white) Glycosides
Phytates
Oxalates, etc.
5. Antinutritional factors Sources Major functions
Trypsin/ chymotrypsin
inhibitors
Legumes (soybean , mung
bean, horse gram, sweet pea,
mung bean, etc), egg white,
patoto
Inhibits activity of trypsin/
chymotrypsin
Lectins Red kidney beans, yellow wax
bean
Induces RBCs clumping and
Haemolysis
Goitrogens Sweet potatoes, beans,
cabbage, turnips, ground nut,
rape seed and mustard
Cause goitor by limiting iodine
absorbtion
Thiaminases Fish, shellfish, red cabbage Destroy thiamine
Saponins Oats, spinach, chest nuts,
many plants like fodder
Haemolysis, anti-spermal
activity
Goosypols Cotton seed Haemolytic effects, reduce
lysine and Fe availability, retard
growth
Tannins All vascular plants Reduce protein/ enzyme
availability, retard growth,
reduced weight
6. Antinutritional factors Sources Major functions
Non protein amino acids Fava bean, forage crops Cause favism, hair loss in
humans and haemolysis
Solanin Potato, tomato, egg plant Gastrointestinal and
neurological disorders
Antivitamin factors (A, D,
B12)
Soy bean, red kidney bean Reduce availability of
Vitamin A, D, B12
Phytates All legumes,
sesame(husk)
Reduce Ca and Fe
absorption
Oxalates All legumes,
sesame(husk)
Reduce Ca absorption,
kidney stone formation
Avidin Egg white Binds with biotin and
suppress its function
7. Protease Inhibitors
Inhibit the proteolytic activity of certain enzymes by
forming a insoluble E-I complex.
Trypsin, chymotrypsin, pepsin, elastase and pronase
inhibitors .
Heat labile inhibitor, can be reduced at normal processing
temperatures.
Major 2 categories:
1. Low mol. wt. inhibitors (6-10 kDa)- specific for
chymotrypsin and other enzymes
2. High mol. wt. inhibitors (20-25 kDa)- specific for trypsin
8. Nutritional significance
Reduce the activity of different proteases
growth reduced protein digestion
Hypertrophy and hyperplasia of pancreas
Mode of action
Pancreas CCK
(TI)
Trypsin
Dietary protein
Trypsin-TI
Proteolysis
(Anderson et al., 1979)
9. Lectins (phytohaemagglutinins)
Lectins are glycoproteins containing 4-10% carbohydrate;
Mol. wt : 100-150 kDa
Most lectins are composed of 4 subunits and each subunit
has a sugar binding site.
e.g.- Ricin in castor bean
-Concanavalin in jack bean
Ricin is extremely toxic. Lethal dose- 0.001µg/g body wt. of
mice.
LD50 for humans- 1.6 mg for human adult
Properties:
Ability to combine with carbohydrate membrane receptors
(Pusztai, 1989).
10. Lectins have the capability to directly bind to the intestinal
muscosa, interacting with the enterocytes and interfering
with the absorption and transportation of nutrients
(particularly carbohydrates) during digestion .
Effects:
Haemagglutination
Retard growth
11. Goitrogens
Goitrogens are the phenolic glycosides.
Sorghum and ground nut are the major source.
Functions:
Interfere with iodine uptake
Inhibit the synthesis and secretion of thyroid hormones.
Result enlargement of thyroid gland (Goitre)
Other results are reduced growth and reproductive
performance.
12. Cyanogens
Cyanogens are glycosides of sugar/ sugars and cyanide.
Beans/nuts Cyanogen
Almond (Prunus amygdalus
var.amara)
Amygdalin
Apricot(Prunus armeniaca) linamarin
Lima beans (Phaseolus lunatus) Phaseolunatin
Sorghum Dhurrin
14. Potent inhibitor of Cytochrome oxidase
Interruption in ETC
No ATP formation
CN- CNS and cardiac arrest, Paralysis
Skin color goes pink from cyanide-Hb
complexes.
Headache, confusion, breathing
problems, coma, death
15. SAPONINS
Saponins are a heterogenous group of naturally occuring foam
producing triterpenes (C30) or steroidal glycosides (C27) that occur
in wide range of plants, including pulses and oil seeds like kidney
beans, chickpea, soy bean, lupin and sunflower.
Functions:
1. Saponins binds with cholesterol in lumen Complex
Unavailable for absorption Hypocholesterolaemia
2. Bind with RBCs and cause Haemolysis
3. Depression of growth rate
4. Enzyme inhibition and reduction in nutrient absorption
5. Alter the cell wall permeability, e.g. saponins from Bulbosterma
paniculatum has anti-spermal effects on human spermatozoa and
inhibit the acrosome activity.
(Akande et al., 2010)
16. TANNINS
Tannins are water soluble phenolic compounds with a mol. wt >500 Da
with the ability to precipitate the proteins from aqueous solutions.
2 groups: 1) Hydrolyzable tannins
2) Condensed tannins (Proanthocyanidins)
Widely distributed in leguminous forages and seeds.
Tannins + dietary proteins/ enzymes less digestive complex
Also shows anti-trypsin and anti- α amylase activity
Ability to complex with vitamin B12 (Liener, 1980)
Interference with iron absorption
Intestinal damage and reduced growth
17. ANTIMETALS (PHYTATES & OXALATES)
PHYTATES:
Phytic acid (inositol phosphate ) - principal storage form of P in many
plant tissues, especially in bran & seeds.
Could be toxic when consumed in unprocessed foods.
Phytate Free Phosphates (P)
Functions:
Strong binding affinity to Ca, Mg, Fe and Zn; form insoluble complex
reduced bioavailability of minerals
Probiotics produce phytase free form of P and metal ion &
improve intestinal absorption
Phytase
(Rumen m.o.)
18. OXALATES:
Like phytates, oxalates bind minerals (Ca & Mg) and interfere with
their metabolism.
If diet is deficient in Calcium
oxalates remains free in intestine
Free oxalate is absorbed and form insoluble complex
with Ca2+
Calcium-oxalate crystals (Kidney stones) block the renal
tubules
Urinary calculi and hypocalcaemia
People with the tendency to form kidney stones are advised to avoid oxalate-
rich diet.
19. GOSSYPOLS
Gossypols is a naturally occurring polyphenolic compound present
in pigment gland of cotton seed (Gosssipium species).
0.4-2.4% gossypol present in cotton seed.
It binds with ε-amino group of lysine in proteins So
reduced lysine and protein availability retard growth
Chelate with Fe reduce Fe bioavailability reduced
O2 carrying capacity of Hb Circulatory failure & Anemia
may cause death.
General symptoms of gossypol toxicity:
1. Depressed appetite
2. Loss of weight
3. Labored breathing
4. Cardiac irregularity
5. Discolouration of egg yolk McDonald et al., 1995
20. SOLANINE
Glycoalkaloid.
It’s a part of plant’s natural defence.
Found in the species of nightshade family (Solanaceae).
Potato, Tomato and egg plant are main source of solanine.
How it reacts: Solanine
Interacts with mitochondrial membrane
Opens K+ channels increasing membrane potential
Ca2+ ions moves towards mitochondria
High conc. of Ca2+ triggers cell damage
21. Potatoes – solanine amount 0.2 mg/g (Normally)
But when exposed to light, its amount- 1-2 mg/g
It is very toxic even in small quantities (2-5 mg/ kg body wt.)
Green colour indicates- high conc. of solanine.
In potato tubers, 30–80% of the solanine develops in and close to the
skin.
Solanins gives bitter taste.
Symptoms of solanine poisoning:
Gastrointestinal and neurological disorders.
Nausea, diarrhea, vomiting, stomach cramps and headache.
Paralysis and jaundice – in severe cases.
23. BENEFICIAL EFFECTS OF ANFS
Anti-oxidant/ Anti-ageing activity:
Flavanoids- potent inhibitor of molecular O2 , act as free
radical scavengers (anti-oxidants).
Saponins – anti-ageing activity, which is related to their
free scavenging action (Hongping et al., 1993)
Saponins are also reported to improve learning process
and memory retention in experimental animals ( Zang
and Hu, 1985).
Saponins inhibit lipid peroxide formation in tissues.
Saponins also elevate the blood & brain superoxide
dismutase activity.
24. PHARMACEUTICAL APPLICATIONS
Saponins can increase the permeability of intestinal mucosa and
raises the possibility of interesting nutritional and
pharmacological uses (Cheeke, 1970).
Saponins are useful in treatment of Hypercholesterol in blood.
Flavanoids pharmacological effects are:
1. Chelating metals, thus sparing ascorbate from oxidation
2. Acting on aggregation of RBCs (in diseased states).
3. Kievotone, the potencial breast cancer fighting chemical is
found in Hyacinth bean.
4. Saponins, tannins, flavanoids have antimicrobial action.
5. Visoltricin, a novel metabolite of Fusarium tricinctum was
reported to be toxic to human tumor cells.
(Soetan, 2008)
