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Medicinal properties of onion and garlic



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Therapeutic and Medicinal value of onion and garlic
Dr P. C. Tripathi and Dr K. E. Lawande
Therapeutic and Medicinal value of onion and garlic
Onion and garlic are beneficial herbs usually grown in annual. All parts of
these plants produce a strong odour when crushed. Onion is one of the oldest
cultivated herbs. Onion is believed to have originated in Central Asia, possibly in
Iran- Pakistan region. Onions have been revered not only for their culinary use, but
also for their therapeutic properties. As early as the 6th century, onions were used
as a medicine in India. Onion was popular with the ancient Greeks, Romans and
Egyptians for seasoning of foods. The pungency of onions made them popular
among poor people throughout the world who could freely use this inexpensive
vegetable to spark up their meals. Today China, India, the United States, Russian
and Spain are among the leading producers of onions. Onion has great therapeutic
value. They are stimulants and mild counter-irritant. It has been used as a herbal
remedy for centuries in colds, coughs, bronchitis and influenza. Onions are well-
known for their easily assimilable iron content. They are therefore beneficial in
treating anemia. Recent researches establish that the Onion as an effective
preventive against heart attacks. It is an effective remedy for cholera also. Onions
are highly beneficial in the treatment of the disorders of urinary system. Onions are
very effective in bleeding piles. Other uses of this herb are teeth disorders, ear
disorders and tuberculosis.
Garlic has remained a very popular plant in traditional medicine in addition
to its use as a condiment and food, since ancient times. There is evidence that
garlic played a significant role in the diet and pharmacy of the Indians, the Chinese,
the Russians and indeed most civilizations. The earliest recorded evidence of
garlic consumption dates as far back as 2900 B.C. in the inscription of the Cheops
pyramids of Egypt. The pyramid builders were given rations of garlic to increase
their stamina, build their strength, and protect them from disease.
Western medicine system relies on medical practices, which overlooked
preventative measures and concentrated on curing established ailments. But
since past few decade the medical community has become increasingly aware of
the importance of preventative medicine and herbs. The research has been
conducted throughout the world on curative and preventative properties of onion
and garlic and promising results have been exhibited in prevention and cure of
cardiovascular diseases, cancer prevention, inflammation, diabetes, immune system
enhancement, antioxidant, detoxification, digestive disorders, anti-bacterial, fungal,
and viral, allergies and asthma etc.
Onion and garlic in folk medicines
Onion has been used for healing both internally and externally. Internally,
onion has been recommended to treat colds, cough, bronchitis, whooping cough,
asthma and other respiratory problems. It is believed to helping in congestion in the
lungs and expands the airways. Onion is also used internally to relieve excess gas
and calm an upset stomach. A mixture of rue and onion is used to rid of parasites of
the digestive system. Onion is also thought to stimulate appetite. When applied
externally, fresh onion juice prevents bacterial and fungal infections. It can be
applied to wounds and stings on the skin, to remove warts and to stimulate hair
growth. It is even also used to reduce unwanted skin blemishes. Warm onion juice
dropped in the ear is said to help relieve earache. Baked onion was used for the
treatment of boils.
Garlic bulbs are the most frequently usedin many medicines. In India they
are prepared in several ways including extracting the juice or making paste. This
has been taken to relieve problems such as cough and fever, or applied externally to
prevent the greying of hairs and to improve skin conditions such as eczema and
scabies. It has even been applied to the noses of hysterical patients to calm them
down. Garlic also features in traditional medicine in other parts of the world. In
Nepal, East Asia and the Middle East it has been used to treat several types of
illnesses including fevers, diabetes, rheumatism, intestinal worms, colic, flatulence,
dysentery, liver disorders, tuberculosis, facial paralysis, high blood pressure and
bronchitis. Extracts of the bulbs have been widely used in folk medicine. Whooping
cough in children has been treated by administering a drink made with a hot water
extract of the dried garlic bulb mixed with honey. Hot water extracts of garlic are
also taken to kill intestinal worms. Garlic an extract is traditionally taken orally to
settle the stomach, treat coughs reduce fever. Warmed garlic juice, or a mixture
made with oil and boiled bulb has been dropped into the ear to relieve earache and
deafness. In Ayurvedic and Siddha medicine, garlic juice has been used to alleviate
sinus problems. In Unani medicine, an extract is prepared from the dried bulb which
is inhaled to promote abortion or taken to regulate menstruation. Unani physicians
also use garlic to treat paralysis, forgetfulness, tremor, colic pains, internal ulcers
and fevers.
Chemical compositions
Onion and garlic are members of the Alliaceae family. Onion has been used
as a herbal remedy from time immemorial. It is high food value with low fat,
protein and carbohydrates and rich calcium and riboflavin. The chemical
composition of onion varies from variety to variety, cultural practices and climatic
conditions. Onion contains essential oil and organic sulphides. It is rich in
powerful sulfur-containing compounds that are responsible for their pungent odors
and for many of their health-promoting effects. Onions contain allyl propyl
disulphide and many others derivatives of allyl propyl di sulphides. In addition,
onions are very rich in chromium, a trace mineral that helps cells respond to insulin,
plus vitamin C, and numerous flavonoids, most notably, quercitin.
Similar to onion, garlic has also been used as a herbal remedy from time
immemorial. It is high food value, low in protein, fat and carbohydrates and rich
calcium and riboflavin. The chemical composition of garlic varies from variety to
variety, cultural practices and climatic conditions. Garlic contains about 62 percent
water 6.0 percent protein, 29 percent fats, sucrose traces amount of Ca, Fe, Zn and
phosphate salts and small amounts of thiamin, riboflavin, niacin and ascorbic acid.
Garlic contains 0.06 to 0.1 per cent oil and di allyl di sulphide is the major
constituent of this oil. Besides this small amount of allyl propyl disulphide is also
present. The chemical composition of onion and garlic is given in Table 1.
Table 1:Chemical composition of onion and garlic (raw)
Water (g/100g)
Food energy (Calories)
Protein (g/100g)
Total Lipids (g/100g)
Ash (g/100g)
Carbohydrates (g/100g)
Total dietary fibers (g/100g)
Calcium (mg/100g)
Iron (mg/100g)
Magnesium (mg/100g)
Phosphorus (mg/100g)
Potassium (mg/100g)
Sodium (mg/100g)
Zinc (mg/100g)
Copper (mg/100g)
Manganese (mg/100g)
Selenium (u/100g)
Vitamin C(mg/100g)
Riboflavin (mg/100g)
Niacin (mg/100g)
Pantothenic acid (mg/100g)
Vitamin B-6 (mg/100g)
Folate (ug/100g)
Vitamin B12 (ug/100g)
Vitamin A (ug/100g)
Vitamin E (ug/100g)
Vitamin K (ug/100g)
Saturated fatty Acid (g/100g)
Monosaturated fatty Acid
Poly unsaturated fatty Acid
Pyruvic acid (umole/ml)
Therapeutic and medicinal value
Onion helps in maintaining healthy bones. A new compound namely, 2- L-glutamyl-
trans-s-1-propenyl -l- cysteine sulfoxide (GPCS) is identified in onion recently which inhibits
the activity of osteoclasts. The osteoclast cells are responsible for break down bones. More
intakes of GPCS through onion inhibit the action of osteroclasts. This compound of onion is
more beneficial to women who are more prone to osteoporosis during menopause. Onion may
found better substitute to the allopathic medicines such as Foramax, alendronate prescribed to
prevent excessive bone loss during menopause. These medicines have several side effects such
as, irritation of the upper gastrointestinal mucosa, esophageal ulcers etc while onion has no
side effects. This character of onions also helps in strengthening the bones in aging peoples and
ultimately restore the vigour of the body.
Garlic and garlic products offers beneficial ability to enhance the immune system .
Never less, garlic offers many other beneficial aspects. It has been proven effective in cancer,
cold and flu, heart diseases, allergies, bronchitis, arthritis, fungal , bacterial and yeast
infections etc. The combined effect of all these helps in restoring the vigour year after year.
The qualities of garlic are especially appealing to people with heart problems or anyone
interested in cardiovascular health. Garlic is also known to have anti-tumor capabilities. It has
been known for quite some time that garlic is a natural immune system enhancer. It helps the
body fight off the infections and bacteria, which constantly threaten our health. Since
traditional Western medicine has not been able to offer consumers any sort of protection
against such ailments as the common cold and flu, people are turning to garlic to enhance their
2.0Hypoglycemic effect
The higher the intake of onion, the lower the level of glucose found during oral or
intravenous glucose tolerance tests. The hypoglycemic properties of onion extract were
identified as early as 1923. The experimental and clinical evidence suggests that allyl propyl
disulfide, thiols, isomers of allyl propyl di sulphides and related compounds are responsible for
this effect. These compounds lower blood sugar levels by increasing the availability of free
insulin . The allyl propyl disulfide and its isomers compete with insulin to occupy insulin
inactivating sites in the liver . This results in an increase in the amount of insulin available to
utilize glucose in cells resulting lower blood sugar. In addition, onions are a very good source
of chromium. Chromium is mineral component molecule, which helps cells to respond
appropriately to insulin. Clinical studies of diabetics have shown that chromium can decrease
fasting blood glucose levels, improve glucose tolerance, lower insulin levels, and decrease total
cholesterol and triglyceride levels, while increasing good HDL-cholesterol levels. Marginal
chromium deficiency is common all over the world and chromium levels are depleting due
consumption of refined sugars, white flour products and lack of exercise. One cup of raw onion
can fulfill almost 20% of the daily requirement of chromium. Apart from hypoglycemic effect,
few non-sulfur having hyperglycemic have been identified.
In many parts of the world, garlic is used as a remedy for diabetics in traditional
medicine. In various studies, oral administration of garlic to human volunteers produced a
significant hypoglycemic effect at the end of the fourth week. The hypoglycemic effect of
garlic may be due to increase glycogenesis in the liver and better utilization of glucose in the
peripheral tissues. The blood sugar lowering effect of garlic was ascribed to allicin and related
disulfide-containing compounds. The SH-group compounds present in garlic are antagonistic
to the action of insulin. This hypoglycemic activity of garlic juice is closely comparable to that
of allopathic drugs tolbutamide, which is usually prescribed for diabetes.
3.0Hypocholesterolemic effect
The onions are rich in flavonoides. Among the flavonoides, the antocianos are
responsible for the pink or violet color of certain varieties of onion, while the quercetin are
colourless . The quercetins have antirust function. The quercetin contributes to the inhibition
of the oxidation of lipo proteins of low density (LDL-Cholesterol) and minimize the risk of
cardiovascular diseases. The other flavonoides presents in the onion have been found effective
in reduction of arterial tension and blood clogging activity .The regular consumption of onions
has been shown to reduce high cholesterol levels and high blood pressure which helps in
prevention of atherosclerosis and diabetic heart diseases and reduce the risk of heart attack .
These beneficial effects are attributed to sulfur compounds, chromium, flavonoides and
vitamin B6 present in onions.
The effectiveness of garlic in the prevention and treatment of atherosclerosis and
vascular hypertension have been proved in both animal experiments and human clinical
observations. The administration of garlic in both raw and boiled forms prevented the increase
total cholesterol and tryglycerides in serum. A marked decrease in coagulability and increase in
blood fibrinolytic activity were observed after the ingestion of garlic. The hypocholesterolemic
action of garlic is ascribed to allicin present in garlic which can react with -SH group. In
experiments human volunteers were who were given 10g of garlic daily showed significant
decrease in blood cholesterol level within two months. It was cocluded that regular use of
garlic reduce blood cholesterol and pressure and found beneficial in prevention of stroke.
The active ingredient allicin present in onion and garlic, is effective in helping to
promote proper circulation throughout the body. When taken for a couple of months, garlic can
drop the level of cholesterol in the blood by 15%. When garlic supplementation is combined
with a positive diet change, blood cholesterol levels can drop enough to reduce heart attack risk
by 30%.
4.0 Anti carcinogenic effect
Some studies indicate that the sulfur compounds of onion exert a protective effect in the
beginning of the carcinogénesis by increasing process of enzymatic modulation in the
metabolism of the cancerigenic substances. The studies conducted in humans have shown a
protective effect of onion against esophagus cancer and stomach cancer. The use of onions
regularly may significantly reduced risk of developing colon cancer. Onions contain a number
of flavonoids, particularly quercitin, has been shown to check the growth of tumors in animals
and to protect colon cells from the damaging effects of certain cancer-causing substances.
Cooking meats with onions may help reduce the amount of carcinogens produced when meat is
Garlic was traditionally used for the treatment of cancer of the uterus. Numerous
reports, including several important epidemiological studies, have asserted that it has a
favorable effect on various forms of cancer. Cytologically, the effects of garlic were similar to
those induced by colchicines. These produces blockage of the metaphase cells and scattering,
as well as abnormal condensation of metaphase chromosomes. The inhibitory effect of garlic
on nitrate reducing bacteria and their production in gastric juice indicates its use in the
treatment of gastric cancer. Some studies indicate that the sulfur compounds of garlic provide
protective effect in the beginning of the carcinogénesis by interfering in the metabolism of the
carcinogenic substances.
5.0Antiasthmatic and anti pulmonary disorders
The compounds derived from the onions have shown anti-asthmatic activity. The
antiasthmatic and anti-inflammatory capacity of the onions is attributed to the presence of
thio-sulfonates (sulfur compounds). The action mechanism seems to be related to an inhibition
in the synthesis of ciclooxygenase and lipooxygenase, enzymes. These enzymes take part in the
metabolism of the eicosanoides, which induce bronchial obstruction.
Inhalation of pulped and crushed garlic is traditionally used in the treatment of
pulmonary disorders in various countries. Studies have confirmed that a concentration of
1:5000 of garlic juice completely inhibited the growth of bacteria causing tuberculosis i.e.
Mycobacterium tuberculosis. This effect is not destroyed by boiling and prolonged storage .
6.0Anti-Inflammatory and Anti-Bacterial Activity
Several anti-inflammatory agents present in onions have been found helpful in reducing
the severity of pain and swelling of joints and rheumatoid arthritis, sour throat, sinusitis,
tonsillitis, allergic inflammatory and respiratory congestion during common cold. Onion
contains compounds that inhibit lipoxygenase and cyclooxygenase resulting markedly reducing
inflammation. Onions' anti-inflammatory effects are due not only to their vitamin C and
quercitin, but to other active components called iso thiocyanates. These compounds work
synergistically to provide relief from inflammation. In addition, quercitin and other flavonoids
found in onions work with vitamin C to help kill harmful bacteria, making onions an especially
good addition to soups and stews during cold and flu season.
Garlic has been found to have a very active antimicrobial effect, and many authors are
of the opinion that there is abundant evidence that the antibiotic value of the plant is on a par
with that of penicillin and other antibiotics. The extract of garlic has fungicidal action in high
concentrations while low concentrations have fungistatic action. The antiviral activity was
found to occur at concentrations below toxicity level to the tissue culture. These antiviral
concentrations may be used in man or animals without any danger of significant toxicity . The
antimicrobial principle of garlic is rapidly formed from a precursor which breaks down readily
when the garlic is crushed. Hence, it is more effective when used crushed than segmented.
Allicin, one of the active principles of freshly crushed onion and garlic products, has a variety
of antimicrobial activities. Allicin in its pure form was found to exhibit antibacterial activity
against a wide range of Gram-negative and Gram-positive bacteria, including Escherichia coli;
antifungal activity, particularly against Candida albicans; antiparasitic activity, including
some major human intestinal protozoan parasites such as Entamoeba histolytica and Giardia
lamblia; and antiviral activity. The main antimicrobial effect of allicin is due to its chemical
reaction with thiol groups of various enzymes, e.g. alcohol dehydrogenase, thioredoxin
reductase, and RNA polymerase.
7.0 Wormicidal properties
Garlic has wormicdal properties. It has been found that garlic is superior to piperazine
citrate with respect to vermicidal potency. This confirms its traditional claim as antihelmintic
for ascariasis and oxyuriasis . Garlic is also used to treat pinworms and other parasitic
infections by many naturopaths. The volatile oil of garlic inhibits liver lesions and decreases
infiltrated cells. The volatile oil elicits an intense inhibitory action on the formation of lipid
peroxides and its potency is stronger than that of the reference substance, Vitamin .E .
Investigations into the biologically active substances of garlic verified its medicinal value for
gastric ulcers and pancreatitis.
Onion and garlic are used for healing wounds, burns, ear ache, yeast infection and
many other diseases and disorders. The quantity of onion and garlic in diet is an important
factor. It is advised that one medium size bulb of onion weighing 50 to 60g onion and two to
four cloves of garlic weighing 5 to 8 gram garlic should be used in daily diet. By the virtue of
these properties of onion and garlic, these plants are becoming the prime choice not only of
naturopaths but also many trained allopathic practitioners. Many people are describing them as
wonder drugs or the poor men’s antibiotics.
... Onions occupy prime importance because of their medicinal and antioxidant compounds (Vidyavati et al. 2010). Studies have shown medicinal properties of onion in regulating many disorders in the human beings (Tripathi and Lawande 2006;Kumar and Goel 2019). ...
Purpose: This study was carried out to assess the effect of irradiated chitosan as an elicitor on the biochemical traits associated with resistance to purple blotch disease in onion . Materials and Methods Chitosan was electron beam irradiated at 100 kGy dose to obtain low molecular weight chitosan. Irradiated chitosan at 20 and 40 ppm concentration and different time intervals was used as a biological elicitor cum antimicrobial agent against purple blotch disease in onion. Field grown onion (Variety Basanvant 780) plants were foliar sprayed with irradiated chitosan and the biochemical responses were monitored using parameters viz. chlorophylls, carotenoids, antioxidant enzymes, phenols and antifungal enzyme β glucanse using standard methods. Results Compared to control treatment, a positive correlation with irradiated chitosan treatment was observed for increase in β-1, 3-glucanase, peroxidase activity, and contents of total phenolics, chlorophylls and carotenoids, which cumulatively contributed to resistance response against the purple blotch disease. Irradiated chitosan (40 ppm) treated onion plants at 30, 45, 60 DAT showed a higher total phenolics, β-1,3-glucanase activity and peroxidase activity besides enhanced antioxidant properties. Conclusion The results suggest that irradiated chitosan has elicited resistance responses against purple blotch diseasein onion . The increased production of antioxidant metabolites may provide value addition to onion as a food commodity.
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