Onions, like garlic, are members of the Allium family, and both are rich in powerful sulfur-containing compounds that are responsible for their pungent odors and for many of their health-promoting effects.

 

The odor in onion is due to organic sulfur compounds and is produced only when the tissues are cut or injured, by enzyme action on a water-soluble amino acid. Heating, freezing and drying prevent the enzyme action. That is why cooking produces a different odor, flavor and pungency. Cooking converts some of the odoriferous compounds to sugars. Because some of the nutritive and medicinal value is lost in cooking, many food experts and herbalists recommend that you add raw onion to your diet.¹²

 

On the following pages is a list of the chemical constituents in Allium cepa.¹³ The location in the plant where the chemical is found, their medicinal actions and where Allium cepa lands on the list of plants species with the highest amount of that constituent are also given. Amounts in parts per million (ppm) will be listed if available.

 

1(F)-BETA-FRUCTOSYL-SUCROSE (bulb) No biological activities reported for this chemical. Onion and Shallot are the only species listed containing this chemical.

1-(METHYLSULFINYL)-PROPYL-METHYL-DISULFIDE (bulb) Antiaggregant activity. Onion and Shallot are the only species listed containing this chemical.

1-METHYLDITHIO-PROPANE (essential oil) No activities reported. Onion and Shallot are the only species listed containing this chemical.

1-METHYLTRITHIO-PROPANE (Essential Oil) No activities reported. Onion and Shallot are the only species listed containing this chemical.

1-O-CAFFEOYL-BETA-D-GLUCOSE (leaf) No activities reported. Onion and Shallot are the plant species listed with the 2nd highest amount of this constituent.

1-O-FERULOYL-BETA-D-GLUCOSE (leaf) No activities reported. Onion and Shallot Plant species listed with highest amount of this chemical.

1-O-P-COUMAROYL-BETA-D-GLUCOSE (leaf) No activities reported. Onion and Shallot are the plant species listed with highest amount of this chemical.

1-PROPYLTRITHIO-PROPANE (essential oil) No activities reported. Onion and Shallot are the only species listed containing this chemical.

2,3-DIMETHYL-(DL)-BUTANE-CIS-1-CIS-DITHIAL-S,S'-DIOXIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

2,3-DIMETHYL-5,6-DITHIA-BICYCLO(2,2,1)HEXANE-5-OXIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

2,3-DIMETHYLTHIOPHENE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

2,4-DIMETHYLTHIOPHENE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

2,5-DIMETHYLTHIOPHENE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

2-METHYL-BUT-2-EN-1-AL (bulb) No activities reported. Onion and Shallot are the plant species listed with the 2nd highest amount of this constituent.

2-METHYL-BUTYR-2-ALDEHYDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

2-METHYL-PENT-2-EN-1-AL (essential oil) No activities reported. Onion and Shallot are the plant species listed with highest amount of this chemical.

24-METHYLENE-CYCLOARTENOL (bulb) No activities reported. Onion and Shallot are the plant species listed with highest amount of this chemical.

28-ISOFUCOSTEROL (bulb) No activities reported. Onion and Shallot are the plant species listed with highest amount of this chemical.

3,4-DIMETHYL-2,5-DIOXO-2,5-DIHYDROTHIOPHENE (plant) No activities reported. Onion and Shallot are the second plant species listed with the highest amount of this constituent.

3,4-DIMETHYLTHIOPHENE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

31-NORCYCLOARTENOL (bulb) No activities reported. Onion and Shallot are the plant species listed with highest amount of this chemical.

31-NORLANOSTENOL (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

4-ALPHA-METHYL-ZYMOSTENOL (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

5-DEHYDRO-AVENASTEROL (seed) No activities reported. Onion and Shallot are the plant species listed with highest amount of this chemical.

5-HEXYL-CYCLOPENTA-1,3-DIONE (bulb) Antiseptic activity. Onion and Shallot are the only species listed containing this chemical.

5-OCTYL-CYCLOPENTA-1,3-DIONE (bulb) Antiseptic activity. Onion and Shallot are the only species listed containing this chemical.

6(G)-BETA-FRUCTOSYL-SUCROSE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

9,12,13-TRIHYDROXY-OCTADEC-10-ENOIC-ACID (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

9,1O,13-TRIHYDROXY-OCTADEC-11-ENOIC-ACID (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

ABSCISSIC-ACID (bulb) Juvabional and phytohormonal activity. Onion and Shallot are the plant species listed with highest amount of this chemical.

ACETAL (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

ACETIC-ACID (bulb) Biological activities include: acidulant, antibacterial, antiotitic, antisalmonella, antivaginitic, expectorant, fungicide, keratitigenic, mucolytic, osteolytic, perfumery, protisticide, spermicide, ulcerogenic and verrucolytic. Allium cepa is number eighteen on the plant species with the highest amount of this constituent.

ALANINE (bulb) The biological activities are antioxidant, cancer-preventative and oxidant. Allium cepa doesn't make the top plant list for this constituent.

ALLICIN (bulb) The list of the biological activities of this constituent is about 63 actions long. Some of the most important for herbalists are: allergenic, anthelmintic, antiatherosclerotic, antibacterial, antibiotic, anticholinesterase, antidiabetic, antiflu, antiglaucomic, antihypertensive, antiinflammatory, antioxidant, antiplatelet, anticeptic, antitriglyceride, antitumor, antiviral, candidicide, fungicide, hypoglycemic, and immunostimulant. There are 2 species listed with this constituent. Allium cepa is second after garlic.

ALLIIN (bulb) The biological activities are antiaggregant, antibacterial, antibiotic, antidiabetic, antihepatotoxic, antineuralgic, antioxidant, antiplatelet, antiradicular, antisarcomic, antithrombotic, antitumor, hepatoprotective, hypocholesterolemic, hypoglycemic, immunostimulant, lipolytic, phagocytotic and squalene-monooxygenase-inhibitor. Allium cepa L. is third on the list of plant species with highest amount of this constituent.

ALLIOFUROSIDE-A (pericarp) 220 ppm. No activities reported. Onion and Shallot are the only species listed containing this chemical.

ALLIOSPIROSIDE-A (pericarp) 4,600 ppm. No activities reported. Onion and Shallot are the only species listed containing this chemical.

ALLIOSPIROSIDE-B (fruit) 500 ppm. No activities reported. Onion and Shallot are the only species listed containing this chemical.

ALLIOSPIROSIDE-C (fruit) 491 ppm. No activities reported. Onion and Shallot are the only species listed containing this chemical.

ALLIOSPIROSIDE-D (fruit) 71 ppm. No activities reported. Onion and Shallot are the only species listed containing this chemical.

ALLYL-PROPYL-DISULFIDE (bulb) Biological activities are hypoglycemic, insulin-sparing and occuloirritant. There are 2 species listed with this constituent. Allium cepa is second after garlic.

ALPHA-AMYRIN (bulb) Analgesic, antiedemic, antiinflammatory, antinociceptive, antitumor, antiulcer, cytotoxic, gastroprotective, hepatoprotective and insectifuge. Allium cepa is number five on the top plant species list.

ALPHA-TOCOPHEROL (bulb) 0.4-30 ppm. Anticancer, anticonvulsant, antimutagenic, antioxidant, antiradicular, antitumor, antitumor-promoter, cancer-preventive. Allium cepa doesn't make the top plant list for this constituent.

ALUMINUM (bulb) 0.3-385 ppm. Antisilicotic, antivaginitic, candidicide, encephalopathic. Allium cepa doesn't make the top plant list for this constituent.

ARABINOSE (bulb) No biological activities reported. Allium cepa is number eleven on the top plant species list for this constituent.

ARACHIDIC-ACID (seed) No biological activities reported. Allium cepa doesn't make the top plant list for this constituent.

ARGININE (bulb) 1,580-17,222 ppm. Possibly antidiabetic, antiencephalopathic, antihepatitic, antihypertensive, antiimpotence, antiinfertility, possibly antioxidant, aphrodisiac, diuretic, hypoammonemic, NO-genic, pituitary-stimulant, spermigenic, vasodilator. Allium cepa doesn't make the top plant list for this constituent.

ARSENIC (bulb) 0.002 - 0.076 ppm The biological activity is anorexic and allium cepa is not on the top plants list for this constituent.

ASCORBIC-ACID (bulb) 60-2,703 ppm.The list of the biological activities of this constituent is about 82 actions long. Some of the most important relating to this species for herbalists are analgesic, antiCrohn’s, antiaggregant, antiaging, antiarthritic, antiasthmatic, antiatherosclerotic, antibacterial, anticataract, anticold, antidiabetic, antieczemic, antigingivitic, antihistaminic, antihypertensive, antiinflammatory, antimigraine, antiobesity, antiosteoarthritic, antiosteoporotic, antioxidant, antiperiodontic, antiseptic, antishingles, antitumor, antiviral, asthma-preventive, cancer-preventive, cold-preventive, diuretic, hypocholesterolemic, hypotensive immunostimulant, vasodilator and vulnerary. Allium cepa doesn't make the top plant list for this constituent.

ASH (bulb) 4,000-63,000 ppm. No biological activities reported. Allium cepa doesn't make the top plant list for this constituent.

ASPARAGINE (bulb) Biological activities are antisickling and diuretic. Allium cepa is number eighteen on the top plant species list for this constituent.

ASPARTIC-ACID (bulb) 640-6,967 ppm. Biological activities are antimorphenic, neuroexcitant, and roborant. Allium cepa doesn't make the top plant list for this constituent.

BARIUM (bulb) 4-28 ppm. No biological activities reported. Allium cepa doesn't make the top plant list for this constituent.

BENZYL-ISOTHIOCYANATE (bulb) Some of the biological activities relevant to herbalist include allergenic, anthelmintic, antiasthmatic, antibacterial, antibiotic, antitumor, antiviral, flatulent, fungicide, irritant, and laxative. Allium cepa is number three on the top plant species list for this constituent.

BETA-CAROTENE (bulb) 52 ppm; (flower) 28 ppm; (leaf) 12-158 ppm. There are 45 biological activities listed and Allium cepa doesn't make the top plant list for this constituent. It is antioxidant, antitumor, gastroprotective and immunostimulant among others.

BETA-SITOSTEROL (bulb) Antibacterial, anticancer, antiedemic, antiinflammatory, antioxidant, antitumor, antiviral, febrifuge, hypocholesterolemic, and hypoglycemic among 43 listed activities. Allium cepa doesn't make the top plant list for this constituent.

BETA-TOCOPHEROL (seed) No biological activities reported. Allium cepa is the highest plant species with this constituent of four plants listed.

BORON (bulb) 1-45 ppm. Androgenic, antiosteoarthritic, antiosteoporotic and estrogenic. Allium cepa doesn't make the top plant list for this constituent.

BRASSICASTEROL (seed) No biological activities reported. Allium cepa is the highest plant species with this constituent of seven plants listed.

BROMINE (bulb) 1-15 ppm. No biological activities reported. Allium cepa is number twenty-two on the plant species with the highest amount of this constituent.

CADMIUM (bulb) 0.005- 0.38 ppm. Hypertensive, lithogenic and nephrotoxic. Allium cepa is number twenty-eight on the plant species with the highest amount of this constituent.

CAFFEIC-ACID (bulb) Analgesic, antibacterial, anticancer, antidepressant, antiedemic, antihistiminic, antioxidant, antiseptic, antiviral, fungicide and sedative among over 100 activities. Allium cepa doesn't make the top plant list for this constituent.

CALCIUM (bulb) 200-3,008 ppm; (leaf) 420-5,385 ppm. Antiallergenic, antianxiety, antiatherosclerotic, antiinsomniac, antiosteoporotic, antiperiodontitic among other activties. Allium cepa doesn't make the top plant list for this constituent.

CALCIUM-OXALATE (bulb) Emetic, inflammatory, laxative and lithogenic. Allium cepa is number fourteen on the plant species with the highest amount of this constituent.

CAMPESTEROL (bulb) Antioxidant and hypocholesterolemic. Allium cepa is number seven on the plant species with the highest amount of this constituent.

CARBOHYDRATES (bulb) 73,200-798,000; (leaf) 47,000-603,000 ppm. There are no biological activities reported, though, these are building blocks of foods for the body. Allium cepa doesn't make the top plant list for this constituent.

CATECHOL (bulb) Allergenic, antioxidant, cancer-preventive, antiseptic among other activities. Allium cepa is the highest plant species with this constituent of ten plants listed.

CEPAENES (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

CEPOSIDE-D (seed) No activities reported. Onion and Shallot are the only species listed containing this chemical.

CHOLEST-7-EN-3-BETA-OL (bulb) No activities reported. Allium cepa is number one out of two plant species listed with the highest amount of this constituent.

CHOLESTEROL (bulb) Antioxidant. Allium cepa is number five out of several plant species listed with the highest amount of this constituent.

CHOLINE (bulb) 830 ppm. Antidiabetic, cerebrotonic, hepatoprotective, hypotensive, ileorelaxant and memorigenic among other activities. Allium cepa is twenty-ninth out of thirty-one plants listed with this constituent.

CHROMIUM (bulb) 0.057 –– 4 ppm. Antiaging, antiatherosclerotic, antidiabetic, antitriglyceride, hypocholesterolemic, hypoglycemic and hypotensive among other activities. Allium cepa doesn't make the top plant list for this constituent.

CIS-1-(PROPENYL-DITHIO)-PROPANE (essential oil) No activities reported. Onion and Shallot are the only species listed containing this chemical.

CIS-2,3-DIMETHYL-5,6-DITHIA-CYCLO(2,2,1)HEPTANE-5-OXIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

CIS-3,5-DIETHYL-1,2,4-TRITHIOLANE(leaf) No activities reported. Onion and Shallot are the only species listed containing this chemical.

CIS-PROPANETHIOL-S-OXIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

CITRIC-ACID (bulb) Activities include: allergenic, antiatherosclerotic, antibacterial, anticoagulent, antiseptic, antitumor, disinfectant, flavor and possibly laxative. Onion and Shallot are the only species listed containing this chemical.

COBALT (bulb) 0.001 –– 0.2 ppm; (seed) 2.5 ppm. Cardiomyopathogenic and erythrocytogenic activities. Allium cepa is number four on the plant species with the highest amount of this constituent.

COPPER (bulb) 0.3 –– 11; (seed)18.2 ppm. Antiarthritic, antidiabetic, antiinflammatory, antinociceptive, contraceptive, hypocholesterolemic and schizophrenigenic activities. Allium cepa is number ten on the plant species with the highest amount of this constituent.

CYANIDIN-3-O-BETA-D-DIGLYCOSIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

CYANIDIN-3-O-LAMINARIBIOSIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

CYANIDIN-BIOSIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

CYANIDIN-DIGLYCOSIDE (bulb) No activities reported. Allium cepa is number one out of three plant species listed with the highest amount of this constituent.

CYANIDIN-MONOGLYCOSIDE (bulb) No activities reported. Allium cepa is number one out of three plant species listed with the highest amount of this constituent.

CYCLOALLIIN (bulb) Antiaggregant, fibrinolytic and lachrymatory activities. Allium cepa is number two out of three plant species listed with the highest amount of this constituent.

CYCLOARTENOL (bulb) Antibacterial, antiinflammatory, antirhreumatic, antistaphylococcic, hypocholesterolemic and ubiquiot activities. Allium cepa is number three on the plant species with the highest amount of this constituent.

CYCLOEUCALENOL (bulb) Antibacterial and antistaphylococcic activities. Allium cepa is number one on the plant species with the highest amount of this constituent.

CYSTEINE (bulb) AntiAddisonian, antibiotic, anticataract, anticytotoxic, antiopthamolic, antioxidant, antitumor, antiulcer, cancer-preventive, detoxicant, glutathionergic and ophthalmic-antialkali activiteis. Allium cepa is number twelve on the plant species with the highest amount of this constituent.

CYSTINE (bulb) 210 –– 2,289 ppm. Adjuvant and antihomocystinuric activities. Allium cepa doesn't make the top plant list for this constituent.

D-MANNITOL (bulb) No activities reported. Allium cepa is number three on the plant species with the highest amount of this constituent.

DIALLYL-DISULFIDE (essential oil) AntiHIV, antibacterial, antioxidant, antitumor cancer-preventive, fungicide, hypocholesterolemic, hypoglycemic, immunostimulant among others. Allium cepa is number two out of two plant species listed with the highest amount of this constituent.

DIALLYL-SULFIDE (essential oil) Antibacterial, anticancer, antioxidant, antiseptic, hypocholesterolemic among others. Allium cepa is number four out of seven plant species listed with the highest amount of this constituent.

DIALLYL-TRISULFIDE (essential oil) Antibacterial, anticancer, antioxidant, antiseptic, hypocholesterolemic, antiviral among others. Allium cepa is number two out of two plant species listed with the highest amount of this constituent.

DIHYDROALLIIN (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

DIMETHYL-DISULFIDE (bulb) Antithyroid and perfumery activities. Allium cepa is number four out of five plant species listed with the highest amount of this constituent.

DIMETHYL-SULFIDE (essential oil) Flavor and irritant activities. Allium cepa is number two out of nine plant species listed with the highest amount of this constituent.

DIMETHYL-TRISULFIDE (essential oil) No activities reported. Allium cepa is number three out of three plant species listed with the highest amount of this constituent.

DIPHENYLAMINE (bulb) 14 –– 11,000 ppm. Antidiabetic, hypoglycemic and nephrotoxic activities. Allium cepa is number two out of two plant species listed with the highest amount of this constituent.

DIPROPYL-DISULPHIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

DIPROPYL-TRISULFIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

EICOSEN-1-OL (seed) No activities reported. Onion and Shallot are the only species listed containing this chemical.

EO (bulb) 50 –– 150 ppm. No activities reported. Allium cepa doesn't make the top plant list for this constituent.

ETHANOL (bulb) Antibacterial, antiatherosclerotic, antiseptic and expectorant among other activities. Allium cepa is number eleven on the plant species list with the highest amount of this constituent.

FAT (bulb) 1,000 –– 36,079; (leaf) 6,000 –– 77,000 ppm. There are no biological activities reported. Allium cepa does not make the top plant list for this constituent.

FERULIC-ACID (bulb) Analgesic, antibacterial, anticancer, antiinflammatory, antioxidant, antispasmodic, antiviral, fungicide and uterosedative among many other activities. Allium cepa is number twenty-five on the plant species list with the highest amount of this constituent.

FIBER (bulb) 4,400 –– 126,000; (leaf) 11,000 –– 141,000 ppm. Antidiabetic, antihypertensive, antitumor, antiulcer, diuretic, hypocholesterolemic, hypotensive, laxative and vasodilator among others. Allium cepa does not make the top plant list for this constituent.

FLUORINE (bulb) 0.04 –– 0.8 ppm. No activities reported. Allium cepa does not make the top plant list for this constituent.

FRUCTOSAN (bulb) No activities reported. Allium cepa is number two out of two plant species listed with the highest amount of this constituent.

FRUCTOSE (bulb) 65,600 –– 162,600 ppm. Antidiabetic, antinauseant, laxative and sweetner activities. Allium cepa is number twenty-five on the plant species list with the highest amount of this constituent.

FUMARIC-ACID (bulb) Acidulant, antidermatitic, antihepatocarcinogenic, antioxidant, antipsoriac, antitumor and flavor. Allium cepa is number three on the plant species list with the highest amount of this constituent.

GAMMA-GLUTAMYL-LEUCINE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GAMMA-GLUTAMYL-PHENYLALANINE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GAMMA-GLUTAMYL-PHENYLALANINE-ETHYL-ESTER (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GAMMA-GLUTAMYL-S-METHYL-CYSTEINE (plant) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GAMMA-L-GLUTAMYL-ARGININE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GAMMA-L-GLUTAMYL-CYSTEINE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GAMMA-L-GLUTAMYL-ISOLEUCINE (bulb) No activities reported. Allium cepa is number one out of two plant species listed with the highest amount of this constituent.

GAMMA-L-GLUTAMYL-S(2-CARBOXY-N-PROPYL)L-CYSTEINE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GAMMA-L-GLUTAMYL-S-(1-PROPENYL)L-CYSTEINE-SULFOXIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GAMMA-L-GLUTAMYL-S-(2-CARBOXY-BETA-METHYL-ETHYL)-CYSTEINYL-GLYCINE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GAMMA-L-GLUTAMYL-S-(2-CARBOXY-BETA-METHYL-ETHYL)-CYSTEINYL-GLYCINE-ETHYL-ESTER (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GAMMA-L-GLUTAMYL-VALINE ESTER (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GIBBERELLIN-A-4 (root) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GLUCOFRUCTAN (bulb) No activities reported. Allium cepa is number two out of two plant species listed with the highest amount of this constituent.

GLUCOSE (bulb) 102,000 –– 158,600 ppm. Acetylcholinergic, antiedemic, antihepatotoxic, antiketotic, antivaricose, hyperglycemic and memory-enhancer activities reported. Allium cepa is number nine on the plant species list with the highest amount of this constituent.

GLUTAMINE (bulb) Antialcoholic, antidepressant, antisickling, antiulcer and catabolic are activities reported. Allium cepa is also number nine on the plant species list with the highest amount of this constituent.

GLUTAN (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

GLYCINE (bulb) 490 –– 5,341 ppm. Antiacid, antialdosteronic, antigastritic, antiprostatitic, antiulcer and cancer-preventive among other activities. Allium cepa does not make the top plant list for this constituent.

GLYCOLIC ACID (bulb) Cholesterolic, diuretic, hepatonic and irritant. Allium cepa is the number one plant species with the highest amount of glycolic acid.

GRAMISTEROL (bulb) No activities reported. Allium cepa is the second highest plant species with this constituent.

HEXADECEN-1-OL (seed) No activities reported. Onion and Shallot are the only species listed containing this chemical.

HISTIDINE (bulb) 190 –– 2,071 ppm. Antiarteriosclerotic, antinephritic, antioxidant, antiulcer, antiuremic, essential and oxidant are reported activities. Allium cepa does not make the top plant list for this constituent.

IRON (bulb) 2 –– 135; (leaf) 34 –– 436; (seed) 235 ppm. Antiakathisic, antianemic, anticheilitic and antimenorrhagic. Allium cepa does not make the top plant list for this constituent.

ISOLEUCINE (bulb) 420 –– 4,578 ppm. Possibly antiencephalopathic, antipellagric and essential are reported activities. Allium cepa does not make the top plant list for this constituent.

KAEMPFEROL (bulb) Antiaggregant, antiallergic, antibacterial, anticancer, antihistaminic, antigingivitic, antiinflammatory, antioxidant, antiplaque, antiulcer, antiviral, hepatoprotective and vasodilator are a few among many activities reported. Allium cepa is number fourteen on the top plant species list.

KAEMPFEROL-3,4'-DI-O-BETA-D-GLUCOSIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

KAEMPFEROL-4',7-DI-O-BETA-D-GLUCOSIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

KAEMPFEROL-4'-O-BETA-D-GLUCOSIDE GLUCOSIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

KILOCALORIES (bulb) 380 –– 3,750/kg; (leaf) 260 –– 3,330/kg. No activities reported. . Allium cepa does not make the top plant list for this constituent.

LEAD (bulb) 0.01 –– 1.4 ppm. No activities reported. Allium cepa does not make the top plant list for this constituent.

LEUCINE (bulb) 410 –– 4,469 ppm. Antiencephalopathic and essential activities. Allium cepa does not make the top plant list for this constituent.

LINOLEIC ACID (seed oil) Antiarteriosclerotic, antiarthritic, anticoronary, antifibrinolytic, antihistamine, antiinflammatory, hepatoprotective and hypocholestrolemic among others. Allium cepa does not make the top plant list for this constituent.

LITHIUM (bulb) 0.152 –– 0.324 ppm. Antiviral, antidepressant and anti PMS among other biological activities. Allium cepa is also number twenty-nine on the plant species list with the highest amount of this constituent.

LOPHENOL (bulb) No activities reported. Allium cepa is number one on the plant species with the highest amount of this constituent.

LYSINE (bulb) 560 –– 6,104 ppm. Antialkalotic, antiherpetic, essential and hypoarginanemic activities. Allium cepa does not make the top plant list for this constituent.

MAGNESIUM (bulb) 76 –– 1,230 ppm. Antiaggregant , antianginal, antiarrhythmic, antiarthritic, antiasthmatic, antiatherosclerotic, anticoronary, antidiabetic, antiglaucomic, antiosteoporotic and antistroke among several other activities. Allium cepa does not make the top plant list for this constituent.

MALIC-ACID (bulb and leaf) Antiatherosclerotic, antibacterial, antioxidant synergist, antiseptic and antitumor among other activities. Allium cepa does not make the top plant list for this constituent.

MANGANESE (bulb) 1 –– 38; (seed) 19.4 ppm. Antianemic, antidiabetic and hypoglycemic among other activities. Allium cepa does not make the top plant list for this constituent.

MERCURY (bulb) 0.001 ppm. Nephrotoxic. Allium cepa does not make the top plant list for this constituent.

METHANOL (bulb) AntiHIV and antidote. Allium cepa is number seven on the plant species with the highest amount of this constituent.

METHIONINE (bulb) 100 –– 1,090 ppm. Anticataract, antioxidant, cancer-preventive, antiparkinsonian, and essential among others. Allium cepa does not make the top plant list for this constituent.

METHIONINE-METHYLSULFONIUM (plant) No activities reported. Onion and Shallot are the only species listed containing this chemical.

METHIONINE-SULFONE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

METHYL-ALLIIN (bulb) No activities reported. Allium cepa is the second highest plant species listed with this constituent.

METHYL-CIS-PROPENYL-DISULFIDE (plant) No activities reported. Onion and Shallot are the only species listed containing this chemical.

METHYL-DITHIO-METHANE (essential oil) No activities reported. Onion and Shallot are the only species listed containing this chemical.

METHYL-PROPENYL-TRISULFIDE (plant) No activities reported. Onion and Shallot are the only species listed containing this chemical.

METHYL-PROPYL-DISULFIDE (bulb) No activities reported. Allium cepa is number two out of three plant species listed with the highest amount of this constituent.

METHYLPROPYL-TRISULFIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

MEVALONIC-ACID (bulb) 0.5 ppm. No activities reported. Allium cepa is number seven on the top plants list for this constituent.

MOLYBDENUM (bulb) 0.1 –– 2.3 ppm. Possible antitumor and anticancer activity in the esophagus. Allium cepa is number twenty-four on the top plants list for this constituent.

MUFA (bulb) 230 –– 2,230 ppm. Allergenic, antiinflammatory, cancer-preventive and hypocholesterolemic among other activities. Allium cepa does not make the top plant list for this constituent.

MYRISTIC-ACID (bulb) 10 –– 100 ppm. Antioxidant, cancer-preventive, hypocholesterolemic and lubricant among other activities. Allium cepa does not make the top plant list for this constituent.

MYROSINASE (bulb) No activities reported. Allium cepa is number one out of two plant species listed with the highest amount of this constituent.

N-PROPYL-MERCAPTAN (bulb) Flavor. Onion and Shallot are the only species listed containing this chemical.

NIACIN (bulb) 1- 75; (leaf) 7 - 90 ppm. Antidermatitic, antihistimine, antiinsomnic and sedative among other activities. Allium cepa does not make the top plant list for this constituent.

NICKEL (bulb) 0.05 –– 2.5; (seed) 0.03 - 4 ppm. Antiadrenalinic, possibly anticirrhotic and insulin-sparing. Allium cepa does not make the top plant list for this constituent.

NITROGEN (bulb) 1,700 –– 17,690 ppm. No activities reported. Allium cepa does not make the top plant list for this constituent.

NONADECANOIC-ACID (bulb) No activities reported. . Allium cepa is number one out of two plant species listed with the highest amount of this constituent.

OLEANOLIC-ACID (bulb) AntiHIV, antiallergic, antiatherosclerotioc, antibacterial, antigingivitic, antiinflammatory, antioxidant, antiviral, antitumor and cardioprotective among other activities. Allium cepa is number seventeen on the top plants list for this constituent.

OLEIC-ACID (bulb) 230 –– 2,230 ppm and in (seed oil) Antiinflammatory, cancer-preventive and hypocholesterolemic among other activities. Allium cepa does not make the top plant list for this constituent.

OXALIC ACID (bulb) 10 ppm. Antiseptic among other activities. Allium cepa does not make the top plant list for this constituent.

P-COUMARIC-ACID (bulb) Antibacterial, antiseptic, antioxidant, antitumor, cancer- preventive and chemopreventive among other activities. Allium cepa does not make the top plant list for this constituent.

P-HYDROXYBANZOIC-ACID (bulb) 107 ppm. No activities reported. Onion and Shallot are the only species listed containing this chemical.

PAEONIDIN-GLYCOSIDE (bulb) No activities reported. Allium cepa is number one out of three plant species listed with the highest amount of this constituent.

PALMITIC-ACID (bulb) 240 - 2,325 ppm. Antioxidant, hypercholesterolemic and lubricant among other activities. Allium cepa does not make the top plant list for this constituent.

PANTOTHENIC-ACID (bulb) 1 –– 16 ppm. Antiarthritic, antifatigue, antihypercholesterolemic and cancer-preventive among other activities. Allium cepa does not make the top plant list for this constituent.

PECTIN (bulb) Antibacterial, antidiabetic, antitumor in the colon, antiulcer, cancer-preventive, demulcent and peristaltic among other activities. Allium cepa does not make the top plant list for this constituent.

PELARGONIDIN-MONOGLYCOSIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

PENTOSAN (bulb) No activities reported. Allium cepa is number four on the top plants list for this constituent.

PEROXIDASE (bulb) No activities reported. Allium cepa is number five on the top plants list for this constituent.

PHENYLALANINE (bulb) 300 –– 33,270 ppm. Antidepressant among other activities. Allium cepa does not make the top plant list for this constituent.

PHLOROGLUCINOL (bulb) 100 ppm. Antiseptic, antispasmodic, antitumor-promotor, cancer-preventive, decalcifier, fungicide and goitrogenic activities. Allium cepa is number one on the plant species with the highest amount of this constituent.

PHLOROGLUCINOL-CARBOXYLIC-ACID (bulb) 100 ppm. No activities reported. Onion and Shallot are the only species listed containing this chemical.

PHOSPHORUS (bulb) 275 –– 4,038; (leaf) 310 –– 5,513 ppm. Antiosteoporotic, immunostimulant and osteogenic activities. Allium cepa does not make the top plant list for this constituent.

PHYTOHORMONE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

PHYTOSTEROLS (bulb) 150 –– 1,455 ppm. ) No activities reported. Allium cepa is number twenty-five on the top plants list for this constituent.

POTASSIUM (bulb) 1,514 –– 22,164 ppm. Antiarrhythmic, antidepressant, antifatigue, antihypertensive, antispasmodic, diuretic and vasodilator among other activities. Allium cepa does not make the top plant list for this constituent.

PROLINE (bulb) 370 –– 4,033 ppm. No activities reported. Allium cepa does not make the top plant list for this constituent.

PROP-CIS-ENYL-PROPYL-DISULFIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

PROP-CIS-ENYL-PROPYL-TRISULFIDE DISULFIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

PROP-TRANS-ENYL-PROPYL-DISULFIDE DISULFIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

PROP-TRANS-ENYL-PROPYL-TRISULFIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

PROPAN-1-OL (bulb) No activities reported. Allium cepa is number one out of two plant species listed with the highest amount of this constituent.

PROPANE-1-THIOL TRISULFIDE (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

PROPIONAL (bulb) No activities reported. Onion and Shallot are the only species listed containing this chemical.

PROPIONALDEHYDE (bulb) Flavor and perfumery activities. Allium cepa is number two on the top plants list for this constituent.

PROSTAGLANDIN-A-1 (bulb) 1 ppm. Cancer-preventive and hypotensive. Allium cepa is number one out of two plant species listed with the highest amount of this constituent.

PROTEIN (bulb) 10,940 –– 162,000; (leaf) 18,000 –– 231,000 ppm. No activities reported. However, proteins are fundamental components of all living cells and are essential in the diet of animals for the growth and repair of tissue. Allium cepa does not make the top plant list for this constituent.

PROTOCATECHUIC-ACID (bulb) 4,500 –– 17,540 ppm. Antiarrhythmic, antiasthmatic, antibacterial, antiinflammatory, antioxidant, antiseptic, antiviral, cardioprotective and immunostimulant among others. Allium cepa is number one on the plant species list with the highest amount of this constituent.

PUFA (bulb) 620 –– 6,005 ppm. AntiMS, antiacne, antieczemic and antipolyneuritic. Allium cepa does not make the top plant list for this constituent.

PYROCATECHOL (bulb) anticancer (breast), antihepatotoxic, antioxidant, antiseptic, CNS-stimulant, cardiovascular, dermatitigenic, dye, insectifuge, nematicide and quinone-reductase-reducer. Allium cepa are the only species listed containing this chemical.

PYRUVIC-ACID (fruit) 1,034 ppm. Flavor activity. Allium cepa is number two on the plant species list with the highest amount of this constituent.

QUERCETIN (bulb) 48,100 ppm. Analgesic, antiCrohn’’ s, antiGTF, antiHIV, antiPMS, antiaggregant, antiaging, antiallergic, antialzheimeran, antiarthritic, antiasthmatic, antiatherosclerotic, antibacterial, anticataract, anticystitic, antidepressant, antidermatic, antiflu, antigastric, antihistaminic, antiinflammatory, antimalarial, antioxidant, antipancreatic, antiplaque, antipolio, antispasmodic, antitumor, antiulcer, antiviral, capillariprotective, candidicide, fungicide, neuroprotective and vasodilator among around one hundred other activities. Allium cepa is number three on the plant species list with the highest amount of this constituent.

QUERCETIN-3,4'-DI-O-BETA-D-GLUCOSIDE (bulb) 1,700 –– 5,600 ppm. No activities reported. Allium cepa L. is the only species listed containing this chemical.

QUERCETIN-3-O-BETA-D-GLUCOSIDE (bulb) 40 ppm. Antiinflammatory and cancer-preventive. Allium cepa is number one on the plant species list with the highest amount of this constituent.

QUERCETIN-4',7-DI-O-BETA-D-GLUCOSIDE (bulb) 160 ppm. No activities reported Allium cepa L.is the only species listed containing this chemical.

QUERCETIN-4-O-BETA-D-GLUCOSIDE (bulb) 100 –– 800 ppm. No activities reported Allium cepa L.is the only species listed containing this chemical.

QUINIC-ACID (bulb) Choleretic activity. Allium cepa is number nine on the plant species list with the highest amount of this constituent.

RAFFINOSE (bulb) Flatugenic activity. Allium cepa L. is number twenty-three on the plant species list with the highest amount of this constituent.

RHAMNOSE (bulb) No activities reported. Allium cepa L. is number twenty-three on the plant species list with the highest amount of this constituent.

RIBOFLAVIN (bulb) 0.4 –– 15 ppm. Anticataract and antimigraine among other activities. Allium cepa does not make the top plant list for this constituent.

RIBOSE (bulb) No activities reported. Allium cepa L. is number one on the plant species list with the highest amount of this constituent.

RUBIDIUM (bulb) 0.14 –– 6.6 ppm. No activities reported. Allium cepa does not make the top plant list for this constituent.

RUTIN (bulb) Antiaggregant, antiallergic, antiatherosclerotic, antibacterial, anticancer, anticataract, antidiabetic, antiglaucomic, antihypertensive, and antioxidant among other activities. Allium cepa does not make the top plant list for this constituent.

S-(2-CARBOXY-PROPYL)-GLUTATHIONE (bulb) 125 ppm. No activities reported. Allium cepa is number one out of two plant species listed with the highest amount of this constituent.

S-(BETA-CARBOXYBETA-METHYL-ETHER)-CYSTEINE (bulb) No activities reported Allium cepa L.is the only species listed containing this chemical.

S-ALLYL-CYSTEINE (bulb) No activities reported. Allium cepa is number two out of two plant species listed with the highest amount of this constituent.

S-METHYL-CYSTEINE (bulb) No activities reported. Allium cepa is number one out of three plant species listed with the highest amount of this constituent.

S-METHYL-CYSTEINE-SULFOXIDE (bulb) antidiabetic and antihypercholesterolemic activities. Allium cepa is number one out of three plant species listed with the highest amount of this constituent.

S-PROP-1-ENYL-CYSTEINE-S-OXIDE (bulb) 26 ppm. No activities reported Allium cepa L.is the only species listed containing this chemical.

S-PROPYL-CYSTEINE-SULFOXIDE (bulb) No activities reported. Allium cepa is number one out of two plant species listed with the highest amount of this constituent.

SAPONIN (bulb) No activities reported. Allium cepa L. is number thirty on the plant species list with the highest amount of this constituent.

SELENIUM (bulb) 0.001 –– 0.003 ppm. Analgesic, anticoronary, antimetastatic, antiosteoarthritic, antioxidant, antitumor, fungicide and imminostimulant among other activities. Allium cepa does not make the top plant list for this constituent.

SELENO-HOME-CYSTINE CYSTEINE (plant) No activities reported Allium cepa L.is the only species listed containing this chemical.

SELENO-METHIONINE OXIDE (bulb) No activities reported Allium cepa L.is the only species listed containing this chemical.

SELENO-METHYL-SELENOCYSTEINE (bulb) No activities reported Allium cepa L.is the only species listed containing this chemical.

SELENO-METHYL-SELENOMETHIONINE (bulb) No activities reported Allium cepa L.is the only species listed containing this chemical.

SELENOSIDE (plant) No activities reported Allium cepa L.is the only species listed containing this chemical.

SERINE (bulb) 350 –– 3,815 ppm. Cancer preventive activity. Allium cepa does not make the top plant list for this constituent.

SFA (bulb) 260 –– 2,520 ppm. No activities reported. Allium cepa does not make the top plant list for this constituent.

SILICON (bulb) 1 –– 75 ppm. Antiarteriosclerotic activity. Allium cepa does not make the top plant list for this constituent.

SILVER (bulb) 0.038 –– 0.054 ppm. Antibacterial and astringent activity. Allium cepa does not make the top plant list for this constituent.

SINAPIC-ACID (bulb) Antibacterial, antihepatoxic, antioxidant, antiperioxynitrate, JAF50:5884, cancer-preventive and fungicide activities. Allium cepa L. is number sixteen on the plant species list with the highest amount of this constituent.

SODIUM (bulb) 8 –– 2,052 ppm. Hypertensive activity. Allium cepa does not make the top plant list for this constituent.

SPIRAEOSIDE (bulb) 10,000 –– 11,300 ppm. Aldose-reductase-inhibitor, antioxidant and quinone-reductase-inducer activities. Allium cepa is number one out of three plant species listed with the highest amount of this constituent.

STEARIC-ACID (bulb) 120 –– 195 ppm. Flavor, lubricant and hypocholesterolemic among other activities. Allium cepa does not make the top plant list for this constituent.

STIGMAST-7-EN-3-BETA-OL (seed) No activities reported. Allium cepa L. is number one on the plant species list with the highest amount of this constituent.

STIGMASTEROL (bulb) Antiinflammatory, antioxidant, antiviral, cancer-preventive, hypocholesterolemic and sedative among others. Allium cepa is number fourteen on the plant species list with the highest amount of this constituent.

STRONTIUM (bulb) 57 –– 162 ppm. No activities reported. Allium cepa L. is number twenty-seven on the plant species list with the highest amount of this constituent.

SUCCINIC-ACID (bulb) Cancer-preventive among others. Allium cepa is number eight on the plant species list with the highest amount of this constituent.

SUCROSE (bulb) 82,600 –– 145,900 ppm. Antihiccup, antiopthamalic, demulcent, flatugenic, hypercholesterolemic, and vvulnerary among others. Allium cepa is number fourteen on the plant species list with the highest amount of this constituent.

SULFUR (bulb) 80 - 4,075 ppm. Antiacne, antiarthritic, antiosteoarthritic, antiseptic, laxative and parasiticide among others. Allium cepa is number twenty-four on the plant species list with the highest amount of this constituent.

TARTARIC-ACID (bulb) Flavor and irritant parasiticide among others. Allium cepa is number eight on the plant species list with the highest amount of this constituent.

THIAMIN (bulb) 0.3 –– 6; (leaf) 0.5 –– 6.4 ppm. Antifatigue, antigastritic and antiheartburn among other activities. Allium cepa does not make the top plant list for this constituent.

THIOPROPANAL-S-OXIDE (bulb) No activities reported Allium cepa L.is the only species listed containing this chemical.

THIOPROPIONAL-S-OXIDE (bulb) No activities reported Allium cepa L.is the only species listed containing this chemical.

THREONINE (bulb) 280 –– 3,052 ppm. Possibly antioxidant, antiulcer, essential and flavor activities. Allium cepa does not make the top plant list for this constituent.

TITANIUM (bulb) 0.38 –– 11 ppm. No activities reported. Allium cepa does not make the top plant list for this constituent.

TRANS-1-(PROPENYL-DITHIO)-PROPANE (essential oil) No activities reported Allium cepa L.is the only species listed containing this chemical.

TRANS-2,3-DIMETHYL-5,6-DITHIA-CYCLO(2,2,1)HEPTANE-5-OXIDE (bulb) No activities reported Allium cepa L.is the only species listed containing this chemical.

TRANS-3,5-DIETHYL-1,2,4,-TRITHIOLANE (leaf) No activities reported Allium cepa L.is the only species listed containing this chemical.

TRANS-S-(1-PROPENYL)-CYSTEINE-SULFOXIDE (bulb) No activities reported Allium cepa L.is the only species listed containing this chemical.

TRIGONELLINE (seed0 13 ppm. Anticancer (cervix and liver), antihyperglycemic, antimigraine, antiseptic, antitumor (cervix and liver), epidermal-stimulant, hypocholesterolemic, hypoglycemic, mutgenic, osteoregulator and propecic activities. Allium cepa is number nine on the plant species list with the highest amount of this constituent.

TRYPTOPHAN (bulb) 170 –– 1,853 ppm. Antihypertensive, antiinsomniac, antidepressant, antimenopausal, antioxidant, essential and sedative among other activities. Allium cepa does not make the top plant list for this constituent.

TSEPOSIDES (seed) No activities reported Allium cepa L.is the only species listed containing this chemical.

TULIPOSIDE-A (root) Antiallergic activity. Allium cepa L.is the only species listed containing this chemical.

TULIPOSIDE-B (root) Antiallergic activity. Allium cepa L.is the only species listed containing this chemical.

TYROSINE (bulb) 290 –– 3,161 ppm. Antiulcer and cancer-preventive among other activities. Allium cepa does not make the top plant list for this constituent.

VALINE (bulb) 270 –– 2,943 ppm. Antiencephalopathic, essential and flavor activities. Allium cepa does not make the top plant list for this constituent.

VANILLIC-ACID (bulb) 258 ppm. Anthelmintic, antibacterial, anticancer, antifatigue, antiinflammatory, antiseptic, antitumor, cancer-preventive and laxative among others. Allium cepa is number three on the plant species list with the highest amount of this constituent.

VIT-B-6 (bulb) No activities reported. Allium cepa L. is number twelve on the plant species list with the highest amount of this constituent.

WATER (bulb) 866,000 –– 918,000; (leaf) 922,000 ppm. No activities reported. Allium cepa does not make the top plant list for this constituent.

XYLITOL (bulb) Possibly anticariogenic, antihemolytic, possibly antiplaque, diuretic, flatulent, laxative and sweetner among other activities reported. Allium cepa is number one out of two plant species listed with the highest amount of this constituent.

XYLOSE (bulb) Antidiabetic, diagnostic and dye activities. . Allium cepa is number eight on the plant species list with the highest amount of this constituent.

ZINC(bulb) 2 –– 53; (seed) 34 ppm. Anticataract, anticold, antiinfective and antitryglyceride among many other activities. Allium cepa does not make the top plant list for this constituent.

ZIRCONIUM (bulb) 0.76 –– 1 ppm. . No activities reported. Allium cepa does not make the top plant list for this constituent.

 

The vast array of chemical constituents in Allium cepa and the multitude of biological activities they perform validates the historical use of onion as a valued commodity and healthful food and herb. These biological activities also render much promise to future use of onion to maintain and restore health. Let’s also remember the numerous constituents in onion with no biological activities yet reported.

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¹³ Dr. Duke's Phytochemical and Ethnobotanical Databases, "Specific Queries of the Phytochemical Database—Chemicals in: Allium cepa L. (Liliaceae) -- Onion, Shallot," www.ars-grin.gov/duke, accessed 20 May 2007.