Onions (Allium cepa L.) is a vegetable that is the most widely cultivated species of the genus Allium. Its close relatives include the garlic, leek, chive, and Chinese onion.


  • Polyphenols[1]
    • Catechin
    • Epicatechin
    • Kaempferol
    • Protocatechuic acid
    • Quercetin

Healing Properties

Antifungal (anti-fungal)

Anti-obesity (weight loss)

Prevents weight gain related to high fat diet.[1]

Blood Health

Anti-platelet (antiplatelet)

Helps prevent blood clots.


Commonly referred to as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time.

Hypolipidemic (antihyperlipidemic)

Items with lipid-lowering effects, used in the treatment of high levels of fats, such as cholesterol, in the blood.

  • Onion & Garlic oils decreased the levels of triglycerides, total cholesterol, and LDL-Cholesterol and increased the serum level of HDL-Cholesterol.[2]

Disease / Symptom Treatment


Counteracts the effects of an High Fat Diet on body weight, adipose tissue weight, and serum lipid profiles.


  1. Study Type: Plant Study
    Title: LC-ESI-QTOF/MS Characterisation of Phenolic Acids and Flavonoids in Polyphenol-Rich Fruits and Vegetables and Their Potential Antioxidant Activities
    Author(s): Gu C, Howell K, Dunshea FR, Suleria HAR
    Institution(s): School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville 3010, VIC, Australia.
    Publication: Antioxidants (Basel)
    Date: Sep 2019
    Abstract: Polyphenols are naturally occurring compounds found largely in fruits and vegetables. The antioxidant properties of these polyphenols including total phenolic content (TPC), total flavonoid content (TFC), tannin content, 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH), 2,2'-azinobis-(3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS) scavenging abilities and ferric ion reducing antioxidant power (FRAP) were measured among sixteen (16) plant foods (mango, blueberry, strawberry, black carrot, raspberry, dark grapes, garlic, ginger, onion, cherry, plum, apple, papaya, peach, pear and apricot) by modifying, standardising and translating existing antioxidant methods using a 96-well plate reader. Eighteen targeted phenolic acids and flavonoids were characterised and quantified using high-performance liquid chromatography-photometric diode array (HPLC-PDA) and verified by modifying an existing method of liquid chromatography coupled with electrospray-ionisation triple quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF/MS). While most of these compounds were accurately detected by the HPLC-PDA at a low concentration, a few polyphenols in low concentrations could be only be characterised using the LC-ESI-QTOF/MS method. Our results showed that mango possessed the highest overall antioxidant activity, phenolic acid and flavonoid content among the selected fruits. Factor analysis (FA) and Pearson's correlation tests showed high correlations among ABTS, DPPH, FRAP and phenolic acids, implying the comparable capabilities of scavenging the DPPH/ABTS free radicals and reducing ferric ions from the antioxidant compounds in the samples. Phenolic acids contributed significantly to the antioxidant activities, and flavonoids contributed more to tannin content based on the correlations. Overall, methods modified and standardized in this study can provide better understanding of high throughput technologies and increase the reliability of antioxidant data of different plant foods.
    Link: Source

  2. Title: Anti-obesity and Hypolipidemic effects of garlic oil and onion oil in rats fed a high-fat diet
    Author(s): Chao Yang, Lihua Li, Ligang Yang, Hui Lǚ, Shaokang Wang and Guiju Sun
    Publication: Nutrition & Metabolism
    Date: 20 June 2018
    Abstract: Background Until now, little research concerning the lipid-lowering and anti-obesity functions of garlic oil and onion oil has been performed. The objective of this study was to explore the effects of garlic oil and onion oil on serum lipid levels in hyperlipidemia model rats, to provide a scientific basis for the prevention of hyperlipidemia through a dietary approach, and to explore the potential health benefits of garlic and onion. Method Ninety-six male Sprague-Dawley rats were randomly allocated into eight groups based on their body weight and serum levels of triglycerides (TG) and total cholesterol (TC). The rats received repeated oral administration of volatile oils extracted from garlic and onion for 60 days. Serum lipids and parameters of obesity were examined. Results The volatile oils suppressed the HFD-induced body weight gain and tended to decrease adipose tissue weight. The oils decreased the levels of TG, TC and LDL-C and increased the serum level of HDL-C compared with the rats in the hyperlipidemia model groups (P < 0.05). The oils were also effective at improving the lipid profile and alleviating hepatic steatosis. Conclusion Our results implied that garlic oil and onion oil have anti-obesity properties that can counteract the effects of an HFD on body weight, adipose tissue weight, and serum lipid profiles.
    Link: Source