ALI ONION (ALLIUM CEPA L.): BIOACTIVE COMPOUNDS, HEALTH BENEFITS, AND POTENTIAL APPLICATIONS OF BY-PRODUCTS

A COMPREHENSIVE REVIEW ON MEDICINAL IMPORTANCE OF ONION Allium cepa L

Abstract

Onions (Allium cepa L.) are extensively farmed and often used as food which contains numerous bioactive molecules with medicinal importance. This review covers the bioactive compounds, health benefits and uses of onions as well as onion by-products. Onions contain many phytochemicals such as polyphenols, flavonoids and organosulfur compounds that contribute to antioxidative property, antimicrobial activity and prevention of diseases. Onions are also antioxidant, containing a particularly high amount of flavonoid quercetin, thus offering more protection from oxidative stress and chronic diseases. Antibacterial effects of onion extracts Studies have even shown anticancer effects where onion compounds were potentially inhibiting the growth of certain tumors and affecting apoptosis in some cancer cells. Onions could also protect the heart through reducing cholesterol and platelet aggregation. This review highlights the hepatoprotective and neuroprotective effects of onion bioactive compounds. The non-edible outer layers of onions are particularly rich in bioactive compounds and have new trade applicability as functional foods or nutraceuticals. Although onions offer healthful but unexplored potential as a source of chemo preventive agents, additional studies are warranted to understand better their mode of action allowing the optimization for dietary applications as well food industry uses. This review overall highlights the promising role of onions as a functional food and bioactive agent to control various disease-states.