In vitro XANTHINE OXIDASE INHIBITORY POTENTIAL OF ONION OIL

Allium cepa L., (A. cepa) is the common onion, which is most predominantly cultivated species of the genus Allium. In recent years, there is an interest to find out new sources of edible oils such as plant seeds is increasing due to their nutritional, industrial and medicinal importance. Consumption of onions has been significantly increasing in the world mainly because of the health benefits they possess. A. cepa possessed high content of both non-volatile and volatile organosulphur compounds, which are responsible for the typical pungency, smell and taste of onion. Onion extracts have been recently reported to be effective in cardiovascular disease, and possess many other biological activities including antimicrobial, antioxidant, anticarcinogenic, antimutagenic, antiasthmatic, immunomodulatory and prebiotic activities. Gout, is a disease resulting from increased uric acid accumulation in joints and muscles and due to increased activities of xanthine oxidase enzyme which is involved in nucleotide metabolism. Xanthine oxidase converts xanthine to hypoxanthine and further to uric acid. The present study is focused on evaluating the in vitro xanthine oxidase inhibitory (XOI) activity of onion oil and to screen the phytochemical constituents present in it. The in vitro xanthine oxidase inhibitory activity and phytochemical screening of onion oil were done by standard procedures. The results showed that onion oil possessed xanthine oxidase inhibitory activity in vitro. The oil showed a dose dependent increase in the inhibitory activity, which was less when compared to the standard drug allopurinol. Since, the oil inhibited the xanthine oxidase activity, it may help to treat gout and other disorders associated with increased activity of xanthine oxidase. The oil is rich in alkaloids and also showed the presence of terpenoids, carbohydrates, flavonoids and phlobatannins. Presence of these phytochemicals might have contributed to the beneficial activity of the oil. Thus, the study concluded that onion oil possessed potent in vitro xanthine oxidase inhibitory activity.