DRUMSTICK (MORINGA OLEIFERA L.) LEAVES: A POTENTIAL SOURCE OF NATURAL LIPID ANTIOXIDANTS

ABSTRACT Antioxidant activity of methanolic extract of drumstick leaves (200, 500 and 1,000 ppm) in soybean oil was assessed by an accelerated oxidation test (70C, 10 days) and a heating test (180C, 1 h). The extract significantly ( P ≤ 0.05) suppressed the formation of peroxides and thiobarbituric acid‐reactive substances (TBARS) during accelerated oxidation, even at a level of 200 ppm. On heating test, conjugated dienes, conjugated trienes and TBARS values of the oil treated with the extract were significantly ( P ≤ 0.05) lower than those of the control sample (oil without any antioxidant/extract). The antioxidant activity of the extract at 500 and 1,000 ppm was greater ( P ≤ 0.05) than that of synthetic antioxidant, butylated hydroxyanisole on both accelerated oxidation and heating tests. Results of this study revealed high thermal stability of antioxidant components of drumstick extract and the antioxidant potential of the extract in inhibiting lipid peroxidation of soybean oil. Thus, the extract of drumstick leaves is recommended as an alternative source of natural antioxidants. PRACTICAL APPLICATIONS Toxicological effects of synthetic antioxidants and consumer preference for natural products have resulted in increased interest in the application of natural antioxidants with special focus on those available in edible plants. In this study, methanolic extract of drumstick leaves showed an excellent antioxidant activity in soybean oil on accelerated oxidation and heating tests. Its antioxidant activity was comparable or even greater with that of a synthetic antioxidant, butylated hydroxyanisole. Then, drumstick leaves extract can be regarded as a “natural” source of antioxidants, having potential application in edible oils and lipid‐containing food products to retard or inhibit their lipid oxidation. In addition, consumption of such products can impart health benefits to the consumer.