Antioxidant property of Decalepis hamiltonii Wight & Arn.

ABSTRACT

Aromatic edible root of D. hamiltonii was subjected to the extraction of the antioxidant rich fraction. Different parts of root namely whole tuber, peel, tuber without peel and medullary portion were extracted with dichloromethane (European Patent No. W02005063272). The extract was found to contain flavor compound 2-hydroxy-4-methoxybenzaldehyde (2H4MB), which was identified by TLC and GC. Medullary portion was found to be rich in 2H4MB, (73.73 mg g(-1) dry tissue) followed by peel, containing 68.34 mg g(-1) 2H4MB. Different concentration of dichloromethane extracts were subjected for antioxidant assay by DPPH (1,1 dihydroxy 2-picryl hydrazyl) method, this has shown 44, 46.7% radical scavenging activity in case of medullary, peel extracts and 67.3% in case of pure 2-hydroxy-4-methoxybenzaldehyde at 100 ppm concentration, whereas ascorbic acid used as standard showed 94.3% activity. In beta-carotene linoleate model system (b-CLAMS) 43.46 and 45.7% antioxidant activity was observed in medullary and peel extracts at 100 ppm concentrations respectively, whereas standard 2-hydroxy-4-methoxybenzaldehyde exhibited 69.64% at 100 ppm and BHA (butylated hydroxyl anisole) 90.1% activity also at 100-ppm level. Similarly hydroxyl radical scavenging activity was found to be 48.36, 46.86, 48.26 and 73.60% in whole tuber, medullary, peel and standard 2-hydroxy-4-methoxy benzaldehyde respectively at 100 ppm levels. This is the first report on the antioxidant activity of D. hamiltonii. Results have shown that 2H4MB is one of the major constituents responsible for antioxidant activity. Hence the extract of D. hamiltonii can be utilized for the production of antioxidant rich fractions required for various health benefits.