Antioxidant and metal chelating activities of Lagenaria siceraria (Molina) Standl peel, pulp and aerial parts in relation to their total phenol and flavonoid content

Abstract

Objective: The aim of the present study was to evaluate the antioxidant activity and total phenol and flavonoid content of different parts (peel, pulp and aerial parts) of Lagenaria siceraria. Method: Successive extraction was done by cold percolation method using solvents of different polarity viz. petroleum ether, toluene, ethyl acetate, acetone, water. Total phenol content was determined by Folin-Ciocalteu’s reagent method and flavonoid was determined by aluminium chloride colorimetric method. The antioxidant assays evaluated were 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, 2, 2’-Azino-bis-(3-ethyl) benzothiazoline-6-sulfonic acid (ABTS) radical cation scavenging activity and Ferric reducing antioxidant power. Results: L. siceraria peel possessed maximum phenol and flavonoid content in acetone and toluene extracts respectively. FRAP was maximum in acetone extract of peel. The peel extract demonstrated stronger DPPH activity with IC 50 value of 111 µg/ml followed by pulp extract. The same extract was effective in scavenging ABTS radical with an IC 50 value of 39 µg/ml while other parts were ineffective. Conclusion: This work demonstrated good antioxidant activity of L. siceraria vegetable cultivated in India and recommends that the peel of this vegetable may be of interest from a functional point of view as a major source of natural antioxidant.