Effect of sequential extraction on total phenolic content (TPC) and antioxidant activities (AA) of Luffa acutangula Linnaeus dried pulps

Abstract

Dried pulps of Luffa acutangula was sequentially extracted using four solvents, i.e., hexane, chloroform, ethyl acetate, and methanol. The extracts were analyzed for their total phenolic contents (TPC) and antioxidant activities (AA) using diphenylpicrylhydrazyl (DPPH) radical scavenging, ferric reducing power and metal chelating assays. The highest value of TPC (28.04 ± 0.37 µg GAE per mg extract) was obtained from the chloroform extract of L. acutangula. The methanol extract of L. acutangula (698.14 ± 19.87 µM TE per mg extract) and the chloroform extract (367.77 ± 9.97 µM AscAE per mg extract), ethyl acetate extract (348.19 ± 22.28 µM AscAE per mg extract) showed the highest radical scavenging and reducing activities, respectively. The ethyl acetate extract of L. acutangula indicated the highest in metal chelating activity (EC50 = 1.72 ± 0.2 mg · mL-1). The highest correlation (r = 0.91) was observed between TPC and reducing power values of the extracts of L. acutangula. TPC in the chloroform extracts was strongly correlated with the reducing power (r = 0.91). Sequential extraction using hexane followed by chloroform could be considered as the most appropriate procedure for extracting phenolic compounds by reducing power from this L. acutangula.