Bioactive Novel Polyphenols from the Fruit of Manilkara zapota (Sapodilla)

Abstract

Activity-guided fractionation of a methanol extract from the fruit of Manilkara zapota cv. Tikal resulted in the isolation of two new antioxidants, methyl 4-O-galloylchlorogenate (1) and 4-O-galloylchlorogenic acid (2), along with eight known polyphenolic antioxidants, namely, methyl chlorogenate (3), dihydromyricetin (4), quercitrin (5), myricitrin (6), (+)-catechin (7), (−)-epicatechin (8), (+)-gallocatechin (9), and gallic acid (10). Of the 10 polyphenols, 1 showed the highest antioxidant activity (IC₅₀ = 12.9 μM) in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assay and displayed cytotoxicity in the HCT-116 and SW-480 human colon cancer cell lines with IC₅₀ values of 190 and 160 μM, respectively. Compound 2 showed high antioxidant activity (IC₅₀ = 23.5 μM) in the DPPH free-radical assay and displayed cytotoxicity in the HCT-116 and SW-480 human colon cancer cell lines with IC₅₀ values of 154 and 134 μM, respectively.