Antioxidant, free radical-scavenging activity and cytotoxicity of different solvent extracts and their phenolic constituents from the fruit hull of mangosteen (Garcinia mangostana)

Abstract

Antioxidative, skin protective activities, and cytotoxicity of three extracts (water, methanol, and hexane) from the fruit hull of mangosteen (Garcinia mangostana Linn. (Guttiferae)) and their phenolic constituents such as α-mangostin, epicatechin, and tannin, were evaluated. The amounts of α-mangostin, total flavonoid, and total tannin were different among the three extracts, except those of total tannin in methanol and hexane extracts. For the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical scavenging, hydroxyl radical-scavenging, and inhibition of lipid peroxidation experiment, the water extract showed higher activity than the methanol extract and hexane extract. α-Mangostin, epicatechin, and tannin also revealed these antioxidant and free radical-scavenging activities. When added simultaneously with H₂O₂ (200 μM) to keratinocyte cells, the water extract (50 μg/mL), epicatechin (200 μM), and tannin (200 μM) effectively protected cells from oxidative damage, but the methanol extract, hexane extract, and α-mangostin did not. The methanol extract and hexane extract exhibited moderate cytotoxicity, whereas α-mangostin showed strong cytotoxicity. The present study provides the evidence that Garcinia mangostana extracts, especially the G. mangostana water extract, act as antioxidants and cytoprotective agents against oxidative damage, which is at least partly due to its phenolic compounds in mangosteen.