The results showed that both extracts of G. mangostana fruit rinds extracts promoted free radical scavenging activity (EC50=5.56–10.94 μg/mL) comparing with Trolox (EC50=1.91 μg/mL). The young fruit rind extract promoted free radical scavenging activity (EC50=5.56 μg/mL) 2 times stronger than the mature fruit rind extract, while α-mangostin standard showed no activity (EC50N150 μg/mL) (Table 1).