ABSTRACT
Pometia pinnata belonging to the Sapindaceae family has been traditionally used as the therapeutic agent for burns andwounds in Indonesia. Based on the result of the experiment conducted, the ethyl acetate fraction of P. pinnata leavesshowed strong α-glucosidase inhibitory activity. After two flavonol rhamnoside compounds were isolated from ethylacetate fraction of P. pinnata leaves methanol extract using chromatography method, their structures were identifiedas kaempferol-3-O-rhamnoside (1) and quercetin-3-O-rhamnoside (2). The ultra-performance liquid chromatographyelectrospray ionization time-of-flight mass spectrometry (UPLC-ESI-TOFMS) chromatogram showed compounds1 and 2 were the major compounds of the ethyl acetate fraction. In this study, the structure–activity relationshipamong the kaempferol, quercetin, and their derivatives bearing sugar moiety were also evaluated. Among tested eightcompounds, kaempferol 7 (percent inhibition = 80.10% ± 0.8) and quercetin 8 (percent inhibition = 82.93% ± 0.4) hadstronger α-glucosidase inhibitory activity than that of other derivatives. Among kaempferol derivatives bearing sugarmoiety, compound 1 showed the strongest activity. Moreover, compound 2 showed strong α-glucosidase inhibitoryactivity among quercetin derivatives. Therefore, it can be confirmed that the hydroxyl group at C-3 position is veryimportant for α-glucosidase inhibitory activity of flavonol compounds.