α-Glucosidase inhibitory effect of flavonoid extracts from crown of god fruit.

Abstract

Crown of God fruit (Phaleria macrocarpa) empirically can treat diabetes mellitus, a disease with high concentration of blood glucose. The purpose of this study is to obtain flavonoid compound from the fruit that can reduce blood glucose through in vitro inhibition activity of α-glucosidase. The fruit were obtained from the Department of Forest Resources Conservation and Ecotourism, Faculty of Foresty, Bogor Agriculture University. Three maturity stages were used based on the fruit color, very red, greenish red, and reddish green and its enzyme activity compared to acarbose as positive control. The result indicated that flavonoid extracts with 1% w/v were highest (40.26%) in the very red fruit compared to the other two, but lower compared to acarbose (96.80%). Further extraction for flavonoid compound was performed on the fruit which has highest inhibition to obtain flavonol and flavon compound. Flavonol extract showed higher α-glucosidase inhibition, 41.97%, compared to flavon, 8.81%. Flavonol which has highest inhibition among flavonoid compound, was fractionated using column chromatography. Chloroform, acetic acid, and water used as eluent with ratio of 67.5:45:6. The result of chromatography gave 7 fractions and the most active fraction was fraction 2 with enzyme inhibition of 80.80%. Maximum absorption for fraction 2 was at 257 nm, which confirmed flavonoid compound. The result of infrared spectrum contained functional groups of -OH, C=O (keton), heteroaromatic ring, and benzene o-subsitution, also confirmed the presence of flavonoid compound.