Screening on Marker Compound Tyrosinase Inhibitor Xylocarpus granatum’s stem.

Abstract

The purpose of this study is to screen marker component as tyrosinase inhibitor of Xylocarpus granatum’s stem. The bark and stem were extracted with methanol and tested for tyrosinase inhibitory activity (monophenolase and diphenolase). The stem extract (IC50 monophenolase: 45.12 μg/mL and diphenolase: 31.59 μg/mL) was more potent as tyrosinase inhibitor compared to the bark extract. The IC50 values of stem extract are not significantly different (p< 0.05) with respect to kojic acid as positive control (IC50 monophenolase: 17.43 μg/mL and diphenolase: 20.69 μg/mL). Fractionation was performed on stem extract using silica gel column chromatography and yielded 13 fractions (1 to13). Fraction 3 was the most active fraction (IC50 monophenolase: 18.02 μg/mL and diphenolase: 21.15 μg/mL). This fraction was separated further with preparative thin layer chromatography (TLC) resulted 8 fractions (A to H). Fraction D was the most potent extracts as tyrosinase inhibitor (IC50 monophenolase: 18.73 μg/mL and diphenolase: 21.92 μg/mL). The marker components are compounds with Rf values of 0.25 and 0.63 at TLC plate G60F254. The results of phytochemical test, ultraviolet-visible, and infrared spectroscopy on fraction D showed that the active compounds as tyrosinase inhibitors are flavonols.