Screening The Total Extracts And Fractions Of Some Curcuma Species For Tyrosinase Inhibitory Activity

Abstract

Curcuma genus has been illustrating for possessing numerous medicinal treatments such as antioxidant, anti-inflammation, hepatic problems, cough, diabetes rheumatism, etc. and also willing to work as a skin lightening agent. C. longa L. is the most famous in this genus for the ability to light up the skin which has been applied much in cosmetic industry. The mechanism for this effect is the inhibitory ability on the melanogenesis existing on our skin. Tyrosinase is an enzyme which participates throughout the formation of melanin, a protein which can cause black spot on the skin. Several inhibitors have been developed in order to prevent the activity of tyrosinase leading to downgrade the melanogenesis. This project was performed to explore for a new natural source of tyrosinase inhibitor from Curcuma genus by screening the activity on 9 species from their total extracts with colorimetric quantitative assay on 96-well plate. The most potential extract would then be separated by preparative chromatography (PC) method and screen again on the fractions. The active fractions would then be analyzed via liquid chromatography – mass spectrometry (LC – MS) to determine the active components. The results of this study demonstrated that C. leucorrhiza had the potential to develop a new natural tyrosinase inhibitor with the IC50 value was 47.97 ppm. The IC50 value of the active fractions was also calculated: F2, IC50 = 98.31 ppm; F3, IC50 = 44.14 ppm; F4, IC50 = 98.71 ppm; F5, IC50 = 76.82 ppm; F6, IC50 = 94.29 ppm. Eleven compounds from these active fractions were suggested by LC-MS and all belonged to currcuminoids.