Abstract: Intsia palembanica is the most potential plant having tyrosinase inhibitor
over 30 Indonesian plants that have been searched. Its
active compound namely (-)-robidanol, (+)-epirobidanol and 4-dehydroxyrobidanol
had been identified and showed the tyrosinase inhibitory activity. The study
aims to obtain the kinetic enzyme inhibition type of the three active compounds.
About 3 g of I. palembanica methanol extract was fractionated using n-hexane
soluble part, ethyl-acetate soluble part and aqueous soluble part. Compounds
were isolated for the most active part (ethyl-acetate soluble part) by silica
gel column chromatography. Purification of fractions was performed using preparative
High Performance Liquid Chromatography (HPLC). Kinetic inhibition against tyrosinase
on monophenolase and diphenolase were analyzed by Lineweaver-Burk plot. The
results showed that three active compounds showed different kinetic inhibition
type on monophenolase and diphenolase. The kinetic characteristics of (-)-robidanol,
the most active inhibitor, on monophenolase were Km increased and
Vmax did not changed while on diphenolase were Vmax decreased
and Km did not change. In conclusion, (-)-robidanol is a competitive
inhibitor for monophenolase and a non-competitive inhibitor for diphenolase.
The kinetic data is useful for further research on mechanism of action of the
whitening agent that will be formulated.
L.K. Darusman, I. Batubara, T. Mitsunaga, M. Rahminiwati, E. Djauhari and K. Yamauchi, 2012. Tyrosinase Kinetic Inhibition of Active Compounds from Intsia palembanica. Research Journal of Medicinal Plants, 6: 615-620.