摘要：This study was carried out to investigate the in vitro effects of isopanduratin A and 4-hydroxypanduratin A isolated from Kaempferia pandurata R OXB . on melanin biosynthesis and tyrosinase activity. Two chalcone compounds, isopanduratin A and 4-hydroxypanduratin A, were isolated from the ethyl acetate fraction of ethanol extract as the active principles. Compared with phenylthiourea (IC50=34.3 μ M ) as a positive control, the depigmentation IC50 values for isopanduratin A and 4-hydroxypanduratin A were 10.6 μ M and 23.2 μ M , respectively. The compounds also significantly inhibited the activity of tyrosinase, the enzyme that converts DOPA (3,4-dihydroxyphenylalanine) to dopachrome in the biosynthetic process of melanin. The IC50 values of isopanduratin A and 4-hydroxypanduratin A for tyrosinase were 10.5 μ M and >30 μ M , respectively, while that of phenylthiourea was 47.6 μ M . The tyrosinase protein level was also significantly decreased by isopanduratin A and 4-hydroxypanduratin A. The results indicate that isopanduratin A and 4-hydroxypanduratin A isolated from K. pandurata R OXB . are promising compounds that could be useful for treating hyperpigmentation as skin-whitening agents.
