In vitro anti-melanogenic effect of Perilla frutescens leaf extracts

Introduction: Perilla frutescens (L.) Britt leaves contain various phenolic compounds, especially flavonoids, which potentially inhibit tyrosinase, the key enzyme catalyzing the melanin synthesis pathway. This work aimed to investigate the anti-melanogenic effect of Perilla frutescens extracts through the inhibition of non-cellular as well as cellular tyrosinase activities. Methods: The total extract from Perilla frutescens leaves was obtained by percolation method with 50% ethanol followed by liquid–liquid partition with ethyl acetate (EA) and chloroform (CF) to obtain the EA, CF and EA/CF extracts. The mushroom tyrosinase inhibitory effect of the obtained extracts was screened by dopachrome formation reactions from its substrate 3,4-dihydroxy-L-phenylalanine. The extracts with potential activity were further evaluated for the anti-melanogenic effects in the B16F10 melanoma cell line. Results: EA and EA/CF extracts significantly inhibited mushroom tyrosinase activity with the IC50s of 0.14 and 0.07 mg/mL, respectively, in the same range of that from kojic acid (0.12 mg/mL). Consistently, in B16F10 cells, these extracts inhibited tyrosinase enzyme; their IC50 values were 2 times lower than that of kojic acid. Moreover, both EA and EA/CF extracts remarkably reduced melanin levels in a concentration-dependent manner. Conclusion: The EA and EA/CF extracts from Perilla frutescens leaves were able to inhibit melanogenesis by reducing tyrosinase activity.