In vitro anti-melanogenic effect of Perilla frutescens leaf extracts

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.

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.

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.

The EA and EA/CF extracts from Perilla frutescens leaves were able to inhibit melanogenesis by reducing tyrosinase activity.