Inhibitory Effects of Bakuchiol, Bavachin, and Isobavachalcone Isolated from<i>Piper longum</i>on Melanin Production in B16 Mouse Melanoma Cells

An EtOH extract of fruits of Piper longum was found to exhibit a potent inhibitory effect against alpha-melanocyte-stimulating hormone (alpha-MSH)-induced melanin production in B16 mouse melanoma cells. Bioassay-directed fractionation led to the isolation of prenylated phenolic compounds bakuchiol, bavachin, and isobavachalcone. These compounds and the crude extract of the fruits of P. longum may have suppressive effects against pigmentation by melanin in the skin.