Annona squamosa L. leaves inhibit alpha-melanocyte-stimulating hormone (α-MSH) stimulated melanogenesis via p38 signaling pathway in B16F10 melanoma cells.

Background: Annona squamosa L. is a branched shrub, which is believed to be originated from the America and West Indies. Fruits of this plant are commonly known as custard apple, sugar apple, or sweetsops. A number of studies have proven a range of biological activities associated with various parts of A. squamosa.

Aims: The main aim of the present investigation was to evaluate potential inhibitory effects of A. squamosa leaf extract (ALE) on melanogenesis and its underlying mechanisms in B16F10 murine melanoma cells.

Methods: Inhibitory effects of A. squamosa leaf extract (ALE) on melanogenesis were primarily assessed by determining melanin contents. Effects of ALE on tyrosinase activity and the expression of proteins associated with melanogenesis were then determined. GC-MS analysis was carried out to identify the phytochemical profile of A. squamosa leaf extract.

Results: Antimelanogenic effects of ALE were found to exert through the inhibition of melanocyte inducing transcription factor (MITF) and activation of p38. GC-MS analysis identified ent-kaur-16-en-19-ol, 18-oxokauran-17-yl acetate, and β-sitosterol as major phytochemicals.

Conclusion: To our knowledge, this is the first study on the antimelanogenic effects of A. squamosa leaves, rationalizing the use A. squamosa leaf extract as a natural depigmentation agent for the treatment of skin diseases and the development of cosmetic products with enhanced skin-lightening capabilities.