Screening for melanogenesis-controlled agents using Sudanese medicinal plants and identification of active compounds in the methanol extract of Terminalia brownii bark

We isolated and identified compounds in medicinal plant extracts that could control melanogenesis. Sudanese medicinal plants were extracted with methanol (MeOH) and 50 % ethanol (EtOH)/water, yielding 104 extracts that were screened for melanogenic activity using B16 melanoma cells. The MeOH extract of Terminalia brownii bark dose-dependently enhanced intracellular and extracellular melanogenesis, with no cytotoxicity. Furthermore, we isolated and identified the components in T. brownii MeOH extract. Gallic acid (1), α,β-punicalagin (2), α,β-terchebulin (3), ellagic acid 4-O-α-l-rhamnopyranoside (4), ellagic acid (5), and 3,4,3′-tri-O-methylellagic acid (6) were isolated by chromatography and identified using nuclear magnetic resonance (NMR), matrix-assisted laser desorption/ionization (MALDI) or ultra-performance liquid chromatography–time-of-flight mass spectrometry (UPLC–TOFMS), and ultraviolet (UV) spectroscopy data. Among the isolated compounds, 2, 3, 5, and 6 enhanced melanogenesis. Furthermore, compound 1 inhibited intracellular and extracellular melanogenesis with no cytotoxicity.