[Two new acyclic terpenoids from Croci Stigma]

This study isolated chemical constituents from the ethyl acetate fraction of the methanol-dichloromethane extract from Croci Stigma and conducted their structural elucidation by a combination of chromatographic techniques, including silica gel column chromatography, reversed-phase ODS column chromatography, Sephadex LH-20 gel chromatography, and preparative high-performance liquid chromatography(HPLC), alongside spectroscopic methods such as nuclear magnetic resonance(NMR), high-resolution mass spectrometry(HR-MS), and circular dichroism(CD). Five compounds were isolated and identified as crosatin A(1), crosatin B(2), crosatin C(3), crosatin D(4), and(2E,4E)-2-methyl-6-oxo-hepta-2,4-dienoic acid(5). Among them, compounds 1 and 2 are novel compounds, while compounds 3 and 4 were isolated for the first time as new natural products from natural sources. The inhibitory effects of compounds 1-5 on melanogenesis in B16F10 melanoma cells were evaluated in vitro. The results demonstrated that at a concentration of 50 μmol·L~(-1), compounds 1 and 5 significantly reduced α-MSH-induced melanin content in B16F10 cells in a concentration-dependent manner, which suggested their potential as melanogenesis inhibitors and promising skin-whitening agents.