Grevillosides J-Q, Arbutin Derivatives from the Leaves of Grevillea robusta and Their Melanogenesis Inhibitory Activity

From the 1-BuOH-soluble fraction of a MeOH extract of the leaves of Grevillea robusta, new arbutin derivatives and related compounds, named grevillosides J-Q (1-8), together with eight known compounds (9-18) were isolated. Various kind of acyl groups were attached to β-D-glucose at the 6-position through an ester linkage. Their structures were mainly elucidated from one- and two-dimensional NMR spectroscopic data. For exploitation as skin-lightening and anti-chloasma agents, the inhibitory activities of the isolated compounds as well as ones isolated in previous experiments (19-31) toward tyrosinase and melanin-producing B16 cells were assayed. Several compounds showed promising activity.