Melanogenesis Inhibitory Activity of Monoterpene Glycosides from Gardeniae Fructus

A new iridoid glycoside, 10‐ O ‐(4″‐ O ‐methylsuccinoyl)geniposide ( 7 ), and two new pyronane glycosides, jasminosides Q and R ( 13 and 14 , resp.), along with nine known iridoid glycosides, 1 – 6 and 8 – 10 , and two known pyronane glycosides, 11 and 12 , were isolated from a MeOH extract of Gardeniae Fructus , the dried ripe fruit of Gardenia jasminoides (Rubiaceae). The structures of new compounds were elucidated on the basis of extensive spectroscopic analyses and comparison with literature. Upon evaluation of compounds 1 – 14 on the melanogenesis in B16 melanoma cells induced with α ‐melanocyte‐stimulating hormone ( α ‐MSH), three compounds, i.e. , 6‐ O ‐ p ‐coumaroylgeniposide ( 3 ), 7 , and 6′‐ O ‐sinapoyljasminoside ( 12 ), exhibited inhibitory effects with 21.6–41.0 and 37.5–47.7% reduction of melanin content at 30 and 50 μ M , respectively, with almost no toxicity to the cells (83.7–106.1% of cell viability at 50 μ M ).