Melanogenesis inhibitory and fibroblast proliferation accelerating effects of noroleanane- and oleanane-type triterpene oligoglycosides from the flower buds of Camellia japonica.

A 28-noroleanane-type triterpene oligoglycoside, camellioside E (4), an oleanane-type triterpene oligoglycoside, camellioside F (5), and the known compounds camelliosides A (1) and D (3) were isolated from a 50% EtOH extract of Camellia japonica flower buds from Korea. The principal constituents (1 and 5) significantly inhibited melanogenesis in theophylline-stimulated B16 melanoma 4A5 cells. Camellioside B (2), a major constituent of C. japonica grown in Japan, showed potent inhibition of melanogenesis [95.0 ± 1.0% (p < 0.01) at 20 μM]. The inhibitory effects of 1, 2, and 5 were stronger than that of the reference compound, arbutin. We believe the melanogenesis inhibitory effects of 2 and 5 are partly related to the proliferation inhibitory effects in B16 melanoma 4A5 cells. Conversely, camelliosides tended to enhance proliferation in normal human neonatal skin fibroblasts. Interestingly, camellioside B (2) significantly accelerated fibroblast proliferation. This biological selectivity could make camellioside B useful for treating skin disorders. Herein, we report the first scientific investigation of a triterpene that displays an inhibitory effect on melanogenesis, but that also has an enhancing effect on fibroblast proliferation.