Guaiane Sesquiterpenes from the Rhizome of Curcuma xanthorrhiza and Their Inhibitory Effects on UVB-induced MMP-1 Expression in Human Keratinocytes
A new guaiane sesquiterpene, (1 R,4 S,5 S,10 R)-10-methyl guaianediol (1), along with five known compounds, 10-methylalismoxide (2), (+)-alismoxide (3), isozedoarondiol (4), zedoarondiol (5), and zedoalactone B (6), were isolated from the rhizomes of Curcuma xanthorrhiza Roxb. Compounds 1-6 were isolated from this plant for the first time. Chemical structures were determined using nuclear magnetic resonance (NMR), electron ionization mass spectrometry (EI/MS), polarimetry, circular dichroism (CD), and infrared spectroscopy (IR). Compounds 3 and 4 decreased MMP-1 expression in UVB-treated human keratinocytes by about 8.9-fold and 7.6-fold at the mRNA level, and by about 9.2-fold and 6.6-fold at the protein level, respectively. Results indicate that the isolated compounds have anti-aging effects by inhibiting MMP-1 expression in skin cells.