15,16 epoxy 8(17),13(16),14 labdatrien 12xi ol 2' hydroxy 4',6' dimethoxychalcone 2,3 dihydro 4',7 di o methylkaempferol Alpinia tonkinensis extract diterpene furanolabdane plant extract unclassified drug Alpinia tonkinensis article carbon nuclear magnetic resonance diastereoisomer drug isolation drug structure medicinal plant nonhuman
Issue Date:
2004
Publisher:
Natural Medicines
Citation:
Volume 58, Issue 5, Page 230-233
Abstract:
The labdane-type diterpene 15,16-epoxy-8(17),13(16),14-labdatrien-12??-ol (1) was isolated
together with 2'-hydroxy-4',6'-dimethoxychalcone and 2,3-dihydro-4',7-di-O-methylkaempferol from the
rhizomes of the endemic Vietnamese medicinal plant Alpinia tonkinensis Gagnep. (Zingiberaceae).
Although both diastereomers of the furanolabdane alcohol 1 provided by the chiral center at the 12-position
have already been reported as semisynthetic intermediates, the absolute configuration at the 12-position,
which affects the chemical shifts of the 17-exomethylene protons, remains to be clarified. In this study, the
natural furanolabdane 1, which possessed the same 1H- and 13C-NMR spectroscopic data as those of one of
the semisynthetic diastereoisomeric pair, was determined to be in the (12S)-form from spectroscopic data
and by applying the modified Mosher's method.
