Hydrolytic reaction of plant extracts to generate molecular diversity:: New dammarane glycosides from the mild acid hydrolysate of root saponins of Panax notoginseng

Molecular diversity was generated by hydrolyzing the crude root saponins of Panax notoginseng (BURK.) F. H. CHFN under mild acidic condition (AcOH/EtOH 1 : 1). From the acid hydrolysate, five new dammarane glycosides, named notoginsenoside T-1 (=(3beta,6alpha,12beta,20E,23RS)-24,25-epoxy-6-[(beta-D-glueopyranosyl)oxy]dam mar-20(22) -ene-3,12,23-triol; 1), notoginsenoside T-2 (=(3beta,6alpha,12beta,20E,23RS)-24,25-epoxy-6-[(beta0-D-glucopyranosyl)oxy]-23-methoxydammar-20(22)-ene-3,12-diol 2), notoginsenoside T-3 (=(3beta, 6alpha,12beta 20S)-6-[(beta-D-glucopyranosyl)oxy]-20-etlioxydammar-24-ene-3,12-diol; 3), notoginsenoside T-4 (= (3beta,6alpha,12beta,20S,22E,24RS)-6-[(beta-D-glucopyranosyl)oxy]dammar-22-ene-3,12.20,24,25-pentol; 4), and notoginsenoside T-5 (=(3beta,6alpha,12beta, 24E)-6-[beta-D-xylopyranosyl-(1-->2)-beta-D-glueopyranosyl)oxy]dammara-20(21),24-diene-3,12-diol;5), were isolated, together with 15 known dammarane glycosides, and their structures were elucidated on the basis of spectroscopic evidence. Among the known compounds, ginsenosides Rg(3) and Rh-1 were isolated as major constituents, in addition to ginsenosides Rg(5) Rh-4, and a mixture of (20R)- and (20S)-25-hydroxyginsenoside Rh-1. all of which were obtained from P. notoginseng for the first time.