Chemical Studies On The Roots And Rhizomes Of Helleborus Thibetanus

The roots and rhizomes of Helleborus thibetanus Franch., a member of the family of Ranunculaceae are called'XiaoTaoErQi', one species of'Shaanxi qiyao'and waidly distrubutied in Shaanxi, Sichuan and GanSu provinces. It can used for treatment of cystitis, urethritis, sores and traumatic injury in Chinese folk medicine. The chemical constituents of'XiaoTaoErQi'have been reported rarely and the chemical and active principles are not clear so far. Therefore, we have continued our previous studies on the chemical constituents of the title plantTwelve compounds were isolated and purified from the ethanol extract of the roots and rhizomes of H. thibetanus by silica gel column chromatography, Sephadex LH-20 and recrystallization, along with silica gel TLC analysis. The structures of seven compounds were identified on the basis of chemical and spectral methods including NMR and comparing with authentic samples. They areβ-sitosterol (HTC-C1), hellebrigenin (3β,5β,14β-trihydroxy-19-oxo-bufa-20,22-dienolide) (HTC-C2), daucosterol (HTC-C3), 3β,14β,16β-trihydroxy-5α-bufa-20,22-dienolide (HTC-C5), deglucohellebrin (5β,14β-dihydroxy-19-oxo-3β-[(α-L-rhamnopyranosyl)oxy]bufa- 20,22-dienolide (HTB50-W1), 14β-hydroxy-3β-[(β-D-glucopyranosyl)oxy]-5α-bufa- 20,22-dienolide (HTB-50W2), 14β,16β-dihydroxy-3β-[(β-D-glucopyranosyl)oxy]-5α- bufa-20,22-dienolide (HTB-50W3).Among these compounds, HTB50-W2 is a new compound, HTC-C5 is a new natural compound, both belong to the class of 5α-bufadienolides. HTB-W3 is a glycosides of HTC-C5. And other five compounds have not been identified.In this thesis, we also summarized the studies on chemical constituents of Helleborus genus in the past few years.