Two new bufadienolides and one new pregnane from Helleborus thibetanus.

Two new bufadienolides, 3β,14β,16β-trihydroxy-5α-bufa-20,22-dienolide ( 1 ) and 14β-hydroxy-3β-[β-D-glucopyranosyl-(1→6)-(β-D-glucopyranosyl)oxy]-5α-bufa-20,22-dienolide ( 2 ), one new pregnane, 3β-hydroxypregna-5,16-diene-20-one-1β-yl sulfate ( 3 ), along with one known pregnane ( 4 ) were isolated from the dried roots and rhizomes of Helleborus thibetanus . Their structures were elucidated by the extensive use of 1D and 2D NMR experiments, together with IR and HRESIMS spectra and the results of enzymatic hydrolysis. [ABSTRACT FROM AUTHOR]