Studies on chemical constituents from Uncaria rhynchophylla

Objective: To study the chemical constituents from Uncaria rhynchophylla.Methods: Chemical constituents were isolated and purified by repeated column chromatography(silica gel,Toyopearl HW-40C and preparative HPLC).Their structures were elucidated on the basis of spectral data analysis.Results: Six compounds(1-6) were isolated and their structures were identified by comparison of their spectral data with literature values as follows: Hirsuteine N-oxide(1),cadambine(2),corynoxeine(3),vincoside Lactam(4),rhynchophylline(5),isorhynchophylline(6).Conclusion: Hirsuteine N-oxide has been encountered for the first time in natural sources.