Chemical constituents from the stems of Marsdenia tenacissima.

Chemical investigation into the EtOH extract of the stems of an ethnological herbal medicine Marsdenia tenacissima led to the isolation of eight sesquiterpenes (1 − 8) including two unreported eudesmane analogues (1 and 2), one undescribed pyrrole glycoside (9), two phenolic glycosides (10 and 11) and one polyoxygenated cyclohexene (12). Structures of these compounds were elucidated by spectroscopic means and comparison with known analogues, and the absolute configurations of the previously unreported molecules were established on the basis of time-dependent density functional theory (TD-DFT) based electronic circular dichroism (ECD) calculation and specific optical rotation analysis. Our bioassays have established that compound 7 exerted mild activity with an IC 50 value of 45.74 ± 0.91 μM, but unfortunately none of them showed obvious inhibition against α-glucosidase. [Display omitted] • Undescribed sesquiterpenes and pyrrole glycoside were isolated from Marsdenia tenacissima. • The absolute configurations were established by analyses of ECD and [α] D data. • Compound 7 showed mild inhibition against the LPS-induced NO release in RAW264.7 cells. [ABSTRACT FROM AUTHOR]