Structure elucidation and absolute configuration determination of C26, C27 and C30 tirucallane triterpenoids from the leaves of Picrasma quassioides (D. Don) Benn
Seven undescribed tirucallane-type triterpenoids, kumunorquassins A‒E and kumuquassins K and L, along with nine known analogues, have been isolated from the leaves of Picrasma quassioides (D. Don) Benn. Their structures and absolute configurations were elucidated based on comprehensive spectroscopic analyses, single-crystal X-ray diffraction analysis and electronic circular dichroism (ECD). The absolute