Ursane Triterpenes and Norisoprenoids from Retz. and Their Chemotaxonomic Significance.

A total of 31 compounds were isolated from the ethyl acetate and -butanol fractions of Retz., which contained one ursane triterpenoid, 2,3,19-trihydroxy-23-formyl-urs-12-en-28,21olide (), and five norisoprenoids: (2,6,9)-9-hydroxy-4-megastigmen-3-one-2D-glucopyranoside (); (2,6,9)-9-hydroxy-megastigman-4,7-dien-3-one-2D-glucopyranoside (); (+)-isololiolide D-glucopyranoside (); (2,8)-loliolide D-glucopyranoside (); and (2,8)-loliolide D-glucopyranoside (). It also contained 25 known compounds ( and ). The chemical structures of the compounds, inclusive of their absolute configurations, were ascertained using spectroscopic methods such as NMR, HR-MS, and quantum chemical calculations (computational NMR and ECD), in combination with relevant literature data. Moreover, the chemotaxonomic significance of the isolated substances was discussed, with compounds , , and potentially broadening the application of triterpenes as taxonomic markers for the classification of the genus .