Minor triterpenes from an aqueous extract of the hook-bearing stem of Uncaria rhynchophylla

Abstract

Six new triterpenes, uncarinic acids K—P (1–6), along with 24 known analogues, were isolated as minor constituents of an aqueous decoction of the hook-bearing stems of Uncaria rhynchophylla (Gou-teng). By comprehensive spectroscopic data analysis, their structures were elucidated as derivatives of olean-12-en-28-oic acid and urs-12-en-28-oic acid with different oxidized forms at C-3, C-6, and/or C-23, respectively. Cell-based preliminary bioassay showed that the (E)-/(Z)-coumaroyloxy and (E)-/(Z)-feruloyloxy units at C-27 of olean-12-en-28-oic acid and urs-12-en-28-oic acid played roles in their bioactivities.

Graphical Abstract

Keywords:

• Rubiaceae
• Uncaria rhynchophylla
• triterpene
• uncarinic acids K—P

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Sciences Foundation of China (grant nos. 81630094), CAMS Innovation Fund for Medical Science (grant no. 2017-I2M-3-010), and The Drug Innovation Major Project (grant no. 2018ZX09711001) is acknowledged.