Triterpenoids from the hook-bearing stems of Uncaria rhynchophylla

Abstract

An unprescribed nortriterpenoid with an aromatic E ring, uncanortriterpenoid A (1), together with fourteen known triterpenoids (2–15), were isolated from the hook-bearing stems of Uncaria rhynchophylla Miq. Based on extensive spectroscopic analyses, the NMR data of 2, 5, and 10 in CD₃OD were assigned for the first time, and the wrongly assigned δ_C of C-27 and C-29 of 2 were revised. Among the known compounds, 7, 13, and 15 were isolated from this species for the first time, and 15 represents the first lanostane triterpenoid bearing an extra methylidene at C-24 for the Rubiaceae family. Additionally, compounds 6 and 14 exhibited moderate ferroptosis inhibitory activity, with an EC₅₀ value of 14.74 ± 0.20 μM for 6 and 23.11 ± 1.31 μM for 14.

Keywords:

• Uncaria rhynchophylla
• Rubiaceae
• phytochemicals
• triterpenoids
• ferroptosis inhibitory activity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China (No. 82173951 and 81872978).