Open Access

ARTICLE

Triterpenoids from Uncaria rhynchophylla and Their PTP1B Inhibitory Activity

by Shuaibin Luo¹, Xuemei Zhang², Kang He¹, Juan Zou^1,*, Chang-An Geng^2,*

1 Guizhou University of Traditional Chinese Medicine, Guiyang, 550025, China
2 State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming, 650201, China

* Corresponding Authors: Juan Zou. Email: ; Chang-An Geng. Email:

Phyton-International Journal of Experimental Botany 2022, 91(8), 1809-1816. https://doi.org/10.32604/phyton.2022.020935

Received 20 December 2021; Accepted 18 January 2022; Issue published 14 April 2022

Abstract

Uncaria rhynchophylla (Gouteng) is a famous traditional Chinese medicine used for psychiatric and hypotensive purposes in China. In this study, the ethyl acetate (EtOAc) part of U. rhynchophylla was revealed with protein tyrosine phosphatase 1B (PTP1B) inhibitory activity. Subsequent investigation on the EtOAc part yielded one new triterpenoid, 3β-formyloxy-6β,19α-dihydroxyurs-12-en-28-oic acid (1) and four known ones, 3β,6β,19α-trihydroxyurs-12-en-28-oic acid (2), 2-oxopomolic acid (3), 3β,19α-dihydroxy-6-oxo-olean-12-en-28-oic acid (4) and sumaresinolic acid (5). The structure of compound 1 was determined by extensive HRESIMS, IR, 1D and 2D NMR spectroscopic analyses. Two ursane-type triterpenoids (2 and 3) showed selective inhibition on PTP1B with IC₅₀ values of 48.2 and 178.7 μM. The enzyme kinetic study suggested that compounds 2 and 3 were mix-type inhibitors on PTP1B with K_i values of 15.6 and 132.5 μM. This investigation manifests the antidiabetic potency of U. rhynchophylla with triterpenoids as the active constituents.

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Keywords

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