<i>In Vitro</i> Hypoglycemic Diterpenoids from the Roots of <i>Croton yunnanensis</i>
Zhi‐Yong Jiang, Chunjiang Liu, Qi Niu, Xinyu Yan, Die Xiao, Honglei Zhang, Chun-Qiu Huang, Sheng-Li Shi, Ai‐Xue Zuo, Hongping He
Abstract
Fifteen compounds including nine new diterpenes were isolated from the roots of Croton yunnanensis . By HRESIMS, NMR, ECD data, and X-ray diffraction analysis, the new compounds were characterized as eight neo -clerodane diterpenes (compounds 1 – 8 ) and one 15,16-dinor- ent -pimarane diterpene ( 9 ). All diterpenes were assayed for their hypoglycemic activities. Compounds 1 – 4, 6, 7, and 10 promoted glucose uptake activity in insulin-resistant 3T3-L1 adipocytes. Compounds 1 and 6 showed insulin sensitizing activity, potentiating conspicuously their glucose uptake activity at a concentration of 20 μM when treated synergistically with low-concentration insulin at 1 nM.