Inhibition of protein tyrosine phosphatase 1B by lupeol and lupenone isolated from Sorbus commixta

Protein tyrosine phosphatase 1B (PTP1B) appears to be an attractive target for the development of new drugs for type 2 diabetes and obesity. In our preliminary test, a MeOH extract of the stem barks of Sorbus commixta Hedl. (Rosaceae) showed strong PTP1B inhibitory activity. Bioassay?guided fractionation of the MeOH extract resulted in the isolation of two lupane?type triterpenes, lupenone (1) and lupeol (2). Compounds 1 and 2 inhibited PTP1B with IC₅₀ values of 13.7 ± 2.1 and 5.6 ± 0.9 μM, respectively. Kinetic studies revealed that both the compounds 1 and 2 are non?competitive inhibitors of PTP1B that decrease V_max values with no effect on K_m values.     

Triterpenoids of Colletia spinosissima

The neutral components from the stems of Colletia spinosissima Gmel. include lupenone, sitosterol lupeol, daucosterine. Acid hydrolysis of the glycoside fraction afforded ethyl sinapate and two homologous degradation products from the corresponding sapogenins. Mild hydrolysis of the glycoside fraction afforded the intact sapogenins, which have been tentatively assigned the structures (VIIb) and (VIIIb). The chemistry of the latter compounds has been explored.     

狼毒大戟三萜类和酸类化合物的分离鉴定

用溶剂提取和硅胶柱色谱方法,从狼毒大戟中分得两个三萜化合物和一个酸类化合物,经物理常数和色谱分析鉴定为羽扇豆酮、羽扇豆醇乙酯和没食子酸。     

An antibacterial biphenyl derivative and other constituents of Atylosia trinervia

The structure of a new antibacterial biphenyl, atylosol, from Atylosia trinervia was elucidated as 3-hydroxy-4-isopentenyl-5-methoxybiphenyl. In addition, lupenone, lupeol and sitosterol were also isolated.     

Triterpenoids of Pterocarpus santalinus: Constitution of a new lupene diol

The bark of Pterocarpus santalinus has been found to contain β-amyrone, lupenone, epi-lupeol, lupeol, sitosterol and a new lupene diol whose constitution has been established as lup-(20)29-en-2α,3α-diol.