Alashanines A–C, Three Quinone-Terpenoid Alkaloids from <i>Syringa pinnatifolia</i> with Cytotoxic Potential by Activation of ERK
Shungang Jiao, Huiming Huang, Lifang Wang, Shana Wuken, Changxin Liu, Lu-Lu Kang, Juan Liu, Zhongdong Hu, Pengfei Tu, Luqi Huang, Xingyun Chai
Abstract
Three quinone-terpenoid alkaloids, alashanines A–C ( 1 – 3 ), possessing an unprecedented 6/6/6 tricyclic conjugated backbone and quinone–quinoline-fused characteristic, were isolated from the peeled stems of Syringa pinnatifolia . Their structures were elucidated by analysis of extensive spectroscopic data and quantum chemical calculations. A hypothesis of biosynthesis pathways for 1 – 3 was proposed on the basis of the potential precursor iridoid and benzoquinone. Compound 1 exhibited antibacterial activities against Bacillus subtilis and cytotoxicity against HepG2 and MCF-7 human cancer cell lines. The results of the cytotoxic mechanism revealed that compound 1 induced apoptosis of HepG2 cells through activation of ERK.