熊果酸
立体化学
化学
根茎
圆二色性
电喷雾电离
三萜类
二维核磁共振波谱
戒指(化学)
一氧化氮
质谱法
传统医学
有机化学
色谱法
医学
作者
Wenjing Ren,Chi-Cheng Io,Rong Jiang,Kei-Fong Ng,Jia‐Zheng Liu,Liping Bai,Wei Zhang,Zhi‐Hong Jiang,Yuhong Liu,Guo‐Yuan Zhu
标识
DOI:10.1021/acs.jnatprod.2c01136
摘要
Amethystoidesic acid (1), a triterpenoid with an unprecedented 5/6/6/6 tetracyclic skeleton, and six undescribed diterpenoids, amethystoidins A-F (2-7), were isolated from the rhizomes of Isodon amethystoides along with 31 known di- and triterpenoids (8-38). Their structures were fully elucidated via extensive spectroscopic analysis including 1D and 2D NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and electronic circular dichroism (ECD) calculations. Compound 1 is the first example of a triterpenoid possessing a rare ring system (5/6/6/6) derived from a contracted A-ring and the 18,19-seco-E-ring of ursolic acid. Compounds 6, 16, 21, 22, 24, and 27 significantly inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, which could be partly mediated by the downregulation of LPS-induced inducible nitric oxide synthase (iNOS) protein expression.
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