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1. chinaXiv:201707.00474 [pdf]

Cycloheximide congeners produced by Streptomyces sp. SC0581 and photoinduced interconversion between (E)- and (Z)-2,3-dehydro-anhydrocycloheximides

Yang, Li; Wu, Ping; Xue, Jinghua; Tan, Huitong; Zhang, Zheng; Wei, Xiaoyi
分类: 生物学 >> 植物学

Three new cycloheximide congeners, 2,3-dehydro--epi-isocycloheximide (1), (E)- and (Z)-2,3-dehydro-anhydrocycloheximides (2 and 3), together with three known compounds, anhydroisoheximide (4), cycloheximide (5), and isocycloheximide (6), were obtained from the cultures of Streptomyces sp. SC0581. Their structures were elucidated by extensive spectroscopic analysis in combination with theoretical conformational analysis and ECD computations. The photoinduced interconversion between 2 and 3 was observed and verified and the possible reaction path and mechanism were proposed by theoretical computations. The antifungal and cytotoxic activities of 1–6 were evaluated and suggested that 2,3-dehydrogenation results in the loss of the activities and supported the OH- is important to the activities of cycloheximide congeners.

提交时间: 2017年07月14日 点击量:100, 下载量:50

2. chinaXiv:201705.00892 [pdf]

Bioactive Pentacyclic Triterpenoids from the Leaves of Cleistocalyx operculatus

Wang, Chen; Wu, Ping; Tian, Shuai; Xue, Jinghua; Xu, Liangxiong; Li, Hanxiang; Wei, Xiaoyi
分类: 生物学 >> 生物化学

Thirteen new pentacyclic triterpenoids, cleistocalyxic acids AK (1, 2, 4, 5, and 713) and cleistocalyxolides A (3) and B (6), and fifteen known analogues (1428), based on taraxastane, oleanane, ursane, multiflorane, and lupane skeletons, were isolated from the leaves of Cleistocalyx operculatus. The structures of 113 were elucidated by analysis of their spectroscopic data and ECD/TDDFT computations. Cleistocalyxolide A (3), presumed to be derived from the known taraxastane-type compound 14, has a rare rearranged triterpenoid backbone. Cleistocalyxic acid B (2) displayed cytotoxicity against HepG2, NCI-N87, and MCF-7 cancer cell lines with IC50 values ranging from 3.2 to 6.5 M and cleistocalyxic acid D (5) was active against HepG2 and NCI-N87 cells with the values around 5.0 M. The non-cytotoxic cleistocalyxic acid E (7) inhibited production of IL-6 by 68.1% and TNF- by 53.7% in LPS-induced RAW 264.7 macrophages at the concentration of 2 M.

提交时间: 2017年05月19日 点击量:591, 下载量:154

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