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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
Subjects: Biology >> Botany

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.

submitted time 2017-07-14 Hits1534Downloads815 Comment 0

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
Subjects: Biology >> Biochemistry

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.

submitted time 2017-05-19 Hits3196Downloads1484 Comment 0

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