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Bioactive Enmein-Type ent-Kaurane Diterpenoids from Isodon phyllostachys

Yang, Jin, Wang, Wei-Guang, Wu, Hai-Yan, Du, Xue, Li, Xiao-Nian, Li, Yan, Pu, Jian-Xin, Sun, Han-Dong
Journal of natural products 2016 v.79 no.1 pp. 132-140
Isodon phyllostachys, X-ray diffraction, aerial parts, diterpenoids, humans, inhibitory concentration 50, neoplasms, nitric oxide, nuclear magnetic resonance spectroscopy
Thirty-two enmein-type ent-kaurane diterpenoids, including 13 new compounds, were isolated from the aerial parts of Isodon phyllostachys. Compounds 1 and 2 are the first examples of 3,20:6,20-diepoxyenmein-type ent-kauranoids, and the structures of these new compounds were established mainly by analyzing NMR and HREIMS data. The absolute configurations of 1 and 8 and the relative configuration of 9 were determined using single-crystal X-ray diffraction. Compounds 11, 15, 20, and 21 were active against five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW-480), with IC₅₀ values ranging from 1.2 to 5.0 μM. Compounds 3, 11, 15, 17, 20, 21, 25, and 29 strongly inhibited NO production in LPS-stimulated RAW264.7 cells, with IC₅₀ values ranging from 0.74 to 4.93 μM.