New ursane-type triterpenoids from Clerodendranthus spicatus

Five new ursane-type triterpenoids, spicatusoids A-E (1, 3-6), and three known ones (2, 7, and 8), and a known oleanane-type triterpenoid (9) were isolated from the aerial parts of Clerodendranthus spicatus. Their structures were elucidated by spectroscopic methods. In particular, the structure of 3 including its absolute configuration was confirmed by single-crystal X-ray diffraction analysis. Cell viability of all the compounds against rat kidney fibroblast cells (NRK-49F) with or without TGF-β1 induction and human cancer cells (HL-60, SMMC-7721, A-549, MCF-7, and SW-480) was examined by using MTT or MST assays. It was found that, with exception of 1, all the tested compounds could inhibit cell proliferation in TGF-β1 induced NRK-49F cells with compounds 2 being most active.

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