Three new clerodane-type diterpenes, 6R,16-dihydroxycleroda-3,13-dien-15- oic acid (1), 6α,16-dihydroxycleroda-4(18),13-dien-15-oic acid (2), and 4α,18β-epoxy-16-hydroxyclerod-13-en-15-oic acid (3), and four new protoberberine alkaloids, (-)-8-oxo-10-hydroxy-2,3,9-trimethoxyberberine (4), (-)-8-oxo-2,11-dihydroxy-3,10-dimethoxyberberine (5), (-)-8-oxo-11-hydroxy-2,3, 9,10-tetramethoxyberberine (6), and (-)-8-oxo-2,10-dihydroxy-3,9,11- trimethoxyberberine (7), together with 11 known substances, were isolated from a methanol extract of the stems of Polyalthia longifolia var. pendula. The structures of 1-7 were elucidated on the basis of spectroscopic data analysis. Compounds were evaluated for their antiproliferative activities against A549 and MCF-7 cancer cells, and among the substances tested, only 16-oxo-cleroda-3,13- dien-15-oic acid (8) exhibited cytotoxicity.
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