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Trichiliasinenoids A–C (1–3), three new limonoids with an unprecedented C-29-C-7 connecting carbon skeleton formed by migration of C-7 from C-6 to C-29 of a mexicanolide-type limonoid precursor were isolated from the leaves and twigs of Trichilia sinensis. Their structures were assigned by spectroscopic analysis, and the absolute configurations were determined by X-ray crystallography (1) and ECD calculation (2 and 3). A possible biosynthetic pathway of 1 was also proposed. Compound 2 exhibited moderate cytotoxicity against HL-60 cells and weak cytotoxicity against SMMC-7721cells.

Five new compounds, namely fimbricalyxoids A–D (1–4) and 13-O-methylfimbricalyx B (5), together with five known compounds (6–10) were isolated from the leaves and stems of Strophioblachia fimbricalyx. Fimbricalyxoid A (1), a cleistanthane diterpenoid, possesses a rare 3,20-oxybridge, while fimbricalyxoids C–D (3–4) are the first seco-ring-A pentanorditerpenoids. Their structures and absolute configuration were established based on NMR and MS data and ECD calculation (1). Compounds 1, 6, and 7 exhibited cytotoxicity against five human tumor cell lines with IC50 values in the range of 1.4–8.2 μM.

Dysoxylentin A (1), the first 21-nortriterpenoid bearing a 2-(propan-2-ylidenyl)furan-3(2H)-one functional group was isolated from the stem of Dysoxylum lenticellatum. Its structure was elucidated by extensive spectroscopic analysis. A plausible biosynthetic pathway was postulated. Dysoxylentin A exhibited selective cytotoxicity against HL-60 tumor cell line. (C) 2011 Elsevier Ltd. All rights reserved.