Four new triterpenoids, 6beta-hydroxy-3-oxo-11alpha,12alpha-epoxyolean-28,13beta-olide (1), 3beta,6beta-dihydroxy-11alpha,12alpha-epoxyolean-28,13beta-olide (2), 3beta,6beta-dihydroxy-11-oxo-olean-12-en-28-oic acid (3), and 3beta-hydroxy-12-oxo-13Halpha-olean-28,19beta-olide (4), and five known triterpenes, 19alpha-hydroxy-3-oxo-olean-12-en-28-oic acid (5), 6beta-hydroxy-3-oxo-olean-12-en-28-oic acid (6), sumaresinolic acid (7), siaresinolic acid (8), and oleanolic acid (9), were isolated from the resin of Styrax tonkinensis. The structures of these triterpenoids were determined by physicochemical and spectroscopic methods. The configuration of compound 4 was confirmed by X-ray crystallographic analysis. All these triterpenoids inhibited HL-60 cell growth with IG(50) values ranging from 8.9 to 99.4 microM. Oleanolic acid (9) was the most effective antiproliferative agent, with an IG(50) value of 8.9 microM. While 3beta,6beta-dihydroxy-11-oxo-olean-12-en-28-oic acid (3) exhibited the least effective growth inhibition among these triterpenoids, it induced HL-60 cells to undergo differentiation as measured by an NBT reduction assay.

Thirteen diterpenoids (1-13), including two new norditerpene lactones (1-2) and eight new rosane diterpenoids (3-10), were isolated from the roots of Euphorbia ebracteolata. The structures were determined by 1D and 2D NMR, HRESIMS, and electronic circular dichroism (ECD). The ECD-based empirical rule for α,β-unsaturated-γ-lactones was applied to determine the absolute configurations of 1 and 2. Compounds 7, 10, and 13 exhibited significant inhibition of nitric oxide production in RAW 264.7 lipopolysaccharide-induced macrophages, with IC50 values of 2.44, 2.76, and 1.02 μM, respectively.

Four new polyketide derivatives, Trichodermatides A-D (1-4) were isolated from the marine-derived fungus Trichoderma reesei. Trichodermatide A (1) is an unprecedented example of a polyketide with a ketal-containing pentacyclic skeleton. The chemical structures and absolute configurations of compounds 1-4 were elucidated by extensive spectroscopic methods, especially 2D NMR and CD spectral analysis, and supported by their proposed biosynthesis pathway. The cytotoxicity of 1-4 was evaluated against A375-S2 human melanoma cell line.