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A phytochemical study on Spermacoce ocymoides has led to the isolation of a novel bis-indole alkaloid, spermaocymine A (2), together with the known alkaloid 4-methyl-borreverine (1), as well as an anthraquinone, 8-hydroxy-2-(hydroxymethyl)-1-methoxyanthracene-9,10-dione (3). The structures of the isolated compounds were elucidated by analyzing spectroscopic and spectrometric data, including one-dimensional (1D)- and 2D-NMR and high resolution (HR)-MS. Newly isolated alkaloid 2 was a C-3,14-stereoisomer of 1, the first natural stereoisomer of related bis-indoles containing an indeno[1,2-b]indole skeleton with an epiminoethano bridge. When 1-3 were assayed against five tumor cell lines including multi-drug resistant cells, compound 1 exhibited potent antiproliferative activity with IC 50 values of 6.2-11.5 µM.

Cryptolaevilactones (CLs) A-L, found in the leaves and twigs of Cryptocarya laevigata, are unique natural meroterpenoids with a spiro[3.5]nonane skeleton. We report the total synthesis of a simplified model compound of CLs A-C. The synthetic route included introduction of a styryl group and coupling of a lactone moiety to a spiro ring system, which was constructed by a pinacol-like rearrangement.

The first total synthesis of (±)-neocaryachine (1) was achieved using a radical cyclization to produce the dibenzo-9-azabicyclo[3.3.1]nonane pavine skeleton, following a Bischler-Napieralski reaction to construct an intermediate benzylisoquinoline. The resulting racemic mixture was separated by chiral column chromatography to provide pure (+)- and (-)-1.

New clerodane diterpene, 16-hydroxy-pentandralactone (1) and known diterpene acuminolide (2) were isolated from the methanol extract of Vitex cofassus leaves. The chemical structure and the absolute configuration of 1 were determined by MS, NMR and electron circular dichroism (ECD) experiments. The isolated compounds were evaluated for their antiproliferative activities against a panel of human tumor cell lines, including a multidrug-resistant (MDR) cell line. Both compounds showed potent antiproliferative activities against all the tested cell lines with IC 50 values of 5.4-11.4 µM. Their effects on cell viability were also tested using vascular endothelial growth factor (VEGF)-stimulated human umbilical vein endothelial cells (HUVECs). Compound 1 inhibited VEGF-stimulated HUVEC proliferation in a dose-dependent manner. Based on these results, compound 1 could be a candidate for antitumor agent and inhibitor of angiogenesis.