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Eleven new cytotoxic cembranolides, michaolides A-K (1-11), and crassolide (12) were isolated from the CH(2)Cl(2) extract of the Formosan soft coral Lobophytum michaelae. Their structures were established by extensive spectral analysis. The cytotoxicity of the isolates against selected cancer cells was measured in vitro.

Phytochemical investigation of the roots of Calophyllum blancoi growing in Taiwan resulted in the isolation of three new pyranoxanthones, blancoxanthone (1), acetyl blancoxanthone (2) and 3-hydroxyblancoxanthone (3), in addition to two known pyranoxanthones, pyranojacaeubin (4) and caloxanthone (5). Structural characterization of the isolated compounds was determined by spectral analyses especially 2-D NMR. Biological study of the isolated xanthones revealed that blancoxanthone (1) exhibited significant anti-coronavirus activity.

Chromatographic fractionation of the acetone extract of the seeds of Calophyllum blancoi yielded six pyranochromanone derivatives; apetalic acid (1), isoapetalic acid (2), apetalic acid methyl ester (3), apetalic acid 5-O-acetate (4), isoapetalic methyl ester (5), and isoapetalic acid 5-O-acetate (6). In addition, one new dihydrocoumarin derivative, isorecedensolide (7), was also isolated together with recedensolide (8). The structures of the isolated compounds were established through analysis of NMR spectral data including 2D techniques as well as other physical and spectroscopic methods. Compounds 3, 4, 5, 7, and 8 showed mild activity against KB (human oral epidermoid carcinoma) and Hela (human cervical epitheloid carcinoma) tumor cell lines.

In addition to casearlucin A (3), two new clerodane diterpenes, caseamembrols A (1) and B (2) have been isolated from the leaves and twigs of Casearia membranacea by bioassay-guided fractionation. The structures of the new compounds were established on the basis of extensive 1D- and 2D-NMR spectroscopic analysis. Compounds 1-3 exhibited significant cytotoxicity against human prostate (PC-3) cancer cells.

Fractionation of the ethanolic extract of the seeds of Calophyllum inophyllum L. has resulted in the isolation of four novel pyranocoumarin derivatives, designated as inocalophyllins A (1), B (2) and their methyl esters (3, 4) in addition to the known calophyllolide. The structures of these compounds have been determined on the basis of spectroscopic analysis including MS, heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC) and two dimensional incredible natural abundance double quantum transfer experiment (2D-INADEQUATE). Two new methylated products, 5 and 6 were also prepared by methylation of compounds 1 and 2, respectively.

Two new taxane diterpenoids, tasumatrols A (1) and B (2), have been isolated from extracts of the leaves and twigs of Taiwanese Taxus sumatrana. Tasumatrol A is a rare 5/6/6 taxene system, having a novel gamma-lactone at C-10 and C-19. The structures of compounds 1 and 2 were determined on the basis of two dimensional (2D)-NMR techniques, including correlation spectroscopy (COSY), 1H-detected heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond connectivity (HMBC) experiments.