| Research Abstract |
1. Constituents of Davallia mariesii MOOR
Constituents of Davallia mariesii (Davalliaceae), a fern having an inhibitory activity against protein kinase C, were examined and totally twenty-two kinds of phenolic compounds, carboxylic acid glycosides, flavonoid glycosides, and tannins have been isolated. The structures of these compound were determined by means of spectral (UV, IR, FAB-MS, and 1D and 2D NMR) and chemical methods. Among them, tannins (dimeric, trimeric, and tetrameric condensed tannins) showed an inhibitory effect against protein kinase C.
2. Constituents of Spiranthes sinensis (PERS.) AMES var. amoena (M. BIEBERSON) HARA, Ephemerantha lonchophylla (HOOK. F) P. F. HUNT et SUMMERH, and E. Fimbriata (BL.) P. F. HUNT et SUMMERH
Eight isoprenylated dihydrophenanthrene derivatives from Spiranthes sinensis var. amoena (Orchidaceae) have been isolated and identified by means of 2D NMR methods. Three of them exhibited a weak cytotoxic activity against cancer (Balb 3T3/H-ras) cells (in vitro) and a weak antibacterial activity against grampositive bacteria. Constituents of Ephemerantha lonchophylla and E. fimbriata (Orchidaceae) were also examined and several bibenzyls, phenanthrenes, and dihydrophenanthrenes were isolated.
3. Inhibitor of DNA Topoisomerase II from Woodfordia fruticosa KURZ
Woodfruticosin, a novel cyclic dimeric hydrolysable tannin, has been isolated from the leaves of Woodfordia fruticosa (Lythraceae) and its structure was established. This compound exhibited a stronger inhibitory activity against DNA topoisomerase II than etoposide or adriamycin, which are well known topoisomerase II inhibitors. Also, it showed a weaker growth inhibitory activity against various human tumor cells than etoposide or adriamycin (in vitro), but it showed a remarkable activity against PC-1 cells and a moderate activity against MKN45 and KB cells (in vitro). Furthermore, it had in vivo growth inhibitory activity against sc inoculated colon 38.
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