Traditional aqueous kava extracts were the most probable cause of hepatitis in two patients presenting with markedly elevated transaminases and hyperbilirubinaemia. A consequent survey of 27 heavy kava drinkers in New Caledonia showed elevated gamma glutamyl transferase in 23/27 and minimally elevated transaminases in 8/27. We conclude that not only commercially available, but also traditionally prepared kava extracts may rarely cause liver injury. The increased activity of gamma glutamyl transferase in heavy kava consumers in the presence of normal or minimally elevated transaminases is probably not a sign of liver injury, but rather reflects an induction of CYP450 enzymes.
Screening of plants from New Caledonia for antiplasmodial activity against Plasmodium falciparum revealed that methanolic extracts of the leaves and bark of Tristaniopsis calobuxus, T. yateensis, and T.glauca inhibited the growth of chloroquine-sensitive and -resistant clones. Ellagic acid and the new compound 3,4,5-trimethoxyphenyl-(6'-O-galloyl)-O-beta-D-glucopyranoside were identified as the active constituents (IC50 0.5 and 3.2 microM, respectively). The growth inhibition of both clones was comparable. The compounds showed negligible or very low cytotoxicity to human skin fibroblasts and Hep G2 cells when tested at concentrations ranging from 0.5 to 100 microM.
The known alkaloids (-)-antofine (1), dehydroantofine (5),(-)-cryptowoline (6), (4- cryptowolidine (7), and (-)-cryptowolinol (8), were isolated from the New Caledonian lauraceous plant Cryptocarya phyllosternon, together with five new bases: two secophenanthro-indolizidines, (-)-phyllostemine (2) and (-)-phyllosteminine (3), one pyrrolidinylacetophenone, (-)-phyllostone (4), and two quaternary tetrahydrobenzylisoquinolines, (+)-phyllocryptine (9) and (+)-phyllocryptonine (10). Chemical and spectroscopic methods were used for identification and structural investigation. A synthesis of phyllocryptonine has permitted its stereostructure to be determined.
Three new 3,4-seco-cycloartanes, secaubryenol (1), secaubrytriol (2), and secaubryolide (3), were isolated from an exudate collected on the aerial parts of Gardenia aubryi, in addition to the known (24S)-cycloartane-24,25-diol-3-one, coccinetane A, herbacetin 3,8-dimethyl ether, hibiscetin 3,8,3',4'-tetramethyl ether, and conyzatin. The structures of 1 and 2 were established by mass spectrometry and NMR experiments, while the relative configuration of 2 was defined unequivocally using X-ray crystallography. The in vitro cytotoxic activity of compounds 1-3 was evaluated against four human solid tumor cell lines.
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