• Natural Product Sciences
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• v.12 no.3
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• pp.138-143
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• 2006

Our continuing interest on Garcinia and Mesua species has led us to carry out a detail study on the chemistry of the root bark of Garcinia mangostana (Guttiferae) since this part of the plant has not been investigated before, and the strm bark of Mesua corneri (Guttiferae) an uninvestigated species. This study has yielded six xanthones, ${\alpha}-mangostin$ (1), ${\beta}-mangostin$ (2), ${\gamma}-mangostin$ (3), garcinone-D (4), mangostanol (5) and gartanin (6) from Garcinia mangostana and two xanthones rubraxanthone (7) and inophyllin B (8) from Mesua corneri. Structural elucidations were achieved using $^1H,\;^{13}C$ NMR and MS data. The crude hexane and chloroform extracts of the root bark of Garcinia mangostana and the hexane extract of the stem bark of Mesua corneri were found to be active against CEM-SS cell lines with $IC_{50}$ values less than $30\;{mu}g/ml$. Moreover, ${\gamma}-mangostin$ gave a very low $LC_{50}$ value of $4.7\;{mu}g/ml$ while rubraxanthone gave an $LC_{50}$ value of $5.0\;{mu}g/ml$ indicating these two compounds to be potential lead compounds for anti-cancer activity against the CEM-SS cell line. This paper reports the isolation and identification of these compounds as well as bioassay data for the crude extracts, ${\gamma}-mangostin$ and rubraxanthone.

• Natural Product Sciences
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• v.4 no.3
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• pp.180-183
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• 1998

The ethanol extract from the leaves of Juniperus chinensis was found to be cytotoxic towards HeLa cells. Bioassay-guided fractionation of the EtOAc soluble faction directed by the microtitration cytotoxic assay revealed that the cytotoxic compound was deoxypodophyllotoxin. All the tumour cell lines tested (KU8112F-chronic mylogeneous leukemia, TK 10-renal carcinoma, UACC 62-melanoma and CEM-SS-T-lymphoblastic leukemia) were found to be susceptible to deoxypodophyllotoxin, however, the minimum effective concentration (MEC) required to reduce the cell population by 100 percent was different between cell lines.

• Natural Product Sciences
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• v.5 no.4
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• pp.172-176
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• 1999

A total of 43 extracts from 21 species of Malaysian flowering plants were screened for antimicrobial and cytotoxic activities. Antimicrobial activity was tested against fungi, including yeast and candida, as well as Gram-positive and Gram-negative bacteria, and cytotoxicity was assayed using the CEM-SS and HT-29 cell lines. The methanol extracts of the roots and stems of Plumeria acutifolia showed the highest antimicrobial activity, i.e. against Saccharomyces cerevisiae and Candida lipolytica, and mostly moderate activity against the other microbes such as Aspergillus ochraceous and Saccharomyces lipolytica. Phyllanthus emblica also showed moderate activity especially that of the methanol extracts. The methanol extract of the roots of Plumeria acutifolia showed the strongest cytotoxic activity $(CD_{50}=\;3\;{\mu}g/ml)$. Most of Zingiberaceae species gave negative results for antimicrobial activity and showed low cytotoxic activity.