| Literature DB >> 11000035 |
B N Zhou1, J M Hoch, R K Johnson, M R Mattern, W K Eng, J Ma, S M Hecht, D J Newman, D G Kingston.
Abstract
Analysis of cytotoxicity data of extracts from the National Cancer Institute's Active Repository by the COMPARE protocol was carried out using camptothecin as a reference point. Extracts identified by this process were further characterized by a selective yeast bioassay for inhibitors of topoisomerase I and by a biochemical assay for compounds that stabilize the topoisomerase I-DNA covalent binary complex. Five of the extracts were positive in the yeast bioassay, and eight extracts showed activity on the assay that monitors stabilization of the topoisomerase I-DNA complex. Four of the latter extracts were inactive in the yeast bioassay, and thus would not have been identified as hits without the COMPARE preselection process. One of the extracts, from Pyrenacantha klaineana, was selected for detailed investigation, and fractionation of this extract yielded camptothecin and 9-methoxycamptothecin as the bioactive constituents.Entities:
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Year: 2000 PMID： 11000035 DOI： 10.1021/np000058r
Source DB: PubMed Journal: J Nat Prod ISSN： 0163-3864 Impact factor: 4.050