title: Inhibitors of DNA topoisomerase I and II isolated from the Coptis rhizomes.
abstract: A water extract of Coptis chinensis was found to have the ability to stabilize the cleavable complex with mammalian DNA topoisomerase I. As the result of bioassay-guided fractionation, two protoberberine alkaloids, epiberberine and groenlandicine, were identified as active principles with topoisomerase I-mediated DNA cleavage activity in vitro. These two alkaloids did not induce topoisomerase II-mediated DNA cleavage. During further examination of the structurally related protoberberine alkaloids, berberrubine which is produced during the processing of Coptis rhizome as traditional medicine, was identified as a specific inducer of topoisomerase II-mediated DNA cleavage in vitro. These results indicated that protoberberine alkaloids are a chemical family which can induce cleavable complexes with topoisomerases I and II.
mesh_terms: D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001600:Berberine Alkaloids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry*; D013329:Structure-Activity Relationship; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors
chemical_list: D000470:Alkaloids; D001600:Berberine Alkaloids; D004791:Enzyme Inhibitors; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors; C009090:protoberberine