Planta Med. 1995 Oct; 61(5): 414-8.

Inhibitors of DNA topoisomerase I and II isolated from the Coptis rhizomes.

Kobayashi Y, Yamashita Y, Fujii N, Takaboshi K, Kawakami T, Kawamura M, Mizukami T, Nakano H.

Tsukuba Research Laboratories, Kyowa Hakko Co., Ltd., Ibaraki, Japan.

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.