Cytotoxic mechanism of flavonoid from Temu Kunci (Kaempferia pandurata) in cell culture of human mammary carcinoma.

The cytotoxic activity of flavonoid from Temu Kunci (Kaempferia pandurata) was tested by brine shrimp lethality test and cell culture of human mammary carcinoma. This compound is pinostrobin, and has antitumor activity. However, the critical biochemical target of these pinostrobin has not been identified. In our present studies, we used DNA topoisomerase I which was isolated from human tumor. This result showed that pinostrobin inhibited DNA topoisomerase I activity. Pinostrobin may be interfere with DNA breakage-reunion reaction by stabilizing a key covalent intermediate between DNA and the enzyme, resulting in the cleavage DNA. An inhibition in the activity of DNA topoisomerase I is suggesting that this could be a possible mechanism of pinostrobin from Temu Kunci for the cytotoxicity observed in cell culture of human mammary carcinoma.