As a kind of diterpenoida, paclitaxel is a new antitumor drug. The combined use of paclitaxel and anthracyline antibiotic drug such as daunorubicin can gain more remarkable curative effect and less toxicity in the process of clinic treatment. In order to study more about the mechanism of their synergistic action, the influence of paclitaxel on the antitumor effect of daunorubicin under metabolic condition was investigated in this paper by UV-visible spectrophotometry, fluorescence spectrophotometry, differential pulse voltammetry and UV-visible spectroelectrochemistry methods. The results demonstrate that paclitaxel and daunorubicin can form intermolecular hydrogen bonds. Furthermore, paclitaxel’s long chain can wind the aglycone of daunorubicin and the peripheral of the adduct formed by daunorubicin and DNA. Consequently, the side-effects of daunorubicin are decreased and its curative effect is enhanced.

Key words: paclitaxel, daunorubicin, DNA, spectroelectrochemistry