Abstract: The antitumor activity and mechanism of component A produced by myxobacteria AHB103-1 were elementarily discussed in the article. The MTT method was adapted to study the concentration and the action time of the component A for four tumour cell HepG2, MDA-MB-231, 293T and B16, and the effect on HepG2 between it and some clinical drugs was compared. The fluorescence microscope and electron microscope were utilized to study its action mechanism on HepG2. The results showed that the metabolite’s antitumor activity was lower than paclitaxel, but higher than epirubicin, irinotecan, and oxaliplatin. More than 90% of inhibition rate for four tumor cell was reached when the sample concentration ≥15 μg/mL. However, the inhibition rate fell with the decreasing of the sample concentration. On the other hand, the ideal results could be gotten with the handling time for four tumour cell chosen 24 h, when the sample concentration was 30 μg/mL. However, when the sample concentration was 1.88 μg/mL, the suitable handling time should be chosen 48 h for B16, 293T and HepG2, but 72 h for MDA-MB-231. Finally, the observation results by fluorescence microscope and electron microscope respectively proved from morphology the apoptosis of HepG2 induced by the component A.

Key words: secondary metabolite, antitumor activity, inhibition rate, cell apoptosis