Abstract: The microcalorimetric method was used to study the antibacterial activity on the bacteria’s multiplying metabolismand the non multiplying metabolism. The metabolismthermogenic curves of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), under the action of the synthesized Schiff base and its 3d, 4f complexes (2L, 2LZnYb), were obtained. The results showed that the multiplying metabolism and the non multiplying metabolism of bacteria could be analyzed by the thermogenic curves using the thermokinetic equations. On the multiplying metabolism, the two compounds (ZL, 2LZnYb) have strong activity for E. coli. (IC50 (half-inhibitory concentration) is 6.1 and 5.1 mg·L-1, respectively) and weak activity for S. aureus (IC50 is 310.1 and 595.9 mg·L-1, respectively). The introduction of Zn and Yb with the compound slightly increased the inhibition on the multiplying metabolism of E. coli but greatly decreased the effect on that of S. aureus. The activity of these two compounds showed great difference on the non multiplying metabolism. Regardless of E. coli or S. aureus, 2L just showed a notable inhibition and MSC50 (the minimum stationary-cidal concentration 50) of 2L was 6.4 and 209.7 mg·L-1 for the two microorganisms, respectively. Thus, 2L may become a novel kind of potential antibacterial candidate.

Key words: Schiff base, Microcalorimetric, Antibacterial activity, Multiplying, Non multiplying