Microcalorimetric study about biological effect of a synthetic complex: La(Glu)(Im)6(ClO4)3·4HClO4·4H2O

A complex of lanthanum perchloric acid coordinated with glutamic acid, La(Glu)(Im)6(ClO4)3·4HClO4·4H2O was synthesized and characterized. The biological effect of the complex was evaluated by microcalorimetry on the growth of E. coli DH5α. Power–time curves of the growth metabolism of E. coli DH5α were studied using a TAM Air Isothermal Microcalorimeter at 37 °C. From the power–time curves, the parameters such as growth rate constants (k), inhibitory ratio (I), the maximum heat power (Pm) and the time of the maximum heat power (tm) were obtained. The results show that the concentrations of the complex affect obviously the growth metabolism of E. coli DH5α. The stimulatory effect on growth of E. coli DH5α was observed when the concentration of the complex was kept in the range of (0–0.5 μg mL−1). In contrast to the lower concentration, in the case of higher concentration of the complex (0.5–5.0 μg mL−1), an inhibitory effect occurred.