Abstract:

Four new metal complexes were synthesized by the reaction of tetrandrine(Tet, extracted from Stephania tetrandra S. Moore) with M(NO3)2·3H2O(M=Cu,Zn,Co,Ni) in ethanol and characterized by FT-IR and UV. The power-time curves of bacteriostatic activities of Tet, its four metal complexes and metal nitrates with different concentrations(c) were determined by the titration microcalorimetry method. The growth rate constants(μ) of E.coli were calculated using logistic equation. The relationships of μ-c for the investigated systems were established and the inhibitory concentrations were optimized. By comparing their optimized inhibitory concentrations, it was found that the bacteriostatic activities of the four metalTet complexes on E.coli were superior to those of M(NO3)2·3H2O and Tet.

Key words: Tet, metal complexes, characterization, microcalorimetry, E.coli, the best inhibitory concentration.