Abstract: Both molecular structure and electron action influence the antimicrobial activities of preservatives. For improving the research and development efficiency,the relationships between molecular structure of preservatives and activities including minimum inhibition concentration(MIC) and half life(t0.5) of inhibiting Escherichia coli were studied after some parameters including 8 molecular connectivity indexes and 5 quantum chemistry parameters of 19 preservatives containing α,β-unsaturated carbonyl group were calculated and optimizationally selected by genetic algorithm. Then,the equations of quantitative structure activity relationship were obtained by SPSS software. The equation of MIC showed that MIC is significantly correlated with the third order cluster index 3χvpc,the fourth order path-cluster index 4χvpc,the energy of the highest occupied molecular orbital EHOMO as well as the energy difference ΔE of the highest occupied molecular orbital and the lowest unoccupied molecular orbital. The intension of anti-microbial actions of preservatives increase with increases of 4χvpc and EHOMO,but decrease with increases of 3χvc and ΔE. The equation of half life showed that t0.5 is significantly correlated with the fourth order path-cluster index 4χvpc,the fifth order path index 5χvp,energy of the lowest unoccupied molecular orbital ELUMO,as well as the energy difference Δ E of the highest occupied molecular orbital and the lowest unoccupied molecular orbital. The anti-metabolic capabilities of preservatives increase with increases of 4χvpc,5χvp,and ΔE,but decrease with increase of ELUMO.

Key words: quantitative-structure activity relationship； &alpha, ,&beta, -unsaturated carbonyl group； food preservatives