Abstract:

The antibacterial activity, antibacterial mechanism and application in the cosmetics of clove complex extracted by different solvents were explored. Inhibition zone, minimum inhibitory concentration（MIC）and fractional inhibitor concentration（FIC）were determined to show the antibacterial activity of clove extracts. The results show that the FIC of the combination of ethyl acetate extract（C-EA）and n-hexane extract（C-NH）of clove is less than 1, which has synergistic or additive effects on the tested bacteria. When the ratio of the two is 1∶1（g ∶g）, the antibacterial effect of clove complex（C-C_1∶1）is the best. The antibacterial mechanism of C-C_1∶1 was inferred through the growth inhibition curve and scanning electron micrograph of microorganisms. The results show that the main inhibition mechanism of C-C_1∶1 to the tested bacteria is in its logarithmic growth and stable period. It is inferred that C-C_1∶1 can cause the deformation of the bacteria by destroying the cell wall structure, thus achieving the bacteriostasis and sterilization effect. The antibacterial effect of C-C_1∶1 in the cosmetics was determined via the preservative efficacy challenge test. The results show that 4.76 g/L of clove complex can pass the test, which is superior to the same mass concentration ofphenoxyethanol.

Key words: clove complex, antibacterial activity, antibacterial mechanism, preservative efficacy challenge