Abstract:

Clove, cinnamon and kaempferol with remarkable antifungal activity were selected from 39 herbs. In order to obtain an optimal combinatorial formula, minimum inhibitory concentrations (MICs) of three kinds of plant extracts and their various combinatorial formulas to Aspergillus niger, Aspergillus oryzae, Rhizopus nigricans and Saccharomyces were determined through double broth dilution method. Meanwhile, effects of temperature, pH value and UV irradiation on stability of combinatorial formula were also evaluated. The optimal combination ratio of clove, cinnamon and kaempferol extracts was 5:3:2 (V/V). This optimal combinatorial formula exhibited a MIC of 1.25%, which was much lower than those of cinnamon or kaempferia extract. Moreover, temperature, pH and UV irradiation had no effect on stability of combinatorial extracts.

Key words: plant extract, combination, minimum inhibitory concentration (MIC), stability