Abstract:Forsythia suspensa leaves were used as raw materials for phillyrin extraction by ultrasonic assisted semi-bionic method. According to the results of one-factor-at-a-time method, a four-factor and three-level response surface methodology was applied with ethanol concentration, liquid-to-solid ratio, extraction time, temperature as influencing factors. The antibacterial activity was determined by the filter paper method, and the effects of temperature, pH and UV on the antibacterial retention rate of phillyin were studied. The results of variance analysis showed that the regression model better reflected the relationship between the yield of phillyrin and ethanol concentration, liquid-to-solid ratio, extraction time, temperature. The optimum extraction conditions were obtained: the ethanol concentration was 40%, the liquid-to-liquid ratio was 36:1, the extraction temperature was 48 °C and the extraction time was 100 min. Under these condition, the yield of phillyrin reached 4.42%, which was higher than other extraction methods. Antibacterial activity test showed that phillyrin could inhibit Staphylococcus aureus, Escherichia coli, Salmonella and Bacillus subtilis. In addition, the diameters of inhibition zone of the four tested strains were 8.33, 9.85, 8.85, and 8.81 mm respectively. The high temperature, strong acid and strong base could weaken the antibacterial effect of phillyrin, while UV had little effect on the antibacterial effect of phillyrin.
