Extraction of Total Flavonoids from Zingiber mioga and in Vitro Antibacterial Activities

Abstract:

To determine the optimal extraction of total flavonoids from Zingiber mioga by the response surface methodology and then to study the in vitro antibacterial activities. On the basis of single factor experiments，a 4-factor，3-level Box-Behnken center-united experiment was conducted. The Box-Behnken experiment optimized the processing conditions by response surface methodology. Then the extract from the optimal conditions was concentrated. Finally，the in vitro antibacterial activitie were determined by oxford plate tests and doubling dilution method. The optimal conditions were as follows：ethanol concentration 94.75%，treatment temperature 100 ℃，liquid-to-solid ratio 85∶1（mL∶g），treatment time 70 min. Under the optimal conditions，the extraction rate of total flavonoids was 39.87%，of which the relative error was only 2.26% compared with the predicted value of 40.79%；total flavonoids from Zingiber mioga had no inhibitory effects on Escherichia coli，Saccharomyces cerevisiae and Aspergillus niger，but did inhibit the growth of Bacillus subtilis and Staphyloccocus aureus with the minimal inhibitory concentration（MIC） 3.245 9 mg/mL and 1.622 9 mg/mL and the minimal bactericidal concentration（MBC） 12.983 5 mg/mL and 6.491 8 mg/mL，respectively. CONCLUSION Total flavonoids from Zingiber mioga could be a new type of antibacterial agents and the extraction was suitable for the regression analysis and parameter optimization by response surface methodology.