Optimization of Ultrasonic-assisted Extraction Process for Total Triterpenoids from Lonicera confuse and Its Antibacterial and Antioxidant Activity

The ultrasonic-assisted extraction process of total triterpenoids from Lonicera confuse(TTL)was optimized using the response surface methodology(RSM),and antibacterial and antioxidant activity was analyzed. Taking total triterpenoids yield as evaluation index,on the basis of single factor experiments,the ultrasound extraction process of TTL was optimized using the method of RSM. Double dilution method was used to determine inhibitory effect of TTL against 10 species of common pathogenic bacteria,and free radical scavenging test was employed to investigate antioxidant activity. The results showed that the optimum extraction condition of TTL were as follows: ethanol concentration 60%,ratio of solid to liquid 1∶26 (g/mL),ultrasonic temperature 63 ℃,extraction time 60 min. The yield of total triterpenoids under the optimum conditions was found to 3.37%±0.02%,which was close to the model predictive value. TTL had different degrees of inhibition on the tested strains,and had the strongest inhibitory effects on Escherichia coli,Staphylococcus aureus,Pseudomonas aeruginosa,Streptococcus pyogenes and Streptococcus pneumoniae. The minimum inhibitory concentration(MIC)and the minimum bactericidal concentration(MBC)were all less than 12.5 mg/mL. Moreover,it has good scavenging effect on DPPH and ABTS free radicals,and the scavenging effect has a dose-effect relationship with the concentration of TTL.The optimized ultrasonic-assisted extraction process of TTL was stable and feasible,and the extract had strong broad-spectrum antibacterial effect and good antioxidant activity.