Antibacterial and Antiviral Effects of Strictosamide

Objective:To observe the antibacterial and antiviral activities,and provide certain experimental data for strictosamide that is intended for upper respiratory tract infection.Method: The in vitro antibacterial activities on standard staphylococcus aureus and other 9 strains were observed by both test-tube and plating methods,and the protective effects on mice infected by staphylococcus aureus and streptococcus pneumonia were also observed.Mice were divided into 5 groups,such as normal group,model group,reduning group(crude drugs 8.7 g·kg-1),low and high dosage(20,40 mg·kg-1) of strictosamide groups.They were injected intraperitoneally once a day for 7 days.At 1 h after the last injection,staphylococcus aureus or streptococcus pneumonia was injected intraperitoneally to mice,and then the death of mice was observed within 7 days.The in vitro antiviral activities were observed on the model of MDCK cells infected by influenza A(A/PR8/34(H1N1)) and B(B/Jingfang 98-76) virus,and the in vivo antiviral activities were observed by the model of mice infected by influenza A virus.Mice were divided into 5 groups,such as normal group,model group,reduning group(crude drugs 8.7 g·kg-1),low and high dosage(20,40 mg·kg-1) of strictosamide groups.They were injected intraperitoneally once a day for 5 days,and virus was given to mice by nose on the first day.After the last injection,the lung lesions and pathological changes were observed,and the pulmonary index was also calculated.Result: Strictosamide had inhibiting effects on standard escherichia coli and other 6 strains in vitro with MIC of 5 g·L-1.At 10 g·L-1,the diameters of inhibiting bacteria circle of diplococcus pneumonia and other 4 strains were 13-25 mm.At 40 mg·kg-1,the survival rate of mice infected by staphylococcus aureus and streptococcus pneumonia was 70% and 55%,separately.Strictosamide showed inhibitory effects on both influenza A and B viruses in vitro with IC50 values of 0.649,0.323 g·L-1,respectively.It also significantly inhibited increased pulmonary index and improved pulmonary pathological lesions of the infected mice caused by influenza A virus,and the inhibitory rate of pulmonary index was 39.8% at 40 mg·kg-1.Conclusion: Strictosamide possesses antibacterial and antiviral activities.