In vitro and in silico screening of novel typhoid drugs from endangered herb (Enicostema axillare).

In the present study, antibacterial activity of swertiamarin from Enicostema axillare (Lam) was checked against three different human gram-negative pathogens namely Salmonella typhi, Klebsiella pneumoniae and Shigella flexneri. Minimum inhibitory concentration assay revealed low dose and efficient activity of swertiamarin on the above said pathogens. Though swertiamarin is a well-studied and characterized compound, there is no experimental proof available for its antibacterial activity. To gain more insight about the antibacterial efficiency of swertiamarin against typhoid causing S. typhi, a comparative molecular docking of S. typhi OmpF (3NSG) was performed with swertiamarin and other typhoid drugs available in the market which exposed better activity strength of swertiamarin compared with that of the other drugs. Further, molecular dynamics of S. typhi OmpF-swertiamarin shows good flexibility and stability at 100 ns. The outcome of this work will definitely provide an idea of using very low dose of swertiamarin as a potent and promising drug against typhoid fever.Communicated by Ramaswamy H. Sarma.