In vitro and in vivo evaluation of the inhibitory effect of Limnophila indica (Linn.) Druce on shigellosis

Abstract

The research aimed to evaluate the anti-Shigella and antacid activities of the methanolic extract of Limnophila indica. The whole plant of L. indica was extracted using methanol and then subjected to preliminary chemical screening. The in vitro antibacterial screening on two Gram-positive and two Gram-negative bacteria as well as three Shigella species of which two bacteria were antibiotic-resistant were evaluated by disc diffusion method. Castor oil-induced diarrhoea on Wistar albino rats was performed by using loperamide as a standard control. The in vitro antacid activity was tested by artificial stomach model. The neutralization efficiency, capacity, volume and hydrogen ions consumed were also evaluated. The preliminary chemical screening on methanolic extract of L.indica showed the presence of phenolic compounds, flavonoids, alkaloids, fats and oils. It was proved to be a potent antibacterial agent against the four bacterial strains. Screening against Shigella species revealed that it was a powerful antibacterial agent towards antibiotic-resistant Shigella species. In the case of in vivo antidiarrheal activity, the plant has shown a dose-dependent activity and the lowest dose at 100 mg/kg gave a much better result than loperamide (P<0.01). The in vitro antacid study showed a mild activity. As the plant L. indica has been proved to be a competent antibacterial as well as a compelling antidiarrheal agent with mild antacid activity, this plant can be very well suggested to be an eminent substitute for the various synthetic anti-dysentery and antidiarrheal agents available in the market.