Antidiarrhoeal Activity of Diterpenes of Andrographis paniculata (Kal-Megh) against Escherichia coli Enterotoxin in in vivo Models

Abstract

The alcoholic extract of Andrographis paniculata exhibited significant antidiarrhoeal activity against E. coli enterotoxins in animal models. The activity was further located in n-butanol fraction, which led to the isolation of four diterpenes, andrographolide (7), neoandrographolide (2), deoxyan-drographolide (3), and andrographiside (4). Among the four diterpenes, andrographolide and neoandrographolide showed similar activity to loperamide against E. coli LT and LT/ST enterotoxins. Andrographolide was found to be superior against ST enterotoxin, the most common cause of epidemics of neonatal diarrhoea.