Antidiarrhoeal evaluation of root extract, its bioactive fraction, and lupinifolin isolated from Eriosema chinense.

The roots of the plant Eriosema chinense are traditionally used by the tribal people of North East India for treatment of diarrhoea. Therefore, the present investigation was undertaken to scientifically validate the traditional claim that these roots have an antidiarrhoeal effect. Ethanol extract along with three fractions, ethyl acetate, chloroform, and hexane, as well as isolated lupinifolin from the chloroform fraction, were screened for the normal faecal excretion rate and castor oil-induced diarrhoea model. The results demonstrated a significant (p < 0.05) reduction in normal faecal output at ethanol extract 400, chloroform fraction 100, chloroform fraction 200, and lupinifolin 10 mg/kg p. o. after the 3rd, 5th, and 7th hours of treatment. Also, the same dose level of ethanol extract, chloroform fraction, and lupinifolin depicted maximum protection from diarrhoea in the castor oil-induced diarrhoea model showing a ceiling effect at chloroform fraction 100 mg/kg p. o. Ethanol extract at 400, its bioactive fraction chloroform fraction at 100, and lupinifolin at 10 mg/kg p. o. significantly inhibited peristaltic index, intestinal fluid volume, and PGE₂-induced enteropooling. They also restored alterations in biochemical parameters such as nitric oxide, total carbohydrates, protein, DNA, superoxide dismutase, catalase, and lipid peroxidation. The ethanol extract, chloroform fraction, and lupinifolin demonstrated a significant recovery from Na+ and K+ loss and a pronounced antibacterial activity against bacterial strains mainly implicated in diarrhoea. Phytochemical analysis revealed the ethanol extract and chloroform fraction to be highly rich in flavonoids, phenols, alkaloids, and tannin contents, whereas lupinifolin (a prenylated flavanone), isolated and quantified by HPTLC for the first time, was found to comprise 6.480 % and 6.718 % (w/w) of the ethanol extract and chloroform fraction, respectively. The antidiarrhoeal activity of the chloroform fraction was found to be the highest, followed by those of the ethanol extract and lupinifolin, which may be due to the presence of lupinifolin along with other phytoconstituents. Thus, the study scientifically validated the antidiarrhoeal potential of the roots from E. chinense, which may be attributed to antimotility- and antisecretory-type effects with a potential antibacterial activity.