Methanol extract and solvent fractions of <i>Paullinia pinnata Linn.</i> (Sapindaceae) exhibit anti-diarrhoeal potential using in vivo model

Abstract

Background and aim: To experimentally justify the ethnomedicinal claim of the usage of Paullinia pinnata in the management of diarrhoea.

Methods: Antidiarrhoeal activity of crude extract and solvent fractions at 100 - 400 mg/kg was done using castor oil-induced diarrhea and gastrointestinal motility test using rats.

Results: LD₅₀ was noted to be greater than 5 g/kg. Paullinia pinnata methanol extract (PPME) gave a decrease in faecal output in a non-dose dependent manner at tested doses, with the highest and lowest inhibitions found to be 71.53% and 57.53% at 200 and 400 mg/kg, respectively. The PPME (200 mg/kg)reduced stooling frequency in a manner comparable to that of the standard drug, Loperamide® (75.92% at 5 mg/kg). No activity was observed for the aqueous fraction at 50 and 100 mg/kg, unlike the DCM fraction which produced 44.50% and 63.50% inhibitions at 50 and 100 mg/kg, respectively. Also, a dose-dependent increase in inhibition of gastrointestinal (GI) motility (56.45% and 64.49%) was observed with 100 and 200 mg/kg PPME, respectively. However, a sharp reduction in activity (29.4%) was noted at the highest dose (400 mg/kg) compared to 59.16% in animals administered with 5 mg/kg atropine (positive control). DCM fraction also showed a similar pattern of activity as observed in castor oil-induced diarrhoea, with dose-dependent increase in antidiarrhoeal activity. The 50 and 100 mg/kg doses inhibited GI motility by 48.68% and 58.05 %, respectively.

Conclusion: This study suggests that P. pinnata methanol leaf extract possesses antidiarrhoeal potential with bioactive compounds residing in the non-polar fraction.