Activity of methanol root extract of Parquetina nigrescens (Afzel.) Bullock on castor oil-induced diarrhoea in mice

This study aimed at providing pharmacological rationale for the ethnomedicinal use of Parquetina nigrescens root in the treatment of diarrhoea. The antidiarrhoeal activity of methanol root extract of P. nigrescens(MPN) was determined using castor oil-induced diarrhoea (COD), castor oil-induced enteropooling (COE) and gastrointestinal motility (GIT) tests. In COD, MPN at all doses significantly (p≤0.01) delayed the onset of diarrhoea and significantly (p≤0.05) decreased the number of wet faeces (with percentage inhibition of 52.2; 53.33 and 71.13 at 25, 50 and 100 mg/kg) respectively. The frequency of defecation was significantly (p≤0.01) decreased at 50 and 100 mg/kg. In COE, MPN at all doses significantly (p≤0.01) reduced the volume of intestinal content with percentage inhibition of intestinal fluid accumulation of 79.36; 47.62; 68.25 at doses of 25, 50 and 100 mg/kg respectively against control. In the GIT test, MPN significantly (p≤0.01) decreased the distance travelled by charcoal with a percentage reduction of peristalsis index of 41.19; 47.26; 43.46 at doses of 25, 50 and 100 mg/kg respectively against control. The percentage inhibition of GIT at all doses of MPN was 50.48, 39.00 and 45.62 respectively. MPN possesses antidiarrhoeal activity thus, the credence for its ethnomedicinal use in the treatment of diarrhoea. Keywords: Diarrhoea, castor oil, enteropooling, gastrointestinal motility, Parquetina nigrescens