Acute toxicity, antidiarrheal and antisecretory properties of methanol extract of <i>Lavandula stoechas</i> L aerial part in mice

Purpose: To determine the polyphenol content of the methanol extract (ME) of Lavandula stoechas L. aerial part and its anti-diarrheal and antisecretory activities in mice. Method: Methanol was used to extract the plant's powder. Spectrophotometric techniques were employed to determine the extract's total phenol, flavonoid and tannin content. The effect of the extract on secretion and diarrhea at three concentrations (50, 250 and 500 mg/kg) was evaluated by castor oil method. The extract was administered to the rats orally and loperamide at a dose of 5 mg/kg served as reference drug. Acute toxicity of two single doses (2 and 5 g/kg) of the plant extract was determined using OECD method. Results: Pretreatment of mice with ME (50, 250 and 500 mg/kg) caused a dose-dependent and significant (p ≤ 0.001) delay in onset of diarrhea. Inhibition of mass intestinal content at the highest dose reached 74.75 ± 4.45 % compared to the reference drug, loperamide (85.82 ± 4.7 %). Inhibition of defecation increased in a significant (p ≤ 0.001) and dose-dependent manner with the most remarkable inhibition at the highest dose (53.73 ± 2.98 %), which was very close to that of loperamide (59.62 ± 1.57 %). Conclusion: The methanol extract of Lavandula stoechas is high in polyphenols and significantly and dose-dependently inhibits intestinal secretion as well as diarrhea in mice. The extract is safe. This provides a plausible scientific basis for the traditional use of the plant to treat diarrhea. Studies in humans is needed to determine the compound's active ingredient(s) responsible for the anti-diarrheal effect and also to elucidate its mechanism of action.