Evaluation of anti-diarrhoeal activity of L-citrulline in mice

Abstract

Background: L-citrulline is a naturally occurring physiological non-essential amino acid that plays an important role in the metabolism and regulation of nitric oxide. Nitric oxide is important for physiologic processes of gastrointestinal tract, like motility and absorption. L citrulline is majorly synthesized in the small intestine and considered safe for consumption. However, there is paucity of literature on its anti-diarrhoeal effects. Hence, this study investigated the anti-diarrhoeal activity of L-citrulline in mice.

Methods: Anti-diarrhoeal and anti-enteropooling effects of L-citrulline were evaluated by inducing diarrhoea and enteropooling with castor oil. The effect of L-citrulline on normal intestinal motility was also evaluated using charcoal maker. L-citrulline (300 and 600 mg/kg) was administered to test groups, Loperamide (5 mg/kg) was administered to the positive control groups and Normal saline (2ml/kg) was administered to negative control groups. All administrations were via oral route. The results were analyzed using one-way Analysis of variance and Dunnett's post-hoc test.

Results: The control groups in all parameters evaluated showed typical diarrhoeal signs. Diarrhoea protections of 93.33% and 55.49% were observed at 300 and 600 mg/kg of L-Citrulline, respectively. L-Citrulline inhibited fluid accumulation by 35.88% and 28.27% at 300 and 600 mg/kg, respectively. The mean percentage distance travelled by the charcoal maker was inhibited by 13.76% and 2.62% at 300 and 600 mg/kg, of L-citrulline, respectively. The observed antidiarrhoeal effects of L-citrulline could be attributed to its ability to inhibit both intestinal motility and fluid accumulation in the mice.

Conclusion: This study has shown that L-citrulline possess some anti-diarrhoeal potentials. However, there is need for further anti-diarrhoeal studies using other models and lower graded doses of L-Citrulline to further elucidate L-Citrulline anti-diarrhoeal mechanism of action.

Keywords: L-citrulline, anti-diarrhoeal activity, Loperamide, castor oil