Effect of Azadirachta indica leaves extract on acetic acid-induced colitis in rats: Role of antioxidants, free radicals and myeloperoxidase

ObjectiveTo evaluate the healing effects of extract of dried leaves of Azadirachta indica (Neem) on acetic acid-induced colitis in rats. Neem tree is known as ‘arishtha’ in Sanskrit, meaning ‘reliever of sicknesses’.Methods50% ethanolic extract of Azadirachta indica leaves was administered orally, once daily for 14 days in rats after the induction of colitis with acetic acid and 500 mg/kg dose of extract was found to have an optimal effect against acetic acid-induced colonic damage score, weight and adhesions (Macroscopic). Effect of Azadirachta indica extract was then further studied on various physical (mucous/blood in stool, food and water intake and body weight changes), colonic mucosal damage and inflammation (microscopic), antibacterial and biochemical parameters viz. i) antioxidants (superoxide dismutase, catalase and reduced glutathione) and ii) free radicals (nitric oxide and lipid peroxidation) and myeloperoxidase (acute inflammatory marker) activities in acetic acid-induced colitis.ResultsAzadirachta indica extract decreased colonic mucosal damage and inflammation (macroscopic and microscopic), mucous/bloody diarrhea, fecal frequency and increased body weight. Azadirachta indica extract showed intestinal antibacterial activity and enhanced the antioxidants but decreased free radicals and myeloperoxidase activities. Acute toxicity study indicated no mortality or other ANS or CNS related adverse effects even with 5.0 g/kg dose (10 times of effective dose) indicating its safety.ConclusionsAzadirachta indica seemed to be safe and effective in colitis by its predominant effect on promoting antioxidant status and decreasing intestinal bacterial load, free radicals and myeloperoxidase responsible for tissue damage and delayed healing.