Comparative Evaluation of Analgesic and Anti-inflammatory Activity of Ethanolic Bark Extract of Azadirachta indica and Seed Extract of Holarrhena antidysenterica in Experimental Animal Models

Protection reactions against tissue injury, infection and some pathological conditions is a common feature of pain and inflammation. Non-steroidal anti-inflammatory drugs and corticosteroids and opioids are commonly used for the management of these, but are known to cause gastric irritation and renal toxicity, immunosuppression, and tolerance and dependence. Thus, plant-based drugs could offer more natural and safe treatment options. The present study aimed at the evaluation of the analgesic and anti-inflammatory activity of ethanolic bark extract of Azadirachta indica and ethanolic seed extract of Holarrhena antidysenterica on the experimental animal models. The plants were harvested, identified, shade dried, dried powdered and extracted with ethanol by cold maceration. Phytochemical screening tests showed the presence of alkaloids, flavonoids, glycosides, saponins, tannins, terpenoids and phenolic compounds in both extracts. Acute oral toxicity testing (OECD guidelines) did not result in deaths or significant toxic effects and dosages of 200 mg/kg and 400 mg/kg were chosen for pharmacological evaluation. Analgesic activity was evaluated by hot plate, tail immersion, acetic acid induced writhing models and formalin induced paw licking model in rats, and anti-inflammatory activity was evaluated in carrageenan induced paw edema model in rats. The two extracts exhibited dose dependent analgesic and anti inflammatory activity. The neem bark extract exhibited relatively high activity compared to kutaj seed extract especially at 400mg/kg concentration. The observed effects could be due to flavonoids, phenolics, alkaloids, tannins and terpenoids that are known to inhibit the release of inflammatory mediator and prostaglandin synthesis. The research helps to substantiate the traditional use of both plants in pain and inflammatory conditions.