Evaluation of Analgesic Activity of Ethanolic Leaf Extract of Carica papaya in Albino Mice

Pain management in veterinary practice increasingly explores plant-derived analgesic compounds as alternatives or complements to conventional opioids and non-steroidal anti-inflammatory drugs, particularly given the cost and availability constraints in rural Nigeria. Carica papaya, cultivated widely across all geopolitical zones of Nigeria, contains bioactive compounds including carpaine, papain, and flavonoids with documented anti-inflammatory properties. This study investigated the analgesic activity of ethanolic leaf extract of Carica papaya in albino mice using the acetic acid-induced writhing test and the hot plate test. Sixty mice were distributed into six groups: negative control receiving normal saline, positive control receiving aspirin at 100 mg/kg, and four extract groups receiving 100, 200, 400, and 800 mg/kg respectively. In the writhing test, percentage inhibition of writhing was 28.4, 45.7, 63.2, and 71.5 percent for the four extract groups compared with 68.3 percent for aspirin. In the hot plate test, reaction latency was significantly prolonged in the 400 and 800 mg/kg groups at 60 and 90 minutes post-administration compared with the control. These results demonstrate dose-dependent analgesic activity for the extract, suggesting involvement of both peripheral and central pain pathways. Phytochemical screening confirmed the presence of alkaloids, tannins, flavonoids, and saponins. Further studies are needed to isolate the active constituents responsible for the analgesic effects observed. Keywords: Carica papaya, analgesic, writhing test, hot plate test, phytochemistry.