Analgesic effect of methanolic extracts of leaf, bark and fruit of Averrhoa bilimbi Linn

Abstract

Background: Averrhoa bilimbi Linn. (Oxalidiaceae) is very popular in folk remedy because the plant has high medicinal value and majority parts of the plant such as leaf, fruit and flower are used to treat fever, mumps, pimple, inflammation, rheumatism, itches, boils, bilious colic, stomach ache, aphthous ulcer, cough, cold, syphilis, hypertension, diabetes etc. However, so far no scientific work has been performed which may support its use in pain. Objective: The present study was undertaken to evaluate possible analgesic actions of methanol extracts of Averrhoa bilimbi Linn. (Oxalidiaceae) leaf, bark and fruits in animal models to support its traditional use for first time. Methods: The crude methanolic extracts of Averrhoa bilimbi Linn. (Oxalidiaceae) leaf, bark and fruits were investigated for the evaluation of analgesic potential in mice. Analgesic activity was assessed by using acetic acid induced writhing method, formaldehyde induced paw licking method and tail immersion method. Results: Methanolic extract (250 and 500 mg/kg) of leaf demonstrated maximum analgesic effect in tail immersion suggesting it to be a centrally acting analgesic. On the other hand leaf extract (250 and 500 mg/kg) reduced acetic acid induced pain significantly (p<0.05) and bark extract (500 mg/kg) also reduced acetic acid induced pain significantly (p<0.05) but the effect is less than standard Diclofenac (100 mg/kg, 61.29% inhibition) (p<0.001). In the formalin induced paw licking time test, methanolic leaf extracts reduced nociception induced by formalin injection in both phases significantly (p<0.05-0.001) among which at higher dose (500 mg/kg) was most effective in later phase (41.81% inhibition) (p<0.001).The results demonstrate the analgesic properties of extracts. Conclusion: The study indicates that methanolic extracts of Averrhoa bilimbi has significant analgesic action which support the traditional use of this plant. Bangladesh Medical Res Counc Bull 2022; 48: 120-126