Comparative effect of Lannea coromandelica (Houtt.) Merr. leaves and stem barks on acetic acid induced pain model in mice and chromogenic reagents: exploring the analgesic potential and phytochemical groups

Lannea coromandelica (Houtt.) Merr (Anacardiaceae), a Bangladeshi medicinal plant, has long been used in indigenous medicine. The plant is reported to be used in the traditional medicine for all local swelling, pain and inflammation and in the treatment of tumour, ulcers, cancer, sprains, bruises, skin diseases, and dysentery. Both the leaves and the stem bark have painkilling and astringent property and so, mixed with toothpowder for use in toothache. The leaves are copped as fodder and fed the livestock in inflammatory and digestive problems. In this study, ethanol extracts of the leaves and stem bark of this traditionally valuable medicinal plant were screened for analgesic activity on acetic acid induced Swiss-albino mice- Mus musculus in vivo for the first time as well as studied for some important phytochemical groups. The dried extracts were dissolved in 99.8% ethanol and qualitatively analysed for bioactive chemical groups-alkaloids, glycosides, steroids, gums, reducing sugars, tannins, flavonoids, and saponins using standard chromogenic reagents. The colour intensity or the precipitate formation was used as analytical responses to these tests. Both the extracts were found to contain steroidal compounds, tannins, gums, reducing sugars, alkaloids as well as flavonoids as their major bioactive phytochemical groups. In analgesic activity test, the bark extract produced 92.92 % writhing inhibition and the leaf extract produced 95.14% writhing inhibition at the dose of 250 mg/kg of body weight compared to the standard diclofenac Na that inhibit 78.54% writhing inhibition at the dose of 25 mg/kg body weight by acetic acid induced writhing model in mice. Based on the results, it could be concluded that the ethanol extract of Lannea coromandelica (Houtt.) Merr leaves and bark possess significant analgesic activity and mood of action might involve a peripheral mechanism. The results rationalize its use in folkloric remedies especially against pain and inflammation.