Phytochemical Study and Evaluation of Anti-Inflammatory Properties of Aqueous Extract of Picralima nitida (Apocynaceae) Seeds in Wistar Rats

Abstract

Aim: The aim of this study was to evaluate the anti-inflammatory effect of Picralima nitida (Apocynaceae) seeds, a plant widely used in traditional African medicine for the treatment of various pathologies. Methods: The aqueous extract of Picralima nitida seeds (EAPn) obtained by the decoction              method was used for toxicological, photochemical and pharmacological tests. The acute                       oral toxicity study was carried out by administering 1 ml of a single dose of 300, 2000                          and 5000 mg/kg body weight of EAPn to three batches of mice, in accordance with the                  guidelines of the Organisation for Economic Co-operation and Development. Qualitative phytochemical screening was carried out in accordance with the techniques described in                the work of Emina et al. Using the method of Winter et al., the anti-inflammatory activity of EAPn was tested using 24 wistar rats. Edema was induced by injection of 1% carrageenan under the plantar pad of the rats' right hind leg. 300 mg/kg BW. of EAPn and 10 mg/kg BW. of indomethacin (INDOCID) were administered by gavage to the test batches, while the control batch received distilled water. Results: In the presence of EAPn and indomethacin, treated batches showed a significant (p < 0.05) decrease in mean paw edema compared with the control group from 1st to 6th hour. At 4ᵉ hours, inflammation inhibition rates were 94.5 ± 0.33% and 78 ± 1% (p < 0.001) respectively for indomethacin and EAPn. EAPn thus showed anti-inflammatory effects similar to those of indomethacin. Oral administration of EAPn at a single high dose of 5000 mg/kg BW produced no mortality in mice during the 14-day observation period. We deduce that the lethal dose of EAPn is greater than 5000 mg/kg BW. The extract is therefore considered non-toxic by the oral route. Qualitative phytochemical screening of the aqueous extract revealed the presence of several chemical groups with therapeutic potential, including flavonoids, saponosides, alkaloids and tannins. Conclusion: the chemical groups present in EAPn could be responsible for the anti-inflammatory effects observed. This study offers an accessible and sustainable alternative for the management of inflammatory diseases.