Evaluation of the Anti-Inflammatory, Antidepressant and Antioxidant Activity of Schweinf. ex Hiern Fadogia ancylantha Plant Leaf Extracts

Fadogia ancylantha is an indigenous African medicinal plant widely used in traditional medicine for immune boosting and the treatment of infections and inflammation. This study investigated the phytochemical composition, antioxidant, anti-inflammatory, and antidepressant activities of ethanol and methanol leaf extracts of F. ancylantha. Phytochemical analyses were conducted using standard chemical screening and spectrophotometric methods. Antioxidant activity was evaluated using the DPPH assay whilst anti-inflammatory activity was done using the carrageenan-induced paw oedema model in rats and the cyclooxygenase assay. Antidepressant activity was assessed using the tail suspension, forced swim, and sucrose preference tests. Both ethanol and methanol extracts contained saponins, tannins, flavonoids, and phenolic compounds. The ethanol extract exhibited higher TPC (0.3914 ± 1.8 mg GAE/g) than the methanol extract (0.2183 ± 1.4 mg GAE/g). Similarly, the ethanol extract showed a higher TFC (0.27373 ± 1.31 mg QE/g) than the methanol extract (0.26587 ± 1.31 mg QE/g). The ethanol extract demonstrated concentration-dependent DPPH radical scavenging activity comparable to ascorbic acid. The extract produced dose-dependent anti-inflammatory effects, with higher doses exhibiting greater activity than lower doses. The extract also reduced COX-1 activity in a concentration-dependent manner, with the 200 µg/mL concentration showing activity comparable to indomethacin. In behavioural studies, treatment produced a dose-dependent reduction in immobility time in the tail suspension test and significantly increased sucrose preference, with the 400 mg/kg dose showing the strongest antidepressant-like effect. These findings suggest that the ethanol leaf extract possesses significant antioxidant, anti-inflammatory, and antidepressant properties, supporting its potential for therapeutic development in depressive disorders.