Phytochemistry, Analgesic and Anti-Inflammatory Activities and Acute Toxicity Studies of Phragmanthera Usuiensis (Oliv.) M.G. Gilbert

Plants have played a significant role in healthcare throughout history by providing medicinal substances. Phragmanthera usuiensis leaves have been used by traditional practitioners for the treatment of oxidative stress-related diseases in the study area, primarily for treating arthritis. The objective of the study was to investigate the phytochemical composition, analgesic effect, anti-inflammatory effect, and acute toxicity of the methanolic extract of P. usuiensis leaves. The phytochemical composition of the methanolic extract of P. usuiensis leaves was studied using qualitative and quantitative methods. The analgesic effect was investigated through the hotplate method, and the anti-inflammatory activity through the carrageenan-induced paw edema model. Investigation of acute toxicity was carried out as per the OECD guidelines on acute oral toxicity – Acute Toxic Classic (ATC) method, with the acute toxicity being administered orally by gavage. Treatment of the animals was initiated at the starting dose level of 300 mg/kg body weight and carried out with six animals (three animals per step). Treatment of animals at the next dose of 2000 mg/kg body weight was delayed until the survival of the previously dosed animals was ensured. The methanolic extracts of P. usuiensis possess several phytochemicals that exhibited promising free analgesic and anti-inflammatory effects. The phytochemicals found in the methanol extract include alkaloids, tannins, glycosides, saponins, steroids, flavonoids, terpenoids, phenols, coumarins, and free sugars. All groups of test animals did not exhibit any serious toxic or lethal effects even at the administration of the limit dose, 2000 mg/kg body weight. The study has successfully validated the use of Phragmanthera usuiensis leaf as having activity that potentially can be used to treat oxidative stress-related disorders like arthritis. Moreover, the study confirmed that these plants exhibit analgesic and anti-inflammatory actives. Additionally, it established the safety of the extracts for use as medicinal agents in the management of oxidative stress.