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Aims: This study aims to evaluate the in vivo acute and sub-acute toxicity; and the antimicrobial activity of Anonidium mannii stem bark ethanolic extract. Study Design: This is an experimental study. Location and Duration of the Study: The work was conducted from 15 November 2020 to 31 May 2021 at several laboratories (the Faculty of Medicine and Pharmaceutical Sciences Laboratory of the University of Douala, the Animal Physiology Laboratory of the Faculty of Medicine and Biomedical Sciences at the University of Yaoundé 1 and in the Hematology and Bacteriology Laboratories of the District Hospital of the Cité des Palmiers, Douala, Cameroon). Methodology: The in vivo acute and subacute toxicities studies were conducted following the guidelines of the OECD on Wistar rats, while the in vitro antimicrobial activity was evaluated using the microdilution method on bacterial (Neisseria gonorrheae, Escherichia coli, Salmonela spp) and fungal (Candida albicans) strains. Results: Phytochemical screening revealed the presence of alkaloids, anthraquinones, coumarins, flavonoids, phenols, reducing sugars, tannins, triterpenes. An oral administration of the extract did not induce an abnormal variation of the physiological parameters in rats, at doses of 2000 and 5000 mg/kg body weight for 14 days. After twenty-eight days of observation during the study of subacute toxicity, the extract showed good safety in terms of subacute toxicity. No deaths were recorded at the different doses; and clinical and physiological parameters analyses revealed a non-significant statistical difference. All bacterial strains in the presence of the extract were inhibited, as well as C. albicans. The extract exhibited strong antibacterial activity against N. gonorheae (MIC 15.6 μg/mL), E. coli (MIC 62.5 μg/mL) and Salmonella spp (MIC 15.6 μg/mL). Conclusion: These results could justify the use of A. mannii stem bark in the traditional pharmacopoeia for the treatment of gonococcal disease, diarrhea, abscesses and food poisoning. more...

Aims: This study aimed at identifying the phytochemical constituents, to evaluate and compare the in vitro antioxidant potential of the methanolic extracts of the leaves, trunk (wood and bark) and roots (wood and bark) of Anonidium mannii (Oliv) Engl. and Diels which is used in Cameroon for the treatment of rheumatism. Place and Duration of Study: The work was conducted at the Pharmacochemistry and Natural Substances Laboratories of the Faculty of Medicine and Pharmaceutical Sciences, University of Douala. All the experiments were carried out from the 15th October 2019 to the 31th July 2020. Methodology: Phytochemical screening was based on conventional techniques focusing on color reactions and precipitation. The evaluation of the antioxidant power was carried out by the method of scavenging the free radical DPPH of the extracts and by reading the absorbance for each concentration at 517 nm. Results: The phytochemical screening of the extracts revealed the presence of alkaloïds, flavonoïds, anthraquinones, coumarins, terpenes, steroïds, saponins, phenols and anthocyanins. All extracts tested showed antioxidant activity, particularly root wood with an IC50 = 1.85 µg/ml identical to the standard (BHT: Butylhydroxytoluène). Conclusion: Due to evidence that reactive oxygen species play a causal role in auto-immune diseases, such as rheumatoid arthritis, these results justify the use of the leaves or the stem bark of A. mannii in the traditional pharmacopeia for the treatment of rheumatism. However, the wood of the roots having presented the best activity (IC50 = 1.85 µg/ml). It would be beneficial to suggest this plant part to the local populations for the management of that pathology. This study is the first comparative biological study conducted on the different parts of A. mannii. more...