Ethnopharmacological guided investigation of Cameroonian medicinal plants for anti-shigella drug discovery

Every year, shigellosis is responsible for about 165 million cases of morbidity and one million death, with over 99% recorded in tropical low-income countries, African countries being the most affected. Although available treatment regimen recommended by the WHO are available, they challenged by several limitations including their limited effectiveness and numerous side effects. It is therefore urgent to search for alternative avenues of treatment. The history of drug discovery is rich with tales of medicinal plants being reliable source of new drugs. Moreover, populations in endemic regions mostly rely on their medicinal plants for treatment. Therefore, exploring medicinal plants using an ethnopharmacological guided approach could provide an alternative medicine for the treatment of shigellosis. This study aims to investigate plants used in traditional medicine in Cameroon as potential source of natural product for a treatment of diarrhoea. Guided by both ethnopharmacological and literature surveys, a total of 45 plant parts (leaves, stem bark, fruit, root) were collected from 30 medicinal plants (27 genus/18 family). A total of 180 extracts were prepared by maceration using ethanol, methanol, Water/ethanol (30/70), and water. All extracts were submitted to antishigellal screening out of which 9 exhibited activity with MICs values ranging from 250 to 1000 µg/mL. Aqueous extracts of Pseudospondias longifolia were the more active and were selected for future investigations that will include, acute and subacute toxicities and in vivo antishigellal activity in rats. Potent extracts will be selected for a formulation of an antishigellal phytodrug and the stability and in vivo efficacy of the phytodrug will be evaluated.
Keywords: Shigellosis, medicinal plants, antishigellal phytodrug