Beninese Medicinal Plants as a Source of Antimycobacterial Agents: Bioguided Fractionation andIn VitroActivity of Alkaloids Isolated fromHolarrhena floribundaUsed in Traditional Treatment of Buruli Ulcer

Abstract

Buruli ulcer (BU) imposes a serious economic burden on affected households and on health systems that are involved in diagnosing the disease and treating patients. Research is needed to find cost-effective therapies for this costly disease. Plants have always been an important source of new pharmacologically active molecules. Consequently we decided to undertake the study of plants used in traditional treatment of BU in Benin and investigate their antimycobacterial activity as well as their chemical composition. Extracts from forty-four (44) plant species were selected on account of reported traditional uses for the treatment of BU in Benin and were assayed for antimycobacterial activities. Crude hydroethanolic extract from aerial parts of Holarrhena floribunda (G. Don) T. Durand and Schinz was found to have significant antimycobacterial activity against M. ulcerans (MIC = 125 µg/mL). We describe here the identification of four steroidal alkaloids from Mycobacterium ulcerans growth-inhibiting fractions of the alkaloidal extract of the aerial parts of Holarrhena floribunda. Holadysamine was purified in sufficient amount to allow the determination of its MCI (=50 µg/mL). These results give some support to the use of this plant in traditional medicine.

Therapeutic Potentials of Ethanolic Extract of Leaves of Holarrhena Floribunda (G. Don) Dur. And Schinz (Apocynaceae)

“…Previous studies showed that extracts and fractions from stem bark of H. floribunda had a good in vitro antiplasmodial activity against the chloroquine-resistant strain FCR-3 isolated from Gambia and the chloroquine-sensitive standard strain 3D7 (Fotie et al, 2006). This activity could be related to the plant alkaloids contents (Janot et al, 1959;Yemoa et al, 2015). According to Saxena et al (2003) and Ramazani et al (2010) several classes of secondary metabolites are responsible for the antimalarial activity, but the most important and diverse potential bioactivity has been observed with alkaloids.…”

“…It grows as a shrub or a tree. The plant is widely distributed in West Africa, where several parts of the plant are used for medicinal purposes (Yemoa et al, 2015). The stem-bark and leaves are used to treat various diseases including malaria, fever, dysentery, amoebic diseases, diarrhoea, sterility, amenorrhea and diabetes (Bouquet & Debray, 1974; Kerharo & Adam, 1974;Arbonnier, 2000;Fotie et al, 2006;Bayala et al, 2006).…”

Ethnopharmacological reports on anti-Buruli ulcer medicinal plants in three West African countries

“…Extraction methods generally mimic herbal practitioners' approach to prepare decoctions or infusions using mainly water and palm wine (Yemoa et al, 2014(Yemoa et al, , 2011Addo et al, 2007;Kone et al, 2007Kone et al, , 2009. Other extraction procedures include the use of ethanol or organic solvents of increasing polarity (hexane, dichloromethane, ethyl acetate and water) to partition plant materials.…”

Approche ethnobotanique et ethnopharmacologique des plantes utilisées dans le traitement traditionnel de l’ulcère de Buruli à Akonolinga (Cameroun)

“…C'est ainsi que de nombreux malades ont recours, très souvent, et en première intention, à la médecine traditionnelle et aux plantes pour traiter cette pathologie (Johnson et al, 2004;Renzaho et al, 2007;Porten et al, 2009;Yemoa et al, 2008Yemoa et al, , 2015. Des travaux ont été entrepris pour mieux étudier ces plantes et thérapies traditionnelles afin de disposer des informations par rapport à l'efficacité et/ou l'innocuité de ces dernières.…”

“…Des travaux ont été entrepris pour mieux étudier ces plantes et thérapies traditionnelles afin de disposer des informations par rapport à l'efficacité et/ou l'innocuité de ces dernières. Plusieurs espèces de plantes médicinales traditionnellement utilisées pour traiter l'UB ont été identifiées, leur composition chimique définie et leurs activités antibactériennes sur Mycobacterium ulcerans, ainsi que leur toxicité déterminées en Afrique de l'Ouest de manière globale (Tsouh Fokou et al, 2015, et plus spécifiquement au Benin (Yemoa et al, 2008(Yemoa et al, , 2011(Yemoa et al, , 2015, au Ghana (Addo et al, 2007), en Côte d'Ivoire (Coulibaly et al, 2011). Au Cameroun, les travaux de Pouillot et al (2007), Landier et al (2011) soit par massage et désinfection de la lésion avec les décoctions préparées (64,3%), soit par application locale en cataplasme (14,3%) ou par badigeonnage (3,6%), soit par projection sur les lésions ou plaies ulcéreuses, de la préparation contenue dans des fragments de feuilles de bananier préalablement ramollies au feu de bois (14,3%).…”