Ethnopharmacological assessment of plants used in elephantiasis treatment: a study on Elephantorrhiza. elephantina, Pentanisia prunelloides, and Dioscorea sylvatica

Medicinal plants play a significant role in traditional African medicine, particularly in the treatment of elephantiasis, a debilitating condition often overlooked despite its severe socio-economic impacts. This study investigated the ethnopharmacological properties of three medicinal plants, Elephantorrhiza elephantina (Burch.) Skeels, Pentanisia prunelloides Walp, and Dioscorea sylvatica Eckl commonly used in South Africa to treat elephantiasis. Water, ethanol, and acetone extracts from these plants were evaluated for their antimicrobial, anthelmintic, anti-inflammatory, and cytotoxic activities. The antimicrobial activity of the extracts was assessed using the microplate method against four bacterial strains and, one fungal strain. The anti-mycobacterial activity was also assessed using Mycobacterium tuberculosis and microbial inhibition was measured through visual MIC determination enhanced with INT-Iodonitrotetrazolium chloride (a colorimetric viability indicator). Pharmacological properties of plant extracts were then investigated using 5-Lipoxygenase model assay, MTT assay for cytotoxicity activity and standard methods for larval motility using Haemonchus contortus for anthelmintic activity. All three plants demonstrated antibacterial properties, with E. elephantina showing the most potent activity with MIC value of 0.098 mg/mL. D. sylvatica ethanol and aqueous extracts exhibited the strongest antifungal effects against Candida albicans with MIC value 0.049 mg/mL, comparable to amphotericin B. The ethanol and acetone extracts of E. elephantina were highly active against Mycobacterium tuberculosis, with a minimal inhibitory concentration (MIC) of 0.195 mg/mL, comparable to the control. P. prunelloides and D. sylvatica extracts demonstrated activity against the mycobacterial strain, with MIC values ranging from 0.195 to 0.781 mg/mL. E. elephantina and P. prunelloides ethanol extracts showed good larval mortality, highlighting their potential as anthelmintic agents. The acetone and ethanol extracts of D. sylvatica exhibited high cytotoxicity across all tested concentrations on the adenocarcinoma cells from the human duodenum (HuTu). However, P. prunelloides exhibited no toxicity, as there was no significant drop in cell viability across all concentrations and time points tested. The extracts of E. elephantina and P. prunelloides exhibited a good inhibitory effect against 5-lipoxygenase. The findings suggest that the plant extracts tested could possess various bioactive compounds that could be effective in managing parasitic and associated opportunistic infections. However, the observed cytotoxicity warrants caution and further research to ensure safe therapeutic applications.