The antioxidant, cytotoxicity and antimicrobial activities of medicinal plants used for male sexual healing in Venda, Limpopo Province

Abstract

Sexually transmitted infections represent one of the main health problems related to reproductive and sexual function, constituting one of the main causes of infertility. Plants have been employed traditionally in treating diseases for centuries. Elephantorrhiza burkei, Securidaca longepedunculata and Wrightia natalensis medicinal plants were selected for this study based on their use in traditional medicine to treat sexual health problems in Limpopo Province. The aim of the study was to determine antimicrobial and antioxidant properties of the selected plants. Different extraction procedures coupled with solvents of varying polarities were used in the extraction of the plant materials. Possible microbial contaminants were identified using the VITEK 2 instrument. Qualitative phytochemical analysis was determined using standard chemical tests and Thin-Layer Chromatography. Total polyphenol content was quantified calorimetrically. Antioxidant activity was quantified using 2, 2-diphenyl- 1-picrylhydrazyl (DPPH) and ferric reducing power assays. In vitro antimicrobial activities were determined using a broth micro-dilution assay and bioautography. Combinational effects of the addition of multiple plant species on antimicrobial activity were investigated for additive, synergistic and antagonistic interactions. The plant species phytochemical profile contained polyphenols that are known to have antimicrobial effects against two Gram-positive bacteria, Staphylococcus aureus (ATCC 29213) and Enterococcus faecalis (ATCC 29212), a Gram-negative bacterium, as well as the fungus, Candida albicans (ATCC 10231). Elephantorrhiza burkei exhibited high antioxidant activity and antimicrobial activity against the test pathogens, although most of the interactions were antagonistic and indifferent. Toxicity was found in the herbal treatment and acute toxicity was found in the selected plants. Based on the good correlations which were found in E. burkei, it was selected for bioactivity guided by an isolation of antibacterial compounds. Elephantorrhiza burkei was not successfully isolated, but the fraction collected showed exceptional biological activity that validates its usage against disease-causing pathogens related to sexually transmitted infections, which compromises male sexual health. This study suggests that the evaluated plants are potential sources of novel anti-infective agents. Further in vivo and in vitro studies are recommended for all the plants, respectively.