Abstract:
Backround: Ethnobatanical knowledge is mostly confined among the locals, hence proper enquiry, and documentation of medicinal plants in a specific area can aid the constantly evolving scientific community in protecting different species and developing long-term cure to the menace of various ailments. In many African societies, men still rely on the long cultural history of utilizing medicinal plants to treat and manage their sexual health. There are many lifestyle risks factors (alcoholism, diabetes, sexually transmitted diseases and psychological factors) that affect men sexual and reproductive health. The current renewed global interest in traditional medicine and natural products to sustain health dictates the investigation of ethnobotanical important medicinal plants into their efficacy and safety against male sexual disorders such as impotence and erectile dysfunction. The current study aims to investigate the importance of selected ethnobotanical plants used by local men in villages under the Thengwe tribal council and also to determine their biological activities associated with men sexual health.
Methodology: The study was conducted in two phases after obtaining ethical approval from the University of South Africa ethics committee and permission to conduct the study from the Thengwe Tribal Council, Vhembe district in Limpopo province (South Africa). During phase 1, Twenty-one plant species were selected based on their ethnobotanical uses in the treatment and management of sexual health in men. A total of 23 participants (males) of different age groups ranging between 18 to 80 years were identified and selected from various villages to participate in the interviews. Among them, were from ages 18-30 (27%), 31-40 (22%), 41 to 50 (17%), 51 to 60 (16%) and those above 60 years (17%). All the participants gave their assent for the use of their ethnobotanical knowledge, in accordance with the principle of educated prior informed consent. A quantitative matrix method as developed by De Beer & Van Wyk (2011) was used to determine Species Popularity Index (popularity or importance of each species) and the Ethnobotanical Knowledge Index (participant knowledge of plant local use). The Relative Frequency of Citation (RFC) indices was also utilized to further get insight into the importance of plant species in villages under The Thengwe tribal authority.
During phase 2 of the study, ten medicinal plants were selected for biological activity evaluation based on the availability of plant material, the species popularity and Relative Frequency of Citation indices. Acetone extracts were investigated for their antioxidant activity, anti-inflammatory activity against 15-lipoxygenase, inhibition of nitric oxide production on RAW 264.7 macrophages and antimicrobial activity against both Neisseria gonorrhoeae and Candida albicans. Preliminary phytochemical analysis was also done by determination of total flavonoids and total phenolic content. Cytotoxicity of the extracts was assessed using the XTT reduction assay against Vero monkey kidney cells.
Results: The most popular species according to their species popularity index (SPI) and the relative frequency citation (RFC) were B. mollis (4.52; 0.95), G. livingstonei (4.29; 0.83), R. caffra (4.54; 0.91), S. longepedunculata (4.03; 0.78), S. panduriforme (3.80; 0.78), S. prunioides (4.67; 0.95) and O. tenax (4.42; 0.91). The highest ethnobotanical knowledge index (EKI) value on avarage was found in age group 61 and above (0.81), followed by age group 51-60 (0.74) and 41 – 50 (0.75). High usage of traditional medicine poses considerable risk of loss of biodiversity in the area, and an agent intervention to prioritise plant resources for conservation and sustainable use is required. Diospyros mespiliformis extract was less toxic and showed significant antioxidant (IC50 = 8.34 μg/ml), anti-inflammatory (IC50 = 63 μg/ml) and antigonococcal (MIC= 0.39 mg/ml) activities. Extracts from Garcinia livingstonei and Rhoicissus tridentata also exhibited promising bioactivity. While these three extracts seem to inhibit the production of nitric oxide, the rest of the plant extracts seem to promote its production. Medications such as sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra) work by enhancing the effects of nitric oxide in the body to promote better blood flow to the penis, which can help with erectile function. Therefore, maintaining healthy nitric oxide levels is important for preventing erectile dysfunction, and reducing nitric oxide can have the opposite effect.
Conclusion: Medicinal plants have been used for ages and contain chemicals that can assist men to treat, maintain and manage their sexual health. Ethnobotanical studies have revealed many important medicinal plants used traditionally in the treatment and management of men sexual health, but only few of them have been validated scientifically. The current study demonstrated for the first time the importance and potential of the selected medicianal plants used traditionally in the treatment and management of men sexual health. These plants have potential therapeutic effects and can be used as leads in the development of new pharmaceuticals to manage men sexual disorders.
