Phytochemical Screening and Anti-bacterial Activity of Selected Medicinal Plants Used to Treat Skin Diseases in the Eastern Cape, South Africa.

Skin infections are prevalent globally, with most cases being self-limiting and exhibiting low mortality rates. Approximately one-third of the population suffers from skin diseases, making them the fourth most common health issue worldwide. Despite their widespread nature, the significance of these infections is often underestimated. This study investigates the antibacterial properties of crude extracts from three medicinal plants: Aloe ferox, Tetradenia riparia, and Carpobrotus edulis, known for their traditional use against skin diseases. The extraction process involved using solvents such as petroleum ether, dichloromethane, ethyl acetate, and methanol from the dried leaves of these plants. The antibacterial activity was assessed through microdilution assays and disc-diffusion methods. The total phenolic content was found to range from 10.9 mg GAE/g DW to 30.4 mg GAE/g DW, while flavonoid levels varied between 5.5 CAE/g DW and 15.1 CAE/g DW. Minimum inhibitory concentrations (MIC) were recorded from 0.39 mg/mL to over 12.5 mg/mL, with inhibition zones measuring between 0 mm to 3 mm. Notably, methanol extracts demonstrated the highest antibacterial activity and total phenolic content compared to other solvents used. A significant correlation was identified between biological activity and total phenolic content. Among the tested bacteria, Staphylococcus aureus exhibited the highest resistance to the crude extracts. The findings suggest that A. ferox, T. riparia, and C. edulis are rich in phenolic compounds and hold potential as therapeutic agents for treating skin diseases.