Phytochemical screening and anti-bacterial activity of medicinal plants used to treat skin diseases in the Eastern Cape, South Africa.
Skin infections are widespread all throughout the world, and the majority of them are self?limiting and have a low fatality rate. However, due to their relationship with diseases like human immunodeficiency virus and acquired immune deficiency syndrome (HIV/AIDS), which cause impaired immunity, these infections have recently been linked with an increase in morbidity. As a result, skin and mucosal infections affect more than 90% of HIV-positive patients. Hence, in this study crude extracts from three plants; Aloe ferox, Tetradenia riparia and Carpobrotus edulis were evaluated against antibacterial species that are known to cause skin disorders. Dry plant material was extracted with petroleum ether, dichloromethane, ethyl acetate and methanol and their activity was determined with the use of the microdilution assay and the disc-diffusion method. Total phenolic and flavonoid content were measured spectrophotometrically with the use of established protocols. The total phenolics ranged from 10. 9 mg GAE/g DW to 30. 4 mg GAE/g DW while the flavonoid levels ranged from 5. 5 CAE/g DW to 15.1 CAE/g DW. The minimum inhibition values ranged from 0. 39 mg/ml to values greater than 12,5 mg/ml. Zones of inhibition ranged from 0 mm to 3 mm. A correlation was found between biological activity and total phenolic. The highest minimum inhibitory activity and level of phenolics was observed in the methanol extracts, which exhibited higher antibacterial activity as compared to petroleum ether, dichloromethane and ethyl acetate extracts. Staphylococcus aureus appeared to be the most resistant bacteria. Therefore, the results of this study indicate that A. ferox and T. riparia are rich sources of phenolic compounds and are promising candidates for the development of skin disorders antibiotics.