Therapeutic potential of Gnidia capitata L. F. : investigations on its antityrosinase, antibacterial, antioxidant and anticancer activities

BACKGROUND : Gnidia capitata L. F. belongs to the family Thymelaeaceae, and has been widely reported for its ethnobotanical uses, especially for the treatment of several human ailments which include skin conditions. However, there is limited information about the pharmacological properties of this plant as a potential cosmetic agent or pharmaceutical. The aim of this study was to evaluate the therapeutic potential of G. capitata for its anti-tyrosinase, antibacterial, antioxidant, anticancer and anti-mycobacterial properties. MATERIALS AND METHODS : G. capitata was extracted with methanol (MeOH), ethyl acetate (EtOAc), dichloromethane (DCM) and hexane (n-Hex). All extracts were tested in vitro for activities against Propionibacterium acnes (ATCC 11827) and Mycobacterium tuberculosis H37Rv (ATCC 27294). Tyrosinase inhibitory activity was screened using tyrosinase from Agaricus bispor. Antioxidant activity was investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. RESULTS : EtOAc, DCM and n-Hex extracts of the plant showed antibacterial activity against P. acnes with MICs of 125 μg/ml. The DCM and n-Hex extracts showed anti-mycobacterial activity with MICs of 500μg/ml. The methanolic extract showed the highest antioxidant activity with an IC50 of 41.83μg/ml. CONCLUSION : The findings presented in this study may explain the potential use of G. capitata for the treatment of certain skin conditions. The potent antioxidant activity could help control the negative effects associated with inflammatory mediators that are produced during the immune response in people that are affected by skin conditions.The Cape Peninsula University of Technology, Medical Research council; South Africa and the National Research Foundation.http://journals.sfu.ca/africanem/index.php/ajtcamam2018Plant Production and Soil Scienc