Study on the antioxidant activity and in vitro antifungal activity of Verbascum speciosum methanolic extract

The present study was conducted to determine the antioxidant and antifungal effects of methanol extract from aerial part of Verbascum speciosum. The total phenolic and flavonoid content and the antioxidant activity of the plant extract were determined by using the Folin-Ciocalteau and the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays. The total phenols and flavonoid content of leaves were determined as 82±6.43 mg GAE/g extract and 30.79±0.5 mg RE/g extract, respectively. The extract exhibited significant radical scavenging activity with IC50 value of 32.35μg/ml. The methanolic extract was investigated for its antifungal activity against some fungal reference strains which include: Candida albicans, Candida tropicalis, Candida parapsilosis, Candida krusei, Candida dubliniensis, A. flavus, A.niger, Penicillium and Alternaria. For minimum inhibitory concentrations (MICs) determination, a broth microdilution method according to CLSI M27-A and M38-A for yeasts and filamentous species was performed. The results showed that the highest in vitro antifungal activities were against C. parapsilosis and Alternaria. However, there were no significant differences between different fungal species. These results indicate a high potential of antifungal properties of this methanolic extract. Therefore, it can be suggested to be an effective replacement treatment for fungal infections or for the preservation of foods against pathogenic and toxigenic microorganisms.