Biological activities of Vitis vinifera L. leaves

The fractions of different polarity, namely chloroform, ethylacetate, n-butanol, and remaining water fractions, were fractionated from an aqueous extract of V. vinifera leaves. The antibacterial, antifungal, antiviral, antioxidant activities, and total phenolic content of these fractions were investigated. The chloroform fraction showed a promising effect against Herpes simplex virus type-1 (HSV-1) and Parainfluenza viruses (PIV). The results indicated that all the fractions were more pronounced against gram-positive bacteria (S. aureus and E. faecalis) than against gram-negative bacteria (E. coli and P. aeruginosa). On the other hand, the fractions showed equal antifungal activity against the genus Candida (C. albicans and C. parapsilosis). Additionally, the antioxidative potential of different fractions of V. vinifera was evaluated using various antioxidant measurements, i.e. 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, metal chelating, and superoxide radical scavenging effects. The ethylacetate fraction possessed the highest antioxidant activities except in the case of iron chelation. On the other hand, the chloroform fraction showed the best performance in the iron chelation assay. In our study, the analysis of the relationship between the antioxidant activity of the fractions and their phenolic content showed a positive correlation coefficient. However, such a correlation was not found for the antimicrobial and antiviral properties. In conclusion, the data presented in the study demonstrated that CHCl3 Fr. produced significant activity against PIV and HSV-1. The results of the antiviral and antioxidant activities supported the utilization of V. vinifera leaves in folk medicine.