We investigated the phenolic composition, radical scavenging activity, and antimicrobial activity of grapevine leaf extracts from two red grape varieties, Vranac and Merlot (Vitis vinifera L.). The extracts were prepared from healthy grapevine leaves and those infected by Plasmopara viticola (downy mildew). The phenolic composition of the grapevine leaf extracts was determined using spectrophotometric assays and reverse-phase high performance liquid chromatography (RP-HPLC). The radical scavenging activity of grapevine leaf extracts was determined by the 2,2-diphenyl-1-picrylhydrazyl assay, and their antimicrobial activity was determined by microwell dilution tests. The total phenolic content was higher in healthy grapevine leaf extracts than in infected grapevine leaf extracts. The RP-HPLC analysis detected significant amounts of flavonols, phenolic acids, and flavan-3-ols, and small amounts of stilbenes in the grapevine leaf extracts. Compared with the infected grapevine leaf extracts, the healthy grapevine leaf extracts were richer in flavonols, phenolic acids, and flavan-3-ols, but had lower stilbenes contents. All extracts showed strong free radical scavenging activity, which was strongly correlated with the total phenolic content (R(2) = 0.978). The extracts showed a stronger antimicrobial activity towards Gram-positive bacterial strains than towards Gram-negative bacterial strains and yeast. The phenolic compounds in grapevine leaves were responsible for their strong radical scavenging and antimicrobial activities. Together, these results demonstrate that grapevine leaves have high nutritional value and can be used as a fresh food and to prepare extracts that can be used as additives in food and medicines.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.