Chemical profiling and biological activities of “green” extracts of willow species (Salix L., Salicaceae): Experimental and chemometric approaches

Willow bark extract (Salix spp., Salicaceae) has been used since ancient times as an analgesic, antipyretic and anti-inflammatory agent. In this paper, microwave-assisted extraction (MAE) was applied for the extraction of little-studied leaves and bark of six different species of the genus Salix with potential medicinal value. MAE extracts were evaluated in terms of their content of total phenolics, total flavonoids, selected phenolic constituents (salicin, chlorogenic acid, rutin, quercetin, naringenin) and antioxidant activity. Extracts with the highest content of target compounds were assessed for acetylcholinesterase inhibitory potential. Chemometric analysis was performed to identify clusters of samples based on the quantities of target phenolic compounds. Chemical composition varied among the analyzed species, as well as between leaves and bark of the same willow species. The extracts exhibited significant scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl (OH) radicals. Chemometric tools enabled selection of species and plant part (leaf or bark) with the most favorable chemical profile, which could be further explored as sources of bioactive compounds for nutraceutical and pharmaceutical purposes. [Display omitted] •Microwave-assisted extraction was applied on bark and leaf of six willow species.•Chemical composition and antioxidant activity of these extracts was reported.•Chemometric tools identified species with the most favorable chemical profile.•Anti-acetylcholinesterase activity of S. amplexicaulis and S. purpurea was assessed.