Novel perspectives on two Digitalis species: Phenolic profile, bioactivity, enzyme inhibition, and toxicological evaluation

The present study outlines the phenolic composition of methanolic extracts of Digitalis ferruginea and Digitalis lamarckii aerial parts and evaluates their biological activities. The quantification of phenolic compounds was carried out by HPLC-DAD analysis. Antioxidant properties were assessed using different assays. Enzyme inhibition was tested on AChE, BChE, α-amylase, α-glucosidase, and tyrosinase. The antimicrobial properties of the extracts were determined using the microdilution method. Genotoxicity of the extracts was assessed on Drosophila melanogaster by comet assay. D. lamarcki extract was richer in phenolic compounds than D. ferruginea, with chlorogenic acid as dominant compound in both D. lamarckii and D. ferruginea extracts (2.99 and 1.30 mg/g, respectively). Both extracts showed similar values in terms of antioxidant activity. The extracts showed enzyme inhibitory activity on above-mentioned enzymes and moderate antimicrobial activity (MIC range 0.625-10 mg/mL). D. ferruginea extract (20 mg/mL) indicated the absence of genotoxicity, while all concentrations of D. lamarckii extract showed significant DNA damage. Antigenotoxic effect was more evident in the group treated with D. lamarckii extract, 80 mg/mL (%R = 80.3). The results emphasized the biological potential of examined plants and encourage further studies for their potential use as phytopharmaceuticals.