The aim of the present study was to correlate the antioxidant, antimicrobial, and cytotoxic activities of hydroalcoholic extracts obtained from the aerial parts of three Dracocephalum moldavica L. cultivars with their polyphenolic compositions. The polyphenols were identified and quantified using spectrophotometrical methods and LC-MS analysis. Their antioxidant capacities were assessed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. Their in vitro antimicrobial efficacies were assessed using the agar well diffusion and broth microdilution methods. Their cytotoxicity was investigated on normal diploid foreskin fibroblasts (BJ) and on colorectal adenocarcinoma (DLD-1) cell lines. The results pointed out significant amounts of polyphenolic compounds in the compositions of the tested cultivars, with rosmarinic acid as the main compound (amounts ranging between 5.337 ± 0.0411 and 6.320 ± 0.0535 mg/mL). All three cultivars displayed significant antioxidant (IC50 ranging between 35.542 ± 0.043 and 40.901 ± 0.161 µg/mL for the DPPH assay, and for the FRAP assay 293.194 ± 0.213 and 330.165 ± 0.754 µmol Trolox equivalent/mg dry vegetal material) and antimicrobial potential (especially towards the Gram-positive bacteria), as well as a selective toxicity towards the tumoral line. A significant positive correlation was found between antioxidant activity and the total phenolic acids (r2 = 0.987) and polyphenols (r2 = 0.951). These findings bring further arguments for strongly considering D. moldavica cultivars as promising vegetal products, which warrants further investigation.
Keywords: BJ cell lines; D. moldavica; DLD-1 cell lines; antimicrobial; antioxidant; cultivars; cytotoxic; extract; polyphenols.