The antioxidant and antimicrobial properties of phenol-rich extracts of Dracocephalum forrestii W. W. Smith shoot cultures grown in the nutrient sprinkle bioreactor

Abstract Dracocephalum forrestii is known as a medicinal plant in China. The present work evaluates the potential of its shoots to biosynthesise phenolic compounds during bioreactor cultivation. Qualitative UPLC-PDA-ESI-MS analysis revealed the presence of nine caffeic acid derivatives in the hydromethanolic extract. Quantitative UPLC-PDA analysis then found the predominant compounds to be rosmarinic acid (17.90 mg/g DW) and salvianolic acid B (6.5 mg/g DW). Regarding antioxidant activity, the extract demonstrated strong potential to scavenge both DPPH and O 2∙− radicals (NBT) (IC 50 values 30.67 μg/ml and 69.06 μg/ml, respectively) and reduce Fe 3+ ions (1319 μM Fe(II)/g DW of extract – FRAP test). The extract also showed moderate growth-limiting activity against 13 selected pathogenic bacteria and fungi strains, with the MIC and MBC values ranging from 2.5 to 5.0 mg/ml in most cases.