Methanolic extracts from the biomass of Verbena officinalis cultured under continuous artificial light and in darkness on 12 variants of the Murashige and Skoog medium containing different concentrations (0.5-3.0 mg/L) of plant growth regulators: 6-benzyladenine, kinetin, 1-naphthaleneacetic acid and indole-3-butyric acid, were analysed for the amounts of verbascoside and phenolic acids, before and after acid hydrolysis, using the HPLC-DAD method. The amounts of verbascoside were very high (max. 2454.12 mg/100 g DW - light, and 2135.59 mg/100 g DW - darkness). The total amounts of phenolic acids reached a maximum of 46.02 mg/100 g DW (free phenolic acids) and 141.05 mg/100 g DW (bound compounds). The main metabolites were: ferulic, o-coumaric and caffeic acids. The maximum amount of verbascoside was 3.28 times higher than in extracts from the herb of the parent plant. The cultures could be proposed as a potential biotechnological source for selected biologically active compounds.
Keywords: HPLC-DAD analysis; White light; bound phenolic acids; darkness; free phenolic acids; plant growth regulators.