The accumulation of free and bound phenolic acids in Anethum graveolens L. in vitro cultures cultivated on the Murashige and Skoog medium variants – preliminary results

Phenolic acids, constitute a biologically attractive group of compounds showing among others antioxidant, immunostimulating and anticancer properties. These compounds occur in plants either in the free form or bound in glycoside and/or ester structures. Plant in vitro cultures can be a rich source of these compounds. Our earlier studies proved that Anethum graveolens L. (Apiaceae) callus cultures cultivated on Murashige and Skoog (MS) medium were an interesting source of free phenolic acids. The aim of the present studies was to analyze the contents of free and bound phenolic acids in biomass cultivated on the same MS medium variants.

The callus cultures were cultivated on seven MS medium variants supplemented with plant growth regulators (PGRs): BAP (cytokinin) and NAA (auxin) in the concentration range from 0.1 to 3.0 mg/l. Methanolic extracts from biomass from in vitro cultures and fruits from the native plant after acid hydrolysis (2 M HCl, 2 × 2h) were analyzed for phenolic acid contents by an HPLC method. In total, eleven phenolic acids and cinnamic acid were analyzed.

All examined extracts contained six metabolites. The main metabolites in the biomass from in vitro cultures were: salicylic acid (SA), p-hydroxybenzoic acid (p-HBA), ferulic acid (FA) and vanillic acid (VA). The analysis proved a significant effect of PGRs concentrations in the tested MS medium variants on the contents of the metabolites under study. The total content ranged from 77.83 to 120.40 mg%, the content of SA from 33.92 to 61.46 mg%, p-HBA from 22.33 to 42.55 mg%, FA from 0.23 to 11.76 mg%, VA from 4.87 to 9.16 mg%. The largest content of phenolic acids was observed on the MS medium variant containing 0.5 mg/l BAP and 2 mg/l NAA. Fruit extracts analyzed for comparison contained SA (71.76 mg%) and syringic acid (46.76 mg%) as the dominating compounds while the total content amounted to 154.14 mg%. The biomass from in vitro cultures of A. graveolens can be a potential source of SA and p-HBA.