Regular paper The influence of L-phenylalanine, methyl jasmonate and sucrose concentration on the accumulation of phenolic acids in Exacum affine Balf. f. ex Regel shoot culture

Phenolic acids are an important group of plant second-ary metabolites with various, valuable therapeutic prop-erties. Apart from plants growing in the open air, tissue cultures can be an alternative source of the secondary metabolites. The yield of their accumulation in in vitro cultures can be increased by different methods, includ-ing culture medium supplementation with precursors, elicitors and changing the standard amounts of the medium components. The purpose of this study was to investigate the influence of the precursor (L-phenylala-nine), the elicitor (methyl jasmonate) and a higher su-crose concentration on the phenolic acids accumulation in the agitated shoot cultures of Exacum affine Balf. f. ex Regel (Gentianaceae). Qualitative and quantitative analy-ses of the phenolic acids in methanolic extracts from the biomass were conducted by applying the HPLC method. Fourteen phenolic acids and cinnamic acid were found in all samples. The total content of free phenolic acids in-creased from approximately 0.242 % to 0.635 % (2.6-fold) and the total content of the whole phenolic acids (free and bound) — from 0.712 % to 1.160 % (1.6-fold). The studies show that the best variant for the accumulation of most of the identified phenolic acids contained 6 % of sucrose (double the standard amount), L-phenylalanine 1.6g L–1 of medium and methyl jasmonate 100 mM. The analysis of the results in the experiment presented here showed that it is possible to increase the accumulation of the phenolic acids in Exacum affine shoot cultures — by adding the precursor (L-phenylalanine), the elicitor (methyl jasmonate) and by increasing the sucrose con-centration