The influence of N-substituted β-alanines containing naphthoquinone and thiazole moieties on the growth of St. John’s Wort (Hypericum Perforatum L.) and its ability to accumulate metabolites

In recent years, the growing interest in medicinal plants and their products led the producers of pharmaceuticals to start utilizing the biomass of cultivated plants instead of collecting the biomass that naturally appears in nature. Most of these plants are grown organically; therefore, they are highly exposed to the pathogens that lower the yield of medicinal plants and modify the chemical composition of the plant extracts. The aim of this work was to evaluate and compare the effect of N -substituted β -alanine derivatives containing 1,4-naphthoquinone and thiazole fragments on the growth of St. John’s wort and its ability to accumulate valuable metabolites. Five β -alanine compounds were used during this research, and three well known compounds (3-indolylacetic acid, 2-methyl-1,4-naphthoquinone, N -phenyl -N -tiocarbamoyl- β -a lanine) were chosen for comparison. The shoots of medicinal plants were evaluated for their growth after treatment with different concentrations (0.25–5 mg/l) of β -alanine derivatives. The highest growth-regulating effect on Hypericum perforatum L. was shown by N -(1,4-naphthoquinon-2-yl)- β -alanine ( 1 ) (1 mg/l) and N -phenyl- N -[(5-(phenyl)methylidene)-4-oxo-2(4H)-thiazolyl]- β -alanine ( 5 ) (1 mg/l); therefore, they were chosen for the further research. The shoots of St. John’s wort were grown on the Murashige & Skoog (MS) medium supplemented with compounds 1 and 5 . The highest amount of pigments (carotenoids, chlorophylls a and b ) after a short period of cultivation was obtained in the leaves of shoots grown on the MS + 1 (1 mg/l) medium; however, treatment with compound 5 increased the content of pigments after a long period (8–9 weeks) of cultivation. According to the results, the highest content of phenolics was found in shoots grown on a medium supplemented with compound 5 . DOI: http://dx.doi.org/10.5755/j01.ct.62.4.3409