Radiation-induced modification of secondary metabolites contents in plants of Salvia officinalis L. and Silybum marianum L.

Aim. Long-term studies of the effect of sublethal doses of pre-sowing low-LET ionizing radiation on seeds have demonstrated the effectiveness of radiation biotechnology to stimulate the accumulation of pharmaceutically valuable secondary metabolites in medicinal raw materials of a number of common medicinal plants in Ukraine. The aim of this research was to evaluate the effectiveness of radiation technology in the case of seeds of Salvia officinalis L. and Silybum marianum L. Methods. X-ray irradiation of seeds at doses up to 50 Gy, spectrophotometric analysis of water-ethanol extracts, fluorescence microscopy of leaf epidermis were used. Results. Doses of pre-sowing X-ray irradiation were selected which maximally stimulate both the increase of biomass of medicinal raw materials and the accumulation of secondary metabolites. In particular for Salvia officinalis L. doses are 5 Gy and 20 Gy, for Silybum marianum L. are 10 Gy and 20 Gy. Conclusions. It is recommended to use two stimulating doses at the same time, as the result of exposure depends essentially on the physiological status of the seeds, growing conditions, varietal characteristics. Increasing the content of flavonoids and phenols in medicinal raw materials has been shown to be a reliable and reproducible marker of stimulating of rosemary acid accumulation in Salvia officinalis leaves. Keywords: radiation-induced stimulation, Salvia officinalis, Silybum marianum, rosemary acid, silibinin.