Dose-dependent effect of H2O2 on hairy roots of Scutellaria baicalensis: growth, composition of fatty acids, and flavones

Scutellaria baicalensis Georgi. is a valuable medicinal plant. The hairy roots strain of S. baicalensis (Sc. baic.-1) from IPP RAS collection was used as a model system for the study. Effects of 1 and 10 mM of hydrogen peroxide (H2O2) were first reported on the growth characteristics of hairy roots, fatty acid (FAs) composition of total lipids, and major root-specific flavones during the cultivation cycle. H2O2 at a concentration of 1 mM exhibited the properties of a signaling molecule: the total FAs content of total lipids increased mainly due to polyunsaturated FAs, including very-long-chain FAs (VLCFAs); the total flavones content was about 1.5-fold higher than in the control. Besides, at 1 mM H2O2 the content of aglycones, especially wogonin, was higher than in the other variants. At 10 mM H2O2, the properties of H2O2 as reactive oxygen species were manifested: inhibition in the growth of hairy root culture was observed against the background of an increase in the content of malondialdehyde; the proportion of saturated FAs and the total proportion of VLCFAs increased; the amount of the aglycone baicalein was also significantly reduced. Based on the data obtained, we can speak about a possible role of VLCFAs in the protection of S. baicalensis roots against oxidative stress.