Antioxidant Activity of Styrylpyrones from Inonotus rheades (Agaricomycetes) Mycelium under Oxidative Stress in Thellungiella salsuginea Cell Suspension Culture.

This study examined effects of the styrylpyrone fraction from mycelium of hymenochaetoid species, Inonotus rheades (Agaricomycetes), on reactive oxygen species inhibition in Thellungiella salsuginea cell culture under oxidative stress. We identified antioxidant effects of styrylpyrones from I. rheades mycelium on oxidative stress in T. salsuginea cell suspension culture using two models of oxidative stress (induced by hyperthermia or hydrogen peroxide). The results showed that the styrylpyrone fraction maintained a high level of cell viability under stress conditions. The effect of pure hispidin on the plant cell culture was insignificant during the development of oxidative damage caused by hydrogen peroxide and was lacking during hyperthermia-induced oxidative stress. Therefore, these results suggest that the protective effect of the styrylpyrone fraction on T. salsuginea cells can be exerted by individual compounds (which are part of the fraction) and their complex.

Phenolic Compounds of Inonotus rheades (Agaricomycetes) Mycelium: RP-UPLC-DAD-ESI/MS Profile and Effect of Light Wavelength on Styrylpyrone Content.

The phenolic compounds of Inonotus rheades (Pers.) Bondartsev and Singer (Hymenochaetaceae), a typical xylotrophic basidiomycete, and accumulation of styrylpyrones in mycelium under the influence of light of different wavelengths were investigated. Six styrylpyrones (cis- and trans-hispidin, cis- and trans-bisnoryangonin, and phellinins A1 and A2) and 5 bis(styrylpyrones) (3,14'-bishispidinyl, hypholomin B, 3-bisnoryangonyl-14'-hispidin, 1,1-distyrylpyrylethane, and rheadinin) were detected in the extract of I. rheades mycelium using reversed phase ultra-performance liquid chromatography with diode array detection and electrospray ionization mass spectrometry (RP-UPLC-DAD-ESI/MS). The results showed that the maximal content of styrylpyrones was observed under the influence of blue light (8.10 mg/g of dry mycelium weight). Moreover, hispidin was the dominant compound in all experimental groups. Pigmentation intensity gradually decreased after shifting the light spectrum into darkness. It can be concluded that cultivation of I. rheades mycelium under the blue part of the light spectrum leads to the accumulation of styrylpyrones that have nutraceutical and medicinal significance.

Effect of Low Temperature Cultivation on the Phytochemical Profile and Bioactivity of Arctic Plants: A Case of Dracocephalum palmatum.

The influence of climatic factors, e.g., low temperature, on the phytochemical composition and bioactivity of the arctic plant Dracocephalum palmatum Steph. ax Willd. (palmate dragonhead), a traditional food and medical herb of Northern Siberia, was investigated. D. palmatum seedlings were grown in a greenhouse experiment at normal (20 °C, NT) and low (1 °C, LT) temperature levels and five groups of components that were lipophilic and hydrophilic in nature were characterized. The analyses indicated that D. palmatum under NT demonstrates high content of photosynthetic pigments, specific fatty acid (FA) profile with domination of saturated FA (53.3%) and the essential oil with trans-pinocamphone as a main component (37.9%). Phenolic compounds were identified using a combination of high performance liquid chromatography with diode array detection and electrospray ionization mass-spectrometric detection (HPLC-DAD-ESI-MS) techniques, as well as free carbohydrates and water soluble polysaccharides. For the first time, it was established that the cold acclimation of D. palmatum seedlings resulted in various changes in physiological and biochemical parameters such as membrane permeability, photosynthetic potential, membrane fluidity, leaf surface secretory function, reactive oxygen species-antioxidant balance, osmoregulator content and cell wall polymers. In brief, results showed that the adaptive strategy of D. palmatum under LT was realized on the accumulation of membrane or surface components with more fluid properties (unsaturated FA and essential oils), antioxidants (phenolic compounds and enzymes), osmoprotectants (free sugars) and cell wall components (polysaccharides). In addition, the occurrence of unusual flavonoids including two new isomeric malonyl esters of eriodictyol-7-O-glucoside was found in LT samples. Data thus obtained allow improving our understanding of ecophysiological mechanisms of cold adaptation of arctic plants.