Diseases associated with metabolic disorders seem to affect more and more people worldwide. Biologically active supplements may prevent or relieve metabolic disorders. Quercetin is known for its potential to inhibit metabolic syndrome. This paper introduces an in vivo experiment on rodents. It featured hypoglycemic, hypocholesterolemic, and hepatotoxic properties of quercetin. Quercetin was obtained from the hairy root extract of Hedysarum neglectum Ledeb. Two doses (50 and 100 mg/kg) were used to evaluate its hypoglycemic potential. Rats with induced diabetes were tested for body weight, glucose, and cholesterol while mice with induced hypercholesterolemia were checked for blood cholesterol changes. Potential biochemical and pathological changes in the liver were also studied on rats. Quercetin treatment caused neither significant health problems nor death in the model animals. It had no effect on body weight, even in the animals with induced diabetes. In addition, quercetin did not increase glucose and cholesterol in the blood and triggered no pathological changes in the liver. Quercetin isolated from H. neglectum hairy root extract demonstrated no hepatotoxicity. Unfortunately, it showed no beneficial effect on cholesterol and glucose levels and had no efficacy against metabolic syndrome. Further research is needed to assess the effect of quercetin on other metabolic markers, e.g., genes associated with the metabolism of lipids, carbohydrates, etc.

Functional products containing natural antioxidants contribute to the improvement of human health indicators, and thus contribute to an increase in life expectancy. Milk is a valuable solubilizer that promotes the dissolution of insoluble substances in a liquid. The paper presents the results of a study under conditions of high-performance liquid chromatography (HPLC) with amperometric detection of antioxidant properties of secondary plant metabolites for the enrichment of dairy products. The objects of the study were biologically active compounds isolated from extracts of callus cultures of plants grown in vitro on liquid nutrient media. The use of HPLC chromatography with an amperometric glass-carbon detector to analyze the antioxidant properties of biologically active substances of plant origin made it possible to identify the following substances from 8 types of individual compounds with a pronounced potential for biological activity: rutin, rosemary acid from Pulmonaria officinalis, trans-cinnamic acid from Scutellaria baicalensis, rutin from Filipéndula ulmária. These compounds are able to effectively inhibit free radical processes in dairy products. The use of high-performance liquid chromatography with amperometric detection can be used as a criterion for evaluating the antioxidant properties of biologically active substances isolated from extracts of callus cultures.

Scutellaria baicalensis is a popular traditional plant in Chinese medicine. Widely distributed biologically active substances of Scutellaria baicalensis are flavonoids (baicalin, baicalein, vogonin and vogonoside), which are responsible for the antitumor activity. Their antitumor effect is due to the absorption of oxidative radicals, the weakening of the activity of NF-kB (nuclear factor-kB), the suppression of the expression of the COX-2 gene and the regulation of the cell cycle. In addition, baicalein, baicalin, and vogonin showed strong antioxidant activity. The root culture in vitro of the medicinal plant Scutellaria baicalensis is characterized by intensive growth. The growth index at the end of the cultivation cycle was 40. The growth curve has a standard S-shape, with pronounced growth phases. The stationary phase was observed from 5-7 weeks of cultivation. The root culture growth index was 22.

Plant metabolites undergo a thorough toxicity test before becoming part of pharmaceuticals or functional food products. In vivo toxicity studies on animals are expensive and time-consuming. Moreover, they require an ethic approval and a lot of expendables. Alternative methods often involve microbial models. As a result, they reduce the number of animal test subjects on further research stages. This study tested the toxicity of several plant metabolites in vitro on Aliivibrio fischeri and gastrointestinal microbiota. The research included rutin, rosmarinic acid, trans-cinnamic acid, quercetin, kaempferol, baicalin, and wogonin (≥ 94%). These plant metabolites were isolated from callus, suspension, and root cultures of Siberian plants. Their toxic effects were tested on the bioluminescent properties of Aliivibrio fischeri. The analysis relied on the method of thin-layer chromatography. Another experiment assessed the toxic effects of these plant metabolites on Propionibacterium jensenii (B-6085), Propionibacterium freudenreichii (B-11921), Lactobacillus freudenreichii subsp. freudenreichii (B-6561), Lactobacillus plantarum (B-884), Bifidobacterium longum (AC-1257), and Bifidobacterium bifidum (AC-1779). The solutions of rutin, quercetin, wogonin, and baicalin (20% ethanol) were toxic towards A. fischeri. Kaempferol was the only metabolite that stimulated the biomass growth of lacto- and bifidobacteria. Quercetin, rutin, and trans-cinnamic acid inhibited the biomass growth of propionic bacteria. The other metabolites suppressed the negative impact of 20% ethanol without affecting the growth of the test strains. A. fischeri tests proved to be a reliable preliminary toxicity assessment of plant materials before in-vivo studies.

Extraction is the initial stage in the study of the chemical composition of plant material. Crude extracts contain bioactive components that can be used in pharmaceuticals, food products, and food additives. Advanced extraction methods produce more yield and consume less time. The choice of a perfect extraction method depends on the target substance, the type of plant material, and its cell structure. Optimal extraction conditions are determined experimentally for each plant species. In this research, we revealed the main extraction factors for cell cultures of medicinal plants, depending on the technological limitations caused by the internal structure of the raw material. The bioactive extraction procedure was optimized using the experimental planning method. The study featured cell cultures of Ginkgo biloba L., Pulmonaria officinalis L., Filipendula ulmaria L., and Scutellaria baicalensis Georgi. The variables to be studied during the extraction experiments included ethyl concentration, temperature, and time. All the extracts were tested for optical density using spectrophotometry, with a full factorial experiment with three variable parameters. The data obtained underwent the analysis of variance (ANOVA) to check the mathematical model that defined the correlation between the flavonoid yield and the main extraction parameters. Using the experimental planning method, we optimized the main factors that facilitated the extraction of bioactive compounds from medicinal plant cell cultures. The volume fraction of the solvent proved to be associated with the largest yield of bioactive compounds from the plant cell cultures. Its optimal amount was the same across the samples (70% ethyl alcohol). The optimal extraction time and temperature for callus cultures of Filipendula ulmaria L. and Scutellaria baicalensis Georgi were 5 h and 35°C, respectively. The callus cultures of Pulmonaria officinalis L. demonstrated the most economically advantageous extraction parameters, i.e., 2 h and 30°C. The optimal extraction parameters for Ginkgo biloba L. were 6 h and 55°C. The study revealed the optimal parameters for the extraction of bioactive compounds from medicinal plant cell cultures with the maximal flavonoid yield. The results be used in further research.