[Spinach and Quinoa - Prospective Food Sources of Biologically Active Substances]

Formally, phytoadaptogens extracted mainly from medicinal plants are not food substances, and their use in preventive nutrition is significantly limited. However, screening studies can detect phytoadaptogens in food plants, however in much smaller quantities. For example, phytoecdysteroids are biologically active substances (BAS), used to relieve chronic fatigue syndrome, reduce nervous and muscle fatigue, improve memory and attention processes. Phytoecdysteroids can be isolated not only from various medicinal plants, but also from food plants like spinach (Spinacia oleracea) and quinoa (Chenopōdium quīnoa). Researchers show interest in possible synergies in the manifestation of a wide range of pharmacological effects, determined by a combination of phytoecdysteroids and other biologically active substances of these food plants. The aim of this research is a brief analytical review of publications characterizing the spectrum of minor biologically active substances of spinach and quinoa, as well as those devoted to the experimental assessment of their pharmacological activity in experiments on laboratory animals. Results. An analysis of the publications presented in the review indicates that spinach and its extracts are promising food sources of phytoadaptogens, carotenoids, phenolic compounds, in particular quercetin, kempferol, phenolic acids (p-coumaric, ferulic), as well as lignans metabolized into biologically active phytoestrogens (enterolactone and enterodiol). The possible prophylactic effect of spinach is being actively studied in vivo in laboratory animals when modeling diseases such as diabetes mellitus, cardiovascular and cancer diseases. Numerous adaptogenic effects and the neuroprotective effect of spinach and its extracts are shown, expressed in improving the memory and learning of animals. Publications of the last decade indicate an increased interest in such a promising food source of high-grade protein and a wide spectrum of biologically active substances, including phytoecdysteroids, as quinoa grains. More than 20 phenolic compounds in free or conjugated forms were found in quinoa grains; tannins, saponins, sterols, phytic acid, and ecdysteroids are present in small quantities. The consumptionof quinoa can have a beneficial effect on the organism, normalizing carbohydrate and lipid metabolism, reducing body weight and preventing excessive lipid peroxidation. The anti-inflammatory effects and antioxidant effects of quinoa are widely discussed. Conclusion. Spinach, quinoa and their extracts are promising food sources of biologically active substances, their pharmacological action is confirmed from the standpoint of evidence-based medicine by in vivo experimental studies. Accordingly, it is advisable to expand the use of these food plants for inclusion in biologically active dietary supplements, functional food ingredients and specialized food products for various purposes.

Keywords: adaptogens; biologically active substances; phytoecdysteroids; plant extracts; quinoa; spinach.