# Phenolic Compound Composition and Biological Activities of Fractionated Soybean Pod Extract
## 1 Introduction  
The progress of science and technology has contributed to civilizational development, and to many previously unknown threats as well. These threats include diseases caused primarily by environmental and food pollution, improper nutrition, and a fast pace of life resulting in stress. Developed and developing countries face health problems with an extensive social range, such as obesity, diabetes, cardiovascular diseases, arterial hypertension, osteoporosis, and various cancers [1, 2]. These diseases can be potentially counteracted by means of appropriate prevention, the many aspects of which are related to proper nutrition. A balanced diet is rich in certain substances and ingredients of natural origin that exert a beneficial influence on the functioning of the human organism [3]. Substances exhibiting positive properties in the treatment and prevention of civilizational diseases include polyphenic compounds. These secondary plant metabolites are ingested with foods of plant origin, and are not synthesized by animals [4]. After ingestion, phenolic compounds are digested and absorbed in the gastrointestinal tract, and the presence of their metabolites has been confirmed in blood serum [5]. The activity of phenolic compounds is related to their chemical structure. They posses one or more aromatic ring with one or morehydroxyl groups attached, with their presence and mutual location determining compound activity [6,7]. Phenolic compounds are classified based on the number and arrangement of their carbon atoms and may be divided into classes such as flavonoids, tannins, stilbenes, lignans, coumarins and phenolic acids. [8,9]. They occur in almost all anatomical parts of plants, but their type and concentration varies depending on the function performed in the plant and its species. An example of specific phenolic compounds to which phytoestrogenic properties are attributed are isoflav. These compounds, together with their derivatives, constitute a significant group of polyphenols the presence of which has been confirmed in soybean seeds [7,10]. Soybean (_Glycine max_ (L.) Merr.) is one of the main economically important crops worldwide due to its rich chemical composition, numerous health promoting properties, and multi-directional applications. Among legumes, soybean seeds constitute a valuable source of nutrients that are important to the human organism [1]. Following the WHO model, soybean seed protein is believed to be wholesome; therefore, it can be used as an animal protein substitute. It is also an excellent source of bioactive compounds offering unique health benefits, which are used in the prevention of such maladies as cardiovascular disease, obesity, type II diabetes, and hormone-dependent cancers [3,11]. For food purposes, soybean seed collected immediately before it reaches full ripeness is also used. Production of this type of soybean is linked with maintaining a considerable amount of leaves and often pods, which are generally treated as industrial waste, although they are sometimes used as animal feed or organic fertilizer [12,13]. They are a valuable source of bioactive compounds that can be used as functional additives replacing synthetic substances. Their nutraceutical value and functional properties have not yet been adequately studied, and knowledge about the active compounds of soybean pods and their potential usage remains limited. At the same time, due to the growing public awareness of the influence of foods on health, increasing attention is being paid to the development of new products with health-promoting properties or the enrichment of existing products with active ingredients. For these reasons, the present study aims to evaluate and compare the chemical composition and biological activity of fractionated extracts from soybean pods in order to determine their potential as a source of bioactive compounds.