# Proximate Composition and Antioxidant Activity of Selected Morphological Parts of Herbs
## 1 Introduction  
In recent years, the interest in antioxidants derived from herbal raw materials has increased significantly due to their health-promoting properties. Their preventive effect is appreciated in the context of chronic non-communicable diseases such as obesity, type II diabetes, atherosclerosis or neurodegenerative diseases, the common risk factor of which is oxidative stress [1]. In biological systems, the formation of free radicals is the result of many metabolic changes, including aerobic respiration and inflammatory reactions. Free radicals have proven useful in the fight against pathogens. This is due to their bacteriostatic and bactericidal effects, but they are also capable of removing cancer cells [2]. Free radicals are responsible for controlling blood flow through blood vessels, removal of xenobiotics from the body, and they are also responsible for transmitting signals within the cell [3; 4; 5]. Under normal conditions, there is a balance between the formation of free radicals and their removal. However, in conditions of disturbed homeostasis, the amount of free radicals increases, beyond the possibility of their systematic and efficient removal by enzymatic and non-enzymatic mechanisms [5]. During aerobic respiration, some of the electrons leavethe complexes of the respiratory chain, reducing the oxygen molecule by a one-electron or two-electron redox reaction, which leads to the formation of reactive oxygen species (ROS) [6; 7]. This causes disturbances at the metabolic level due to high reactivity, short lifetime and extraordinary ease of chemical reactions of free oxygen radicals with cell components [5; 7]. Enzymatic systems located in the mitochondrial matrix and cytoplasm, i.e., superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPx), catalase (CAT) are responsible for the removal of these compounds [5; 8]. Apart from enzyme systems, there are also defense systems based on proteins located in the blood plasma (ceruloplasmin, ferritin, transferrin, or albumin) that remotely bind copper and iron ions, preventing free radical reactions. These proteins interact with uric acid, complementing each others antioxidant potential [8]. Non-enzymatic defense mechanisms against free radicals are some vitamins (C, E, A, including provitamin A-\(\beta\)-carotene), coenzyme Q10 or polyphenic compounds found in plants [9]. The excess of free radicals, including reactive oxygen species, together with the inefficiency in their removal, leads to lipid peroxidation, damage to cell organelles, proteins, and DNA degradation and mutation, which results in chronic non-communicable diseases [10]. The main antioxidant compounds present in plant products are polyphenic compounds, including flavonoids [11]. Antioxidant compounds contained in herbs have following effects: anti-inflammation, antibacterial, antifungal, antiviral and immunostimulation effects [12]. Their effect cannot be reproduced on the basis of individually isolated antioxidant compounds, because the health benefiting effect includes many compounds simultaneously appearing in the plant [13]. Herbal raw materials, long known in traditional folk medicine, are mostly well-tested in terms of antioxidant properties, but there are still raw materials that have not been widely distributed in the phytotherapeutic and pharmaceutical industries [14]. Such raw materials may turn out to be new nutraceuticals, helping pharmacological substances (medicines) in the fight against common diseases. Adequate dietary intake of a variety of antioxidants, such as polyphenols, vitamin C, vitamin E, carotenoids and selenium, is associated with a lower risk of developing chronic non-communicable diseases [14; 15]. Increasing amount of research results suggest that antioxidants affecting cells may also trigger interactions with specific proteins crucial for intracellular signaling cascades, modulating their expression and activity [15]. These compounds also affect epigenetic mechanisms and modulate the intestinal microbiota [16].