# Functional Properties of Fruits of Common Medlar (_Mespilus germanica_ L.) Extract
## 1 Introduction  
Common medlar (_Mespilus germanica_ [PERSON]) is a long-lived plant, belonging to the family Rosaceae. It occurs naturally in Central Asia, Lesser Asia, and the Caucasus. _Mespilus germanica_ was cultivated as early as 3000 years ago in the Mediterranean countries. Subsequently, the plant also became acclimitated to France, Germany, and England. Nowadays, it is found in parks and gardens in southern and western Europe (Figure 1).  
The fruits of medlar have brown-reddish color and they are 1.5-3 cm in diameter; the small ones have a weight of 10-80 g [1]. The hard fruits are harvested in the fall and stored in cold and dark places. Since ancient times, plants have been valued for their healing properties. Today, natural plant-based products with health-promoting effects are used as alternatives to synthetic and chemical medicines. Leaves, fruits, bark, and medlar wood have been used for therapeutic purposes [2]. Extract from the bark of the common medlar tree has found use as a diuretic and has also been used to treat colon infections, diarrhoea, and internal haemorrhage [3]. The leaves, bark, and unripe fruits contain high levels of tannins, which is why they have been used for tanning leather and clarifying wines. The wood is considered to be heavy, hard, and quite pliable, so it has been used to make fishing rods, knives, and tools. The researchers confirmed that thefruit of medlar contains natural antioxidants that can prevent cancer [4]. Moreover, in comparison with other fruits, they have a lot of minerals, and they are low in sugars and high in vitamins. It is generally known that a diet rich in fresh fruit and vegetables is known to be beneficial to human health [5; 6]. Berries, in particular, which are rich in polyphenolic compounds, are known to be a source of antioxidants that may reduce the risk of cardiovascular disease and some forms of cancer [7; 8; 9]. Underutilized fruits are consumed because of their flavor and their health benefits related to their bioactive compounds [10; 11; 12]. An example of this kind of fruit is the common medlar [4]. Due to the increasing demand for natural antioxidant compounds, research into new potential sources of these compounds is justified. Common medlar is a rich source of polyphenolic compounds, particularly phenolic acids [13]. They are valuable components that are widely found in daily foods such as fruits, vegetables, cereals, legumes and wine [14; 15; 16], and show strong antioxidant [17; 18], anti-allergic [19], anti-inflammatory [20], antibacterial [21], antiviral [22] and immunizing properties [23]. In addition, they influence the sensory characteristics of food products, and their quantitative and qualitative composition also determines the sensory quality of fresh fruit and vegetables [24]. Polyphenols, especially flavonoids and phenolic acids, are capable of inhibiting \(\alpha\)-glucosidase and \(\alpha\)-amylase in the carbohydrate metabolism. They can be used to produce nutraceuticals and formulations, used during diabetes treatment [25]. Current antidiabetic therapies are based on synthetic drugs, which often cause side effects [26]. It is widely recognized that diet plays an important role in the management of diabetes [27; 28; 29].  
The medlar fruit (_Mespilus germanica_ L.) has gained commercial importance in recent years, attracting research into its chemical composition. The objective of this study was to examine the antioxidant and antidiabetic activity (in vitro) of medlar fruit extract concentrated in the ion exchange resin.