## 1 Introduction  
One of the most numerous and ubiquitous group of plant metabolites is represented by phenolic compounds constituting an integral part of the human diet. Beside their primary potent antioxidant activity, these compounds display a wide variety of biological functions, mainly related to the intervention in all stages of cancer development including initiation, promotion, progression, invasion, and metastasis [1, 2]. Due to their phenolic content, many extracts from plants and fruits have been shown to reduce the oxidative stress-associated inflammatory diseases and cancer [3, 4, 5], and therefore it may exhibit synergy or additive biological effects due to the unique combination of polyphenols in the extracts prepared from various vegetal samples, using different extraction methods [6, 7, 8]. Anthocyanins, a group of natural pigments from the flavonoid family, are natural water-soluble compounds widely distributed in fruits and berries [9, 10]. They are responsible for the blue, red, and purple colours of many fruits, flowers, and vegetables. These polyphenic substances are glycosides of polyhydroxy- and polymethoxy-derivatives of 2-phenylbenzopyrylium or the flavylium ion [11; 12]. Anthocyanidins are known as the aglycones, being classified as 3-hydroxyanthocyanidins, 3-deoxyanthocyanidins, and O-methylated anthocyaninidins, while anthocyanins can be found as anthocyanin glycosides or acylated anthocyanins. The most common anthocyanin are Cyanidin, Delphinidin, Malvidin, Pelargonidin, Peonidin and Petunidin (Figure 1). Acylated anthocyanins were also identified in plants, being classified into acryl anthocyanins, coumaroyl anthocyanins, caffeoyl anthocyanins, and malonyl anthocyanins [13]. The literature mentions that fruit-berries (such as blackberries, raspberries, blueberries, red or black berries, and red or black grapes) are rich in anthocyanins [14], natural antioxidants which annihilate action of free radicals, combat oxidative stress, and prevent the occurrence of neuro-degenerative diseases, cardiovascular disorders, and early aging [15; 16]. Among different types of fruits, black grape skins and blackberries are distinguished for their high content in anthocyanin pigments [17; 18]. Many studies suggest potential health benefits of anthocyanins [16; 18], but also their use in industry, as natural colorants [18]. For a long period of time, researchers have been investigating the total phenolic content of different berry fruits. Previous research has indicated that the amount and composition of bioactive compounds (e.g., flavonoids, total phenolics, and acids) in blackberry were primarily determined by the genotype of the plant [19]. It was observed that wild-grown blackberry fruits contained higher levels of total phenolics and antioxidant capacity than cultivated blackberry fruits [20]. An important element that influences the biochemical composition of blackberries is determined by the environment, which includes climate parameters (such as light intensity and temperature) but also agricultural factors (such as soil characteristics and plant development stage), among others [21; 22]. It has also been shown in previous research that abiotic conditions have an impact on the quality of fruit, particularly on the useful components of different berry fruits [23]. In response to the above extrinsically conditions, the plant produces defence responses (molecular, physiochemical, physiological, and/or morphological), which include different genes activities that ultimately lead to the synthesis of secondary metabolites with antimicrobial and antioxidant properties [24]. Recently, fruits' antioxidant capacity has attracted much attention as a potentially valuable marker for determining fruit quality [25]. There is a direct relationship between antioxidant capacity and the availability of efficient oxygen radical scavengers (e.g., vitamin C and phenolic compounds), which play a key role in managing oxidative reactions in the human body and possess anti-carcinogenic properties.