The demand for natural products, which are rich in biologically active compositions, grows constantly. The most useful products are the fruits that contain the complex of biologically active compositions (Yeomans, Linseisen and Wolfram, 2005). In various researches (Wang, Cao, and Prior, 1996; Zulueta, Esteve and Frígola, 2009) it is stated that the usage of fruits in the ration makes an essential contribution to the provision of the human organism with antioxidants and useful substances: carotenoids, phenolic compounds, sugars, acids, and others. Fruits and berries consumption decreases the development of chronic and heart diseases (Tzulker et al., 2007; Xu et al., 2010; Liu et al, 2010), reduces the risk of cancer and has a positive effect on comparison with chemotherapy and hormone treatment (Liu and Dong, 2008; Liu et al, 2010).

Nontraditional horticultural crops including actinidia plants play an essential role in the provision of a human organism with micronutrients. Representatives of Actinidia Lindl. species become more and more popular in the world thanks to a wide spectrum of possibilities of its fruits usage (Titlyanov, 1969; Kolbasina, 2007). The most frostresistant species of actinidia: Actinidia kolomikta (Rupr. Et Maxim.) Maxim., Actinidia. arguta (Siebold et Zucc.) Planch. ex Miq., Actinidia polygama (Siebold et Zucc.) Maxim, are of the utmost interest. They outstrip the most famous on the market species of Actinidia: Actinidia deliciosa, also known as the kiwi, in all the biochemical parameters (Kim et al., 2009; Krupa et al., 2011; Zuo et al., 2012; Lee et al, 2015; Leontowiczet al., 2016; Wang et al., 2018). The advantage of these fruits is not only in bright taste but also in the possibility of eating them with the skin in contrast with actinidia species with tomentose fruits. There are the data of the registered pharmaceutical composition from the extracts of A. arguta, A. kolomikta, and A. polygama for prophylaxis and treatment of some immune and non-allergic inflammatory diseases (Latocha, 2017).

On the territory of Russia Actinidia Lindl. species are still considered as a rare and nontraditional small-fruit crop. They are not introduced in industrial culture, but at the same time, they are some of the most perspective crops thanks to rich biochemical composition, longevity, and low maintenance of the plants (Kozak and Imamkulova 2018). Ivan Vladimirovich Michurin received the first domestic cultivars thanks to the primary introduction of lianas. Further on, Ella Ioganovna Kolbasina made an essential contribution thanks to her Actinidacea in situ and breeding studies (Kolbasina et al., 2007). At present, FSBSI FSC for Horticulture is one of the leading research centers of the Russian Federation that keeps in live conditions and breeds the samples collection of Far Eastern species of actinidia (Kozak et al., 2017; Burmenko, et al., 2018).

Despite the studies of actinidia fruits' biochemical composition, the question of the secondary metabolites content and identification get increased attention only in the last decades. However, there is no enough publicly available information about the biochemical parameters of A. polygama fruits. Local and industrial cultivars are mostly studied. The comparative data of the biochemical composition of Actinidia kolomikta and Actinidia polygama fruits, grown in the Central region of Russia, are fragmentary.

Our work aims to compare the biochemical composition of A. kolomikta and A. polygama fruits from FSBSI FSC for Horticulture genetic collection to specify the best sources with the highest biochemical potential for further breeding.

The research were held in 2019-2020 on Actinidia Lindl. experimental plantings of (Federal Horticultural Research Center for Breeding, Agrotechnology, and Nursery (FHRCBAN), Moscow region, Michnevo).

The collection was formed on argillaceous sod-podzolic hard soil. The total area of the plantation is 2 ha, it was planted on the 4 х 2 m (Figure 1).

The laboratory studies showed that the difference of SSC in the fruits of the species under study was not big. On average, SSC depended on the species and varied from 17.78% (Uzorchataya) to 20.25% (Krasna Devica) at A. polygama (Figure 2.) and from 15.97% (Prazdnichnaya) to 22.50% (Chempion) at A. kolomikta (Figure 3).

On average, the SSC value of the fruits was 19.80% at A. kolomikta and 18.64% at A. polygama.

A. kolomikta fruits samples Chempion and Sestra showed the highest values (Figure 3).

It is known that the fruits characteristic taste is determined by the ratio of the sugars and organic acids content (McBride, Johnson, 1987) that is considered to be especially useful as an index of acceptability for a lot of kinds of fruit (Esti et al., 1998). The sugar content, acidity, the content of vitamin C, and other nutrients are essential parameters to evaluate the quality and taste; high levels of SSC, TAC, and SAR often indicate the best taste of the fruits (Esti et al., 1998; Wu et al., 2003; Ivanovaet al., 2021).

Citric and Quinic acids are indicated in the fruits of several actinidia species, and their content predominates over Apple acid (Nishiyama et al., 2008).

A low concentration of acids in A. polygama fruits in combination with a rather high content of Ascorbic acid and carotenoids make them unique and indispensable in dietetic nutrition in particularly for people with hyperpeptic stomach diseases (Kozak et. al., 2018).

The content of titratable acids in the samples under study depends on the species and varies within 0.57 to 2.98% (Figure 4).

ТТА of A. kolomikta fruits was 1.75% at average that notably higher in comparison to the average TTA value of A. polygama fruits (in 2.13 times). In the fruits of A. kolomikta samples, the maximum content of ТТА was stated at Sestra and Prazdnichnaya cultivars, the minimal one – at Vinogradnaya cultivar. Among A. polygama fruits Ostropryanaya sample showed the high result on TTA (1.03%), the minimum value was stated at Uzorchataya genotype fruits (0.57%).

Antioxidant activity of water and ethanol extracts of A. kolomikta fruits is at a high level and does not show essential differences depending on extraction type. On average on A. kolomikta species in 2019-2020 АА of methanol extracts was 94.40%, АА of water ones – 94.51%. An essential difference in AA values depending on extraction type was stated at A. polygama fruits. On average AA of methanol extract was 2.5 – 3.5 times higher than water one that can be connected with quantitative differences of substances, extracted by water and methanol.

AA values of A. polygama fruits vary from 20.27% (Krasna Devica cultivar) to 33.52% (Celebnaya cultivar) at methanol extraction.

The AA values of water extraction – from minimal 7.57% at Osennyaya cultivar to maximum 11.81% at Perchik cultivar. On average on the species in 2019-2020 АА of methanol extract at A. polygama fruits was 27.40%, АА of water extract – 9.23%, that is 3.5 and 10 times lower than the values of A. kolomikta fruits relatively. On average the minimal values of АА were stated at A. polygama fruits of Krasna Devica cultivar (Table 1).

The results variability (V, %) during the studies of the fruits AA for A. kolomikta genotypes was insignificant, for A. polygama ones – for the methanol extracts of Krasna Devica sample and the methanol extracts of Osennyaya and Ostropryanaya samples fruits at an average level. For the rest genotypes, the variability of AA was essential (Table 1)

The majority of literary sources explain the essential difference of total antioxidant activity between species and samples by a high correlation of the vitamin C content and phenolic compounds thanks to the quick interaction of Ascorbic acid with DPPH.

Polyphenolic compounds, contained in fruits, vegetables, and grain crops, are secondary metabolites and are famous for their curative properties (Biglari et al., 2008; Gan and Latiff, 2011; Gong et al., 2012). Despite polyphenol's wide-spreading in plants, researchers and manufacturers of food products have started to be interested in polyphenols only in recent years. This interest is due to a wide spectrum of pharmacological properties, antimicrobial and antiinflammatory activity of polyphenols (Cai et al., 2004; Scalbert et al., 2005), and their strong effect in preventive actions to reduce various diseases associated with oxidative stress (Manach et al., 2004; Rasmussen et al., 2005; Darvesh et al., 2010).

In our studies, A. kolomikta fruit's TPC was almost 10 times (9.98) higher than the average A. Polygama species TPC. Among the studied A. kolomikta genotypes the highest TPC value in 2019-2020 was stated at Lakomka sample fruits (10.25 mg gallic acid (GEA)/1g fruit weight), the lowest one – at Vinogradnaya (7.75 mg gallic acids (GEA)/1g fruit weight). Among the studied A. polygama genotypes the best TPC results were registered at Perchik and Uzorchataya samples fruits. The essential variability of the results is characteristic for these samples as well (Tab. 1). Krasna Devica fruits showed the minimum TPC value – 0,56 mg gallic acid (GEA)/1g fruit weight.

The received results can be explained by the differences of bioactive compounds concentrations that vary depending on ecological factors such as climatic and soil conditions (Pavarini et al., 2012), and on cultivar differences as well (Kim et al., 2005; Usenik et al., 2008) and the degree of fruit ripeness (Manach et al., 2004; Pandey, Rizvi, 2009; Babou et al., 2016).

We conducted the metabolic profiles identification of fruits methanol extracts of 2 Actinidia species samples received via GC-MS analysis. In this paper, we do not give the full list of the identified secondary metabolites of the studied samples but describe three groups in detail, i.e. organic acids, fatty acids, and carbohydrates (sugars in particular).

Organic acids together with sugars are the basic soluble components of ripe fruits cause an essential influence on sourness-sugariness redounding the aroma formation (Neri, Pratella and Brigati, 2003). A lot of fruits on certain stages of ripening accumulate organic acids in their flesh. The main part of this content is one or two acids. Even though the most widely spread organic acids in fruits are Citric and Malic acids, the variety depends on the studied crop. The main part of the present acids in fruits flesh is formed from the synthesized sugars (Sweetman et al., 2009; Etienne et al., 2013). The basic acids are formed and take part in breathing processes, gluconeogenesis, fermentation till ethanol, amino acids synthesis/interconversion, and pigments synthesis (Famianiet al., 2000; Famiani et al., 2005; Famiani et al., 2007; Famiani et al.,2014; Sweetman et al., 2009; Etienne et al., 2013).

The total and an individual number of identified components in methanol extracts of the actinidia studied samples fruits is presented in Table 2. According to the data of Heatherbell (1975) Actinidia chinensis fruits contain the essential amount of Chinic acid in ripe fruits. Small amounts of Phosphoric, Ascorbic, Glucuronic, Galactouronic, Oxalic, Amber, and p-Coumaric acids can be determined as well. Wojdyło et al., (2017) identified 24 polyphenolic compounds in A. arguta fruits. Lim et al. (2006) wrote about the presence of several compounds in A. arguta fruits, i.e. Protocatechic and Caffeic acids, β- D-glucopyranoside, Esculin, Coumarin, and three flavonoids. In the paper of Ren, Han and Chung (2007) it is said about the extraction and identification of polyunsaturated fatty α-Linolic acid in A. polygama fruits. Motyleva et al., (2018) identified ten organics and three fatty acids in water extracts of actinidia fruits.

However, the number of papers on metabolomic profiling of actinidia fruits is not enough, the main problem of many authors is orientation on local cultivars. Also, there is not much data on metabolomic sugar content in actinidia fruits. In the papers of Heatherbell (1975) and Latocha (2017) it is mentioned about only several sugars, such as Glucose, Fructose, and Sucrose.

In our paper, the basic common components of actinidia fruits metabolomic profiles are: acids – Pyruvic, Lactic, Itaconic, Fumaric, Malic, Erythronic, Citric, and Erythro- Pentonic; one fatty acid – Acrylic acid, thirteen monosaccharides (four of which belong to ketoses, and nine ones – to aldose) and two disaccharides (Turanose, Sucrose). Various secondary metabolites identified in the samples of this paper are found individually and can serve as cultivar markers. Thus, for example, Erythrose is found only in Actinidia polygama fruits of Celebnaya sample, as well as Lyxoses are found only in Actinidia polygama fruits.

The fruits component composition and biochemical parameters depend not only on actinidia species, but on the sample as well. As a result of the studies it can be concluded that Chempion and Lakomka genotypes of Actinidia kolomikta, as well as Celebnaya and Uzorchataya ones of Actinidia polygama are the most perspective genotypes for breeding from the point of view of fruits qualitative properties (SSC, ТAА and TPC, metabolomics analysis of secondary metabolites). These samples are also worth noticing from the point of view of using in functional nutrition.