Phenolic Compounds in Berries of Winter-Resistant Actinidia arguta Miq. and Actinidia kolomikta Maxim.: Evidence of Antioxidative Activity

Abstract

Variations between fruit cultivars can significantly impact their biochemical composition. The present research examined the variability in the qualitative and quantitative content of phenolic compounds in berry extracts of Actinidia kolomikta and Actinidia arguta cultivars. Additionally, antioxidant activities of berry extracts were evaluated. The total phenolic, flavonoid, proanthocyanidin contents and hydroxycinnamic acid derivatives were determined using the appropriate methodologies. The average amount of phenolic compounds in A. kolomikta berries (177.80 mg/g) was three times higher than that of A. arguta (54.45 mg/g). Our findings revealed that berries of A. kolomikta and A. arguta accumulated, on average, 1.58 RE/g DW (rutin equivalent/g dry weight) and 0.615 mg RE/g DW of total flavonoids, 1439.31 mg EE/g DW (epicatechin equivalent/g dry weight) and 439.97 mg EE/g DW of proanthocyanidins, and 23.51 mg CAE/g DW (chlorogenic acid equivalent/g dry weight) and 5.65 mg CAE/g DW of hydroxycinnamic acid derivatives, respectively. The cultivars of both species were characterized by higher antioxidant activity of total phenolic compounds determined using CUPRAC and FRAP methods compared to the ABTS^•+ method. The variability in phenolic compounds' qualitative and quantitative content in tested berry extracts was evaluated by applying ultra-high performance liquid chromatography (UHPLC) coupled to mass spectrometry in tandem with electrospray ionization. Significant intraspecific differences in the amounts of total phenolic compounds, total flavonoid compounds, proanthocyanidins, and hydroxycinnamic acid derivatives were determined among cultivars. Four phenolic acids, eight flavonols, two flavones, and five flavon-3-ols were identified in the berry extracts.

Keywords: cultivars; flavan-3-nols; flavones; hydroxycinnamic acid; procyanidins.

Figure 1

Morphological variability of Actinidia kolomikta (Maxim.) (A–E) and Actinidia arguta (Miq.) (F–J) cultivars. Cultivars: (A)—‘Aromatnaja’, (B)—‘Milema’, (C)—‘Matovaja’, (D)—‘Sentiabrskaja’, (E)—‘VIR-2’, (F)—‘Kijivskaja Krupnoplidna’, (G)—‘Figurna’, (H)—‘Purpurova Sadova’, (I)—‘Izumrudna’, (J)—‘Kijivskaja Hibridna’.

Figure 2

Content of total phenolics (a), proanthocyanidins (b), total flavonoids (c), and hydroxycinnamic acid derivatives (d) in berries of A. kolomikta and A. arguta. Data were expressed as mean ± standard deviation (SD) (n = 3). The differences were considered statistically significant at p < 0.05.

Figure 2

Content of total phenolics (a), proanthocyanidins (b), total flavonoids (c), and hydroxycinnamic acid derivatives (d) in berries of A. kolomikta and A. arguta. Data were expressed as mean ± standard deviation (SD) (n = 3). The differences were considered statistically significant at p < 0.05.

Figure 3

Antioxidant activity of different cultivars of A. kolomikta and A. arguta berries. Data were expressed as mean ± standard deviation (SD) (n = 3). Significant differences between cultivars of berries were tested, according to Duncan’s least significant difference (LSD) procedure, at the 1% significance level.

Figure 4

Cultivar arrangement describing (a) TPC (mg GAE/g DW) and CUPRAC (µmol TE/g DW) reducing activity, (b) TPC (mg GAE/g DW) and FRAP (µmol TE/g DW) reducing activity and (c) TPC (mg GAE/g DW) and ABTS (µmol TE/g DW) antiradical activity of A. kolomikta and A. arguta cultivars.

Figure 5

Correlation coefficients between tested bioactivities and functional constituents (a) A. arguta; (b) A. kolomikta. Pearson’s correlation was performed by using the average values of each variable (p < 0.05).