Protective effect of black raspberry seed containing anthocyanins against oxidative damage to DNA, protein, and lipid

Abstract

This study aimed to determine bioactive components and radical scavenging capacity of black raspberry seed extracts as byproducts obtaining during the juice (FSE) and wine (WSE) making process. Cyanidin-3-O-rutinoside was identified as a major anthocyanin and the total anthocyanin contents of fresh and wine seed were 78.24 and 41.61 mg/100 g of dry weight, respectively. The total phenolic and flavonoid contents of FSE and WSE were 2.31 g gallic acid equivalent (GAE) and 360.95 mg catechin equivalent (CE), and 2.44 g GAE and 379.54 mg CE per 100 g dry weight, respectively. The oxygen radical absorbance capacity (ORAC) values were 1041.9 μM TE/g for FSE and 1060.4 μM TE/g for WSE. Pretreatment of the FSE and WSE inhibited the generation of intracellular reactive oxygen species (ROS), DNA and protein damage induced by hydroxyl radicals, and Fe(3+)/ascorbic acid-induced lipid peroxidation in a dose dependent manner. WSE more effectively protected from oxidative damage than FSE. Results from the current study suggest that black raspberry seeds as byproducts from juice and wine processing could be potential sources for natural antioxidants.

Keywords: Antioxidants; Black raspberry seeds; Byproducts; Juice and winemaking; Rubus coreanus Miq.; Seed extract.

Fig. 1

HPLC chromatograms of anthocyanin standards (STD), fresh seed (FS), and wine seed (WS) at 520 nm. Peak #1, cyanidin-3-glucoside; #2, cyanidin-3-rutinoside; #3, peonidin-3-glucoside; #4, malvidin-3-gucoside

Fig. 2

ORAC values corresponding to different concentrations of ethanolic extracts of fresh seed (FSE) and wine seed (WSE). Different letters above bars indicate significant differences between concentratons (p < 0.05)

Fig. 3

Inhibitory effect of fresh seed extract (FSE) and wine seed extract (WSE) against intracellular reactive oxygen species generation in HepG2 cells as measured by DCFH-DA assay. HepG2 cells were labeled with DCFH-DA and treated with different concentrations of FSE and WSE (a) and treated with same concentration (100 μg/mL) of FSE and WSE (b). Fluorescence intensities of DCF due to oxidation of DCFH by cellular ROS generated by H₂O₂ were detected after 2 h (Ex = 485 nm and Em = 535 nm). Different letters above bars indicates significant different from control

Fig. 4

Agarose gel electrophoretic patterns of plasmid DNA breaks by ·OH generated from a Fenton reaction in the presence of ethanolic extracts of fresh seed (FSE) and wine seed (WSE). An amount of 0.5 μL of pBR 322 DNA was incubated 37 °C for 30 min in FeSO₄ and 30 % H₂O₂ with the following additive combinations. Line 1, no addition (plasmid DNA); Line 2, FeSO₄ and 30 % H₂O₂ (DNA damage control); Line 3–6, FeSO₄ and 30 % H₂O₂ in the presence of FS and WS with concentrations of 50, 100, 500, and 1000 μg/mL, respectively

Fig. 5

Protective effect of BSA oxidative damage treated with Fe³⁺/H₂O₂ system in the presence of fresh seed extract (FSE) and wine seed extract (WSE). The densitometry analysis of protective effects at different concentrations of BHT (positive control) and seed extracts on protein. Relative band intensity was calculated % of control

Fig. 6

Inhibitory effect of ethanolic extracts of fresh seed (FSE) and wine seed (WSE) on lipid peroxidation. Trolox was used as a positive control. Each value is expressed as the mean (n = 3)