Antioxidant interactions and mechanisms of anthocyanins and carotenoids dual targeting of ROS production and NF-κB signaling pathways

The objectives of this study were to evaluate the antioxidant interactions and underlying mechanisms of the combinations of purple carrot anthocyanins extracts (PCAE) and red papaya carotenoids extracts (RPCE) using tert-butyl hydrogen peroxide (TBHP)-induced human umbilical vein endothelial cells (HUVEC). The results revealed that cyanidin-3-xylosyl (feruloyl glucosyl) galactoside (731.65±2.66 μg/mg) and lycopene (787.50±5.73 μg/mg) were the dominant anthocyanins and carotenoids in purple carrot and papaya, respectively. Cellular antioxidant assays, including cellular antioxidant activity (CAA) and antioxidant enzymes expression, reactive oxygen species (ROS) and malondialdehyde (MDA) levels, showed that in the combinations which contained more hydrophilic PCAE, the combinations would tend to show synergistic effects. When RPCE were in the majority, the combinations would tend to show antagonistic effects. Reverse transcriptase-PCR and western blot analysis revealed the underlying mechanisms of synergistic/antagonistic antioxidant interactions were that they significantly inhibited intracellular ROS generation, exhibiting either synergistic/antagonistic effects on reducing mitochondrial ROS levels, restoring the mitochondrial membrane potential, and inhibiting the activity of the nicotinamide adenine dinucleotide phosphate oxidase 4. Meanwhile, they also reduced cellular ROS level via inhibition of the nuclear factor kappa-light-chain-enhancer of activated B (NF-κB) signaling pathway, to elevate the activities of antioxidant enzymes based on HUVEC cell model. The synergistic/antagonistic antioxidant effects of phytochemical combinations supported their potential as functional food ingredients for cardiovascular diseases prevention.