ENDOTHELIUM-MEDIATED VASORELAXANT EFFECTS OF CHOKEBERRY (ARONIA MELANOCARPA) EXTRACT, JUICE, AND WASTE: AN EXPERIMENTAL STUDY IN ISOLATED RAT AORTA

Aronia melanocarpa (chokeberry, aronia) is rich in polyphenols and associated with vascular protective effects; however, comparative data on different aronia-derived products and their mechanisms remain limited. This study aimed to compare the vasorelaxant effects of aronia berry extract (AE), aronia waste extract (AWE), and aronia juice (AJ), and to investigate their underlying mechanisms. Preparations from organically grown berries (western Serbia) were chemically characterized using spectrophotometric methods and HPLC. Vasorelaxant activity was assessed in isolated thoracic aorta rings from Wistar rats precontracted with potassium chloride (KCl) or phenylephrine (PE). All preparations induced concentration-dependent relaxation. In KCl-precontracted rings, AE showed the greatest potency (EC₅₀ = 0.97 ± 0.02 mg/mL), followed by AJ (1.74 ± 0.08 mg/mL) and AWE (1.95 ± 0.12 mg/mL). In contrast, under PE-induced contraction, AWE exhibited the highest activity (EC₅₀ = 0.58 ± 0.07 mg/mL), followed by AJ (0.96 ± 0.06 mg/mL) and AE (1.27 ± 0.11 mg/mL). Pre-incubation with the nitric oxide synthase inhibitor L-NAME significantly attenuated relaxation responses, increasing EC₅₀ values for AWE (0.59 ± 0.03 to 2.37 ± 0.01 mg/mL), AE (0.92 ± 0.01 to 4.38 ± 0.05 mg/mL), and AJ (0.95 ± 0.02 to 2.78 ± 0.03 mg/mL) (p < 0.01), indicating a key role of endothelium-derived nitric oxide. These findings demonstrate that aronia-derived products, including processing waste, exert potent NO-mediated vasorelaxant effects and may represent promising functional ingredients for improving vascular function. Further clinical studies are warranted to confirm these effects in humans.