Effects of Aronia melanocarpa Tannins on Oxidative Stress and Immune Dysfunction

Natural polyphenols, particularly tannins, are of interest due to their complex composition and multi-target biological activities. A highly purified tannin fraction was isolated from <i>Aronia melanocarpa</i> fruits, and its composition was characterized by HPLC-MS and IR spectroscopy. The Aronia tannin fraction exhibited comprehensive antioxidant properties, demonstrating superior DPPH radical scavenging activity compared to quercetin and a membrane-protective effect exceeding reference antioxidants. In vivo, Aronia tannins showed a delayed but potent antioxidant effect against cyclophosphamide (CP)-induced oxidative stress, significantly reducing malondialdehyde (MDA) levels, with the maximum effect observed at days 14-21. The immunomodulatory effect involved a complex regulation of the phagocytic system: selective activation of the monocytic arm with simultaneous modulation of neutrophilic activity. Crucially, a high phagocytic completion rate was maintained, indicating support for both bacterial uptake and intracellular killing. Tannins accelerated recovery post-CP, restoring leukocyte and platelet counts. Modulation of neutrophil oxidative metabolism, measured by chemiluminescence, indicates an ability to balance defense activation with prevention of excessive oxidative stress. These findings confirm the potential of the <i>Aronia melanocarpa</i> tannin fraction for correcting oxidative stress and immune dysfunction.