Antioxidant and Protective Effects of the Polyphenolic Glycoconjugate from Agrimonia eupatoria L. Herb in the Prevention of Inflammation in Human Cells

Herein, structural and biological studies of a complex biopolymer (polyphenolic glycoconjugate) isolated from the flowering parts of Agrimonia eupatoria L. (AE) are presented. Spectroscopic analyses (UV–Vis and 1H NMR) of the aglycone component of AE confirmed that it consists mainly of aromatic and aliphatic structures characteristic of polyphenols. AE showed significant free radical elimination activity, i.e., ABTS+ and DPPH·, and was an effective copper reducing agent in the CUPRAC test, eventually proving that AE is a powerful antioxidant. AE was nontoxic to human lung adenocarcinoma cells (A549) and mouse fibroblasts (L929) and was nongenotoxic to S. typhimurium bacterial strains TA98 and TA100. Moreover, AE did not induce the release of proinflammatory cytokines such as interleukin 6 (IL-6) and tumor necrosis factor (TNF-α) by human pulmonary vein (HPVE-26) endothelial cells or human peripheral blood mononuclear cells (PBMCs). These findings correlated with the low activation of the transcription factor NF-κB in these cells, which plays an important role in the regulation of the expression of genes responsible for inflammatory mediator synthesis. The AE properties described here suggest that it may be useful for protecting cells from the adverse consequences of oxidative stress and could be valuable as a biomaterial for surface functionalization.