The anthocyanin content of the Hungarian sour cherry is remarkable. Nutraceutical and pharmaceutical effects of the anthocyanins and their role in disease prevention have been studied extensively. Endothelial cells are involved in the pathogenesis of several inflammatory diseases. The objective of this work was to investigate pure sour cherry extract on human umbilical cord vein endothelial cells (HUVECs) as an inflammatory model. HUVECs were treated with 100 ng/mL lipopolysaccharide (LPS) and 50 mg/mL sour cherry extract or M199 medium as control. The optimal concentration range of the sour cherry extract was investigated and selected based on MTT assay measuring the conversion of the tetrazolium salt to formazan by mitochondrial dehydrogenases. The level of interleukine-8 (IL-8), a pro-inflammatory cytokine, was measured in Luminex MagPlex assay. LPS treatment significantly increased the secretion of IL-8. The pure sour cherry extract was able to attenuate this increment indicating the potent anti-inflammatory effect of pure sour cherry extract. Our results emphasize that pure sour cherry extract could reduce the LPS-induced inflammatory response thereby may improve endothelial dysfunction.