Attenuating Effects of Viburnum cylindricum Buch.-Ham. ex D.Don Extract on LPS-Induced Inflammatory Responses via NF-κB Signaling in Macrophages

Inflammation is a pathological condition characterized by tissue damage and metabolic dysregulation, and is the cause of various inflammatory conditions. Conventional anti-inflammatory drugs have limitations because of their potential long-term adverse effects. Hence, natural product-derived bioactive compounds are emerging as promising alternatives. This study examined the anti-inflammatory effects of Viburnum cylindricum Buch.-Ham. ex D.Don extract (VCE), a traditional medicinal plant extract. VCE significantly inhibited nitric oxide production and inducible nitric oxide synthase expression induced by lipopolysaccharide (LPS) in RAW 264.7 murine macrophages. VCE suppressed the expression of pro-inflammatory cytokines, such as interleukin-6 and interleukin-1β, as well as intracellular reactive oxygen species generation. These effects were mediated by the VCE-induced downregulation of the NF-κB signaling pathway, particularly by inhibiting the phosphorylation of I kappa B kinase, I kappa B alpha, and p65. In addition, although the radical scavenging activity of VCE was lower than that of ascorbic acid, it still exhibited significant radical scavenging capacity in 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picryl-hydrazyl radicals. Therefore, VCE suppresses LPS-induced inflammatory responses and exhibits antioxidant properties, highlighting its potential as a functional food material for managing macrophage-mediated inflammation.