Juniperus communis L. Needle Extract Modulates Oxidative and Inflammatory Pathways in an Experimental Model of Acute Inflammation

Juniperus communis L. is a conifer widely used in traditional European medicine for the management of inflammatory disorders. However, its effects on oxidative stress and inflammation remain incompletely characterized. The present study investigated the antioxidant and anti-inflammatory potential of an ethanolic needle extract of J. communis using in vitro assays and an in vivo model of acute inflammation induced by turpentine oil in rats. Phytochemical profiling by HPLC–DAD–ESI–MS revealed a polyphenol-rich extract dominated by flavonols, flavanols, and hydroxybenzoic acids, with quercetin derivatives and taxifolin as major constituents. In vitro analyses demonstrated radical-scavenging and reducing capacities, exceeding or comparable to reference antioxidants in DPPH, hydrogen peroxide, ferric-reducing, and nitric oxide scavenging assays. In vivo, both therapeutic and prophylactic administration of the extract significantly attenuated oxidative and nitrosative stress, as evidenced by reductions in total oxidant status, oxidative stress index, malondialdehyde, advanced oxidation protein products, nitric oxide, 3-nitrotyrosine, and 8-hydroxy-2′-deoxyguanosine, alongside restoration of total antioxidant capacity and thiol levels. These effects were concentration-dependent. Concomitantly, inflammatory signaling was suppressed, with decreased NF-κB activity and reduced levels of interleukin-1β and interleukin-18. These results support the use of these extracts, whose benefits have been observed in traditional medicine, providing scientific support for the anti-inflammatory and antioxidant capacity of J. communis extract.