Effect of Usnea longisima Ethyl Acetate Extract on Staphylococcus aureus-Induced Experimental Rhinosinusitis in Rats

SUMMARY. The role of oxidant and proinflammatory cytokines in the pathogenesis of rhinosinusitis induced by Staphylococcus aureus has been demonstrated in studies. Usnea longissima ethyl acetate extract (ULE) was obtained from this lichen species. ULE is known to have antibacterial, antioxidant and anti-inflammatory effects. The objective of the study is to investigate the effect of ULE on S. aureus-induced experimental rhinosinusity in rats and compare it with cefazolin. Anesthesia was created through virtue of intraperitoneal injection of 25 mg/kg thiopental sodium to male albino Wistar rats. Then the rats were divided into groups as healthy (HG), ones inoculated with S. aureus (RSG) to their nostril, ones inoculated with S. aureus to their nostril + ULE (REA) applied and ones with S. aureus inoculated to their nostril + cefazolin (RCG) applied. Our biochemical test results revealed the fact that ULE was able to inhibit inflammatory mediators such as nuclear factor kappa B (NF-κB), tumor necrosis factor alpha (TNF-α), an interleukin 1 beta (IL-1β) and cyclooxygenase-2 (COX-2) increase with S. aureus in sinonasal tissue better than cefazolin. Moreover, while ULE significantly suppressed the increase in the amount of malondialdehyde (MDA), the oxidant parameter in the sinonasal tissue, and the decrease in the antioxidant total glutathione (tGSH) and cyclooxygenase-1 (COX-1), cefazolin could not. ULE and cefazolin were observed to be effective on standard bacteria. From our experimental results, it is understood that ULE prevents oxidative and inflammatory damage induced by S. aureus in the sinonasal tissue better than cefazolin. © 2022, Colegio de Farmaceuticos de la Provincia de Buenos Aires. All rights reserved.