Anti-cytokine Storm Activity of Fraxin, Quercetin, and their Combination on Lipopolysaccharide-Induced Cytokine Storm in Mice: Implications in COVID-19.

Background: Cytokine release syndrome (CRS) is the leading cause of mortality in advanced stages of coronavirus patients. This study examined the prophylactic effects of fraxin, quercetin, and a combination of fraxin+quercetin (FQ) on lipopolysaccharide-induced mice. Methods: Sixty mice were divided into six groups (n=10) as follows: control, LPS only, fraxin (120 mg/Kg), quercetin (100 mg/Kg), dexamethasone (5 mg/Kg), and FQ. All treatments were administered intraperitoneally (IP) one hour before induction by LPS (5 mg/Kg) IP injection. Twenty-four hours later, the mice were euthanized. Interleukin one beta (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were quantified using an enzyme-linked immunosorbent assay (ELISA), and lung and kidney tissues were examined for histopathological alterations. This study was conducted at Al-Nahrain University, Baghdad, Iraq, in 2022. Results: FQ reduced IL-1β (P<0.001). All treatments significantly suppressed IL-6, fraxin, quercetin, dexamethasone, and FQ, all with P<0.001. The TNF-α level was reduced more with dexamethasone (P<0.001) and quercetin (P<0.001). Histopathological scores were significantly reduced mainly by quercetin and FQ in the lungs with scores of 12.30±0.20 (P=0.093), and 15.70±0.20 (P=0.531), respectively. The scores were 13±0.26 (P=0.074) and 15±0.26 (P=0.222) for quercetin and FQ in the kidneys, respectively. Conclusion: All used treatments reduced proinflammatory cytokine levels and protected against LPS-induced tissue damage.