Abstract
Inflammatory responses and oxidative stress contribute to the pathogenesis of brain ischemia/reperfusion (IR) injury. Naturally occurring bioflavonoids possess antioxidant and anti-inflammatory properties. The phytochemicals of Juniperus sabina L., known as "Abhal" in Saudi Arabia, have been studied and cupressuflavone (CUP) has been isolated as the major bioflavonoid. This study aimed to investigate the neuroprotective potential of CUP in reducing brain IR damage in rats and to understand probable mechanisms. After 60 min of inducing cerebral ischemia by closing the left common carotid artery (CCA), blood flow was restored to allow reperfusion. The same surgical procedure was performed on sham-operated control rats, excluding cerebral IR. CUP or vehicle was given orally to rats for 3 days prior to ischemia induction and for a further 3 days following reperfusion. Based on the findings of this study, compared to the IR control group, CUP-administered group demonstrated reduced neurological deficits, improved motor coordination, balance, and locomotor activity. Additionally, brain homogenates of IR rats showed a decrease in malondialdehyde (MDA) level, an increase in reduced glutathione (GSH) content, and an increase in catalase (CAT) enzyme activity following CUP treatment. CUP suppressed neuro-inflammation via reducing serum inflammatory cytokine levels, particularly those of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) and enhancing the inflammatory cytokine levels, such as Nuclear factor kappa- B (NF-κB), TANK-binding kinase-1 (TBK1), and interferon beta (IFN-β) in brain tissues. Furthermore, CUP ameliorated the histological alterations in the brain tissues of IR rats. CUP significantly suppressed caspase-3 expression and downregulated the Toll-like receptor 4 (TLR4)/NF-κB signaling pathway as a result of suppressing High mobility group box 1 (HMGB1). To our knowledge, this is the first study to document the neuroprotective properties of CUP. Thus, the study findings revealed that CUP ameliorates IR-induced cerebral injury possibly by enhancing brain antioxidant contents, reducing serum inflammatory cytokine levels, potentiating the brain contents of TBK1 and IFN-β and suppressing the HMGB1/TLR-4 signaling pathway. Hence, CUP may serve as a potential preventive and therapeutic alternative for cerebral stroke.