Quercetin in Attenuation of Ischemic/Reperfusion Injury: A Review.

Ischemia/reperfusion (I/R) injury is a serious pathologic event that occurs due to restriction in blood supply to an organ, followed by hypoxia. This condition leads to enhanced levels of pro-inflammatory cytokines such as IL-6 and TNF-α, and stimulation of oxidative stress via enhancing reactive oxygen species (ROS) levels. Upon reperfusion, blood supply incz reases, but it deteriorates condition and leads to the generation of ROS, cell membrane disruption and finally, cell death. Plant derived-natural compounds are well-known due to their excellent antioxidant and anti-inflammatory activities. Quercetin is a flavonoid exclusively found in different vegetables, herbs, and fruits. This naturally occurring compound possesses different pharmacological activities making it an appropriate option in disease therapy. Quercetin can also demonstrate therapeutic effects via affecting molecular pathways such as NF-κB, PI3K/Akt and so on. In the present review, we demonstrate that quercetin administration is beneficial in ameliorating I/R injury via reducing ROS levels, inhibition of inflammation, and affecting molecular pathways such as TLR4/NF-κB, MAPK and so on. Quercetin can improve cell membrane integrity via decreasing lipid peroxidation. Apoptotic cell death is inhibited by quercetin via downregulation of Bax, and caspases, and upregulation of Bcl-2. Quercetin is able to modulate autophagy (inhibition/induction) in decreasing I/R injury. Nanoparticles have been applied for the delivery of quercetin, enhancing its bioavailability and efficacy in the alleviation of I/R injury. Noteworthy, clinical trials have also confirmed the capability of quercetin in reducing I/R injury.