The protective effects of silymarin on ischemia-reperfusion injuries: A mechanistic review

Ischemia-reperfusion injuries (IRI) occur in different clinical conditions such as stroke, trauma, organ transplantation, and so on. Ischemia damages mainly arise from oxygen depletion in tissues. The lack of oxygen as the last acceptor of electron in the respiratory chain causes a decrease in ATP production and eventually leads to disruption of membrane transport, acidosis, cellular edema and membrane distortion of organelles, and cells. Reperfusion can intensify ischemic injuries by the infiltration of inflammatory cells and also oxygen and calcium overloading. Since the tissue antioxidant contents decreased due to increased generation of reactive oxygen species (ROS) during IRI, the application of antioxidants is considered an appropriate strategy to ameliorate IRI. Silymarin constitutes about 70-80% of silybum marianum dry extract and is known as a strong free radical scavenger with anti-inflammatory properties. In several studies, silibinin as a major component of Silymarin could provide protective effects in various tissue IRI by different mechanisms such as scavenging free radicals, decreasing inflammatory cytokines, inhibiting cellular death, and increasing the expression of antioxidant enzymes. To clarify functional mechanisms, the present article evaluates studies about silymarin effects in different tissues IRI.