**5. α-Tocopherol**

α-Tocopherol is the most popular one among the antioxidants; so, numerous studies were written about the positive effects of α-tocopherol in I/R injury. It can be found on foods, and also used in cosmetic and pharmaceutical industries. It is the bioavailable component of vitamin E, and appropriate consumption is considered to help to diminish risk of many chronic diseases associated to oxidative stress [33].

It is a lipid soluble antioxidant and stabilizer of membranes, has been found to decrease myocardial I/R injury and reverse contractile dysfunction by inhibition on cellular Ca2+ accumulation and reduce lactate dehydrogenase (LDH) release [34, 35]. Hydrophilic analog of α-tocopherol called Trolox has been studied before, and beneficial effects were shown on liver I/R injury [36].

According to Franch et al. [37], the α-tocopherol was compared with control group on rat hepatic I/R injury model. The SOD after I/R period catalases after reperfusion period, and glutathione peroxidase in all periods showed lower activities than those of control group. Erkut et al. [38] came across similar results on their study too. In rabbit skeletal muscle I/R injury model, they found out superoxide dismutase, catalase, and glutathione peroxidase levels that show the cellular injury were lower in α-tocopherol group compared with control group.

### **5.1 Ascorbic acid (vitamin C)**

Vitamin C, one of the most popular vitamins we have heard in everyday life, has powerful antioxidant effects too. Because of the potential benefits, people pay attention to consume certain amount of fruits and vegetables these days. Ascorbic acid can protect the endothelium from direct injury by oxidants (such as H2O2) and prevent microvascular dysfunction. Moreover, it is proven that administration of ascorbic acid helps to decrease I/R injury [39, 40].

Because of its beneficial effects, ascorbic acid has been used in hepatic, cerebral, and renal I/R injury models in the literature [41–43] before and demonstrated positive results for end-organ protection.

#### *Antioxidants*

There are several studies related to the effect of ascorbic acid I/R injury skin flap model. Zaccaria et al. [44] demonstrated positive effects of ascorbic acid compared with control group in rat epigastric island skin flap model. They determined higher percentage of flap survival in ascorbic acid group. On the other hand, according to Yoshida and Campos [45], vitamin c and mannitol (antioxidant group) group did not prevent or reduce the necrosis area compared with control group in rat groin flap I/R injury model.
