**7. Phenolic compounds with wound healing properties**

Though many crude plant extracts have been scientifically demonstrated to have wound healing activities, enriched fractions and isolated compounds from some of these plants have also been shown to possess specific promising wound healing properties. The commonly known effects of the active constituents of plant extracts towards wound healing are known to be through blood clotting, antimicrobial, antioxidant, mitogenic activities and also enhanc‐ ing the expression of vascular endothelial growth factor thereby improving angiogenesis and blood flow as the tissue repair process advances [179, 186–188]. In chronic wounds, agents inducing differentiation of keratinocytes play an important role.

Plant polyphenols are among the most abundant phytochemicals present in the human diet, and they range from simple molecules such as phenolic acids to highly polymerized com‐ pounds, such as condensed tannins [189]. Several plants extracts used in wound healing contain phenolics in the form of procyanidins, flavonoids and phenolic acids [187] as their active ingredients. Tannins and procyanidins are known to actively facilitate wound healing [190].

Resveratrol is a natural polyphenol found predominantly in the skin of red grapes that has been studied extensively for its potential health benefits [191]. Resveratrol is a popular nutritional supplement and ingredient in over‐the‐counter skin care products. In humans, resveratrol was shown to protect against sun damage to the skin, enhance moisture and elasticity, reduce wrinkle depth and intensity of age spots, and protected keratinocytes from nitrous oxide‐induced death [191, 192]. Its positive effect on keratinocytes has beneficial effect on wound healing. Resveratrol administration significantly increased the tensile strength of the abdominal fascia, and increased the hydroxyproline 1 levels *in vivo*. The acute inflammation scores, collagen deposition scores and the neovascularization scores on postoperative days 7 and 14 were found to be significantly higher in the resveratrol treatment group. The amount of granulation tissue and the fibroblast maturation scores were found to be significantly higher on postoperative day 14 in the treatment group when compared to the control group [193].
