Oxidative stress in normal and impaired wound repair

Wound healing is a complex process of recovering the forms and functions of injured tissues. The process is tightly regulated by multiple growth factors and cytokines released at the wound site. Any alterations that disrupt the healing processes would worsen the tissue damage and prolong repair process. Various conditions may contribute to impaired wound healing, including infections, underlying diseases and medications. Numerous studies on the potential of natural products with anti-inflammatory, antioxidant, antibacterial and pro-collagen synthesis properties as wound healing agents have been performed. Their medicinal properties can be contributed by the content of bioactive phytochemical constituents such as alkaloids, essential oils, flavonoids, tannins, saponins, and phenolic compounds in the natural products. This review highlights the in vitro, in vivo and clinical studies on wound healing promotions by the selected natural products and the mechanisms involved.

https://www.mdpi.com/1660-4601/15/11/2360/pdf

Wound Healing Properties of Selected Natural Products.

Many facets of wound healing under redox control require a delicate balance between oxidative stress and antioxidants. While the normal physiology of wound healing depends on low levels of reactive oxygen species and oxidative stress, an overexposure to oxidative stress leads to impaired wound healing. Antioxidants are postulated to help control wound oxidative stress and thereby accelerate wound healing. Many antioxidants are available over the counter or by prescription, but only one, Medihoney®, has been specifically FDA approved for wound healing. Here we review the existing evidence for the use of antioxidants for wound healing, with a review of the pertinent animal and clinical studies. Natural products and naturally derived antioxidants are becoming more popular, and we specifically review the evidence for the use of naturally derived antioxidants in wound healing. Antioxidant therapy for wound healing is promising, but only few animal studies and even fewer clinical studies are available. Because only few products have undergone FDA approval, the consumer is advised to scrutinize them for purity and contaminants prior to use, and this may require direct contact with the companies that sell them. As a field of science, the use of antioxidants for wound healing is in its infancy, and future studies will better elucidate the role of antioxidants in wound healing.

Antioxidant therapies for wound healing: a clinical guide to currently commercially available products.

Plantain banana (M. sapientum var. paradisiaca, MS) has been shown to possess ulcer healing activity. The present work with plantain banana was undertaken with the premise that the drug promoting ulcer healing could have effect on wound healing also. Wound healing activity of MS was studied in terms of (i) percent wound contraction, epithelization period and scar area; (ii) wound breaking strength and (iii) on granulation tissue antioxidant status [estimation of superoxide dismutase (SOD) and reduced glutathione (GSH), free radical (lipid peroxidation, an indicator of tissue damage) and connective tissue formation and maturation (hexuronic acid, hydroxyproline and hexosamine levels)] in excision, incision and dead space wound models respectively. The rats were given graded doses (50-200 mg/kg/day) of aqueous (MSW) and methanolic (MSE) extracts of MS orally for a period of 10-21 days depending upon the type of study. Both extracts (100 mg/kg) when studied for incision and dead space wounds parameters, increased wound breaking strength and levels of hydroxyproline, hexuronic acid, hexosamine, superoxide dismutase, reduced glutathione in the granulation tissue and decreased percentage of wound area, scar area and lipid peroxidation when compared with the control group. Both the extracts showed good safety profile. Plantain banana thus, favoured wound healing which could be due to its antioxidant effect and on various wound healing biochemical parameters.

http://nopr.niscair.res.in/bitstream/123456789/2890/1/IJEB%2047%281%29%2032-40.pdf

Evaluation of wound healing activity of extracts of plantain banana (Musa sapientum var. paradisiaca) in rats.

The current study was performed to investigate mitochondrial protection and anti-aging activity of Astragalus polysaccharides (APS) and the potential underlying mechanism. Lipid peroxidation of liver and brain mitochondria was induced by Fe2+–Vit C in vitro. Thiobarbituric acid (TBA) colorimetry was used to measure the content of thiobarbituric acid reactive substances (TBARS). Mouse liver mitochondrial permeability transition (PT) was induced by calcium overload in vitro and spectrophotometry was used to measure it. The scavenging activities of APS on superoxide anion (O2•－) and hydroxyl radical (•OH), which were produced by reduced nicotinamide adenine dinucleotide (NADH)—N-Methylphenazonium methyl sulfate (PMS) and hydrogen peroxide (H2O2)–Fe2+ system respectively, were measured by 4-nitrobluetetrazolium chloride (NBT) reduction and Fenton reaction colorimetry respectively. The Na2S2O3 titration method was used to measure the scavenging activities of APS on H2O2. APS could inhibit TBARS production, protect mitochondria from PT, and scavenge O2•－, •OH and H2O2 significantly in a concentration-dependent manner respectively. The back of the neck of mice was injected subcutaneously with D-galactose to induce aging at a dose of 100 mg/kg/d for seven weeks. Moreover, the activities of catalase (CAT), surperoxide dismutase (SOD) and glutathione peroxidase (GPx) and anti-hydroxyl radical which were assayed by using commercial monitoring kits were increased significantly in vivo by APS. According to this research, APS protects mitochondria by scavenging reactive oxygen species (ROS), inhibiting mitochondrial PT and increasing the activities of antioxidases. Therefore, APS has the effect of promoting health.

https://www.mdpi.com/1422-0067/13/2/1747/pdf

Mitochondrial protection and anti-aging activity of Astragalus polysaccharides and their potential mechanism.

The effect of supplementing 200 mg/kg body weight palm vitamin E (PVE) and 200 mg/kg body weight α-tocopherol (α-loc) on the healing of wounds in streptozotocin-induced diabetic rats was evaluated. The antioxidant potencies of these two preparations of vitamin E were also evaluated by determining the antioxidant enzyme activities, namely, glutathione peroxidase (GPx) and superoxide dismutase (SOD), and malondialdehyde (MDA) levels in the healing of dermal wounds. Healing was evaluated by measuring wound contractions and protein contents in the healing wounds. Cellular redistribution and collagen deposition were assessed morphologically using cross-sections of paraffin-embedded day-10 wounds stained according to the Van Gieson method. GPx and SOD activities as well as MDA levels were determined in homogenates of day-10 dermal wounds. Results showed that PVE had a greater potency to enhance wound repair and induce the increase in free radical-scavenging enzyme activities than α-Toc. Both PVE and α-Toc, however, were potent antioxidants and significantly reduced the lipid peroxidation levels in the wounds as measured by the reduction in MDA levels.

A. H. M. Fairuz

Papers

Comparative effects of palm vitamin E and α-tocopherol on healing and wound tissue antioxidant enzyme levels in diabetic rats