Effects of dipotassium glycyrrhizinate on wound healing

Wound healing is characterized by cellular and molecular complex events, consisting of three phases–inflammatory, proliferative and remodelling–, and involves cell division, reepithelialization, neovascularization, collagen synthesis, remodelling and structural contraction1 ^, 2.
The healing mechanism occurs physiologically, but there are several local and/or systemic factors that can interfere negatively, for example: contamination, smoking, inadequate treatment, oxygen supply and deficient nutrients due to decreased perilesional vascularity, immunosuppressive disease, medications (corticosteroids, chemotherapy, radiotherapy) and nutritional deficiencies (vitamins B, C, D and E), and aging, regarding the individual’s clinical conditions and chronic diseases, such as cardiovascular diseases, diabetes mellitus and associated neuropathies3 ^- 7.Biological aging is a process in which important physiological, morphological, and biochemical changes gradually occur. Loss of the arrangement between the elastic and collagen fibers in the dermal papillae or decrease in size and proliferation of keratinocytes in the basal stratum lead to epidermis thickness structural and functional changes, clearly identifiable in the elderly skin5. Specifically, the dermis can undergo progressive changes, with a thin thickness due to the fibroblasts rarefaction, collagen synthesis decreasing and elastic fibers fragmentation. Also, changes in the amount of water and glycosaminoglycans occur, creating spaces between elastic and collagen fibers. In addition, cell migration capability and vascularity reduce, and size and secretion of sebaceous and sweat glands decrease5. Those structural changes result in a thin and fragile skin in elderly, vulnerable to mechanical forces and contamination, as well as in a slow process of skin healing5 ^, 7.
In recent years, research has been carried out seeking for alternative methods or drugs to help, correct, improve, or accelerate the skin healing process. Thus, new compounds have been studied, aiming mainly to promote regeneration of the epidermis8 and dermis8 ^- 10.
Glycyrrhiza glabra L., known as licorice, has shown nutritional and pharmacological properties especially assigned to glycyrrhizin11. Another isolated compound, the glycyrrhizic acid (GA), has been used regarding its antitumor, antiallergic, antibiotic and anti-inflammatory properties12 ^- 14. Dipotassium glycyrrhizinate (DPG), a secondary product of GA, has antiallergic, antibiotic and anti-inflammatory effects similar to the corticosteroids’ ones, but without side effects, as skin allergic reactions15 ^, 16. On cells, DPG is able to inhibit the hyaluronidase enzyme and, consequently, avoid the damage to the extracellular matrix, the histamine release and inflammatory chemical mediators, leukotrienes and prostaglandins16.