Effects and Mechanisms of Medicinal Plants on Healing Scars: A Systematic Review

Background: Scars can be a cosmetic disfigurement and can tremendously impact psychological, emotional, and social well-being. Some medicinal plants exert anti-scar properties via various mechanisms of action, many of which have not been clearly defined. Objective: This study will evaluate the effects of these medicinal plants with anti-scar properties and review the known underlying mechanisms related to the treatment and prevention of hypertrophic scars. Methods: The keywords used in the literature search included (Wound healing OR Re-epithelialization OR Regeneration) and (Medicinal plants OR Phyto* OR herb) and (Cytokines OR Collagen OR Fibroblasts). Publications indexed in the Institute for Scientific Information (ISI) and PubMed databases were included in the review. Articles with no accessible full texts, non-English language articles, review articles, studies with non-positive effects, and studies that were not related to the study’s aim were excluded from the study. The agreement for exclusion required all authors to concur. Finally, after reviewing all available literature, 61 articles were included in this systematic review. Results: Currently available evidence shows that medicinal plants and their derivatives seem to have properties that can prevent hypertrophic scars. This is achieved by accelerating the scar healing process, reducing inflammatory cytokines, suppressing proliferation, and inducing apoptosis in scar fibroblasts by regulating several signaling pathways. Additionally, they can reduce collagen deposition and have antimicrobial effects at the wound site. Conclusion: Topical use of medicinal plants as complementary medicine with varying mechanisms of action can reduce scar formation. They exert these properties mainly due to their anti-inflammatory, antioxidant, and antimicrobial properties. Therefore, these mechanisms reduce the healing time of the wound and thus prevent the formation of hypertrophic scars. Medicinal plants can be used safely and efficiently when applied topically to improve or prevent hypertrophic scars.