Phytochemistry and Biological Activity of Medicinal Plants in Wound Healing: An Overview of Current Research

Abstract

Wound healing is a complicated process, and the effective management of wounds is a major challenge. Natural herbal remedies have now become fundamental for the management of skin disorders and the treatment of skin infections due to the side effects of modern medicine and lower price for herbal products. The aim of the present study is to summarize the most recent in vitro, in vivo, and clinical studies on major herbal preparations, their phytochemical constituents, and new formulations for wound management. Research reveals that several herbal medicaments have marked activity in the management of wounds and that this activity is ascribed to flavonoids, alkaloids, saponins, and phenolic compounds. These phytochemicals can act at different stages of the process by means of various mechanisms, including anti-inflammatory, antimicrobial, antioxidant, collagen synthesis stimulating, cell proliferation, and angiogenic effects. The application of natural compounds using nanotechnology systems may provide significant improvement in the efficacy of wound treatments. Increasing the clinical use of these therapies would require safety assessment in clinical trials.

Keywords: herbs; medicinal plants; natural wound dressing; secondary metabolites; skin disorders; wound healing.

Figure 1

Wound-healing process. The wound healing process is commonly categorized into four distinct phases: (A) Homeostasis (coagulation); (B) inflammatory phase (early/ late inflammation); (C) proliferative phase (proliferation/migration/epithelialization/granulation); (D) remodeling phase (maturation/repair). (A) Hemostasis: A clot is formed, providing a temporary barrier to fluid loss and pathogen entry; acts as a reservoir of bioactive factors and antimicrobials; provides provisional extracellular matrix, which supports immune cell infiltration and migration; and initiates tissue repair pathways. (B) Inflammatory phase: Early step with damage-associated molecular patterns activation, free radicals, and reactive molecular species production to recruit immune cells; release of antimicrobial species; infiltrating immune cells that secrete amplifying alarmin signals (endogenous, constitutively expressed, chemotactic, and immune-activating proteins/peptides that are released as a result of degranulation, cell injury or death, or in response to immune induction), and activation of keratinocytes and fibroblasts. (C) Proliferation phase: Migration and proliferation of keratinocytes, fibroblasts, endothelial; resolution of inflammation; collagen/extracellular matrix synthesis; decreased vessel permeability; new capillary and lymphatic vessel angiogenesis; epithelialization; and de novo formation of granulation tissue. (D) Remodeling (maturation): Collagen/extracellular matrix turnover (synthesis and degradation); extracellular matrix reorganization and realignment; extracellular matrix contraction; endothelia and fibroblast apoptosis; repigmentation.

Figure 2

Processes active in acute and chronic wounds. Acute wounds (left side): Adequate angiogenesis with re-epithelialization promotion, fibroblasts’ proliferation, and neutrophils’ anti-infection activities. Chronic wounds (right side): Persistent local bacterial infections, failure formation of novel blood vessels. decreased fibroblasts’ proliferation, and the neutrophils’ anti-infection activities hampered by poor angiogenesis.

Figure 3

The primary bioactive phytochemical structures involved in wound healing.