Investigation of Healing Effects of Cinnamic Acid in a Full-Thickness Wound Model in Rabbit

Wounds represent a major global problem for health care systems, clinicians, patients, and their families. Cinnamic Acid (CA) is a naturally occurring phenolic compound that possesses anti-inflammatory, antimicrobial, and antioxidant properties.

This study aimed to investigate the effects of CA on skin wound-healing in the animal model.

Full-thickness wounds were created on the back of white New Zealand rabbits of both sexes. Animals were divided into six groups (six animals and 12 wounds in each group). Negative control received no treatment, while positive control was treated with phenytoin cream, vehicle group with eucerin, and test groups with 0.1, 1, and 10% CA ointments. The healing activity of CA was evaluated by determining the wound closure rate and hydroxyproline content of wound tissue samples. In addition, the histopathological study of tissue samples of different groups was performed using hematoxylin and eosin staining.

The rate of wound closure and hydroxyproline levels of tissue samples in animals treated with CA 0.1% were significantly (P < 0.05) higher than those of no-treatment and vehicle-treated groups. Histological study revealed the increased number of fibroblasts and hair follicles, increased reepithelialization rate, and enhanced neovascularization in CA 0.1%-treated group when compared to no-treatment and vehicle groups.

Cinnamic acid at low concentrations (< 1%) is potent for skin wound-healing and could be used as a safe and effective topical healing agent. Further studies are needed to confirm our findings.