Full-thickness excisional wounds were made in the left and right sides of the dorsum of anesthetised Swiss mice, and a topical pharmaceutical formulation, developed by including essential oil extracted from the leaves of Croton zehntneri (2 % and 20 % EOCz) in pluronic-127 (PF-127), was administered to mice twice daily for 15 days post-wounding. To evaluate the contribution of trans-anethole, the major constituent of EOCz (85.7 % ), in the wound healing activity of EOCz, the effect of the topical administration of trans-AT on wound tissue repair was also evaluated and compared to other groups. A macroscopic analysis of swelling and exudates was performed and scored as 0 (missing), 1 (light), 2 (moderate) and 3 (intense). The number of capillaries and leukocytes was counted in hematoxylin and eosin (HE)-stained sections of the injured tissue. For extracellular matrix remodelling analysis, fibroblasts and collagen fibres present in the photomicrography of the Masson¡¯s Trichrome (MT)-stained sections were counted. Each experimental group comprised six mice.
At day 3 post-wounding, it was observed that treatment with 20 % EOCz greatly reduced the swelling and exudates with a similar magnitude to the dexamethasone treatment. The inflammatory cell infiltration and angiogenesis were not altered by either the EOCz- or trans-AT treatments. In contrast, an acceleration of the wound closure was observed, with an enhanced number of fibroblasts and collagen fibres in both the 20 % EOCz- and trans-AT-treated mice.
Our data indicate that EOCz exerts significant wound healing activity, demonstrating its relevant therapeutic potential.