Epidermal Regeneration Induced by Comfrey Extract: A Study by Light and Electron Microscopy
Introduction: An accelerated healing of superficial wounds was demonstrated in clinical trials with a topical comfrey preparation (Symphytum × uplandicum Nyman). The effect has previously not been examined in skin models. Methods: An established in vitro model of epidermal cells with the typical strata was used for the observation of effects of applied substances on skin regeneration. Damage corresponding to a typical abrasion was created on day 1 by punching an opening into the epidermal fine structure down to the stratum basale. Samples were either untreated (controls) or exposed to comfrey cream on days 2, 3, 5, and 6. Tissue samples were taken for light and electron microscopy on days 1, 4, and 7. Results and Conclusions: Application of comfrey cream led to a quicker regeneration of skin cells and to an earlier differentiation of the cells towards a normal fine structure with a visible distinction of epidermal strata, keratin, and corneocyte formation within 4-7 days. The study covered the early days of skin regeneration and confirms the benefits observed in published clinical trials and non-interventional studies in patients with abrasions.