Avaliação da atividade cicatrizante de creme à base de óleo essencial de Cordia verbenacea DC para feridas cutâneas em ratos diabéticos

Abstract

The local knowledge of medicinal plants has been a source of investigation of the plants’ effects in order to develop new therapeutic resources utilizing biotechnological innovations. Essential oils are used as analgesics, sedatives, anti-inflammatories, spasmodics, anesthetics, and healing ointments. The goal of this research was to produce a topic cream made from the essential oil of Cordia verbenacea DC. (also known as black sage) and evaluate its healing activity in cutaneous wounds made on diabetics Wistar rats. The material was collected in the city of São Francisco do Sul, SC, Brazil. Using the fresh leaves of the plant, the essential oil was extracted by the Clevenger machine through the steam trapping process. The extracted essential oil was used for production of topical creams at concentrations of 0.5% and 1.0% for cutaneous wound treatment. A total of 100 male Wistar rats were used and divided into five main groups, being each of the groups divided into two subgroups represented by the total time of treatment (8 and 15 days). The groups were named Group 1 – negative control (G1); Group 2 – treatment with a neutral ointment (vehicle) (G2); Group 3 – treatment 0.5% (G3); Group 4 – treatment 1.0% (G4); and Group 5 – positive control (topical cream of Caçendula officinalis based ointment) (G5). In this group a topical cream with calendula (Calendula officinalis) was used. The mellitus type diabetes was induced by an aqueous solution of aloxan (Aloxan-Sigma – St. Louis – USA), in a single dose, varying accordingly with the animal weight. The rats were treated with aloxan at a dose of 50 mg/kg in order to develop diabetes. After the confirmation of hyperglycemia, a cutaneous wound in thickness was made with the help of a 2x2cm mold in the dorsal area of the animal, starting with trichotomy and asepsis with ethanol 70º and topical PVPI. The euthanasia occurred with inhalation of Isoflurane, and tissue fragments were collected and submitted to histological processing for analysis of the healing process and evaluation of the vascular proliferation, tissue organization, leukocyte infiltration, and reepithelialization. The data was submitted to 2-factor ANOVA test (p<0.05) and transferred to the GraphPad Prism software. The macroscopic evaluation of the wounded area did not show statistical significant difference and, at the end of the established period, it was observed a diminishing of the lesion in all groups, differing in aspect and shape of each group submitted to the distinct treatments. The groups G3 and G4 showed improvement of the aspect of the wound with eight days of treatment. At the end of 15 days, groups G3, G4, and G5 had its wounds almost completely closed. Regarding the histological analysis, the healing process was peculiar to each group and time established. The groups treated with 0.5% ointment, 1.0% ointment, and C. officinalis ointment presented moderate to severe reepithelialization with eight days of treatment, and with 15 days of treatment, all groups presented moderate to severe reepithelialization, however, groups G3, G4, and G5 had a complete process of reepithelialization with a reconstructed epithelium, all three epidermal layers delimited, formation of dermal papilla, presence of a corneous layer, and hair follicles in formation. In the treatment of cutaneous wounds in diabetic rats, the ointments containing Cordia verbenacea essential oil presented physiological efficiency with regular contraction of the wound and quality of healing compared to the ointment made of Calendula officinalis, therefore being a potential product to be studied for cutaneous wounds healing in diabetics and furthermore used in other pathologies that involve difficulty in tissue regeneration.