Effects of the topical application of the extract of Vernonia scorpioides on excisional wounds in mice

Vernonia scorpioides is traditionally widely used in Brazil to treat skin problems, including healing of chronic wounds, such as ulcers of the lower limbs and diabetic wounds. This work investigated the healing process on excisional wounds in the skin of mice, treated daily with an ointment containing 20% of the ethanol extract of the leaves of Vernonia scorpioides, compared with the control. A skin wound area of about 4 mm was excised on anaesthetised mice, and after 3, 7 and 14 days of treatment, the lesions were surgically removed and histologically processed. Wound healing activity was determined by the percentage of necrosis area, mononuclear inflammatory cells, fibroblasts and blood vessels. In the acute phase of healing, treatment with piracá extract enlarged the lesions and intensified the necrosis area, compared with the control group. However, the treatment did not inhibit either the recruitment and stimulation of inflammatory cells or the repair process. The results obtained indicate a harmful action of the extract immediately after tissue excision, demonstrated by the increased area of necrotic tissue, clotting and exudates formed in the treated groups. However, the extract did not inhibit the formation of granulation tissue.