Potencial de Stachys byzantina K. Koch no tratamento da inflamação cutânea

Abstract

Stachys byzantina is a plant species widely distributed in some regions of the world. The aerial parts have been used in traditional medicine for thousands of years to treat various diseases, as food and as a food preservative. In Brazil and Mediterranean countries, the popular use of S. byzantina is widespread to treat lung disorders, stomach problems, tonsillitis, headache and other inflammatory conditions. Anti-inflammatory, antibacterial, anxiolytic, antioxidant and antinephritic properties have been reported for other species of the genus Stachys. The main objective of this study was to investigate the potential of S. byzantina to reduce skin inflammation. The anti-inflammatory, antioxidant and cytotoxic potential of the ethanolic extract of the aerial parts and its most promising fraction were evaluated. The ethanolic extract (EE) was partitioned into the following fractions: hexane (HF), dichloromethane (DF), ethyl acetate (AF) and hydroalcoholic fraction (HD). Antioxidant assays were employed to select one of the plant derivatives, evaluating the inhibition of the nitric oxide and hydroxyl radicals, and their response to the βcarotene/linoleic acid and ORAC assays. After screening, HF exhibited the most promising activities. Subsequently, in vitro and in vivo inflammation models were used, including an experiment that mimics psoriasis in mice. Topical application of HF was as efficient as the reference substances used in the mice ear edema tests induced by croton oil (HF 1.0 mg/20 µL edema reduction : 78%), phenol (HF 1.0 mg/20 µL edema reduction: 36%), and imiquimod (HF 12%: edema reduction67%). Furthermore, HF reduced the levels of nitric oxide (IC50: 35.3 µg/mL ± 3.17) and pro-inflammatory cytokines in macrophage cultures, including those related to the pathophysiology of psoriasis (IL-12 at 15.6 µg/mL). No cytotoxicity was found in fibroblasts and keratinocytes, which are cells presented in the skin. The presence of terpenes, steroids, phenols and flavonoids was detected, and α-tocopherol was identified and quantified by HPLC-UV (10.56 ± 0.97 mg/g). The results support the traditional use of S. byzantina for inflammatory conditions and emphasize its therapeutic potential for the treatment of skin inflammations, encouraging future investigations on how to take advantage of its properties in clinical practice.