Bioprospecção de plantas do cerrado Norte-Mineiro: uma abordagem química, toxicológica e cicatricial da Arnica Brasileira Pseudobrickellia Brasiliensis (Spreng.) R.M. King & H. Rob

Abstract

Pseudobrickellia brasiliensis is an important species from the Cerrado, traditionally known as "arnica-do-campo". Despite of its widespread use in popular culture as an anti-inflammatory, analgesic and antimicrobial agent, few studies have been carried out to investigate the chemical composition of the species and to validate its safe biological use in healing. In this sense, the aim of this study was to bioprospect plants from Cerrado Norte-Mineiro through a chemical, toxicological and medicinal approach to Brazilian Arnica P. brasiliensis. The first product is a booklet on the native species of the Pandeiros River Basin. It highlights a new approach to the use of species studied for their metabolism, as well as phytochemical bioprospecting. The second product is the pitch generated by the sensitization campaign for the population of Bonito de Minas on the potential of native plants in the Pandeiros River Basin. The third product carried out phytochemical bioprospecting on different parts of P. brasiliensis collected in the municipality of Coração de Jesus, MG, Brazil. The presence of triterpene, flavonoid, tannin and saponin classes was verified. Flavonoids were evenly distributed among leaves, stem and aerial parts. The quantification of phenolic (37.00±2.45 mg EGA g -1 ) and flavonoid (33.39±0.21 mgEQ g-1 and 74.91±0.50 mgER g -1 ) contents was pronounced in the leaves, as well as the antioxidant activity (IC50: 98.97±0.97 µg mL-1 ). The GC-MS analysis revealed the presence of sesquiterpenes in the essential oil, with α-candinol being the most abundant. In the fourth product, the toxicology of the popular preparation of P. brasiliensis was evaluated using the Organization for Economic Cooperation and Development (OECD) protocols no. 402 and 404 (acute topical), 423 (acute oral) and 408 (subacute) in Swiss mice. As a result, topical administration was found to be safe at GSH level 5 (low toxicity) and non-irritating. With regard to acute oral administration, it showed LD50 >5000 mg kg-1 , low toxicity. However, toxicity was observed in several organs. It was more pronounced after subacute administration (300 and 500 mg kg-1 ) in both sexes, suggesting against oral use in the population. In silico toxicity for compounds isolated from the species indicated a low toxicological potential. The fifth product, the healing effect of the ointment containing the ethanolic extract of the leaves of P. brasiliensis was studied on a model of excisional wounds in C57BL/6 male mice for a period of 14 days. Among the doses tested (5-30%), the effective dose at 50% was 14.15%, which led us to the investigation of the mechanism of the best dose. The results showed a significant reduction in wound area at 3 and 7 days compared to the negative control and commercial Kollagenase®+chloramphenicol ointment. The mechanisms involved were identified by histopathological analysis in H&E, which showed an increase in neovascularization and re epithelialization, in addition to a decrease in inflammation with regulation of the mast cell population as evidenced by toluidine blue staining. Based on these results, the sixth product was generated, a patent claim for the use of P. brasiliensis ointment on skin wounds. Thus, we conclude and validate the safe and effective use of P. brasiliensis.