The Brazilian Cerrado biome consists of a great variety of endemic species with several bioactive compounds, and Anadenanthera peregrina (L.) Speg is a promising species. In this study, we aimed to perform phytochemical characterization and evaluate the antioxidant and antibacterial activities against Staphylococcus aureus and Escherichia coli of the hydroethanolic extract of A. peregrina stem bark. The barks were collected in the Botanical Garden of Goiânia, Brazil. The hydroethanolic extract was obtained by percolation and subjected to physicochemical screening, total phenolic content estimation, high-performance liquid chromatography (HPLC) fingerprinting, and antioxidant (IC50 values were calculated for the 2,2-diphenyl-1-picrylhydrazyl assay - DPPH) and antibacterial activity determination. The pH of the extract was 5.21 and density was 0.956 g/cm3. The phytochemical screening indicated the presence of cardiac glycosides, organic acids, reducing sugars, hemolytic saponins, phenols, coumarins, condensed tannins, flavonoids, catechins, depsides, and depsidones derived from benzoquinones. The extract showed intense hemolytic activity. The total phenolic content was 6.40 g GAE 100 g-1. The HPLC fingerprinting analysis revealed the presence of gallic acid, catechin, and epicatechin. We confirmed the antioxidant activity of the extract. Furthermore, the extract did not inhibit the growth of E. coli colonies at any volume tested, but there were halos around S. aureus colonies at all three volumes tested. These results contribute to a better understanding of the chemical composition of A. peregrina stem bark and further support the medicinal applications of this species.

Pouteria caimito (Sapotaceae) is widely distributed throughout Latin America, including Brazil. The yellow fruits, known as abiu, caimito, or abiurana, are eaten in natura or used to prepare desserts. In addition to being a commercially available Brazilian fruit, P. caimito has also been used as a traditional medicine. Therefore, hexane, ethanol, and aqueous extracts from its leaves were evaluated for radical-scavenging activity. Free radical-scavenging activity was tested using the DPPH assay. Total phenolic and proanthocyanidin contents were also determined. The aqueous extract comprised the highest total phenol and proanthocyanidin contents (173.6 g/mL) and showed the highest radical-scavenging activity (ED50= 36.1 g/mL). Phytochemical analysis of the hexane extract allowed the isolation of spinasterol. We found a high correlation between total phenolic and proanthocyanidin contents and radical-scavenging activity. To our knowledge, this is the first time spinasterol has been isolated from P. caimito leaves.

RESUMO:Nos últimos anos, uma quantidade substancial de evidências tem indicado o papel chave dos radicais livres e outros oxidantes como grandes responsáveis pelo envelhecimento e pelas doenças degenerativas associadas ao mesmo. Por outro lado, substâncias fenólicas são reconhecidamente detentoras de pronunciada atividade antioxidante, muitas vezes envolvidas em tratamentos de pigmentação que resultam em hiperpigmentação ou hipopigmentação cutânea. Para o tratamento desses problemas de pigmentação vários produtos cosméticos e farmacêuticos são utilizados, porém, não são totalmente eficazes ou seguros, o que justifica a intensa pesquisa na busca de novos agentes ativos, principalmente àqueles envolvidos na melanogênese, como a tirosinase. Considerando que algumas substâncias obtidas de plantas apresentam essa atividade, a flora brasileira constitui-se uma importante fonte de pesquisa de novas substâncias. Assim, este trabalho foi realizado para avaliar os fenóis (método de FolinCiocalteau), a atividade antioxidante (CE50) (método de seqüestro do radical livre DPPH), a capacidade de quelação dos íons cobre, e a capacidade de inibição da tirosinase do extrato das folhas da espécie Dipteryx alata Vogel. Os resultados de fenóis totais mostraram uma concentração de 112,3 mg EAG.g -1 no extrato etanólico e 45 mg EAG.g -1 no extrato hexânico. A capacidade antioxidante dos extratos indica que o extrato etanólico, em comparação ao hexânico e ao BHT, possui maior teor de compostos antioxidantes, apresentando os respectivos valores sobre a quantidade de extrato necessária para decrescer a concentração inicial de DPPH em 50%: 52,9 ± 1,3 ppm, 169,1 ± 2,3 ppm, e 181± 6 ppm. Já a capacidade de quelação dos íons cobre mostrou que o extrato etanólico possui capacidade de quelação insignificante. No ensaio de inibição da tirosinase o extrato etanólico demonstrou um percentual de inibição da enzima de 42% após uma hora. Palavras-chave:Dipteryx alata Vogel, DPPH, hiperpigmentação, tirosinase.ABSTRACT: Antioxidant and inhibitory action on tyrosinase from Dipteryx alata Vogel (Baru) leaves. In recent years, a substantial amount of evidence has shown the key role of free radicals and other oxidants as largely responsible for aging and associated degenerative diseases. On the other hand, phenolic substances are known to hold pronounced antioxidant activity, often involved in pigmentation treatments, which result in skin hyperpigmentation or hypopigmentation. For the treatment of these pigmentation problems several cosmetic and pharmaceutical products have been used; however, they are not fully effective or safe, which justifies intense research to find new active agents, especially those involved in melanogenesis such as tyrosinase. Considering that some substances obtained from plants have this activity, the Brazilian flora constitutes an important source of research for new substances. Thus, this study was conducted to evaluate the phenols (Folin-Ciocalteau assay), the antioxidant activity (EC50) (DPPH free radical scavenging assay), ...

RESUMO:Os radicais livres e outros oxidantes demonstram ser parcialmente responsáveis pelo envelhecimento e pelas doenças degenerativas associadas à produção de espécies reativas de oxigênio. Além disto, os compostos fenólicos são reconhecidamente detentores de elevada atividade antioxidante, que geralmente estão envolvidos em tratamentos de problemas de pigmentação da pele, que resultam em hiperpigmentações. Sendo assim este trabalho foi realizado para avaliar o conteúdo de fenóis totais, atividade antioxidante e a capacidade de inibição da tirosinase dos extratos das folhas e cascas do caule da espécie Myracrodruon urundeuva Fr. All. Para determinação do conteúdo de fenóis totais dos extratos orgânicos de M. urundeuva utilizou-se o reativo Folin-Ciocalteau, na avaliação da atividade antioxidante empregando o radical livre DPPH, enquanto que os testes de inibição da enzima tirosinase foram realizados utilizando L-tirosina. A concentração de fenóis totais foi de 77 mg EAG g -1 e 194 mg EAG g -1 nos extratos hexânico e metanólico das folhas e de 45 mg EAG g -1 e 193 mg EAG g -1 nos extratos hexânico e metanólico das cascas do caule. O potencial antioxidante dos extratos indicaram que o extrato metanólico das cascas do caule (10,9 ± 0,5 µg mL -1 ), em comparação ao hexânico (12,9 ± 0,2 µg mL -1 ) e ao BHT (220 ± 7,0 µg mL -1 ), possui atividade antioxidante levemente mais acentuada. No ensaio de inibição da tirosinase, o extrato metanólico das cascas do caule demonstrou a inibição da enzima em 42% após uma hora.Palavras-chave: compostos fenólicos, DPPH, hiperpigmentação, tirosinase.ABSTRACT: Total phenolics, antioxidant activity and tyrosinase enzyme inhibition by Myracrodruon urundeuva Fr. All. (Anacardiaceae) extracts. Free radicals and other oxidants had demonstrated to be partially responsible for aging and for degenerative diseases associated with the production of reactive oxygen species. In addition, the phenolic compounds are recognized as holders of high antioxidant activity, which usually are involved in the treatment of pigmentation problems, resulting in hyper pigmentation. So this study was carried out in order to evaluate the content of total phenols, antioxidant activity and capacity inhibition of tyrosinase in extracts from leaves and stem barks of the species Myracrodruon urundeuva Fr. All. In order to determine the content of total phenols from organic extracts of M. urundeuva, a Folin-Ciocalteau reagent was employed in the evaluation of antioxidant activity,using the DPPH free radical, while the enzyme tyrosinase inhibition tests were performed using L-tyrosine. The amount of total phenols was 77 mg EAG g -1 and 194 in the hexane and methanolic extracts from the leaves and 45 mg EAG g -1 and 193 mg EAG g -1 in the hexane and methanolic extracts of the stem barks. The antioxidant potential of extracts indicated that the methanolic extract of stem bark (10.9 ± 0.5 µg mL -1 ), when compared to the hexane (12.9 ± 0.2 µg mL -1 ) and BHT (220 ± 7.0 µg mL -1 ), presented a slightly higher antioxidant a...

Determination of total phenol, antioxidant activity and inhibition by tyrosinase extract of jatobá (Hymenaea stigonocarpa Mart. ex Hayne) leaves. The jatobá species, also known as Brazilian cherry, are traditionally used for the treatment of various diseases. Chemotaxonomic studies have described the Hymenaea genus as a potential source of phenolic compounds, tannins and flavonoids, which have antioxidant activity, thus being potential inhibitors of tyrosinase, which is the enzyme responsible for skin pigmentation defects. There are approximately 15 species in the genus Hymenaea of which 13 are found in Brazil. This study was conducted to evaluate the phenols, the antioxidant activity, the ability to chelate copper ions and the ability to inhibit tyrosinase of the extract of the H. Stigonocarpa leaves. The plant material (leaves) was harvested from trees in the savannah (Brazilian Cerrado) area of environmental preservation of the FESURV campus -University of Rio Verde -state of Goiás, dried in a forced circulation oven at 42° C for 2 days and subjected to extraction with hexane (hexane crude extract) and extraction with absolute ethanol (ethanol crude extract). When determining the phenolic content performed with the Folin-Ciocalteu reagent, we found that the crude ethanol extract (CEE) presented the highest concentration (235.7 mg gallic acid equivalent per gram of CEE). In the evaluation of radical scavenging activity, using the DPPH free radical, the ethanol extract again showed higher antioxidant activity (IC50 = 19 ± 0.1 ppm). For the procedure for chelation of copper ions, the crude ethanol extract tested showed no such ability. For the process of inhibiting the tyrosinase enzyme, the crude ethanol extract tested after 30 and 60 minutes presented inhibition of 38 and 48%, respectively.