RESUMO:Desde tempos imemoriais, a população passou a utilizar as plantas como fontes de cura de algumas doenças ou como meios para aliviar dores. Até os dias atuais ainda é perceptível o uso de plantas na fitoterapia; devido a essa importância estudos identificam as substâncias bioativas presentes em algumas plantas medicinais, tais substâncias são derivadas do metabolismo secundário dos vegetais e possuem alto potencial antioxidante, sendo capaz de prevenir e inibir a ação dos radicais livres no organismo humano. Deste modo, o objetivo deste trabalho é evidenciar a importância do estudo das substâncias produzidas pelo metabolismo secundário (capazes de prevenir algumas patologias) e demonstrar a ação de cada uma destas substâncias no organismo humano. A metodologia utilizada para a realização deste trabalho foi de cunho bibliográfica, onde foi possível ter acesso a artigos científicos que explanavam sobre a importância e o efeito biológico dos metabólitos secundários. Com base na pesquisa realizada foi identificado os diferentes grupos de metabólicos e seus respectivos efeitos no organismo. Entre o grupo mais abundante de metabólicos estão os polifenóis ou compostos fenólicos que possuem numerosos efeitos biológicos (sequestro de radicais livres, inibição da proliferação celular, bem como seu potencial como agente antibiótico, antialérgico e anti-inflamatório). Além disso, os compostos bioativos apresentam papéis na redução do risco do câncer e doenças cardiovasculares. Diante do exposto, a presente pesquisa bibliográfica demonstrou quão importante é o estudo dos compostos bioativos na promoção a saúde.Palavras-chave: antioxidante, substâncias bioativas, ação biológica. ABSTRACT:Since time immemorial, people began using plants as sources of curing some diseases or as a means to relieve pain. Until today it is still noticeable the use of plants in herbal medicine; due to that importance studies identify bioactive substances in medicinal plants, such substances are derived from the secondary metabolism of plants and have a high antioxidant potential, being able to prevent and inhibit the action of free radicals in the human organism. Thus, the aim of this work is to show the importance of the study of substances produced by the secondary metabolism (able to prevent some diseases) and demonstrate the action of each of these substances on the human organism. The methodology used for this work was a bibliographical nature, where it was possible to have access to scientific articles that They explained about the importance and the biological effect of secondary metabolites. Based on the survey of the different groups and their metabolic effects in the body were identified. Among the most abundant polyphenols are divorced metabolic or phenolic compounds which have numerous biological effects (sequestration of free radicals, inhibition of cell proliferation, as well as its potential as an antibiotic, ant allergic and anti-inflammatory agent). Additionally, bioactive compounds have roles in reducing the risk of cancer a...

Croton argyrophylloides Muell. Arg., from the Euphorbiaceae family, popularly known as marmeleiro prateado or sacatinga, is a plant from the Caatinga biome commonly found in Brazil’s northeastern region. The present study aimed to evaluate the antioxidant activity of the species. The phytochemical study was performed through qualitative analysis of chemical constituents and quantitative determination of the total phenol content through the Folin-Ciocalteu test. The qualitative and quantitative antioxidant tests were performed using the DPPH method (2.2 diphenyl-1-picryl hydrazil) and ferric reducing antioxidant power (FRAP). The minimum inhibitory concentration (MIC) was determined by microdilution in 96-well plates. The ethanolic extract of the leaves of C. argyrophylloides manifested antioxidant action in the quantitative DPPH test with a significant bioactivity of 84.70 AAO% in 500 µg/mL, with an EC50 of 236.79. The content of total phenolic compounds was 946.06 mg of gallic acid equivalents/g of sample, and total flavonoids was 58.11 mg of quercetin equivalents/g of sample, the result obtained for FRAP was 15294.44 µM Trolox/g of sample and ABTS was 718 μM Trolox of sample. The prospecting of the chemical constituents of the leaves of C. argyrophylloides revealed the presence of the main compounds that manifests the antioxidant activity and it was proven by the DPPH method that there is antioxidant activity in the analyzed sample, in addition to demonstrating a significant content of phenolic compounds and total flavonoid content in the species, which corroborates the antioxidant activity of the plant sample. The leaf extracts presented growth inhibition halos of 10 and 12 mm upon Staphylococcus aureus ATCC 25923.

This study quantifies phenolic and flavonoid compounds and evaluates the antioxidant activity by the DPPH (2,2-diphenyl-1-picrylhydrazyl) method, also identifying some secondary metabolites of R. sativus under organic fertilization and water stress. For this, a greenhouse experiment was carried out with the preparation of plant extracts (leaves and roots), quantification of phenolic and flavonoid compounds, analysis of antioxidant activity, and phytochemical screening. Different classes of secondary metabolites (catechins, steroids, saponins, among others) were identified. The DPPH method showed that the leaf extract has higher DPPH radical scavenging activity. The leaf extract had a high content of phenolic compounds, especially in treatments without water stress, either with organic fertilization (1925.59 mg GAE/g extract) or with mineral fertilization (2058.47 mg GAE/g extract). For root extracts, R. sativus developed under water stress and organic fertilization showed higher phenolic content (1383.24 mg GAE/g extract). Regarding flavonoid content, the root extract that showed the highest concentration corresponded to the treatment under water stress and without fertilization (82.1 mg QE/g extract). Therefore, radish was shown to be rich in bioactive compounds and with antioxidant potential in both its leaves and roots.

We evaluated the bioactivity of Morinda citrifolia L., Rubiaceae on Tuta absoluta (Lepidoptera: Gelechiidae) and quantified the phenolic components. Ethanolic extracts of leaves and fruits were used in five concentrations (0.01, 0.02, 0.03, 0.04 and 0.05 mg / L). The leaves of the plants were immersed in the solution (10 s) and placed in contact with five caterpillars of the same instar in Petri dishes. The caterpillars were kept under controlled conditions, temperature of 25 ± 1 ° C, and relative humidity of 65 ± 10%, photophase of 12 h. The experimental design was completely randomized with five concentrations, five replicates with two different extracts, the control being distilled water. The phenolic composition of the extracts was determined by high-performance liquid chromatography (HPLC) based on the retention times using the standard external method. Leaf extracts and fruits of M. citrifolia had bioinseticidal activity against caterpillars (leaves at 0.02 mg / L gave 100% mortality and fruits at 0.03 mg / L gave 46.08% mortality). The greater efficiency of leaves can be attributed to their high percentage of phenolic compounds and flavonoids. Eleven phenolic compounds were identified and quantified in extracts of leaves and fruits that showed significant bioactivity.

Oxidation of lipids in various products, along with the growth of medically important pathogens, has led to a search for medicinal plants with antioxidant and antimicrobial activities. As a result, the aim of this study was to evaluate the antioxidant and antibacterial activity of the essential oil of Eucalyptus globulus (EO-Eg). Antioxidant activity was assessed by using the 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) assay method. Existing components were identified through gas chromatography-mass spectrometry (GC-MS) analysis. Antibacterial activity and minimum inhibitory concentration (MIC) were assessed by using the broth microdilution method with standard multidrug-resistant bacterial strains. The main EO-Eg compounds identified by GC-MS were isopulegol, citronellal, and citronellol, which are primarily used in the industrial sectors. EO-Eg demonstrated excellent antioxidant activity with an effective concentration (EC50) of 4.48 µL/mL owing to the presence of phenolic compounds. Regarding antibacterial activity, the EO-Eg displayed a broad antimicrobial spectrum of antimicrobial activity across the different resistance phenotypes analyzed. The most notable antibacterial activity was observed against Staphylococcus aureus 169 MRSA (MIC = 0.0625%). As a result, our findings suggest that EO-Eg has antioxidant and antibacterial potential against hospital-acquired multidrug-resistant pathogens, which may be correlated with its major components.

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In equine clinics, skin injuries are some of the most frequently treated injuries, this research evaluated the healing potential and antioxidant activity of Abarema cochliacarpos in order to develop a pharmaceutical formulation for treating skin lesions in horses. Firstly, the antioxidant activity of several fractions was evaluated using the 2,2-diphenyl-1-picrylhydrazyl radical method and the thiobarbituric acid test. The determination of phenolic compounds was done by means of the Folin-Ciocalteau test. To assess the wound healing activity the dry powdered stem bark and the aqueous, ethanolic and propylene glycol extracts from the same plant, material were incorporated in a gel formulation and evaluated in equines with induced wounds. Results show that all obtained extracts and their fractions have antioxidant action. Regarding the healing evaluation in equines, the extracts tested and the dry powdered stem bark showed statistically significant activity in the contraction of wounds. Histological analysis revealed the powdered stem bark as the best treatment to induce healing of cutaneous lesions in horses. Experimental studies in animals with different dosages and formulations, besides the isolation of its chemical components, as a tool in the discovery of new healing agents or optimization of the existing ones is recommended.