Propolis is a complex bioactive mixture produced by bees, known to have different biological activities, especially in countries where there is a rich biodiversity of plant species. The objective of this study was to determine the chemical composition and evaluate the antioxidant and cytotoxic properties of Brazilian propolis from the species Plebeia droryana and Apis mellifera found in Mato Grosso do Sul, Brazil. In the ethanolic extracts of P. droryana propolis (ExEP-P) and A. mellifera (ExEP-A) acids, phenolic compounds, terpenes and tocopherol were identified as major compounds. Both extracts presented antioxidant activity against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical, the maximum activities being 500 μg/mL (ExEP-P) and 300 μg/mL (ExEP-A). However, only ExEP-A was able to inhibit lipid peroxidation induced by the oxidizing agent 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH), which inhibited oxidative hemolysis and reduced the levels of malondialdehyde (MDA) in human erythrocytes for 4 h of incubation. The extracts also reduced the cell viability of the K562 erythroleukemia tumour line, with a predominance of necrotic death. Thus, it is concluded that the propolis produced by P. droryana and A. mellifera contain important compounds capable of minimizing the action of oxidizing substances in the organism and reducing the viability of erythroleukemia cells.

Oxidative stress is a metabolic disorder linked with several chronic diseases, and this condition can be improved by natural antioxidants. The fruit pulp of the palm Acrocomia aculeata (Jacq.) Lodd. ex Mart. is widely used in the treatment of various illnesses, but as far as we know, there are no reports regarding the properties of its leaves. Thus, we aimed to evaluate the antioxidant activity of A. aculeata leaf extracts obtained with water (EA-Aa), ethanol (EE-Aa), and methanol (EM-Aa) solvents. The extracts were chemically characterized, and their antioxidant activity was assessed through the scavenging of the free radicals DPPH and ABTS. EE-Aa and EM-Aa showed the highest amounts of phenolic compounds and free radical scavenging activity. However, EA-Aa was more efficient to protect human erythrocytes against AAPH-induced hemolysis and lipid peroxidation. Thus, we further show the antioxidant effect of EA-Aa in preventing AAPH-induced protein oxidation, H2O2-induced DNA fragmentation, and ROS generation in Cos-7 cells. Increased levels of Sirt1, catalase, and activation of ERK and Nrf2 were observed in Cos-7 treated with EA-Aa. We also verify increased survival in nematodes C. elegans, when induced to the oxidative condition by Juglone. Therefore, our results showed a typical chemical composition of plants for all extracts, but the diversity of compounds presented in EA-Aa is involved in the lower toxicity and antioxidant properties provided to the macromolecules tested, proteins, DNA, and lipids. This protective effect also proven in Cos-7 and in C. elegans was probably due to the activation of the Sirt1/Nrf2 pathway. Altogether, the low toxicity and the antioxidant properties of EA-Aa showed in all the experimental models support its further use in the treatment of oxidative stress-related diseases.

No abstract

Oxidative stress plays a key role in the initiation and progression of metabolic diseases, including obesity. Preventing the accumulation of reactive oxygen species and oxidative damage to macromolecules is a beneficial strategy for reducing comorbidities associated with obesity. Fruits from the Spondias genus are known for their antioxidant activity, but they are not available year-round due to their seasonality. In this context, we investigated the antioxidant activity and identified the chemical constituents of the aqueous extract of the stem bark of Spondias purpurea L. (EBSp). Additionally, we evaluated the effect of EBSp consumption on metabolic parameters in mice with obesity induced by a high-fat diet. Chemical analyses revealed 19 annotated compounds from EBSp, including flavan-3-ols, proanthocyanidins, methoxylated coumarin, and gallic and ellagic acids, besides other phenolic compounds. In vitro, EBSp showed antioxidant activity through the scavenging of the free radicals and the protection of macromolecules against oxidative damage. Cellular assays revealed that EBSp reduced the levels of malondialdehyde produced by erythrocytes exposed to the oxidizing agent AAPH. Flow cytometry studies showed that EBSp reduced reactive oxygen species levels in human peripheral blood mononuclear cells treated with hydrogen peroxide. Obese mice treated with EBSp (400 mg.kg-1) for 60 days showed reduced levels of malondialdehyde in the heart, liver, kidneys, and nervous system. The total cholesterol levels in mice treated with EBSp reached levels similar to those after treatment with the drug simvastatin. Together, the results show that the combination of the different phenolic compounds in S. purpurea L. bark promotes antioxidant effects in vitro and in vivo, resulting in cytoprotection in the context of oxidative stress associated with obesity and a reduction in hypercholesterolemia. From a clinical perspective, the reduction in oxidative stress in obese individuals contributes to the reduction in the emergence of comorbidities associated with this metabolic syndrome.

Introdução: Plantas com potenciais terapêuticos têm sido estudadas para o desenvolvimento de novos fármacos. Nectandra membranacea é descrita na literatura como antimalárico e antileishimania, entretanto suas propriedades antioxidantes nunca foram descritas. Assim, os objetivos desse estudo foram: (I) quantificar o conteúdo de compostos polifenóis e flavonoides, (II) caracterizar a atividade antioxidante do extrato hidroalcoólico da casca de N. membranacea (EENM). Métodos: O conteúdo de compostos fenólicos foi determinado de acordo com o método colorimétrico Follin-Ciocalteau, expresso em mg equivalente de ácido gálico (GAE) por g do extrato. O conteúdo de flavonoides foi determinado utilizando cloreto de alumínio, expresso em mg equivalentes de quercetina (QE) por 1 g do extrato. Para os ensaios de captura do radical livre 2,2-difenil-1-picrilhidrazil (DPPH), o EENM foi preparado em diferentes concentrações (1,56-50 µg/mL) e avaliado a capacidade de captura radical DPPH. As diferentes concentrações foram diluidas em solução de etanol 80% de DPPH (0,11 mM) e incubadas a temperatura ambiente, na ausência de luz, durante 30 min e posteriormente avaliada em espectrofotômetro na absorbância de 517 nm. Como antioxidante de referência foi utilizado o ácido ascórbico. Resultados: Os resultados mostram que o EENM apresenta o conteúdo de compostos fenólicos de 585,78mg GAE/1g do extrato e Flavonoides 14,06mg QE/1g do extrato. A capacidade de inibir 50% dos radicais livres DPPH foi de 3.9 µg/mL para o EENM e de 3,54 µg/mL para acido ascórbico. Já a atividade antioxidante máxima do extrato (92±0,3%) e do controle (95±0,2%) foram alcançadas na concentração de 12,5 µg/mL. Conclusões: Os resultados in vitro evidenciam o potencial antioxidante do extrato hidroalcoólico da casca de N. membranácea. Entretanto, outras análises necessitam ser realizadas para confirmar os resultados obtidos. Agências de Fomento: CAPES, CNPq, FundectPalavras-chave: Canela Branca, Fitoquímica, Bioprospecção