Bioavailable phenolic compounds from olive pomace present anti-neuroinflammatory potential on microglia cells

The neuroinflammatory process is considered one of the main characteristics of central nervous system diseases, where a pro-inflammatory response results in oxidative stress through the generation of reactive oxygen and nitrogen species (ROS and RNS). Olive (Olea europaea L.) pomace is a by-product of olive oil production that is rich in phenolic compounds (PCs), known for their antioxidant and anti-inflammatory properties. This work looked at the antioxidant and anti-neuroinflammatory effects of the bioavailable PC from olive pomace in cell-free models and microglia cells. The bioavailable PC of olive pomace was obtained through the process of in vitro gastrointestinal digestion of fractionated olive pomace (OPF, particles size < 2 mm) and micronized olive pomace (OPM, particles size < 20 µm). The profile of the PC that is present in the bioavailable fraction as well as its in vitro antioxidant capacity were determined. The anti-neuroinflammatory capacity of the bioavailable PC from olive pomace (0.03–3 mg L−1 ) was evaluated in BV-2 cells activated by lipopolysaccharide (LPS) for 24 h. The total bioavailable PC concentration and antioxidant activity against peroxyl radical were higher in the OPM than those observed in the OPF sample. The activation of BV-2 cells by LPS resulted in increased levels of ROS and nitric oxide (NO). The bioavailable PCs from both OPF and OPM, at their lowest concentrations, were able to reduce the ROS generation in activated BV-2 cells. In contrast, the highest PC concentration of OPF and OPM was able to reduce the NO levels in activated microglial cells. Our results demonstrate that bioavailable PCs from olive pomace can act as anti-neuroinflammatory agents in vitro, independent of particle size. Moreover, studies approaching ways to increase the bioavailability of PCs from olive pomace, as well as any possible toxic effects, are needed before a final statement on its nutritional use is made

Antiproliferative effect of colonic fermented phenolic compounds from jaboticaba (Myrciaria trunciflora) fruit peel in a 3D cell model of colorectal cancer

Jaboticaba is a Brazilian native berry described as a rich source of phenolic compounds (PC) with health promoting effects. PC from jaboticaba peel powder (JPP) have low intestinal bio-accessibility and are catabolized by gut microbiota. However, the biological implication of PCderived metabolites produced during JPP digestion remains unclear. This study aimed to evaluate the antiproliferative effects of colonic fermented JPP (FJPP) in a 3D model of colorectal cancer (CRC) composed by HT29 spheroids. JPP samples fermented with human feces during 0, 2, 8, 24 or 48 h were incubated (10,000 µg mL−1 ) with spheroids, and cell viability was assessed after 72 h. Chemometric analyses (cluster and principal component analyses) were used to identify the main compounds responsible for the bioactive effect. The antiproliferative effect of FJPP in the CRC 3D model was increased between 8 h and 24 h of incubation, and this effect was associated with HHDP-digalloylglucose isomer and dihydroxyphenyl-γ-valerolactone. At 48 h of fermentation, the antiproliferative effect of FJPP was negligible, indicating that the presence of urolithins did not improve the bioactivity of JPP. These findings provide relevant knowledge on the role of colonic microbiota fermentation to generate active phenolic metabolites from JPP with positive impact on CRC

The hepatoprotective effect of jaboticaba peel powder in a rat model of type 2 Diabetes Mellitus involves the modulation of thiol/disulfide redox state through the upregulation of glutathione synthesis

Jaboticaba peel powder (JPP) is rich in bioactive compounds, mainly soluble and insoluble polyphenols with great antioxidant properties. ,e aim of this study is to evaluate the effects of JPP supplementation on the oxidative stress and hepatic damage in a rat model of type 2 diabetes mellitus (T2DM). Diabetic rats received vehicle or JPP at 2.7 (JPP-I), 5.4 (JPP-II), or 10.8 (JPP-III) g/L in drinking water during 8 weeks. JPP-III attenuated hyperglycaemia and dyslipidemia increased by 86% the liver content of nonprotein thiol groups and by 90% the GSH/GSSG ratio by activating glutathione synthesis. Accordingly, JPP supplementation prevented the loss of activity of the sulfhydryl-dependent enzyme δ-aminolaevulinic acid dehydratase and attenuated hepatic injury assessed by the reduction of serum aspartate aminotransferase activity and liver hypertrophy. Our results support that JPP supplementation to T2DM rats decreases hepatic damage most likely by increasing glutathione synthesis and modulating the thiol/disulfide redox balance

Envolvimento do estresse oxidativo e hipercolesterolemia na aterosclerose e avaliação do efeito protetor do carotenóide astaxantina

A aterosclerose consiste na formação de placas que reduzem o diâmetro dos vasos sanguíneos e é a principal causa das doenças cardiovasculares. O estresse oxidativo tem sido apontado como um importante mecanismo no processo de aterogênese induzido pela hipercolesterolemia. A astaxantina (ASX) é um carotenóide presente em algas e frutos-domar, amplamente estudado por suas propriedades antioxidantes. No presente trabalho, avaliou-se a ocorrência de estresse oxidativo em diferentes estágios de hipercolesterolemia em humanos e a relação entre o estresse oxidativo e o processo inflamatório nesses indivíduos. Adicionalmente, o potencial antiaterogênico da ASX foi avaliado em coelhos hipercolesterolêmicos. No primeiro capítulo demonstramos que a peroxidação lipídica e oxidação de proteínas aumentou em indivíduos com níveis de LDL considerados de alto risco para doenças cardiovasculares (>160mg/dL), enquanto os níveis de LDLox, LDLoxAB, do marcador de processo inflamatório hs-CRP e a atividade das enzimas TrxR-1 e SOD aumentaram em indivíduos com níveis de colesterol considerados altos, mas clinicamente aceitáveis (130-160mg/dL), persistindo este aumento nos sujeitos com LDL > 160mg/dL. A enzima PON1 não teve sua atividade modificada em nenhum dos estágios de hipercolesterolemia estudados. Os resultados apresentados no capítulo I permitem concluir que o estresse oxidativo ocorre concomitantemente ao processo inflamatório durante a hipercolesterolemia. Além disso, a utilização da atividade da enzima PON1 sérica como fator de risco independente para doenças cardiovasculares necessita maiores esclarecimentos. No segundo e terceiro capítulos, observamos que a adição de colesterol (1%) na dieta de coelhos (60 dias) induziu hiperlipidemia sérica, estresse oxidativo no soro e tecido aórtico e formação de ateroma no tecido aórtico. A suplementação de ASX (50-100mg%) concomitante com o colesterol atenuou o estresse oxidativo de maneira mais acentuada no tecido aórtico do que no soro, mas não preveniu o aumento dos lipídios séricos nem a formação de ateroma nos coelhos. Estes resultados indicam que apesar da ausência de efeito hipolipidêmico e antiaterogênico da ASX, esse carotenóide exerce efeitos antioxidantes no soro e tecido aórtico de coelhos hipercolesterolêmicos. Em conjunto, os dados desta Tese indicam a ocorrência de estresse oxidativo durante a hipercolesterolemia em humanos e a ocorrência de aterosclerose e estresse oxidativo em coelhos hipercolesterolêmicos. Apesar da ASX não ter apresentado efeito antiaterogênico neste trabalho, mais estudos são necessários antes de uma conclusão definitiva sobre o potencial deste carotenóide como adjunto na prevenção e tratamento de doenças cardiovasculares.Atherosclerosis consists in the formation of plaques that reduces blood vassels diameter and it is the major cause of cardiovascular diseases. Oxidative stress has been pointed as an important mechanism in atherogenesis process induced by hypercholesterolemia. Astaxanthin (ASX) is a carotenoid present in algaes and seafoods, widely studied by its antioxidant properties. In the present study it was evaluated the ocurrence of oxidative stress at different stages of hypercholesterolemia in humans and the relathionship between oxidative stress and inflamatary process in these subjects. Additionally, the antiatherogenic potential of ASX was evaluated in hypercholesterolemic rabbits. In the first chapter, we demonstrated that lipid peroxidation and protein oxidation increased in subjects with LDL levels considered of high risk for cardiovascular diseases (>160mg/dL), while the levels of LDLox, LDLoxAB, the marker of inflamatory process hs-CRP and the activity of the enzymes TrxR-1 and SOD increased in subjects with LDL levels considered high, but clinically acceptable (130- 160mg/dL), persisting this increase in subjects with LDL > 160mg/dL. The enzyme PON1 did not have its activity modified in none of the studied stages of hypercholesterolemia. The results presented in chapter I allow to conclude that oxidative stress ocurrs concomitantly to the inflamatory process during hipercholesterolemy. Besides, the use of enzyme PON1 activity in serum as an independent risk factor for cardiovascular diseases needs more clarification. In the second and third chapters, we observed that the addition of cholesterol (1%) in the diet of rabbits (60 days) induced serum hyperlipidemia, oxidative stress in serum and aortic tissue and atheroma formation in aortic tissue. ASX supplementation (50-100mg%) concomitant with cholesterol atenuated oxidative stress in a more pronounced way in aortic tissue than in serum, but did not prevent the increase in serum lipids nor atheroma formation in rabbits. These results indicate that despite the absence of hypolipidemic and antiatherogenic effect of ASX, this carotenoid exerts antioxidant effects in serum and aortic tissue of hypercholesterolemic rabbits. Taken together, the data of this thesis indicate the ocurrence of oxidative stress during hypercholesterolemia in humans and the ocurrence of atherosclerosis and oxidative stress in hypercholesterolemic rabbits. Despite ASX not having presented antiatherogenic effect in this work, more studies are necessary before a final conclusion about the potential of this carotenoid as an adjunct in prevention and therapy of cardiovascular diseases

Bioavailable Phenolic Compounds from Olive Pomace Present Anti-Neuroinflammatory Potential on Microglia Cells

The neuroinflammatory process is considered one of the main characteristics of central nervous system diseases, where a pro-inflammatory response results in oxidative stress through the generation of reactive oxygen and nitrogen species (ROS and RNS). Olive (Olea europaea L.) pomace is a by-product of olive oil production that is rich in phenolic compounds (PCs), known for their antioxidant and anti-inflammatory properties. This work looked at the antioxidant and anti-neuroinflammatory effects of the bioavailable PC from olive pomace in cell-free models and microglia cells. The bioavailable PC of olive pomace was obtained through the process of in vitro gastrointestinal digestion of fractionated olive pomace (OPF, particles size −1) was evaluated in BV-2 cells activated by lipopolysaccharide (LPS) for 24 h. The total bioavailable PC concentration and antioxidant activity against peroxyl radical were higher in the OPM than those observed in the OPF sample. The activation of BV-2 cells by LPS resulted in increased levels of ROS and nitric oxide (NO). The bioavailable PCs from both OPF and OPM, at their lowest concentrations, were able to reduce the ROS generation in activated BV-2 cells. In contrast, the highest PC concentration of OPF and OPM was able to reduce the NO levels in activated microglial cells. Our results demonstrate that bioavailable PCs from olive pomace can act as anti-neuroinflammatory agents in vitro, independent of particle size. Moreover, studies approaching ways to increase the bioavailability of PCs from olive pomace, as well as any possible toxic effects, are needed before a final statement on its nutritional use is made

The Hepatoprotective Effect of Jaboticaba Peel Powder in a Rat Model of Type 2 Diabetes Mellitus Involves the Modulation of Thiol/Disulfide Redox State through the Upregulation of Glutathione Synthesis

Jaboticaba peel powder (JPP) is rich in bioactive compounds, mainly soluble and insoluble polyphenols with great antioxidant properties. The aim of this study is to evaluate the effects of JPP supplementation on the oxidative stress and hepatic damage in a rat model of type 2 diabetes mellitus (T2DM). Diabetic rats received vehicle or JPP at 2.7 (JPP-I), 5.4 (JPP-II), or 10.8 (JPP-III) g/L in drinking water during 8 weeks. JPP-III attenuated hyperglycaemia and dyslipidemia increased by 86% the liver content of nonprotein thiol groups and by 90% the GSH/GSSG ratio by activating glutathione synthesis. Accordingly, JPP supplementation prevented the loss of activity of the sulfhydryl-dependent enzyme δ-aminolaevulinic acid dehydratase and attenuated hepatic injury assessed by the reduction of serum aspartate aminotransferase activity and liver hypertrophy. Our results support that JPP supplementation to T2DM rats decreases hepatic damage most likely by increasing glutathione synthesis and modulating the thiol/disulfide redox balance