Effect of polyphenols extracts from Brassica vegetables on erythrocyte membranes (in vitro study)

Anti-Diabetic and Antioxidant Activities of Red Wine Concentrate Enriched with Polyphenol Compounds under Experimental Diabetes in Rats

We obtained red wine concentrate, which was enriched with natural polyphenolic compounds (PC concentrate). The main purpose was to study the hypoglycemic and antioxidant effects of the red wine concentrate, and its impact on key hematological parameters of rats with experimental diabetes mellitus. While administrating the red wine concentrate to rats with diabetes, partial recovering of glucose tolerance was promoted, as well as normalization of glycated hemoglobin level, an increase in the quantity of erythrocytes and hemoglobin concentration. PC concentrate had anti-radical effect, which was determined using 2,2-diphenyl-1-picrylhydrazylradical (DPPH) method and effectively inhibited oxidation of phosphatidylcholine liposomes, induced by 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) as a free radical generator. It was also confirmed that PC concentrate had antioxidant properties in vivo. The contents of lipid peroxidation and protein oxidation products, the activity of catalase, and glutathione peroxidase (GPx) were increased in the plasma of rats with diabetes mellitus. At the same time, the activity of superoxide dismutase (SOD) was decreased. The concentrate of red wine had a corrective effect on investigated indicators and caused their normalization in plasma of diabetic animals.

Red cabbage anthocyanins: Stability, extraction, biological activities and applications in food systems

Red cabbage anthocyanins are of great interest as natural food colorants in the food industry; as they represent the color over a broad range of pH-values compared to anthocyanins from other natural sources. It is important to select an appropriate technique with high recovery of anthocyanins from red cabbage, among which extraction with organic solvents is the most applied extraction method. Currently, novel extraction techniques are employed as an alternative to the solvent extraction method, providing advantages such as higher anthocyanin recovery in a shorter time, lower solvent utilization, and minimum quality degradation. However, the incorporation of extracted anthocyanins into foodstuffs and pharmacological products is limited due to their low bioavailability and relative instability toward environmental adverse conditions, such as pH, temperature, enzymes, light, oxygen and ascorbic acid. In addition to increased structural stability of anthocyanins through glycosylation and acylation, their stability could be improved by copigmentation and encapsulation.

Chromolaena odorata (Siam weed): A natural reservoir of bioactive compounds with potent anti-fibrillogenic, antioxidative, and cytocompatible properties

Protein fibrillation and oxidative damage are closely associated with the development of many chronic diseases such as Alzheimer's disease, Parkinson's disease and transthyretin amyloidoses. This work aimed at evaluating the fibrillogenic, antioxidant, anti-oxidative, hemolytic and cytotoxic activities of phenolic-rich extract from Chromolaena odorata (L) R.M. King & H. Rob aerial parts (COPE). As revealed by Thioflavin-T fluorescence, transmission electron microscopy, NBT redox cycling and ANS fluorescence analyses, COPE suppressed the fibril formation of hen egg-white lysozyme by directly binding to the protein and preventing surface exposure its of hydrophobic clusters. In addition, COPE demonstrated potent radical scavenging activities against DPPH˙ and ABTS˙⁺, chelated ferrous ions, and inhibited metal-catalyzed oxidation of bovine serum albumin. The observed effects could be explained by the high content of flavonoids (22.82 QE/g) and phenolics (190 mg GAE/g) present in COPE. UHPLC-ESI-QTOF-MS/MS analysis of COPE in negative ionization mode revealed that the predominant compounds were phenolics and terpenoids. Furthermore, COPE was found to exert very minimal cytotoxic effects against human red blood cells (≤ 5% hemolysis) and human embryonic kidney (HEK-293) cells (≥ 80% viability). These findings suggested that with further investigations, phenolic-rich extract from C odorata could be effectively valorized for pharmacological applications against protein fibrillogenic and oxidative damage related conditions.

Red cabbage (Brassica oleracea L.) extract reverses lipid oxidative stress in rats

Red cabbage (Brassica oleracea L. var. capitata f. rubra DC.) extract has been demonstrated hypolipidemic and antioxidant capacity. Herein, we investigated the effect of red cabbage aqueous extract (RC) or fenofibrate (FF) in oxidative stress induced by Triton WR-1339 in rats. The antioxidant capacity was evaluated through the superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities and, thiobarbituric reactive species (TBARS) and protein carbonyl (PC) levels in erythrocytes, liver, kidneys, cerebral cortex and hippocampus of male rats. The alterations promoted by Triton WR-1339 in enzymatic antioxidant defense in the liver, kidneys and hippocampus were reversed by RC or FF treatments. The TBARS and PC levels increased in the liver, cerebral cortex and hippocampus of hyperlipidemic rats were decreased by the treatments with RC or FF. These findings demonstrated that RC is a potential therapy to treat diseases not only involving dyslipidemic condition but also oxidative stress.

Sous-vide technique as an alternative to traditional cooking methods in the context of antioxidant properties of Brassica vegetables

BACKGROUND

Vegetables are important components of the human diet. The method used to process them is crucial with respect to the nutritional quality of the ready-to-eat product. The present study aimed to assess whether the sous-vide method could represent an alternative for the traditional cooking of Brassica vegetables.

RESULTS

The sous-vide method appeared to be the most advantageous technique in relation to the preservation of vitamin C, both directly after processing and during the storage of processed vegetables. Among the studied phytochemicals, p-coumaric and gallic acids were found to be the most stable out of all the vegetables cooked by this method.

CONCLUSION

The sous-vide method should be considered as an optimal technique with respect to the thermal treatment of Brassica vegetables. © 2018 Society of Chemical Industry.

Enterodiol is Actively Transported by Rat Liver Cell Membranes

The interaction of enterodiol and the well-described polyphenol epigallocatechin gallate (EGCG) with hepatic membranes has been matter of interest in the last few years. On one hand, EGCG is only able to bind to the phospholipid polar head groups, as it has been already described in synthetic lipid bilayers and erythrocyte membranes but cannot get inserted into the hydrophobic core or be transported into the lumen of membrane vesicles. On the other, enterodiol has no interaction with non-energized membranes either, but it is able to interact and even be transported upon addition of ATP. In fact, the ATPase activity undergoes a twofold increase in the presence of enterodiol but not in the presence of EGCG. This is the first report on the transport of enterodiol by liver membranes, and it may help explain the rather high blood concentrations of this estrogenic enterolignan compared to EGCG, which is extensively metabolized by the intestine and the liver. The present results suggest that a fraction of enterodiol may escape the liver inactivation by being pumped out from the hepatocytes to the bloodstream.

Mentha pulegium crude extracts induce thiol oxidation and potentiate hemolysis when associated to t-butyl hydroperoxide in human's erythrocytes

Mentha pulegium (Lamiaceae) tea has been used as a traditional medicine; however, the modulatory effect of M. pulegium extracts on damage to human erythrocytes associated to t-butyl hydroperoxide (t-BHP) exposure remains to be investigated. Accordingly, we perform this study in order to test the hypothesis that aqueous and ethanolic extracts of M. pulegium could modulate the hemolysis associated to t-BHP exposure, non-protein thiol (NPSH) oxidation and lipid peroxidation (measured as thiobarbituric acid reactive substances - TBARS) in human erythrocytes. Samples were co-incubated with t-BHP (4 mmol/L) and/or aqueous or ethanolic extracts (10-1000 mg/mL) during 120 min to further analysis. We found that both extracts, when associated to t-BHP, potentiate NPSH oxidation and hemolysis. Moreover, both extracts significantly prevents against t-BHP-induced TBARS production. A significant correlation among hemolysis and NPSH levels was found. Taking together, our data points that the association of M. pulegium extracts with t-BHP culminates in toxic effect to exposed erythrocytes, besides its protective effect against t-BHP-induced TBARS production. So, we infer that the use of this extract may exert negative effect during painful crisis in sickle cell anemia. However, more studies are still necessary to better investigate/understand the mechanism(s) involved in the toxic effect resultant from this association.

Anthocyanin rich extract of Brassica oleracea L. alleviates experimentally induced myocardial infarction

Cardioprotective potential of anthocyanin rich red cabbage extract (ARCE) was assessed in H₂O₂ treated rat neonatal cardiomyoblasts (H9c2 cells) and isoproterenol (ISO) induced rodent model of myocardial infarction. H₂O₂ treated H9c2 cells recorded cytotoxicity (48–50%) and apoptosis (57.3%), the same were reduced in presence of ARCE (7–10% & 12.3% respectively). Rats pretreated with ARCE for 30 days followed by ISO treatment recorded favourable heart: body weight ratio as compared to ISO treated group. Also, the mRNA levels of enzymatic antioxidants (sod and catalase) and apoptotic genes (bax and bcl-2) in ARCE+ISO treated group were similar to the control group suggesting that ARCE pretreatment prevents ISO induced depletion of enzymatic antioxidants and apoptosis. Histoarchitecture of ventricular tissue of ISO treated group was marked by infracted areas (10%) and derangement of myocardium whereas, ARCE+ISO treated group (4.5%) recorded results comparable to control (0%). ARCE+ISO treated group accounted for upregulation of caveolin-3 and SERCA2a expression as compared to the ISO treated group implying towards ARCE mediated reduction in membrane damage and calcium imbalance. Molecular docking scores and LigPlot analysis of cyanidin-3-glucoside (-8.7 Kcal/mol) and delphinidin-3-glucoside (-8.5 Kcal/mol) showed stable hydrophobic and electrostatic interactions with β₁ adrenergic receptor. Overall this study elucidates the mechanism of ARCE mediated prevention of experimentally induced myocardial damage.

Antidiabetic Properties of an Apple/Kale Extract In Vitro, In Situ, and in Mice Fed a Western-Type Diet

Type 2 diabetes mellitus (T2DM) is a common and increasingly prevalent metabolic disorder, and effective preventive strategies against this disease are needed. The aim of the present study was to evaluate the potential antidiabetic properties of a dietary apple/kale extract (AKE), which was rich in phlorizin and flavonoids, in laboratory mice. Mice were fed a control diet, a Western-type high-sugar, high-fat diet (WTD), or a WTD plus AKE for 10 weeks. Body weight, food and energy intake, body composition, and blood glucose level were recorded in addition to the postprandial rise in blood glucose concentration after a single administration of glucose (oral glucose tolerance test, OGTT). Furthermore, changes in glucose-induced short-circuit current (I_SC) in response to AKE and phlorizin administration were evaluated in situ in intestinal tissues with Ussing chambers. In addition, the in vitro inhibition of α-glucosidase by AKE was determined. The present data suggest that supplementation of an AKE to a WTD significantly improved both blood glucose levels and OGTT in mice. Furthermore, in situ uptake of glucose was significantly inhibited by AKE. Finally, we showed that AKE significantly inhibits α-glucosidase activity in vitro. We conclude that AKE exhibits antidiabetic properties by a dual mechanism, including the inhibition of α-glucosidase and sodium-dependent glucose transporter 1 (SGLT1). Thus, AKE has the potential to serve as a natural plant bioactive compound for dietary prevention strategies against T2DM.

Assessment of bioactive metabolites and hypolipidemic effect of polyphenolic-rich red cabbage extract

CONTEXT

Cardiovascular disease is the leading cause of death worldwide and the consumption of red cabbage (Brassica oleracea var. capitata f. rubra DC. - Brassicaceae) has been linked with the reduction risk of chronic diseases.

OBJECTIVE

The present study assesses the bioactive metabolites and hypolipidemic effect of red cabbage on rats.

MATERIALS AND METHODS

The content of total phenols, flavonoids, anthocyanins, carotenoids, ascorbic acid and antioxidant capacity were assessed, while individual phenolic acids and flavonoids were detected using reverse phase-high performance liquid chromatography (HPLC) analysis. Acute hypolipidemic activity of aqueous extract of red cabbage (RC - 125, 250 and 500 mg/kg) was investigated using a Triton WR-1339 (400 mg/kg) induced hyperlipidemic Wistar rats compared to fenofibrate (65 mg/kg).

RESULTS

The HPLC analysis of extracts revealed eight phenolic acids, gallic, protocatechuic, p-hydroxybenzoic, m-coumaric, syringic, caffeic, cinnamic, dicaffeoylquinic and three flavonoids, epicatechin, epigallocatechin, gallocatechin. Furthermore, the aqueous extract showed higher amounts of total phenolics (116.00 mg/g), flavonoids (161.32 μg/g) and, antioxidant activity (87.19%) than the hydromethanolic (89.33 mg/g, 123.34 μg/g and 75.07%), respectively. The RC significantly (p < 0.001) ameliorated the levels of cholesterol, triglycerides and lipoproteins alterations in hyperlipidemic rats without toxicity.

DISCUSSION AND CONCLUSION

Herein, the RC presented the higher amounts of phenolics and flavonoids comparing with the hydromethanolic extract. Additionally, the RC showed as the majority compounds, dicaffeoylquinic and cinnamic acids, and the flavonoids epicatechin and gallocatechin. Furthermore, the RC demonstrated a beneficial effect against hypercholesterolemia and hypertriglyceridemia, demonstrating its potential therapeutic effect on these risk factors of cardiovascular diseases.

Beneficial effects of Plantago albicans on high-fat diet-induced obesity in rats

Obesity is a one of the main global public health problems associated with chronic diseases such as coronary heart disease, diabetes and cancer. As a solution to obesity, we suggest Plantago albicans, which is a medicinal plant with several biological effects. This study assesses the possible anti-obesity protective properties of Plantago albicans in high fat diet-fed rats. 28 male Wistar rats were divided into 4 groups; a group which received normal diet (C), the second group was fed HDF diet (HDF), the third group was given normal diet supplemented with Plantago albicans (P.AL), and the fourth group received HDF supplemented with Plantago albicans (HDF+P.AL) (30mg/kg/day) for 7 weeks. Our results showed an increase in body weight of HDF rats by ∼16% as compared to the control group with an increase in the levels of total cholesterol (TC) as well as LDL-cholesterol, triglycerides (TG) in serum. Also, the concentration of TBARS increased in the liver and heart of HDF-fed rats as compared to the control group. The oral gavage of Plantago albicans extract to obese rats induced a reduction in their body weight, lipid accumulation in liver and heart tissue, compared to the high-fat diet control rats. The obtained results proved that the antioxidant potency of Plantago albicans extracts was correlated with their phenolic and flavonoid contents. The antioxidant capacity of the extract was evaluated by DPPH test (as EC50=250±2.12μg/mL) and FRAP tests (as EC50=27.77±0.14μg/mL). These results confirm the phytochemical and antioxidant impact of Plantago albicans extracts. Plantago albicans content was determined using validated HPLC methodology.

Therapeutic effect of apple pectin in obese rats

Obesity is the most common nutritional disorder and is associated with significant comorbidities such as dyslipidemia, atherosclerosis and type 2 diabetes. This pathology is changing worldwide and is a risk factor for cardiovascular disease. This study, carried out on adult male Wistar rats, evaluates the inhibitory effects of supplementation with apple pectin molecule on obesity. Under our experimental conditions, administration of pectin molecule decreased 1) the total cholesterol (TC), LDL-cholesterol (LDL-ch) and triglycerides (TG) levels as well as ASAT, ALAT, LDH, ALP, UREA and uric acid (UC) levels in blood serum; and 2) increased the creatinine levels (CREA), compared to HFD group. TBARS concentrations decreased in liver, kidney, and serum by 20%, 29% and 19%, respectively, in a group treated with high-fat diet and pectin (HFD+Pec) compared to a HFD-treated group. The same treatment with pectin molecule increased superoxide dismutase, glutathion peroxidase and catalase activities by 39%, 14% and 16% in liver; 5%, 7% and 31% in kidney; and 9%, 32% and 22% in blood serum in the HFD Pec-treated group. The anti-obesity effects of the pectin molecule in several organs are mainly due to the interaction of this molecule with both the polysaccharide and the enzyme system which can be determined by phytochemical analysis.

Polyphenol compounds and PKC signaling

BACKGROUND

Naturally occurring polyphenols found in food sources provide huge health benefits. Several polyphenolic compounds are implicated in the prevention of disease states, such as cancer. One of the mechanisms by which polyphenols exert their biological actions is by interfering in the protein kinase C (PKC) signaling pathways. PKC belongs to a superfamily of serine-threonine kinase and are primarily involved in phosphorylation of target proteins controlling activation and inhibition of many cellular processes directly or indirectly.

SCOPE OF REVIEW

Despite the availability of substantial literature data on polyphenols' regulation of PKC, no comprehensive review article is currently available on this subject. This article reviews PKC-polyphenol interactions and its relevance to various disease states. In particular, salient features of polyphenols, PKC, interactions of naturally occurring polyphenols with PKC, and future perspective of research on this subject are discussed.

MAJOR CONCLUSIONS

Some polyphenols exert their antioxidant properties by regulating the transcription of the antioxidant enzyme genes through PKC signaling. Regulation of PKC by polyphenols is isoform dependent. The activation or inhibition of PKC by polyphenols has been found to be dependent on the presence of membrane, Ca(2+) ion, cofactors, cell and tissue types etc. Two polyphenols, curcumin and resveratrol are in clinical trials for the treatment of colon cancer.

GENERAL SIGNIFICANCE

The fact that 74% of the cancer drugs are derived from natural sources, naturally occurring polyphenols or its simple analogs with improved bioavailability may have the potential to be cancer drugs in the future.

Potential Properties of Plant Sprout Extracts on Amyloid β

The aim of this study is to examine the amyloid β (Aβ) inhibition mechanism of plant sprouts' aqueous extracts (PSAE). In this study, we screened the effects of five plant sprouts' extracts on Aβ (1–42) structure modification using gel electrophoresis. In PSAE, no band of Aβ monomer was recognized in Japanese butterbur. Similarly, the Aβ monomer band became light in buckwheat, red cabbage, broccoli, and brussels. The neuroprotective effects of PSAE were evaluated by measuring levels of Aβ in mixtures (Aβ  and PSAE) with Aβ ELISA assay. The treatment with PSAE decreased Aβ levels. The results indicated that the levels of red cabbage, Japanese butterbur, and broccoli were 9.6, 28.0, and 44.0%, respectively. The lowest value was observed with buckwheat. Furthermore, we carried out a Congo Red (CR) and Aβ binding experiment of PSAE to confirm the modification mechanism of PSAE. The correlation coefficient for the absorption spectrum peak of CR was found to be bigger than 0.8 (r = 0.882) which proved that the Aβ levels could be attributed to the peak of CR. In conclusion, we demonstrated that treatment with PSAE effectively decreases Aβ concentration. Thus, the mechanism that decreased the Aβ levels may be modification by PSAE.

The content of total polyphenols in different varieties of Solanum tuberosum grow in Spiš area

Phenolic compounds are the predominant antioxidants in nutrition and their study is currently being paid much attention. These antioxidants act synergistically; polyphenol compounds protect vitamin C and β-carotene, which in turn helps to increase the effect of vitamin E. Potatoes are very popular vegetables in Slovakia, not only in terms that they are easy to prepare, but also by the fact that they combine the wholesomeness of cereals and delicacy and characteristic chemical composition of vegetables. It is important that they find their place in our diet. Nutritional value of potatoes is determined by the content of nutrients such as protein, starch, fat, minerals, and absence of toxins, as well as by a significant content of bioactive components from the group of polyphenols. The study was performed in order to analyse 7 Slovak potato varieties from Spiš area, according to biologically active compounds: such as polyphenols. The content of total polyphenols was determined by the method of Lachman et al., (2003). The lowest determined content of total polyphenol (mg.kg-1 dry matter) in locality Spišský Štvrtok was measured in a variety Victoria (795.05 mg.kg-1 dry matter) and the highest content of total polyphenols in locality Spišský Štvrtok was measured in variety Laura (1238.42 mg.kg-1 dry matter). In the locality Odorín was determine the lowest content of total polyphenols in variety Red Anna (974.09 mg.kg-1 dry matter) and the highest content of total polyphenols was determined in variety Laura (978.95 mg.kg-1 dry matter). Between all varieties in locality Spišský Štvrtok was confirmed the statistically significant difference in the influence of the variety in the contents of total polyphenols (mg.kg-1 DM). This varietal dependence was not appear in samples taken in the locality Odorín. The total polyphenols content of the potatoes can be influenced by other factors, for example locality. In this case, there were statistically significant differences in the content of total polyphenols in variety Laura obtained from two different localities.

Antihypercholesterolemic effect of Cleome arabica L. on high cholesterol diet induced damage in rats

Dietary cholesterol is known to be one of the main risk factors that accelerate oxidation process leading to hypercholesterolemia and attendant cardiovascular diseases. The purpose of this study, carried out on adult male Wistar rats, was to evaluate the inhibitory effects of supplementation with aqueous of Cleome arabica leaf extract on hypercholesterolemia. After 3 months of treatment, animals were sacrificed by decapitation. Blood serum was obtained by centrifugation. Under our experimental conditions, administration of Cleome arabica leaf extract decreased the total cholesterol (TC), LDL-cholesterol (LDL-chol) and triglycerides (TG) levels by 27 %, 52 %, 37 %, respectively, and reduced SGOT SGPT, LDH and PAL levels in blood serum compared to untreated hypercholesterolemic rats. TBARS concentrations decreased by 21 % in liver, 22 % in heart and 30 % in kidney in a group of rats treated with cholesterol and Cleome arabica (Chol C.ar) compared to a Chol-treated group. The same treatment with Cleome arabica leaf extract increased superoxide dismutase and enhanced glutathione peroxidase activity. Catalase activity was found to increase in liver, heart and kidney by 17 %, 16 % and 23 %, respectively, in the C.ar Chol-treated group. The protective effect of Cleome arabica on hypercholesterolemia inducing oxidative stress in several organs was mainly attributed to antioxidant properties. The latter were due to the presence of phenolic acids and flavonoids shown by the obtained HPLC profiles.

Influence of membrane lipid composition on flavonoid-membrane interactions: Implications on their biological activity

The membrane interactions and localization of flavonoids play a vital role in altering membrane-mediated cell signaling cascades as well as influence the pharmacological activities such as anti-tumour, anti-microbial and anti-oxidant properties of flavonoids. Various techniques have been used to investigate the membrane interaction of flavonoids. These include partition coefficient, fluorescence anisotropy, differential scanning calorimetry, NMR spectroscopy, electrophysiological methods and molecular dynamics simulations. Each technique will provide specific information about either alteration of membrane fluidity or localization of flavonoids within the lipid bilayer. Apart from the diverse techniques employed, the concentrations of flavonoids and lipid membrane composition employed in various studies reported in literature also are different and together these variables contribute to diverse findings that sometimes contradict each other. This review highlights different techniques employed to investigate the membrane interaction of flavonoids with special emphasis on erythrocyte model membrane systems and their significance in understanding the nature and extent of flavonoid-membrane interactions. We also attempt to correlate the membrane localization and alteration in membrane fluidity with the biological activities of flavonoids such as anti-oxidant, anti-cancer and anti-microbial properties.

Matrix effects on the stability and antioxidant activity of red cabbage anthocyanins under simulated gastrointestinal digestion

Red cabbage is, among different vegetables, one of the major sources of anthocyanins. In the present study an in vitro digestion method has been used to assay the influence of the physiological conditions in the stomach and small intestine, as well as faecal microflora on anthocyanins stability in red cabbage and anthocyanin-rich extract. The recovery of anthocyanins during in vitro gastrointestinal digestion was strongly influenced by food matrix. The results showed that other constituents present in cabbage enhanced the stability of anthocyanins during the digestion. The amount of anthocyanins (HPLC method) and antioxidant capacity (ABTS and FRAP assays) strongly decreased after pancreatic-bile digestion in both matrices but total phenolics content (Folin-Ciocalteu assay) in these digestions was higher than in initial samples. Incubation with human faecal microflora caused further decline in anthocyanins content. The results obtained suggest that intact anthocyanins in gastric and products of their decomposition in small and large intestine may be mainly responsible for the antioxidant activity and other physiological effects after consumption of red cabbage.