Polyphenol-containing azuki bean (Vigna angularis) extract attenuates blood pressure elevation and modulates nitric oxide synthase and caveolin-1 expressions in rats with hypertension

A Comprehensive Review of the Chemical Constituents and Functional Properties of Adzuki Beans (Vigna angulariz)

The adzuki bean (Vigna angulariz), a member of the Vigna genus within the Leguminosae family, is native to China and extensively cultivated across East Asia. Renowned for its rich nutritional profile, the adzuki bean is abundant in carbohydrates, proteins, and bioactive compounds such as polysaccharides, polyphenols, flavonoids, saponins, and peptides. These components confer a wide range of health-promoting properties, including potent antioxidant, anti-inflammatory, antidiabetic, antiobesity, antibacterial, and neuroprotective effects. Notably, adzuki beans exhibit unique functional properties, such as high resistant starch content and the ability to modulate gut microbiota by promoting beneficial bacteria like Akkermansia, which enhance insulin sensitivity and lipid metabolism. These attributes make adzuki beans particularly effective in managing chronic diseases such as diabetes, obesity, and cardiovascular disorders. Additionally, adzuki beans show promise in addressing conditions like muscle atrophy, osteoporosis, and cancer. Processing methods such as fermentation and heat treatment further enhance their bioactive potential, underscoring their suitability for developing functional foods and nutraceuticals. This review highlights the chemical composition, functional activities, and mechanisms of adzuki beans, providing valuable insights for their application in food and pharmaceutical industries to prevent and manage chronic diseases.

Effects of Different Combinations of Phytochemical-Rich Fruits and Vegetables on Chronic Disease Risk Markers and Gene Expression Changes: Insights from the MiBLEND Study, a Randomized Trial

Adequate fruit and vegetable (F and V) intake, as recommended by the World Health Organization (over 400 g/day), is linked to reduced chronic disease risk. However, human intervention trials, especially with whole F and V and in complex combinations, are lacking. The MiBlend Study explored the effects of various phytochemical-rich F and V combinations on chronic disease risk markers, phytochemical absorption, and gene expression in blood. This randomized cross-over study involved participants consuming two of seven different F and V blends for 2 weeks (450 g/day), following a 2-week low F and V intake period (50 g/day). Each blend represented major phytochemical classes (flavonoids, anthocyanins, carotenoids, and glucosinolates) or combinations thereof. Markers of chronic disease risk, including DNA damage, oxidative stress, and retinal microvasculature, were measured. Increasing F and V intake significantly improved plasma antioxidant capacity, DNA damage protection, and retinal arteriolar dilation. Flavonoid-rich, carotenoid-rich, and complex blends notably reduced DNA damage susceptibility. Anthocyanin-rich and carotenoid-rich interventions were most effective in boosting antioxidant capacity, while blends high in flavonoids, especially combined with anthocyanins, significantly improved retinal microvasculature. Gene expression analysis revealed changes in DNA repair, signal transduction, and transcription processes, indicating mechanisms for these health benefits. The study suggests specific F and V blends can provide targeted health improvements, emphasizing the importance of both overall F and V intake and the specific phytochemical composition for personalized preventive strategies.

Elevating the significance of legume intake: A novel strategy to counter aging-related mitochondrial dysfunction and physical decline

Mitochondrial dysfunction increasingly becomes a target for promoting healthy aging and longevity. The dysfunction of mitochondria with age ultimately leads to a decline in physical functions. Among them, biogenesis dysfunction and the imbalances in the metabolism of reactive oxygen species and mitochondria as signaling organelles in the aging process have aroused our attention. Dietary intervention in mitochondrial dysfunction and physical decline during aging processes is essential, and greater attention should be directed toward healthful legume intake. Legumes are constantly under investigation for their nutritional and bioactive properties, and their consumption may yield antiaging and mitochondria-protecting benefits. This review summarizes mitochondrial dysfunction with age, discusses the benefits of legumes on mitochondrial function, and introduces the potential role of legumes in managing aging-related physical decline. Additionally, it reveals the benefits of legume intake for the elderly and offers a viable approach to developing legume-based functional food.

Antihypertensive effects of the combined extract of Sorghum bicolor, Vigna angularis, and Eleusine coracana in spontaneously hypertensive rats

This study investigated the antihypertensive effects of the combined extract of sorghum, adzuki bean, and finger millet (SAFE) on spontaneously hypertensive rats. The rats were divided into four groups (n = 8): WKY, SHR, SAFE (500 mg/kg SAFE), and CAP (50 mg/kg captopril). SAFE significantly decreased the lean-to-fat mass ratio with no notable changes in body weight, food intake, or food efficiency ratio, and it effectively lowered both systolic and diastolic blood pressures, comparable to CAP. Moreover, it significantly reduced the cardiac mass index and alleviated cardiac fibrosis. SAFE did not induce hepatotoxicity, as indicated by the maintenance of aspartate aminotransferase and alanine aminotransferase levels in the normal range, confirming its safety. Taken together, these findings suggested that SAFE can be used as a dietary supplement for blood pressure regulation and cardiovascular disease prevention.

Exploring the nutritional and health benefits of pulses from the Indian Himalayan region: A glimpse into the region's rich agricultural heritage

Pulses have been consumed worldwide for over 10 centuries and are currently among the most widely used foods. They are not economically important, but also nutritionally beneficial as they constitute a good source of protein, fibre, vitamins and minerals such as iron, zinc, folate and magnesium. Pulses, but particularly species such as Macrotyloma uniflorum, Phaseolus vulgaris L., Glycine max L. and Vigna umbellate, are essential ingredients of the local diet in the Indian Himalayan Region (IHR). Consuming pulses can have a favourable effect on cardiovascular health as they improve serum lipid profiles, reduce blood pressure, decrease platelet activity, regulate blood glucose and insulin levels, and reduce inflammation. Although pulses also contain anti-nutritional compounds such as phytates, lectins or enzyme inhibitors, their deleterious effects can be lessened by using effective processing and cooking methods. Despite their great potential, however, the use of some pulses is confined to IHR regions. This comprehensive review discusses the state of the art in available knowledge about various types of pulses grown in IHR in terms of chemical and nutritional properties, health effects, accessibility, and agricultural productivity.

Nutritional Composition, Efficacy, and Processing of Vigna angularis (Adzuki Bean) for the Human Diet: An Overview

Adzuki beans are grown in several countries around the world and are widely popular in Asia, where they are often prepared in various food forms. Adzuki beans are rich in starch, and their proteins contain a balanced variety of amino acids with high lysine content, making up for the lack of protein content of cereals in the daily diet. Therefore, the research on adzuki beans and the development of their products have broad prospects for development. The starch, protein, fat, polysaccharide, and polyphenol contents and compositions of adzuki beans vary greatly among different varieties. The processing characteristic components of adzuki beans, such as starch, isolated protein, and heated flavor, are reported with a view to further promote the processing and development of adzuki bean foods. In addition to favorable edibility, the human health benefits of adzuki beans include antioxidant, antibacterial, and anti-inflammatory properties. Furtherly, adzuki beans and extracts have positive effects on the prevention and treatment of diseases, including diabetes, diabetes-induced kidney disease or kidney damage, obesity, and high-fat-induced cognitive decline. This also makes a case for the dual use of adzuki beans for food and medicine and contributes to the promotion of adzuki beans as a healthy, edible legume.

Genetic Diversity and Environmental Influence on Yield and Yield-Related Traits of Adzuki Bean (Vigna angularis L.)

Adzuki beans are an important food legume crop in East Asia. A large number of adzuki bean accessions are maintained in the Chinese national seed genebank. A collection of 59 elite cultivars, 389 landraces, and 27 wild adzuki beans were selected and phenotyped extensively for yield and yield-related traits at two different locations (Nanning and Nanyang, China). Ten agronomic and yield-related traits were scored, and the data were subjected to analysis of variance (ANOVA), principal component analysis (PCA), correlation, and cluster analysis. Significant variation was observed for genotypes, locations, and genotype x environment interaction for most traits. Also, there were significant differences in the phenotypes among accessions of different germplasm types. The broad-sense heritability of traits studied ranged from 4.4% to 77.8%. The number of seeds per pod (77.8%), 100-seed weight (68.0%), and number of plant branches (63.9%) had a high heritability. A total of 10 traits were transformed into 3 comprehensive factors by principal component analysis, and the first three principal component factors contributed 72.31% of the total variability. Cluster analysis categorized the 475 adzuki bean accessions into five distinct groups. The results described in this study will be useful for adzuki bean breeders for the development of varieties with high end-use quality.

Finger Millet Ethanol Extracts Prevent Hypertension by Inhibiting the Angiotensin-Converting Enzyme Level and Enhancing the Antioxidant Capacity in Spontaneously Hypertensive Rats

Finger millet (Eleusine coracana) contains high levels of calcium and polyphenols, which have a variety of beneficial functions. We tested the hypothesis that finger millet ethanol extracts (FEs) have an antihypertensive effect in spontaneously hypertensive rats (SHRs). The study groups were assigned as follows: (1) Wistar Kyoto rats (normal); (2) SHRs treated with saline (negative control); (3) SHRs treated with captopril 50 mg/kg bw (positive control); (4) SHRs treated with FE 250 mg/kg bw (FE250); and (5) SHRs treated with FE 500 mg/kg bw (FE500). FE supplementation improved the lipid profiles, including the triglyceride, total cholesterol, and low-density lipoprotein cholesterol levels, without deterioration in liver function. The thiobarbituric acid reactive substance concentration and superoxide dismutase activity significantly improved after the application of FE250 and FE500. Interestingly, FE250 and FE500 application dramatically reduced the systolic blood pressure. FE supplementation exhibited powerful control over the renin-angiotensin system by reducing the angiotensin-converting enzyme levels and renin mRNA expression in the kidney. Additionally, FE500 application ameliorated vascular remodeling, reversed the thickening media, and decreased the media thickness/lumen diameter ratio of the aorta. These results imply that FEs are a potent antihypertensive nutraceutical for regulating the renin-angiotensin system and simultaneously inhibiting oxidative stress.

Black Soybean and Adzuki Bean Extracts Lower Blood Pressure by Modulating the Renin-Angiotensin System in Spontaneously Hypertensive Rats

Hypertension, causing cardiovascular disease, stroke, and heart failure, has been a rising health issue worldwide. Black soybeans and adzuki beans have been widely consumed throughout history due to various bioactive components. We evaluated the antihypertensive effects of black soybean and adzuki bean ethanol extracts on blood pressure, renin-angiotensin system (RAS), and aortic lesion in spontaneously hypertensive rats. A group of WKY (normal) and six groups of spontaneously hypertensive rats were administered with saline (SHR), 50 mg/kg of captopril (CAP), 250 and 500 mg/kg of black soybean extracts (BE250 and BE500), 250 and 500 mg/kg of adzuki bean extracts (AE250 and AE500) for eight weeks. BE250, BE500, AE250, and AE500 significantly (p < 0.05) reduced relative liver weight, AST, ALT, triglyceride, total cholesterol, systolic blood pressure, and angiotensin-converting-enzyme level compared to SHR. The angiotensin II level in AE500 and renin mRNA expression in BE500 and AE500 were significantly (p < 0.05) decreased compared to SHR. The lumen diameter was significantly (p < 0.05) reduced in only CAP. Furthermore, systolic and diastolic blood pressure and angiotensin II level in AE500 were lower than those of BE500. These results suggest that AE exhibit more antihypertensive potential than BE in spontaneously hypertensive rats.

Insight into the potential application of polyphenol-rich dietary intervention in degenerative disease management

In recent times, a great number of plants have been studied in order to identify new components with nutraceutical properties, among which are polyphenols. Dietary polyphenols represent a large group of bioactive molecules widely found in the food of plant origin and they have been found able to prevent the onset and progression of degenerative diseases, and to reduce and control their symptoms. These health protective effects have been mainly related to their antioxidant and anti-inflammatory properties. However, it must be considered that the application of isolated polyphenols as nutraceuticals is quite limited due to their poor systemic distribution and relative bioavailability. The present review highlights the potential effect of dietary intervention with polyphenol-rich food and plant extracts in patients with cancer, diabetes and neurodegenerative, autoimmune, cardiovascular and ophthalmic diseases, as well as the possible molecular mechanisms of action suggested in numerous studies with animal models.

Polyphenol-Rich Extract from Litchi chinensis Seeds Alleviates Hypertension-Induced Renal Damage in Rats

Litchi chinensis seed is a valuable byproduct of the subtropical fruit litchi (L. chinensis Sonn.), whose extract (LSE) has been confirmed to ameliorate dyslipidemia, hyperglycemia, and oxidative stress caused by type 2 diabetes. However, if LSE exerts an effect on anti-hypertension and hypertensive renal damage remains unknown. In this study, 13 polyphenols and one fatty acid were identified by UPLC-Q/TOF-MS. Network pharmacological analysis revealed that the therapeutic effects of LSE may be involved in multitargets and multipathways, such as the TNF signaling pathway, interleukin (IL)-6-mediated signaling pathway, NF-kappa B signaling pathway, removal of superoxide radicals, negative regulation of blood pressure, and so forth. Moreover, spontaneously hypertensive rats (SHRs) were daily gavaged with LSE (60 mg/kg) for 10 weeks. LSE remarkably reduced systolic blood pressure (SBP). The hypertension-induced renal damage was improved by suppressing inflammation and oxidative stress, which was consistent with the prediction of network pharmacology. In addition, LSE treatment remarkably increased the relative abundances of Lactobacillus and the production of short-chain fatty acids in the intestine. Our study indicated that a byproduct of litchi, namely, litchi seed, may be effective in reducing SBP and alleviating hypertensive renal damage.

Identification of anthocyanin compositions in black seed coated Korean adzuki bean (Vigna angularis) by NMR and UPLC-Q-Orbitrap-MS/MS and screening for their antioxidant properties using different solvent systems

The aim of the present research was to investigate the antioxidant properties and anthocyanin profiles in the black seed coated adzuki bean (Vigna angularis, Geomguseul cultivar). The acidic 60% methanol extract (40 μg/mL) contains the highest total phenolic and flavonoid contents (486 ± 3 mg GAE/100 g; 314 ± 10 mg CE/100 g) with potent antioxidant properties (trolox equivalent 1272 ± 26 and 662 ± 24 mg TE/100 g) against ABTS and DPPH radicals compared to other methanol-water ratios (20, 40, 80, and 100%). Ten anthocyanin components were identified in this extract including delphinidin-3,5-O-digalactoside (1), delphinidin-3,5-O-diglucoside (2), delphinidin-3-O-galactoside (3), delphinidin-3-O-glucoside (4), delphinidin-3-O-rutinoside (5), delphinidin-3-O-(p-coumaroyl)glucoside (6), cyanidin-3-O-glucoside (7), petunidin-3-O-galactoside (8), petunidin-3-O-glucoside (9) and petunidin-3-O-(p-coumaroyl)glucoside (10) via NMR spectroscopy and UPLC-Q-Orbitrap-MS/MS analysis. The key anthocyanins 3 and 4 of delphinidin type were isolated by reversed phase C-18 MPLC. Our results indicate that the anthocyanin profiles as well as the high phenolic and flavonoid contents are important factors determining the antioxidant effects of black adzuki bean.

Effect of Vigna angularis on High-Fat Diet-Induced Memory and Cognitive Impairments

High-fat diet (HFD)-induced obesity is related to cognitive and memory dysfunction. Much attention was focused on functional foods as a therapeutic strategy to treat cognitive decline by obesity. In the present study, we confirmed the protective effect of Vigna angularis (VA) on cognitive and memory impairment in an obese mouse model. For 16 weeks, mice were fed HFD and VA extract was administered during 4 weeks at 100 and 200 mg/kg. The cognitive abilities of HFD-induced mice were evaluated using behavioral tests. Compared with the control group, VA groups were improved spatial and recognition ability. In T-maze and novel object recognition tests, VA 100 and VA 200 groups showed increased ratios of exploration of a novel object/route compared to a familiar object/route. Moreover, VA 100 and VA 200 groups reached the platform faster than the control group in a Morris water maze test. Therefore, VA extract may protect against HFD-induced cognitive impairment and memory dysfunction. (PNU-IACUC; approval no. PNU-2019-2166).

The Drosophila Model: Exploring Novel Therapeutic Compounds against Neurodegenerative Diseases

Polyphenols are secondary metabolites of plants, fruits, and vegetables. They act as antioxidants against free radicals from UV light, pathogens, parasites, and oxidative stress. In Drosophila models, feeding with various polyphenols results in increased antioxidant capacity and prolonged lifespan. Therefore, dietary polyphenols have several health advantages for preventing many human diseases, including cardiovascular diseases, cancer, and neurodegenerative diseases. However, the exact role of polyphenols in neurodegenerative diseases is still yet to be completely defined. This review focuses on the most recent studies related to the therapeutic effect of polyphenols in neurodegenerative disease management and provides an overview of novel drug discovery from various polyphenols using the Drosophila model.

Fruits, vegetables, and health: A comprehensive narrative, umbrella review of the science and recommendations for enhanced public policy to improve intake

Fruit and vegetables (F&V) have been a cornerstone of healthy dietary recommendations; the 2015-2020 U.S. Dietary Guidelines for Americans recommend that F&V constitute one-half of the plate at each meal. F&V include a diverse collection of plant foods that vary in their energy, nutrient, and dietary bioactive contents. F&V have potential health-promoting effects beyond providing basic nutrition needs in humans, including their role in reducing inflammation and their potential preventive effects on various chronic disease states leading to decreases in years lost due to premature mortality and years lived with disability/morbidity. Current global intakes of F&V are well below recommendations. Given the importance of F&V for health, public policies that promote dietary interventions to help increase F&V intake are warranted. This externally commissioned expert comprehensive narrative, umbrella review summarizes up-to-date clinical and observational evidence on current intakes of F&V, discusses the available evidence on the potential health benefits of F&V, and offers implementation strategies to help ensure that public health messaging is reflective of current science. This review demonstrates that F&V provide benefits beyond helping to achieve basic nutrient requirements in humans. The scientific evidence for providing public health recommendations to increase F&V consumption for prevention of disease is strong. Current evidence suggests that F&V have the strongest effects in relation to prevention of CVDs, noting a nonlinear threshold effect of 800 g per day (i.e., about 5 servings a day). A growing body of clinical evidence (mostly small RCTs) demonstrates effects of specific F&V on certain chronic disease states; however, more research on the role of individual F&V for specific disease prevention strategies is still needed in many areas. Data from the systematic reviews and mostly observational studies cited in this report also support intake of certain types of F&V, particularly cruciferous vegetables, dark-green leafy vegetables, citrus fruits, and dark-colored berries, which have superior effects on biomarkers, surrogate endpoints, and outcomes of chronic disease.

Lancemaside A, a major triterpene saponin of Codonopsis lanceolata enhances regulation of nitric oxide synthesis via eNOS activation

Background

Many studies on the effect of saponin-rich Codonopsis lanceolata as a bioactive source for improving physical health have been performed. C. lanceolata contains triterpenoid saponins, including lancemasides. These saponins are known to be particularly involved in the regulation of blood pressure or hypertension. This study investigated whether lancemaside A (LA), a major triterpenoid saponin from C. lanceolata, regulates nitric oxide (NO) production via the activation of endothelial NO synthase (eNOS) in human umbilical vein endothelial cells.

Methods

Upon separation with petroleum ether, ethyl acetate, and n-butanol, LA was found to be abundant in the n-butanol-soluble portion. For further purification of LA, HPLC was performed to collect fraction, and LA was identified using analysis of LC/MSMS and ¹³C-NMR values. In in vitro, the effects of LA on NO release mechanism in HUVECs were investigated by Griess assay, quantitative real-time reverse-transcription PCR, and Western blotting.

Results

Our results showed that NO production was efficiently improved by treatment with LA in a dose-dependent manner. In addition, the LA treatment resulted in extensive recovery of the NO production suppressed by the eNOS inhibitor, L-NAME, compared with that in the control group. Additionally, the level of eNOS mRNA was increased by this treatment in a dose-dependent manner. These results suggested that LA is an inducer of NO synthesis via eNOS mRNA expression. Also, the study indicated that LA is involved in activating the PI3K/Akt/eNOS signaling pathway.

Conclusion

These results suggested that LA is an inducer of NO synthesis via eNOS mRNA expression. Also, the study indicated that LA is involved in activating the PI3K/Akt/eNOS signaling pathway. These findings suggest the value of using LA as a component of functional foods and natural pharmaceuticals.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2516-6) contains supplementary material, which is available to authorized users.

Chemical Constituents of Vigna luteola and Their Anti-inflammatory Bioactivity

Seventy-three compounds were identified from the methanol extract of V. luteola, and among these, three new (1–3) were characterized by spectroscopic and mass spectrometric analyses. The isolated constituents were assessed for anti-inflammatory potential evaluation, and several purified principles exhibited significant superoxide anion and elastase inhibitory effects.

Adzuki bean (Vigna angularis) extract reduces amyloid-β aggregation and delays cognitive impairment in Drosophila models of Alzheimer's disease

BACKGROUND/OBJECTIVES

Alzheimer's disease is a neurodegenerative disease that induces symptoms such as a decrease in motor function and cognitive impairment. Increases in the aggregation and deposition of amyloid beta protein (Aβ) in the brain may be closely correlated with the development of Alzheimer's disease. In this study, the effects of an adzuki bean extract on the aggregation of Aβ were examined; moreover, the anti-Alzheimer's activity of the adzuki extract was examined.

MATERIALS/METHODS

First, we undertook thioflavin T (ThT) fluorescence analysis and transmission electron microscopy (TEM) to evaluate the effect of an adzuki bean extract on Aβ₄₂ aggregation. To evaluate the effects of the adzuki extract on the symptoms of Alzheimer's disease in vivo, Aβ₄₂-overexpressing Drosophila were used. In these flies, overexpression of Aβ₄₂ induced the formation of Aβ₄₂ aggregates in the brain, decreased motor function, and resulted in cognitive impairment.

RESULTS

Based on the results obtained by ThT fluorescence assays and TEM, the adzuki bean extract inhibited the formation of Aβ₄₂ aggregates in a concentration-dependent manner. When Aβ₄₂-overexpressing flies were fed regular medium containing adzuki extract, the Aβ₄₂ level in the brain was significantly lower than that in the group fed regular medium only. Furthermore, suppression of the decrease in motor function, suppression of cognitive impairment, and improvement in lifespan were observed in Aβ₄₂-overexpressing flies fed regular medium with adzuki extract.

CONCLUSIONS

The results reveal the delaying effects of an adzuki bean extract on the progression of Alzheimer's disease and provide useful information for identifying novel prevention treatments for Alzheimer's disease.

Quality Characteristics and Antioxidant Activities of Rice/Adzuki Bean Mixtures Cooked Using Two Different Methods

This study explored the optimal preparation and the antioxidant levels of rice/adzuki bean mixtures. We compared the quality and physicochemical characteristics of cooked mixtures of rice and adzuki beans prepared using normal and high-pressure rice cookers, with and without the addition of alcohol (15%, v/v). The water-binding capacity and swelling power decreased upon addition of adzuki beans, but water solubility increased. The peak, trough, final, and setback viscosities decreased, but the breakdown viscosity increased. The total polyphenol and flavonoid contents increased after addition of adzuki beans. Total polyphenol contents in cooked rice/20% (w/w) Arari and Geomguseul bean mixtures in a normal cooker with addition of alcohol were 3.00 and 3.09 times higher than plain rice. The flavonoid contents were 10.33 and 8.90 times higher than plain rice. The predominant phenolic acids in cooked rice/Arari bean mixtures were p-coumaric acid and trans-3-hydroxycinnamic acid, and in cooked rice/Geomguseul bean mixtures, they were syringic acid and trans-3-hydroxycinnamic acid. Overall, phenolic acid levels were higher in mixtures cooked in plain water. The DPPH- and ABTS-radical-scavenging activities increased upon addition of adzuki beans. DPPH radical-scavenging activities in cooked rice/20% (w/w) Arari and Geomguseul bean mixtures in a normal cooker with addition of alcohol were 9.09 and 9.22 times higher than plain rice. ABTS radical-scavenging activities were 8.74 and 9.01 times higher than plain rice. Moreover, rice/adzuki bean mixtures prepared in a normal cooker, with addition of alcohol, exhibited higher antioxidant levels than other samples. We present the antioxidative properties of rice/adzuki bean mixtures prepared in different ways; these data will aid manufacturers.

Potential mechanisms underlying cardiovascular protection by polyphenols: Role of the endothelium

Epidemiological studies have indicated that regular intake of polyphenol-rich diets such as red wine and tea, are associated with a reduced risk of cardiovascular diseases. The beneficial effect of polyphenol-rich products has been attributable, at least in part, to their direct action on the endothelial function. Indeed, polyphenols from tea, grapes, cacao, berries, and plants have been shown to activate endothelial cells to increase the formation of potent vasoprotective factors including nitric oxide (NO) and to delay endothelial ageing. Moreover, intake of such polyphenol-rich products has been associated with the prevention and/or the improvement of an established endothelial dysfunction in several experimental models of cardiovascular diseases and in Humans with cardiovascular diseases. This review will discuss both experimental and clinical evidences indicating that polyphenols are able to promote endothelial and vascular health, as well as the underlying mechanisms.

Anti-Hypertensive Effects of Acacia Polyphenol in Spontaneously Hypertensive Rats

We have previously demonstrated that acacia polyphenol (AP) exerts strong anti-obesity, anti-diabetic, and anti-atopic dermatitis effects. In the present study, we investigated the anti-hypertensive effects of AP. Spontaneously hypertensive rats (SHR) with hypertension and control Wistar Kyoto rats (WKY) were used. WKY and SHR were fed AP-containing food or AP-free food (control group) ad libitum for 4 weeks, and their blood pressures were measured. After AP administration, both systolic and diastolic blood pressures were significantly lower in the SHR group than in the control group. There were no differences in the systolic or diastolic blood pressure of WKY between the AP group and the control group. Angiotensin-converting enzyme (ACE) activity, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase expression, and superoxide dismutase (SOD) activity in SHR kidneys were not altered by AP administration. Blood SOD activity in SHR was significantly higher in the AP group than in the control group. AP exerts anti-hypertensive effects on hypertension but has almost no effect on normal blood pressure. The anti-hypertensive effects of AP may be related to the anti-oxidative effects of increased blood SOD activity.

Antioxidant and angiotensin-I converting enzyme inhibitory activities of phenolic extracts and fractions derived from three phenolic-rich legume varieties

Lentil, black soybean and black turtle bean are commonly consumed legumes of different genera, containing high phenolic contents, which are effective antioxidants and angiotensin-I converting enzyme (ACE) inhibitors. However, these legumes' phenolic compositions and ACE inhibition ability have not been compared. Crude water extract (CE) was semi-purified (SPE) and fractionated using column chromatography. Results showed that purification and fractionation could substantially increase phenolic contents and antioxidant capacities. Heating and variety had great effect on phenolic substances, antioxidant potential and mass yield of extracts and fractions. Only crude extracts showed potent ACE inhibitory activity. Black turtle bean's ACE inhibition potential was largely reduced by cooking. The order from low to high in terms of ACE inhibitory activity was black turtle bean < lentil < black soybean. Identification and quantification of individual phenolic compounds by UV spectroscopy and LC-MSⁿ analysis confirmed 18, 22, and 14 compounds, respectively, for the three legumes.

Garcinia mangostana pericarp extract protects against oxidative stress and cardiovascular remodeling via suppression of p47phox and iNOS in nitric oxide deficient rats

Nω-Nitro-l-arginine methyl ester (l-NAME)-induced hypertension and cardiovascular remodeling are associated with oxidative stress and inflammation. Garcinia mangostana Linn., has been reported to have antioxidant and anti-inflammatory properties. This study investigated whether G. mangostana pericarp extract (GME) could prevent l-NAME-induced hemodynamic alterations, cardiovascular remodeling, oxidative stress and inflammation in rats. Male Sprague-Dawley rats were given 40mg/kg/day of l-NAME in drinking water to induce hypertension, and were simultaneously treated with GME at a dose of 200mg/kg/day. Rats that received l-NAME for five weeks had high blood pressure, left ventricular hypertrophy and thickening of aortic wall. Vascular superoxide production, plasma malondialdehyde (MDA), and plasma tumor necrosis factor alpha (TNF-α) were significantly increased in l-NAME-hypertensive rats (p<0.05). This was consistent with up-regulation of the p47phox NADPH oxidase subunit and iNOS protein expression in aortic tissues (p<0.05). Low levels of plasma nitric oxide metabolites were observed in l-NAME hypertension. GME prevented the development of hypertension and cardiovascular remodeling induced by l-NAME with reduced oxidative stress and inflammation. These data suggest that GME had a protective effect against l-NAME-induced hypertension and cardiovascular remodeling via suppressing p47phox NADPH oxidase subunit and iNOS protein expression resulting in enhancing NO bioavailability.

Identification of urinary metabolites with potential blood pressure-lowering effects in lentil-fed spontaneously hypertensive rats

PURPOSE

Urine samples were obtained from a previously completed study that showed lentil consumption attenuates the increase in blood pressure that occurs over time in spontaneously hypertensive rats (SHRs). The objective of the present study was to compare the metabolite profile of the urine samples from control and lentil-fed SHR in relation to the compounds present in lentils but not in other pulses.

METHODS

The urine samples were from 17-week-old, male SHR fed semi-purified diet prepared with powder (30 %, w/w) from cooked whole pulses or a pulse-free control diet (n = 8/group) for 4 weeks. Pulse powders, control diet and urine samples were extracted using acetonitrile and analyzed by a high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF-MS).

RESULTS

Twenty-seven metabolites were significantly different in urine samples from lentil-fed SHR compared to SHR fed control diet, but only 7 were not present in the urine of SHR fed other pulses. Of these metabolites, only citrulline is linked to blood pressure regulation via production of the vasodilator nitric oxide (NO). Several arginine-related compounds that are NO synthase substrates or inhibitors were detected in lentils but not the control diet or other pulse powders.

CONCLUSIONS

Consumption of lentils increases the availability of arginine and several related compounds that could potentially elevate production of NO and contribute to the blood pressure-lowering effects of lentil-rich diets.

Inhibition of Angiotensin Converting Enzyme, Angiotensin II Receptor Blocking, and Blood Pressure Lowering Bioactivity across Plant Families

Hypertension is a major risk factor for coronary heart disease, kidney disease, and stroke. Interest in medicinal or nutraceutical plant bioactives to reduce hypertension has increased dramatically. The main biological regulation of mammalian blood pressure is via the renin-angiotensin-aldosterone system. The key enzyme is angiotensin converting enzyme (ACE) that converts angiotensin I into the powerful vasoconstrictor, angiotensin II. Angiotensin II binds to its receptors (AT1) on smooth muscle cells of the arteriole vasculature causing vasoconstriction and elevation of blood pressure. This review focuses on the in vitro and in vivo reports of plant-derived extracts that inhibit ACE activity, block angiotensin II receptor binding and demonstrate hypotensive activity in animal or human studies. We describe 74 families of plants that exhibited significant ACE inhibitory activity and 16 plant families with potential AT1 receptor blocking activity, according to in vitro studies. From 43 plant families including some of those with in vitro bioactivity, the extracts from 73 plant species lowered blood pressure in various normotensive or hypertensive in vivo models by the oral route. Of these, 19 species from 15 families lowered human BP when administered orally. Some of the active plant extracts, isolated bioactives and BP-lowering mechanisms are discussed.

Synergistic Antihypertensive Effect of Carthamus tinctorius L. Extract and Captopril in L-NAME-Induced Hypertensive Rats via Restoration of eNOS and AT₁R Expression

This study examined the effect of Carthamus tinctorius (CT) extract plus captopril treatment on blood pressure, vascular function, nitric oxide (NO) bioavailability, oxidative stress and renin-angiotensin system (RAS) in N(ω)-Nitro-l-arginine methyl ester (l-NAME)-induced hypertension. Rats were treated with l-NAME (40 mg/kg/day) for five weeks and given CT extract (75 or 150 or 300 or 500 mg/kg/day): captopril (5 mg/kg/day) or CT extract (300 mg/kg/day) plus captopril (5 mg/kg/day) for two consecutive weeks. CT extract reduced blood pressure dose-dependently, and the most effective dose was 300 mg/kg/day. l-NAME-induced hypertensive rats showed abnormalities including high blood pressure, high vascular resistance, impairment of acetylcholine-induced vasorelaxation in isolated aortic rings and mesenteric vascular beds, increased vascular superoxide production and plasma malondialdehyde levels, downregulation of eNOS, low level of plasma nitric oxide metabolites, upregulation of angiotensin II type 1 receptor and increased plasma angiotensin II. These abnormalities were alleviated by treatment with either CT extract or captopril. Combination treatment of CT extract and captopril normalized all the abnormalities found in hypertensive rats except endothelial dysfunction. These data indicate that there are synergistic antihypertensive effects of CT extract and captopril. These effects are likely mediated by their anti-oxidative properties and their inhibition of RAS.

Asiatic acid alleviates cardiovascular remodelling in rats with L-NAME-induced hypertension

A previous study demonstrated the antihypertensive effect of asiatic acid. The current study investigates the effect of asiatic acid on cardiovascular remodelling and possible mechanisms involved in Nω -nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced hypertensive rats. Male Sprague-Dawley rats were treated with L-NAME (40 mg/kg per day) for 3 weeks in order to induce hypertension. Hypertensive rats were administered asiatic acid (20 mg/kg per day) or vehicle for a further 2 weeks. It was found that hypertensive rats showed high systolic blood pressure, left ventricular (LV) hypertrophy, increases in LV fibrosis, aortic wall thickness and aortic collagen deposition (P < 0.05). Moreover, decreased plasma nitrate and nitrite (NOx) and increased plasma tumor necrosis factor alpha (TNF-α) were observed in hypertensive rats (P < 0.05). This was consistent with downregulation of endothelial nitric oxide synthase (eNOS) expression and upregulation of inducible nitric oxide synthase (iNOS) expression in heart and aortic tissues (P < 0.05). Levels of malondialdehyde (MDA) in plasma, aortic and heart tissues were significantly increased in hypertensive rats (P < 0.05). Asiatic acid markedly reduced blood pressure, alleviated cardiovascular remodelling, and restored plasma NOx and TNF-α as well as eNOS/iNOS expression in heart and aortic tissues (P < 0.05). Additionally, there was a significant reduction of MDA levels in the tissues of treated hypertensive rats. In conclusion, this study demonstrates the therapeutic effects of asiatic acid on blood pressure and cardiovascular remodelling, which is possibly related to the restoration of eNOS/iNOS expression, and the resulting anti-inflammatory and antioxidant activities.

Lifespan Extending and Stress Resistant Properties of Vitexin from Vigna angularis in Caenorhabditis elegans

Several theories emphasize that aging is closely related to oxidative stress and disease. The formation of excess ROS can lead to DNA damage and the acceleration of aging. Vigna angularis is one of the important medicinal plants in Korea. We isolated vitexin from V. angularis and elucidated the lifespan-extending effect of vitexin using the Caenorhabditis elegans model system. Vitexin showed potent lifespan extensive activity and it elevated the survival rates of nematodes against the stressful environments including heat and oxidative conditions. In addition, our results showed that vitexin was able to elevate antioxidant enzyme activities of worms and reduce intracellular ROS accumulation in a dose-dependent manner. These studies demonstrated that the increased stress tolerance of vitexin-mediated nematode could be attributed to increased expressions of stress resistance proteins such as superoxide dismutase (SOD-3) and heat shock protein (HSP-16.2). In this work, we also studied whether vitexin-mediated longevity activity was associated with aging-related factors such as progeny, food intake, growth and movement. The data revealed that these factors were not affected by vitexin treatment except movement. Vitexin treatment improved the body movement of aged nematode, suggesting vitexin affects healthspan as well as lifespan of nematode. These results suggest that vitexin might be a probable candidate which could extend the human lifespan.

Antiangiogenic Effect of Ethanol Extract of Vigna angularis via Inhibition of Phosphorylation of VEGFR2, Erk, and Akt

Though dietary azuki bean (Vigna angularis) seed containing antioxidant proanthocyanidins was known to have multibiological activities including antioxidant, hypotensive, anti-inflammatory, and immunomodulatory activities, the antiangiogenic activity of ethanol extract of Vigna angularis (EVA) was never reported so far. In the present study, the antiangiogenic mechanism of EVA was examined in human umbilical vein endothelial cells (HUVECs). EVA showed weak cytotoxicity in HUVECs, while it significantly suppressed the VEGF induced proliferation of HUVECs. Consistently, wound healing assay revealed that EVA inhibited the VEGF induced migration of HUVECs. Also, EVA abrogated the VEGF induced tube formation of HUVECs in a concentration dependent fashion. Furthermore, Matrigel plug assay showed that EVA significantly reduced the hemoglobin level of Matrigel plug in mice compared to untreated control. Of note, EVA effectively attenuated the phosphorylation of VEGFR2, Erk, and Akt in VEGF-treated HUVECs. Overall, our findings suggest that EVA inhibits angiogenesis in VEGF-treated HUVECs via inhibition of phosphorylation of VEGFR2, ERK, and Akt.

Vigna nakashimae extract prevents hepatic steatosis in obese mice fed high-fat diets

Vigna species are important food resources and are traditionally used for the treatment of various diseases. In this study, we examined the inhibitory effects of Vigna nakashimae (VN) extract on high-fat diet (HFD)-induced hepatic steatosis and elucidated the molecular mechanisms. C57BL/6J mice were fed an HFD with or without VN extract for 16 weeks. VN extract decreased HFD-induced body weight, liver weight, hepatic lipid accumulation, and plasma alanine aminotransferase, and suppressed oxidative stress and inflammation associated with hepatitis. VN extract decreased plasma lipid levels and the expression of lipogenic genes in the livers of HFD-fed mice. VN extract significantly increased phosphorylation of adenosine monophosphate (AMP)-activated protein kinase (AMPK) and acetyl-CoA carboxylase, and expression of fatty acid oxidation genes in the liver of VN-treated HFD mice and HepG2 cells. Further, VN extract inhibited insulin or glucose-stimulated lipogenesis in HepG2 cells. In conclusion, VN extract prevents HFD-induced hepatic steatosis and lipotoxicity through AMPK activation.

Ellagic Acid Prevents L-NAME-Induced Hypertension via Restoration of eNOS and p47phox Expression in Rats

The effect of ellagic acid on oxidative stress and hypertension induced by Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) was investigated. Male Sprague-Dawley rats were administrated with L-NAME (40 mg/kg/day) for five weeks. L-NAME induced high systolic blood pressure (SBP) and increased heart rate (HR), hindlimb vascular resistance (HVR) and oxidative stress. Concurrent treatment with ellagic acid (7.5 or 15 mg/kg) prevented these alterations. Co-treatment with ellagic acid was associated with up-regulation of endothelial nitric oxide synthase (eNOS) protein production and alleviation of oxidative stress as indicated by decreased superoxide production in the vascular tissue, reduced plasma malondialdehyde levels, reduced NADPH oxidase subunit p47phox expression and increased plasma nitrate/nitrite levels. Our results indicate that ellagic acid attenuates hypertension by reducing NADPH oxidase subunit p47phox expression, which prevents oxidative stress and restores NO bioavailability.

Genistein from Vigna angularis Extends Lifespan in Caenorhabditis elegans

The seed of Vigna angularis has long been cultivated as a food or a folk medicine in East Asia. Genistein (4',5,7-trihydroxyisoflavone), a dietary phytoestrogen present in this plant, has been known to possess various biological properties. In this study, we investigated the possible lifespan-extending effects of genistein using Caenorhabditis elegans model system. We found that the lifespan of nematode was significantly prolonged in the presence of genistein under normal culture condition. In addition, genistein elevated the survival rate of nematode against stressful environment including heat and oxidative conditions. Further studies demonstrated that genistein-mediated increased stress tolerance of nematode could be attributed to enhanced expressions of stress resistance proteins such as superoxide dismutase (SOD-3) and heat shock protein (HSP-16.2). Moreover, we failed to find genistein-induced significant change in aging-related factors including reproduction, food intake, and growth, indicating genistein exerts longevity activity independent of affecting these factors. Genistein treatment also led to an up-regulation of locomotory ability of aged nematode, suggesting genistein affects healthspan as well as lifespan of nematode. Our results represent that genistein has beneficial effects on the lifespan of C. elegans under both of normal and stress condition via elevating expressions of stress resistance proteins.

Constituents of Vigna angularis and their in vitro anti-inflammatory activity

Nine non-phenolic compounds, including four furanylmethyl glycosides, angularides A-D, one ent-kaurane diterpene glycoside, angularin A, and four triterpenoid saponins, angulasaponins A-D, were isolated from seeds of Vigna angularis, together with eight known compounds. Their structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic analysis as well as chemical methods. Angularin A, angulasaponins A-C, and azukisaponins III and VI showed inhibition of nitric oxide production in LPS-activated RAW264.7 macrophages, with IC50 values ranging from 13μM to 24μM.

Asiatic acid reduces blood pressure by enhancing nitric oxide bioavailability with modulation of eNOS and p47phox expression in L-NAME-induced hypertensive rats

We investigated the effect of asiatic acid (AA) on hemodynamic status, vascular function, oxidative stress markers, endothelial nitric oxide synthase (eNOS), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit expression in Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced hypertensive rats. Male Sprague-Dawley rats treated with L-NAME (40 mg/kg/day) in drinking water for 5 weeks showed significant increases in mean arterial pressure, heart rate, hindlimb vascular resistance, vascular dysfunction, superoxide anion (O2(•-)) production, and plasma malondialdehyde. Moreover, NO metabolite (NOx) levels were reduced, aortic eNOS expression was downregulated, and NADPH oxidase subunit p47(phox) was upregulated in hypertensive rats (p < 0.05). Hypertensive rats that were administered AA (10 or 20 mg/kg/day) for the last 2 weeks of the study showed significant improvement in hemodynamic status and vascular function. The antihypertensive effects of AA were associated with elevated plasma NOx levels, together with upregulation of eNOS expression. Decreased vascular O2(•-) production, consistent with downregulation of p47(phox) expression, was also observed after AA treatment. Our results are therefore consistent with a model whereby AA reduces blood pressure by enhancing NO bioavailability.

Beneficial effects of polyphenols on cardiovascular disease

In recent years, numerous studies have demonstrated the health benefits of polyphenols, and special attention has been paid to their beneficial effects against cardiovascular disease, the leading cause of death in the world today. Polyphenols present vasodilator effects and are able to improve lipid profiles and attenuate the oxidation of low density lipoproteins. In addition, they present clear anti-inflammatory effects and can modulate apoptotic processes in the vascular endothelium. It has been suggested that most of these effects are a consequence of the antioxidant properties of polyphenols, but this idea is not completely accepted, and many other mechanisms have been proposed recently to explain the health effects of these compounds. In fact, different signaling pathways have been linked to polyphenols. This review brings together some recent studies which establish the beneficial properties of polyphenols for cardiovascular disease and analyzes the mechanisms involved in these properties.

Azuki bean polyphenols intake during lactation upregulate AMPK in male rat offspring exposed to fetal malnutrition

OBJECTIVE

Fetal malnutrition is an early-life inducer of dyslipidemia and glucose intolerance. The aim of this study was to examine whether maternal azuki bean (Vigna angularis) polyphenol (AP) intake during lactation affects the adenosine monophosphate-activated protein kinase (AMPK) pathway and lipid metabolism in offspring exposed to fetal malnutrition.

METHODS

Pregnant Wistar rats were divided into three groups: a control diet offered during gestation and lactation (CC), a low-protein diet during gestation and a control diet during lactation (LPC); and a low-protein diet during gestation and a 1.0% AP-containing control diet during lactation (LPAP). Male pups were randomly selected for the study; half the pups were sacrificed at 3 wk of age and the other half were fed a standard diet and sacrificed at 23 wk. Hepatic triacylglycerol levels, phosphorylation levels of AMPK and acetyl-coenzyme A carboxylase (ACC), and mRNA levels of sterol regulatory element-binding protein-1c (SREBP-1c) were evaluated.

RESULTS

Significant decreases in body weights and hepatic triacylglycerol levels were found in the LPAP compared with the LPC group. Plasma adiponectin levels in the LPAP group were higher than those in the LPC group. AMPK phosphorylation was upregulated in the livers and skeletal muscles in young and adult LPAP compared with LPC rats. ACC phosphorylation was upregulated in skeletal muscles of LPAP rats. SREBP-1c mRNA expression was decreased in the livers of LPAP rats.

CONCLUSION

Our results suggest that maternal AP intake during lactation upregulates AMPK phosphorylation not only in young but also in adult offspring exposed to fetal malnutrition and may lead to decreased hepatic lipid accumulation by ACC phosphorylation and downregulation of SREBP-1c expression.

Constituents from Vigna vexillata and their anti-inflammatory activity

The seeds of Vigna genus are important food resources and there have already been many reports regarding their bioactivities. In our preliminary bioassay, the chloroform layer of methanol extracts of V. vexillata demonstrated significant anti-inflammatory bioactivity. Therefore, the present research is aimed to purify and identify the anti-inflammatory principles of V. vexillata. One new sterol (1) and two new isoflavones (2,3) were reported from the natural sources for the first time and their chemical structures were determined by the spectroscopic and mass spectrometric analyses. In addition, 37 known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Among the isolates, daidzein (23), abscisic acid (25), and quercetin (40) displayed the most significant inhibition of superoxide anion generation and elastase release.

Tetrahydrocurcumin alleviates hypertension, aortic stiffening and oxidative stress in rats with nitric oxide deficiency

Tetrahydrocurcumin (THC), a major metabolite of curcumin, possesses strong antioxidant and cardioprotective properties. However, the activities of THC in hypertension and its associated complications remain unknown. The aim of this study was to investigate the effect of THC on hemodynamic status, aortic elasticity and oxidative stress in rats with N-nitro-L-arginine methyl ester (L-NAME)-induced hypertension. Hypertension was induced in male Sprague-Dawley rats by administration of L-NAME (50 mg kg(-1) body weight) in drinking water for 5 weeks. THC at a dose of 50 or 100 mg kg(-1) per day was administered daily during the fourth and fifth weeks when the hypertensive state had been established. The effects of THC on hemodynamics, aortic elasticity, endothelial nitric oxide synthase (eNOS) protein expression and oxidative stress markers were assessed. Marked increases in blood pressure, peripheral vascular resistance, aortic stiffness and oxidative stress were found in rats after L-NAME administration. THC significantly reversed these deleterious effects by reducing aortic wall thickness and stiffness. These effects were associated with increased aortic eNOS expression, elevated plasma nitrate/nitrite, decreased oxidative stress with reduced superoxide production and enhanced blood glutathione. Our results provide the first evidence that THC attenuates the detrimental effect of L-NAME by improving the hemodynamic status and aortic elasticity concomitant with reduction of oxidative stress. The present study suggests that THC might be used as a dietary supplement to protect against cardiovascular alterations under nitric oxide-deficient conditions.

Anti-inflammatory activity of ethanol extract derived from Phaseolus angularis beans

ETHNOPHARMACOLOGICAL SIGNIFICANCE

Phaseolus angularis Wight (adzuki bean) is an ethnopharmacologically well-known folk medicine that is prescribed for infection, edema, and inflammation of the joints, appendix, kidney and bladder in Korea, China and Japan.

AIM OF STUDY

The anti-inflammatory effect of this plant and its associated molecular mechanisms will be investigated.

MATERIALS AND METHODS

The immunomodulatory activity of Phaseolus angularis ethanol extract (Pa-EE) in toll like receptor (TLR)-activated macrophages induced by ligands such as lipopolysaccharide (LPS), Poly (I:C), and pam3CSK was investigated by assessing nitric oxide (NO) and prostaglandin (PG)E(2) levels. To identify which transcription factors such as nuclear factor (NF)-κB and their signaling enzymes can be targeted to Pa-EE, biochemical approaches including reporter gene assays, immunoprecipitation, kinase assays, and immunoblot analyses were also employed. Finally, whether Pa-EE was orally available, ethanol (EtOH)/hydrochloric acid (HCl)-induced gastritis model in mice was used.

RESULTS

Pa-EE dose-dependently suppressed the release of PGE(2) and NO in LPS-, Poly(I:C)-, and pam3CSK-activated macrophages. Pa-EE strongly down-regulated LPS-induced mRNA expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2. Interestingly, Pa-EE markedly inhibited NF-κB, activator protein (AP)-1, and cAMP response element binding protein (CREB) activation; further, according to direct kinase assays and immunoblot analyses, Pa-EE blocked the activation of the upstream signaling molecules spleen tyrosine kinase (Syk), p38, and transforming growth factor β-activated kinase 1 (TAK1). Finally, orally administered Pa-EE clearly ameliorated EtOH/HCl-induced gastritis in mice.

CONCLUSION

Our results suggest that Pa-EE can be further developed as a promising anti-inflammatory remedy because it targets multiple inflammatory signaling enzymes and transcription factors.

Antioxidant and vascular protective effects of curcumin and tetrahydrocurcumin in rats with L-NAME-induced hypertension

Inhibition of nitric oxide synthesis with N ( ω )-nitro-L-arginine methyl ester (L-NAME) induces marked hypertension and oxidative stress. Curcumin (CUR) has been shown strong antioxidant property. Tetrahydrocurcumin (THU), a major metabolite of CUR, possesses several pharmacological effects similar to CUR; however, it is less studied than CUR. We investigated whether CUR and THU could prevent vascular dysfunction and inhibit development of hypertension in L-NAME-treated rats. Male Sprague-Dawley rats were administered with L-NAME (50 mg/kg/day) in drinking water for 3 weeks. CUR or THU (50 and 100 mg/kg/day) was fed to animals simultaneously with L-NAME. L-NAME administration induced increased arterial blood pressure and elevated peripheral vascular resistance accompanied with impaired vascular responses to angiotensin II and acetylcholine. CUR and THU significantly suppressed the blood pressure elevation, decreased vascular resistance, and restored vascular responsiveness. The improvement of vascular dysfunction was associated with reinstating the marked suppression of eNOS protein expression in the aortic tissue and plasma nitrate/nitrite. Moreover, CUR and THU reduced vascular superoxide production, decreased oxidative stress, and increased the previously depressed blood glutathione (GSH) and the redox ratios of GSH in L-NAME hypertensive rats. The antihypertensive and some antioxidant effects of THU are apparently more potent than those of CUR. This study suggests that CUR and THU prevented the development of vascular dysfunction induced by L-NAME and that the effects are associated with alleviation of oxidative stress.