Cucumis sativus Aqueous Fraction Inhibits Angiotensin II-Induced Inflammation and Oxidative Stress In Vitro

Role of Angiotensin II in Non-Alcoholic Steatosis Development

Fatty liver is a multifactorial disease characterized by excessive accumulation of lipids in hepatocytes (steatosis), insulin resistance, oxidative stress, and inflammation. This disease has a major public health impact because it is the first stage of a chronic and degenerative process in the liver that can lead to steatohepatitis, cirrhosis, and liver cancer. Although this disease is mainly diagnosed in patients with obesity, type 2 diabetes mellitus, and dyslipidemia, recent evidence indicates that vasoactive hormones such as angiotensin II (ANGII) not only promote endothelial dysfunction (ED) and hypertension, but also cause fatty liver, increase adipose tissue, and develop a pro-steatotic environment characterized by a low-grade systemic pro-inflammatory and pro-oxidant state, with elevated blood lipid levels. The role of ANGII in lipid accumulation has been little studied, so this review aims to summarize existing reports on the possible mechanism of action of ANGII in inducing lipid accumulation in hepatocytes.

Cucumber (Cucumis sativus L.) Fruit and Combination with Losartan Attenuate the Elevation of Blood Pressure in Hypertensive Rats Induced by Angiotensin II

Objectives

Cucumis sativus L. (C. sativus) is vegetable commonly used for managing blood pressure and often consumed in combination with standard antihypertensive therapy, despite lack of scientific evidence supporting their use. Combination of herbs and standard medication could have positive or negative effects. Therefore, this study aimed to evaluate the antihypertensive activity of C. sativus and the combined effect with losartan in the hypertensive rat model induced by angiotensin II. Angiotensin II is a component of the renin-angiotensin-aldosterone system that, upon binding to its receptor, constricts blood vessels leading to elevation of blood pressure.

Methods

In an antihypertensive study, rats received C. sativus orally at doses of 9, 18, 27, and 36 mg/kg (full dose); while in a combination study, animals received losartan 2.25 mg/kg combined by either with C. sativus 9 or 18 mg/kg. The standards group received losartan 2.25 mg/kg or 4.5 mg/kg (full dose).

Results

Blood pressure was measured using the tail-cuff method. C. sativus significantly attenuated angiotensin II-induced hypertension as observed in groups receiving C. sativus at 9, 18, 27, and 36 mg/kg at 30 minutes after induction showed the average change (Δ) of systolic blood pressure (SBP) and diastolic blood pressure (DBP) with respect to time zero were 28.8/18.3, 24.8/15.8, 22.8/15.5, and 11.5/9.0 mmHg, respectively. Whereas the average change (Δ) of SBP and DBP in the rats receiving the combination of half doses of C. sativus and losartan were 8.8/9.0 mmHg, respectively. These diminished effects were better than a full dose of C. sativus and comparable with a full dose of losartan (6.5/7.8 mmHg).

Conclusion

The present findings indicate that C. sativus dose-dependently blocks blood pressure elevation induced by angiotensin II. The combination of half dose of C. sativus and losartan has an additive effect in lowering blood pressure.

Aqueous Fraction from Cucumis sativus Aerial Parts Attenuates Angiotensin II-Induced Endothelial Dysfunction In Vivo by Activating Akt

BACKGROUND

Endothelial dysfunction (ED) is a marker of vascular damage and a precursor of cardiovascular diseases such as hypertension, which involve inflammation and organ damage. Nitric oxide (NO), produced by eNOS, which is induced by pAKT, plays a crucial role in the function of a healthy endothelium.

METHODS

A combination of subfractions SF1 and SF3 (C4) of the aqueous fraction from Cucumis sativus (Cs-Aq) was evaluated to control endothelial dysfunction in vivo and on HMEC-1 cells to assess the involvement of pAkt in vitro. C57BL/6J mice were injected daily with angiotensin II (Ang-II) for 10 weeks. Once hypertension was established, either Cs-AqC4 or losartan was orally administered along with Ang-II for a further 10 weeks. Blood pressure (BP) was measured at weeks 0, 5, 10, 15, and 20. In addition, serum creatinine, inflammatory status (in the kidney), tissue damage, and vascular remodeling (in the liver and aorta) were evaluated. Cs-AqC4 was also tested in vitro on HMEC-1 cells stimulated by Ang-II to assess the involvement of Akt phosphorylation.

RESULTS

Cs-AqC4 decreased systolic and diastolic BP, reversed vascular remodeling, decreased IL-1β and TGF-β, increased IL-10, and decreased kidney and liver damage. In HMEC-1 cells, AKT phosphorylation and NO production were increased.

CONCLUSIONS

Cs-AqC4 controlled inflammation and vascular remodeling, alleviating hypertension; it also improved tissue damage associated with ED, probably via Akt activation.

METABOLITE PROFILING, HYPOLIPIDEMIC, and ANTI-ATHEROSCLEROSIS ACTIVITY of MIXED VEGETABLE FERMENTATION EXTRACT

Although positive association between fermented vegetables intake with the risk of coronary heart disease (CHD) has increased attention nowadays, the metabolite profiling and the mechanism of action are still elusive. This study designed to investigate the secondary metabolites, hypolipidemic, and anti-atherogenic effect of mixed vegetable fermentation extract (MVFE). The metabolite screening of the MVFE was assessed using the Liquid Chromatography Tandem Mass Spectrophotometer (LC-MS/MS) method. The result of LC-MS/MS was used as ligands to inhibit the binding of oxidized LDL (oxLDL) and Cluster Differentiation 36 (CD36), Scavenger Receptor A1 (SRA1), Lectin-type oxidized LDL receptor 1 (LOX1). This work was performed with molecular docking using Discovery Studio 2021, PyRx 0.9, and Autodock Vina 4.2 followed by analyzing Network Pharmacology, Protein Protein Interaction (PPI) using Cytoscape 3.9.1 and String 2.0.0. Finally, the clinical effect of MVFE was evaluated using in vivo study. Twenty rabbits were assigned to normal, negative control, and MVFE group that were fed with standard diet, high fat diet (HFD), HFD supplemented with MVFE 100, 200 mg/kg BW, respectively. The serum level of Total Cholesterol (TC) and Low-Density Lipoprotein (LDL-c) were detected at the end of week 4. The LC-MS/MS analysis identified 17 compounds categorized as peptides, fatty acids, polysaccharides, nucleoside, flavonoids, flavanols, and phenolic compounds. Based on the docking study, more negative binding affinity was observed in the interaction between metabolites with the scavenger receptors (SR) than simvastatin. The number of nodes and edges based on Network Pharmacology analysis were 268 and 482, respectively. The PPI network showed that MVFE metabolites exerts its athero-protective effect by modulating various cellular processes including inflammation, improvement of endothelial function, and modulation of lipid metabolism. Blood TC and LDL-c concentrations in the negative control (458.82 ± 82.03; 191.87 ± 92.16 mg/dL) were higher significantly compared to the normal group (87.03 ± 29.27; 43.33 ± 5.75 mg/dL). The MVFE administration decreased the TC (100, 200 mg/kg BW MVFE: 269.96 ± 85.34; 130.17 ± 45.02 mg/dL) and LDL-c level (100, 200 mg/kg BW MVFE = 87.24 ± 22.85; 41.82 ± 11.08 mg/dL) dose-dependently (p < 0,001). The secondary metabolites derived from fermented mixed vegetables extract might be developed as a potential strategy to prevent CHD by targeting the multiple pathways in atherosclerosis.

Characterization of a murine model of endothelial dysfunction induced by chronic intraperitoneal administration of angiotensin II

Endothelial dysfunction (ED) is a key factor for the development of cardiovascular diseases. Due to its chronic, life-threatening nature, ED only can be studied experimentally in animal models. Therefore, this work was aimed to characterize a murine model of ED induced by a daily intraperitoneal administration of angiotensin II (AGII) for 10 weeks. Oxidative stress, inflammation, vascular remodeling, hypertension, and damage to various target organs were evaluated in treated animals. The results indicated that a chronic intraperitoneal administration of AGII increases the production of systemic soluble VCAM, ROS and ICAM-1 expression, and the production of TNFα, IL1β, IL17A, IL4, TGFβ, and IL10 in the kidney, as well as blood pressure levels; it also promotes vascular remodeling and induces non-alcoholic fatty liver disease, glomerulosclerosis, and proliferative retinopathy. Therefore, the model herein proposed can be a representative model for ED; additionally, it is easy to implement, safe, rapid, and inexpensive.

Comparison of pancreatic microcirculation profiles in spontaneously hypertensive rats and Wistar-kyoto rats by laser doppler and wavelet transform analysis

Pancreatic microcirculatory dysfunction emerged as a novel mechanism in the development of hypertension. However, the changes of pancreatic microcirculation profiles in hypertension remain unknown. Pancreatic microcirculatory blood distribution pattern and microvascular vasomotion of spontaneously hypertensive rats (SHRs) and Wistar Kyoto rats (WKYs) were determined by laser Doppler. Wavelet transform analysis was performed to convert micro-hemodynamic signals into time-frequency domains, based on which amplitude spectral scalograms were constructed. The amplitudes of characteristic oscillators were compared between SHRs and WKYs. The expression of eNOS was determined by immunohistochemistry, and plasma nitrite/nitrate levels were measured by Griess reaction. Additionally, endothelin-1, malondialdehyde, superoxide dismutase and interleukin-6 were determined by enzyme-linked immunosorbent assay. SHRs exhibited a lower scale blood distribution pattern with decreased average blood perfusion, frequency and amplitude. Wavelet transform spectral analysis revealed significantly reduced amplitudes of endothelial oscillators. Besides reduced expression of eNOS, the blood microcirculatory chemistry complements micro-hemodynamic profiles as demonstrated by an increase in plasma nitrite/nitrate, endothelin-1, malondialdehyde, interleukin-6 and a decrease of superoxide dismutase in SHRs. Here, we described abnormal pancreatic microcirculation profiles in SHRs, including disarranged blood distribution pattern, impaired microvascular vasomotion and reduced amplitudes of endothelial oscillators.

Iminosugar idoBR1 Isolated from Cucumber Cucumis sativus Reduces Inflammatory Activity

Cucumbers have been anecdotally claimed to have anti-inflammatory activity for a long time, but the active principle was not identified. idoBR1, (2R,3R,4R,5S)-3,4,5-trihydroxypiperidine-2-carboxylic acid, is an iminosugar amino acid isolated from fruits of certain cucumbers, Cucumis sativus (Cucurbitaceae). It has no chromophore and analytically behaves like an amino acid making detection and identification difficult. It has anti-inflammatory activity reducing lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNF-α) in THP-1 cells and ex vivo human blood. It showed selective inhibition of human α-l-iduronidase and sialidases from both bacteria (Tannerella forsythia) and human THP-1 cells. idoBR1 and cucumber extract reduced the binding of hyaluronic acid (HA) to CD44 in LPS-stimulated THP-1 cells and may function as an anti-inflammatory agent by inhibiting induced sialidase involved in the production of functionally active HA adhesive CD44. Similar to the related iminosugars, idoBR1 is excreted unchanged in urine following consumption. Its importance in the diet should be further evaluated.

Effect of Cucumis sativus on Dysfunctional 3T3-L1 Adipocytes

Obesity is caused by lipid accumulation in adipose tissues inducing adipocyte dysfunction, characterized by insulin resistance, increased lipolysis, oxidative stress, and inflammation, leading to increased levels of adipokines. Herein the capacity of the subfractions (SFs) SF1, SF2, and SF3 from the Cucumis sativus aqueous fraction and their combinations (M) to control adipocyte dysfunction in vitro, in 3T3-L1 adipocytes was studied. Adipocytes, previously treated with dexamethasone or IL-1 to induce dysfunction, were incubated with different concentrations of the subfractions for 24 h. 2-deoxyglucose consumption and glycerol release were evaluated, and a surface model was constructed to determine the most effective SF concentrations to improve both parameters. Effective SF combinations were assessed in their capacity to control metabolic, pro-oxidative, and pro-inflammatory conditions. SF1, SF2 (40 μg/ml each) and SF3 (20 μg/ml) improved 2-deoxyglucose consumption by 87%, 57%, and 87%, respectively. SF1 and SF2 (5 μg/ml each) and SF3 (40 μg/mL) increased glycerol secretion by 10.6%, 18.9%, and 11.8%, respectively. Among five combinations tested, only M4 (SF1 40 μg/ml:SF2 60 μg/ml:SF3 30 μg/ml) and M5 (SF1 40 μg/ml:SF2 60 μg/mL:SF3 10 μg/ml) controlled effectively the metabolic, pro-oxidative, and proinflammatory conditions studied. Glycine, asparagine, and arginine were the main components in these SFs.

Safety assessment of a standardized cucumber extract (Q-Actin™): Oral repeat-dose toxicity and mutagenicity studies

Cucumus sativus (cucumber) is one of the most widely consumed fruit vegetables worldwide. Recent discovery of iminosugars in commonly consumed fruits and vegetables has promoted the interest in isolating these compounds and understanding the potential benefits to human health. The objective of the present study was to investigate the general toxicity and mutagenic effects of an aqueous extract of cucumber (Q-Actin), standardized to ≥1% (1-2%) ido-BR1 iminosugar. Single dose of Q-Actin was well tolerated without mortality at 2000 mg/kg body weight (bw) in Sprague Dawley rats. Oral (gavage) administration of Q-Actin up to 1000 mg/kg bw/day was well tolerated followed by repeated administration for a maximum period of 90 days in Sprague-Dawley rats. There were no treatment related changes in clinical observations, ophthalmic examinations, body weights and body weight gains or feed consumption, clinical chemistry and pathological changes compared to control. The mutagenicity as evaluated by Ames assay, in vitro chromosomal aberration test and in vivo micronucleus assay did not reveal any potential of Q-Actin to induce genotoxicity. The results showed that Q-Actin is well tolerated in general toxicity studies and did not induce mutagenicity. The no-observed-adverse-effect level (NOAEL) of the standardized aqueous cucumber extract (Q-Actin) is considered to be ≥1000 mg/kg bw/day, followed by repeated administration for90 days.