Protective effect of zingerone on increased vascular contractility in diabetic rat aorta

Hypoglycemic Ability of Sericin-Derived Oligopeptides (SDOs) from Bombyx mori Yellow Silk Cocoons and Their Physiological Effects on Streptozotocin (STZ)-Induced Diabetic Rats

Patients with diabetes require daily medication to maintain blood sugar levels. Nevertheless, the long-term use of antidiabetics can lose efficacy and cause degeneration in some patients. For long-term diabetes care, integrating natural dietary foods and medicine is being considered. This study investigated the impact of SDOs on blood sugar levels and their physiological effects on diabetic rats. We induced diabetes in male Wistar rats with STZ (50 mg/kg) and then administered an oral glucose tolerance test to determine the SDO dosage comparable to glibenclamide. The rats were divided into nine groups: normal, diabetic, and diabetic with insulin (10 U/kg), glibenclamide (0.6 mg/kg), bovine serum albumin (BSA; 200 mg/kg), soy protein isolate (200 mg/kg), or SDOs (50, 100, and 200 mg/kg). Diabetic rats administered SDOs had a higher body weight and serum insulin but a lower blood sugar than diabetic control rats. Biochemical assays indicated lower AST/SGOT, ALT/SGPT, BUN, and triglycerides but higher HDL in the SDO groups. Immunohistochemistry showed that SDOs reduced damaged islet cells, increased beta-cell size, and improved insulin levels while decreasing alpha cell size and glucagon. The vascular effects of SDOs were like those of normal control treatment and insulin treatment in diabetic rats. SDOs, a yellow silk protein, show potential for long-term diabetes care.

A review of some common African spices with antihypertensive potential

Hypertension is the most common non-communicable disease, with about 1.28 billion hypertensive people worldwide. It is more prevalent in men than women and more common in the elderly. Hereditary, age, obesity, lifestyle, diet, alcohol, and chronic metabolic diseases are the major risk factors of hypertension. Treating hypertension is a complex process as there are several mechanisms responsible for its pathogenesis; hence, a combination of several drugs is used for managing hypertension. Drugs used in managing hypertension are expensive and often come with associated side effects; thus, there is need for alternative means of managing this life-threatening disease. These drugs do not achieve the recommended blood pressure target in most people; more so majority of people with hypertension do not follow the treatment regimen religiously. Some Africans have been reported to become normotensive as a result of dietary consumption of spices. Several spices have been used over the years in Africa to manage hypertension. The aim of this review is to evaluate the ethnomedicinal use, bioactive phytochemical composition, bioactive compounds present, and pharmacological applications of spices commonly used in Africa for managing hypertension. Most of the plants used contained polyphenols, flavonoids, tannins, anthraquinone, flavonoids, cardiac glycosides, and saponins. Dietary supplementation of Xylopia aethiopica and other spices in diet have been proven to significantly reduced plasma angiotensin-I-converting enzyme (ACE) than simvastatin (the reference drug). Toxicological, histological, and hematological evaluation revealed that acute and chronic consumption of most of these spices are safe. Studies have also revealed that some of the spices can be used as alternative therapy alongside usual antihypertensive medications. PRACTICAL IMPLICATION: The prevalent rate of hypertension is on the increase in both the developed and developing countries. People often skip medication due to their busy schedule and anti-hypertensive potential side effects; however, this is not the case with food/spices as most people consumed them daily. Deliberate, right combinations and consistent incorporation of spices with proven anti-hypertensive potential into our diet may be of great benefit in normalizing blood pressure and mitigate other complications on the heart and vital organs.

Neonatal zingerone protects against the development of high-fructose diet-induced metabolic syndrome in adult Sprague-Dawley rats

During the early postnatal period, dietary manipulations can alter the developmental trajectory of the growing offspring, causing beneficial or adverse health outcomes later in adult life. We investigated the potential preventive effects of neonatal zingerone intake on the development of fructose-induced metabolic derangements in rats.Four-day old male and female Sprague-Dawley rat pups (n = 79) were randomly grouped and administered: 10 ml/kg body weight (bwt) of distilled water (W), 10 ml/kg bwt 20% fructose solution (FS), 10 ml/kg bwt fructose solution + 40 mg/kg bwt of zingerone in distilled water (ZF) or 40 mg/kg bwt of zingerone in distilled water (ZW) pre-weaning. After weaning, W and ZW continued on unlimited tap water, while FS and ZF continued on unlimited fructose solution for 10 weeks. Body mass and food and fluid intake were evaluated, plasma was collected for metabolic assays and visceral fat was quantified.Food intake was decreased, fructose and overall caloric intake were increased due to fructose feeding in both sexes (P < 0.05). When compared with the controls, the high-fructose diet significantly raised the terminal body masses of females (P < 0.0001), concentrations of triglycerides, total cholesterol, LDL-c, TG:HDL-c ratio and visceral fat mass relative to bwt in both sexes (P < 0.05). Zingerone prevented (P < 0.05) the fructose-induced increase in body mass (females) and hypercholesterolemia (both sexes). Levels of HDL-c, glycaemic parameters and adiponectin were not affected by the interventions (P > 0.05). Sex-related differences were observed in food, fluid and caloric intake, terminal mass, cholesterol subtypes and visceral fat percentage (P < 0.05).Zingerone could be used strategically in the neonatal phase as a prophylatic management of high-fructose diet-induced metabolic syndrome.

Improved Endothelium-Dependent Relaxation of Thoracic Aorta in Niclosamide-Treated Diabetic Rats

Diabetes-induced endothelial dysfunction is critical for the development of diabetic cardiovascular complications. The aim of this study was to investigate the effect of niclosamide (Nic) on vascular endothelial dysfunction in streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were injected with a single intraperitoneal injection of STZ (75 mg/kg) to induce type 1 diabetes, and Nic (10 mg/kg) was intraperitoneally administered per day for 4 weeks. Endothelial function was evaluated as carbachol (CCh, an endothelium-dependent vasodilator)-evoked relaxation in the experiments performed on isolated thoracic aortas. The changes in the protein expressions of phosphorylated eNOS at serine 1177 (p-eNOSSer1177) and phosphorylated VASP at serine 239 (p-VASPSer239) of the rat aortas were analyzed by western blotting to determine whether NO/cGMP signaling is involved in the mechanism of Nic. STZ-injected rats had higher fasting blood glucose and less body weight compared to control rats (p < 0.05). Nic treatment did not affect blood glucose levels or body weights of the rats. CCh-induced endothelium-dependent relaxation of the aortic rings was significantly decreased in diabetic rats compared to control (Emax = 66.79 ± 7.41% and 90.28 ± 5.55%, respectively; p < 0.05). CCh-induced relaxation response was greater in Nic-treated diabetic rats compared to diabetic rats (Emax = 91.56 ± 1.20% and 66.79 ± 7.41%, respectively; p < 0.05). Phosphorylation of eNOS and VASP in aortic tissues was significantly reduced in diabetic rats, which were markedly increased by Nic treatment (p < 0.05). We demonstrated that Nic improved endothelial dysfunction possibly through the activation of NO/cGMP signaling without affecting hyperglycemia in diabetic rats. Our results suggesting that Nic has potential of repurposing for diabetic cardiovascular complications.

The Possible Protective Role of Zingerone on Ethanol Induced Entrotoxicity of Jejunum in Adult Albino Rats: Light and Scanning Electron Microscopic Study

Introduction:

Zingerone is a nontoxic important extract of dry ginger plant. It is reported that zingerone has an anticancer property, strong anti-inflammatory and antimicrobial properties.

Aim of the Work:

is to evaluate the possible protective effects of zingerone on ethanol-induced lesions on the jejunum of adult male albino rats.

Materials and Methods:

twenty four adult male albino rats were used, divided into 3 groups; A control group (I); consisted of 8 rats, ethanol group (II); contained 8 rats and each rat given 50% v/v alcohol at a dose of 4 g/kg.bw orally for 15 days. Ethanol zingerone group (III); consisted of 8 rats, each received zingerone at a dose of 50 mg/kg and alcohol at the same previous dose daily and orally for 15 days. At the appropriate time, the specimens were taken and prepared for light and electron microscope study.

Results:

Histological examination of jejunum sections of ethanol group (II) showed massive jejunal villi ulcerations with shedding of their surface epithelium, loss of the villous architecture and loss of the microvilli covering some enterocytes. Examination of ethanol zingerone group (III) showed evidence of improvement in the form of nearly normal architecture of the jejunal villi with few areas of ulcerations on the top of some villi and increased cells with mitotic activity.

Conclusion:

Accordingly, we can conclude that zingerone administration can remarkably ameliorate ethanol-induced enterotoxiciy and jejunal ulcerations in rats by its anti-inflammatory properties and by suppressing oxidative stress.

New flavonoid-based compound synthesis strategy for antihypertensive drug development

Hypertension is one of the leading causes of mortality in relation to the cardiovascular conditions and easily the most overlooked and poorly managed disease in mankind. With well over 200 drugs available in the market globally, there is still an urgency to search for antihypertensive alternatives due to the subpar efficacy and unwarranted side effects of the current choices. Present studies reported over 250 types of plant-derived compounds were being investigated for potential pharmacological effects on the vasculature in the last 3 decades. There were numerous literatures that claimed various compounds exhibiting vasorelaxant properties to a certain extent with low numbers of these compounds being successfully adapted into the current medicinal practice for treatment of hypertension. The issue is the scarcity of reviews that summarizes the discovery of this field and the lack of thorough comparison of these compounds to identify which of these vasodilators should be the next face of hypertension management. Thus, this review is aiming towards identifying the relationship between a major class of plant-derived compounds, flavonoid's activity as a vasodilator with their signalling pathways and their structural characteristics according to their vasorelaxant properties. Interestingly, we found that both nitric oxide and voltage-operated calcium channels pathways, and two of the flavonoid's structural characteristics play crucial roles in eliciting strong vasorelaxant effects. We have faith that the insights of this review will serve as a reference for those researching similar topics in the future and potentially lead to the development of more promising antihypertensive alternative.

Zingerone (4-(4-hydroxy-3-methylphenyl) butan-2-one) protects against alloxan-induced diabetes via alleviation of oxidative stress and inflammation: Probable role of NF-kB activation

Diabetes is considered as the most common metabolic disease affecting millions of people all around the world. Use of natural herbal medicines can be effective in treating diabetes. Zingerone (4-(4-hydroxy-3-methylphenyl) butan-2-one) a polyphenolic alkanone extracted from ginger has a broad spectrum of pharmacological properties and thus can be used as a promising candidate against various ailments. In the current study we aimed at demonstrating the protective effect of zingerone against diabetes mellitus and elucidating its possible mechanism. Five groups of animals (I-V) were made with ten animals each. Group I (control) was given normal saline orally. Group II (diabetic positive control) was given alloxan at the dose rate of 100 mg/kg bwt once. Group III and IV was given alloxan once at the dose rate of 100 mg/kg bwt. and received oral treatment of zingerone at a dose rate of 50 and 100 mg/kg bwt respectively daily for 21 days. Group V was given alloxan at the dose of 100 mg/kg bwt. and was treated with standard drug glibenclamide at the dose rate of 4.5 mg/kg bwt. daily for 21 days. According to our findings we confirmed that zingerone restrained the alloxan induced oxidative stress by increasing the activity of reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and reducing the peroxidative damage. We also confirmed that zingerone suppressed the level of redox sensitive transcription factor NFκB and downregulated other downstream inflammatory cytokines like interleukins (IL1-β IL-2, IL-6) and tumor necrosis factor alpha (TNF-α). Moreover, the experimental findings suggested that zingerone improved the insulin levels. Taken together our results indicated that zingerone effectively ameliorated the diabetes induced complications which provide a strong theoretical basis for zingerone to be used clinically for treatment of diabetes.

Arginase overexpression and NADPH oxidase stimulation underlie impaired vasodilation induced by advanced glycation end products

BACKGROUND

Advanced glycation endproducts (AGEs) play a major role in the development of many vascular complications that are mediated by endothelial dysfunction. The present work aimed to investigate the mechanism by which AGEs impair vasodilation.

METHODS

The effect of AGEs on vasodilation induced by acetylcholine or D NONOate was examined by incubating isolated rat aortae with different AGEs concentrations. ACh-induced nitric oxide generation was assessed using the fluorescent probe diaminofluorecein (DAF-FM). The effect of AGEs on expression of mRNA for arginase 2, NADPH oxidase and endothelial nitric oxide synthase (eNOS) were determined by real-time PCR.

RESULTS

One-hour in vitro incubation of rat aortae with AGEs impaired endothelial-dependent vasodilation produced by ACh, while increasing D NONOate-induced vasodilation. Preincubation of aortae with l-ornithine, an arginase 2-inhibitor, prevented the impairment effect induced by AGEs on endothelial-dependent vasodilation. Superoxide scavenging by tempol or NADPH oxidase inhibition by apocynin also blocked the effect of AGEs. AGEs decreased ACh-induced NO production and this was inhibited by both l-ornithine and apocynin. Furthermore, AGEs exposure increased arginase mRNA expression but decreased mRNA expression for eNOS in isolated rat aortae.

CONCLUSION

The present results indicate that AGEs impairs endothelial-dependent vasodilation, and this effect is mediated via arginase overexpression and NADPH oxidase stimulation.

Zingerone alleviates the delayed ventricular repolarization and AV conduction in diabetes: Effect on cardiac fibrosis and inflammation

Background

The study aims to analyse the action of zingerone in diabetes-related cardiac arrhythmias.

Methods

Diabetes was induced by streptozocin while treatment groups received 20 mg/kg zingerone daily. Following extra seven weeks, electrocardiography, extraction of blood, urine and heart for biochemical analysis, histopathology and immunofluorescence were undertaken.

Results

The suppression of QT and QTc prolongation in diabetic rats was indicative of prolonged cardiac repolarisation that was greatly reduced by zingerone treatment. In addition, the reduction in PR interval attested that zingerone improved AV delay in diabetic rats. The fibrogenic transforming growth factor β1 upregulation in diabetic hearts was suppressed by zingerone. The marked glycogen deposition and muscle degeneration seen in diabetic heart sections were also alleviated by zingerone. Furthermore, zingerone prevented the decrease in of the serum anti-inflammatory cytokine adiponectin in diabetics. The heightened levels of oxidative stress markers 8-isoprostane and uric acid in diabetic rats were suppressed. In the diabetic heart, the reduced catalase activity was improved and the excessive expression of angiotensin receptor 1 was inhibited by zingerone.

Conclusion

Cardiac delayed repolarisation and AV conduction in rats with diabetes were halted by zingerone. It appears that inhibition of cardiac fibrosis and associated inflammation-oxidative stress signalling underpins the zingerone effect.

Phenolics from Garcinia mangostana alleviate exaggerated vasoconstriction in metabolic syndrome through direct vasodilatation and nitric oxide generation

BACKGROUND

Exaggerated vasoconstriction plays a very important role in the hypertension, a major component of metabolic syndrome (MetS). In the current work, the potential protective effect of methanol extract of fruit hulls of Garcinia mangostana L. on the exaggerated vasoconstriction in MetS has been investigated. In addition, the bioactive fraction and compounds as well as the possible mechanism of action have been illustrated.

METHODS

The effect of methanol extract of G. mangostana (GMT) fruit hulls on the vascular reactivity of aorta isolated from animals with MetS was investigated through bioassay-guided fractionation procedures. GMT was partitioned with chloroform (I) and the remaining mother liquor was fractionated on a Diaion HP-20 with H2O, 50 and 100 % methanol to give fractions II, III, and IV, respectively. The effect of total extract (GMT), bioactive fraction and the bioactive compounds on the vasoconstriction were examined in aortae isolated from animals with MetS by incubation for 30 min before exposing aortae to cumulative concentrations of phenylephrine (PE). The direct relaxant effect was also examined by adding cumulative concentrations of the bioactive fraction and its bioactive compounds to PE precontracted vessels. In addition, aortic nitric oxide (NO) and reactive oxygen species (ROS) production was investigated.

RESULTS

Bioassay-guided fractionation of GMT revealed isolation of garcimangosone D (1), aromadendrin-8-C-β-D-glucopyranoside (2), 2,4,3'-trihydroxy benzophenone-6-O-β-D-glucopyranoside (3), maclurin-6-O-β-D-glucopyranoside (rhodanthenone) (4), epicatechin (5), and 2,3',4,5',6-pentahydroxy benzophenone (6). Only compounds 2, 4, and 5 significantly alleviated the exaggerated vasoconstriction of MetS aortae and in the same time showed significant vasodilation of PE pre-contracted aortae. To further illustrate the mechanism of action, the observed vasodilation was completely blocked by the nitric oxide (NO) synthase inhibitor, Nω-nitro-L-arginine methyl ester hydrochloride and inhibited by guanylate cyclase inhibitor, methylene blue. However, vasodilation was not affected by the potassium channel blocker, tetraethylammonium or the cyclooxygenase inhibitor, indomethacin. In addition, compounds 2, 4, and 5 stimulated NO generation from isolated aortae to levels comparable with acetylcholine. Furthermore, 4 and 5 inhibited reactive oxygen species generation in MetS aortae.

CONCLUSION

The phenolic compounds 2, 4, and 5 ameliorated the exaggerated vasoconstriction in MetS aortae through vasodilatation-NO generation mechanism.