Effect of S-allylcysteine against diabetic nephropathy via inhibition of MEK1/2-ERK1/2-RSK2 signalling pathway in streptozotocin-nicotinamide-induced diabetic rats

OBJECTIVE

In the current study, we evaluated the ameliorative effect of S-allylcysteine (SAC) against streptozotocin (STZ)-nicotinamide (NAD)-induced diabetic nephropathy (DN) in rats and also an attempt was made to establish the molecular mechanism of SAC.

METHODS

DN rats were orally supplemented with SAC (150 mg/kg body weight) for a period of 45 days and the effect of SAC on urinary albumin excretion, metabolic parameters, and tubular injury biomarkers by ELISA, total levels and phosphorylation of MEK1/2, ERK1/2, and RSK2 by western blotting analysis in control and experimental rats were assessed.

RESULTS

From this study, we observed that SAC considerably decreased polydipsia, poly urea, polyphagia, albuminuria and the levels of urinary N-acetyl-beta-D-glucosaminidase, neutrophil gelatinase-associated lipocalin, transforming growth factor-β1 and SAC effectively altered the pathological changes in DN rats. SAC also reserved renal cortical phosphorylation of MEK1/2, ERK1/2 and RSK2.

CONCLUSION

Hence this study recommended that SAC can successfully protect the DN through regulation of MEK1/2-ERK1/2-RSK2 signalling.

Polyherbal Formulation Ameliorates Diabetic Cardiomyopathy Through Attenuation of Cardiac Inflammation and Oxidative Stress Via NF-κB/Nrf-2/HO-1 Pathway in Diabetic Rats

ABSTRACT

The present study was intended to evaluate the effect of polyherbal formulation (PHF) made with 3 nutraceuticals, such as Piper nigrum, Terminalia paniculata, and Bauhinia purpurea on inflammation and oxidative stress in diabetic cardiomyopathy (DCM), which is induced by streptozotocin and nicotinamide administration in rats. We supplemented DCM rats with PHF (250 and 500 mg/kg/BW) for 45 days and evaluated their effects on oxidative stress markers, proinflammatory cytokines, and messenger RNA expressions of the nuclear factor erythroid 2-related factor-2 (Nrf-2) and its linked genes [heme oxygenase-1 (HO-1), superoxide dismutase, catalase] along with inflammatory genes [tumour necrosis factor α and nuclear factor kappa B (NF-κB)]. Our study demonstrated that PHF successfully attenuated inflammation and oxidative stress via messenger RNA upregulation of Nrf-2, HO-1, superoxide dismutase, and catalase and concomitantly with downregulation of tumour necrosis factor α and NF-κB. Conversely, PHF also protected hyperglycemia-mediated cardiac damage, which was confirmed with histopathological and scanning electron microscopy analysis. In conclusion, our results suggested that PHF successfully ameliorated hyperglycemia-mediated inflammation and oxidative stress via regulation of NF-κB/Nrf-2/HO-1 pathway. Therefore, these results recommend that PHF may be a prospective therapeutic agent for DCM.

Bioactive Compounds in Diabetic Cardiomyopathy: Current Approaches and Potential Diagnostic and Therapeutic Targets

BACKGROUND

Diabetic Cardiomyopathy (DCM) has an adverse effect on health and occurs with or without concurrent vascular disease. Although several pathological mechanisms have been implicated in DCM, oxidative stress is widely thought to be the foremost cause for DCM pathogenesis.

OBJECTIVE

In this review, we focused on the role of bioactive compounds from different sources such as plant and marine products in cardiomyopathy.

RESULTS

Natural Products (NPs) and their constituents were traditionally considered implausible as therapeutic agents. In the last few decades, studies on the use of NPs in the pharmaceutical field have reduced due to problems such as the requirement of compatibility of conventional NP extract libraries with high-throughput selection. The characteristics of NP structures such as high chemical variety, biochemical specificity, and other molecular properties that make them favorable as direct structures for drug synthesis and that distinguish them from combinatorial and synthetic compound libraries have been documented since ancient times.

CONCLUSION

Consequently, the aim of this review was to provide an overview on the recent progress and development of bioactive compounds in DCM and to focus on the cellular mechanisms underlying cardiomyocyte dysfunction in their therapeutic targets.

Reversal of high fat diet-induced obesity through modulating lipid metabolic enzymes and inflammatory markers expressions in rats

In this study, we evaluated the ameliorative potential of Cucurbita maxima seeds oil (CSO (100 mg/kg body weight)) supplementation to high fat diet (HFD)-induced obese rats for 30 days on the changes in body weight, markers of lipid metabolism such as LDL, HDL, triglycerides, total cholesterol, adiponectin, leptin, amylase, and lipase. We also investigated the effects of CSO on the changes of lipid metabolic enzymes such as fatty-acid synthase, acetyl CoA carboxylase, carnitine palmitoyl transferase-1, HMG CoA reductase, and inflammatory markers (TNF-α and IL-6). Administration of CSO revealed significant diminution in body weight gain, altered the activity, expressions of lipid marker enzymes and inflammatory markers. It demonstrated that CSO had considerably altered these parameters when evaluated with HFD control rats. In conclusion, this study suggested that CSO might ameliorate the HFD-induced obesity by altering the enzymes and mRNA expressions important to lipid metabolism.

Antiobesity potential of Piperonal: promising modulation of body composition, lipid profiles and obesogenic marker expression in HFD-induced obese rats

Background

Black pepper or Piper nigrum is a well-known spice, rich in a variety of bioactive compounds, and widely used in many cuisines across the world. In the Indian traditional systems of medicine, it is used to treat gastric and respiratory ailments. The purpose of this investigation is to study the antihyperlipidemic and antiobesity effects of piperonal in high-fat diet (HFD)-induced obese rats.

Methods

Piperonal, an active constituent of Piper nigrum seeds, was isolated and confirmed by HPLC, ¹H and ¹³C NMR spectroscopy. Male SD rats were fed on HFD for 22 weeks; Piperonal was supplemented from the 16th week as mentioned in the experimental design. Changes in body weight and body composition were measured by TOBEC, bone mineral composition and density were measured by DXA, and adipose tissue distribution was measured by 7 T–MRI. Plasma levels of glucose, insulin, insulin resistance and lipid profiles of plasma, liver and kidney, adipocyte hormones and liver antioxidants were evaluated using standard kit methods. Expression levels of adipogenic and lipogenic genes, such as PPAR-γ, FAS, Fab-4, UCP-2, SREBP-1c, ACC, HMG-COA and TNF-α were measured by RT-PCR. Histopathological examination of adipose and liver tissues was also carried out in experimental rats.

Results

HFD substantially induced body weight, fat%, adipocyte size, circulatory and tissue lipid profiles. It elevated the plasma levels of insulin, insulin resistance and leptin but decreased the levels of adiponectin, BMC and BMD. Increased expression of PPAR-γ, FAS, Fab-4, UCP-2, SREBP-1c, ACC, and TNF-α was noticed in HFD-fed rats. However, supplementation of piperonal (20, 30 and 40 mg/kg b.wt) for 42 days considerably and dose-dependently attenuated the HFD-induced alterations, with the maximum therapeutic activity being noticed at 40 mg/kg b.wt.

Conclusions

Piperonal significantly attenuated HFD-induced body weight and biochemical changes through modulation of key lipid metabolizing and obesogenic genes. Our findings demonstrate the efficacy of piperonal as a potent antiobesity agent, provide scientific evidence for its traditional use and suggest the possible mechanism of action.