Macroalgae of Izmir Gulf: Cystoseira barbata, Cystoseira compressa and Cystoseira crinita species have high α-glucosidase and Moderate Pancreatic Lipase Inhibition Activities.

Hyperglycemia and hyperlipidemia have been symptoms of many serious diseases such as diabetes and atherosclerosis overall the world. Thus, drug researchers have focused on new, natural and healthy drug alternatives. Marine macroalgae is a great source of hypoglycemic, hypolipidemic or hypocholesterolemic agents. In this study, we investigated that hypoglycemic, hypolipidemic and cytotoxic potentials of 22 marine macroalgae from the Gulf of Izmir. According to our results, the cold methanol extract of Polysiphonia denudata exhibited the highest antioxidant activity (93.6%) compared to BHA (95.3%). Three Cystoseira species, Cystoseria crinita (91.9%), Cystoseria barbata (90.7%), Cystoseria compressa (89.8%) showed higher α-glucosidase inhibition rates than oral antidiabetic acarbose (79.5%). It has also been observed that same species are potent inhibitors of pancreatic lipase. Cytotoxicity test revealed that these extracts did not cause viability inhibition on MCF-7. The results of maltose- glucose assay indirectly displayed that Cystoseira cold methanolic extracts inhibited maltose consumption better than acarbose on HT29. The results of this screening study show that these Cystoseira species may provide non- toxic bioactive agents to control non-communicable diseases (NCDs) such as cardiovascular disease and diabetes mellitus.

Urotensin receptor antagonist palosuran attenuates cyclosporine-a-induced nephrotoxicity in rats.

BACKGROUND: Cyclosporine-A (CsA) is widely used for immunosuppressive therapy in renal transplantation. Nephrotoxicity is the main dose-limiting undesirable consequence of CsA. Urotensin II (U-II), a novel peptide with a powerful influence on vascular biology, has been added to the list of potential renal vascular regulators. Upregulation of the urotensin receptors and elevation of plasma U-II levels are thought to possibly play a role in the etiology of renal failure. OBJECTIVES: The present study examines this hypothesis by evaluating renal function and histology with regard to the potential role of U-II and its antagonist, palosuran, in the pathogenesis of CsA-induced nephrotoxicity in rats. MATERIAL AND METHODS: Male Sprague-Dawley rats were treated with CsA (15 mg/kg, for 21 days, intraperitoneally) or CsA + palosuran (300 mg/kg, for 21 days). Renal function was measured and histopathology, U-II immunostaining and protein detection with western blotting of the kidneys were performed. RESULTS: Cyclosporine-A administration caused a marked decline in creatinine clearance (Ccr). Fractional sodium excretion (FENa) tended to increase in the CsA-treated rats. Plasma U-II levels decreased in the CsA-treated rats. Cyclosporine-A treatment resulted in a marked deterioration in renal histology and an increase in the expression of U-II protein in the kidneys. Palosuran's improvement of renal function manifested as a significant decrease in serum creatinine levels and a significant increase in urine creatinine levels, resulting in a marked increase in Ccr. Palosuran produced a significant normalization of kidney histology and prevented an increase in U-II expression. CONCLUSIONS: Cyclosporine-A-induced renal impairment was accompanied by an increase in U-II expression in kidneys and a contrary decrease in systemic U-II levels. Palosuran improved the condition of rats suffering from renal dysfunction by preventing the decrease in renal U-II expression without affecting the systemic levels of U-II. The protective effect of palosuran in CsA nephrotoxicity is possibly independent of its U-II receptor antagonism.

Treatment with NADPH oxidase inhibitor apocynin alleviates diabetic neuropathic pain in rats.

Increased reactive oxygen species by the activation of NADPH oxidase (NOX) contributes to the development of diabetic complications. Apocynin, a NOX inhibitor, increases sciatic nerve conductance and blood flow in diabetic rats. We investigated potential protective effect of apocynin in rat diabetic neuropathy and its precise mechanism of action at molecular level. Rat models of streptozotocin-induced diabetes were treated with apocynin (30 and 100 mg/kg per day, intragastrically) for 4 weeks. Mechanical hyperalgesia and allodynia were determined weekly using analgesimeter and dynamic plantar aesthesiometer. Western blot analysis and histochemistry/immunohistochemistry were performed in the lumbar spinal cord and sciatic nerve respectively. Streptozotocin injection reduced pain threshold in analgesimeter, but not in aesthesiometer. Apocynin treatment increased pain threshold dose-dependently. Western blot analysis showed an increase in catalase and NOX-p47phox protein expression in the spinal cord. However, protein expressions of neuronal and inducible nitric oxide synthase (nNOS, iNOS), superoxide dismutase, glutathion peroxidase, nitrotyrosine, tumor necrosis factor-α, interleukin-6, interleukin-1ß, aldose reductase, cyclooxygenase-2 or MAC-1 (marker for increased microgliosis) in the spinal cord remained unchanged. Western blot analysis results also demonstrated that apocynin decreased NOX-p47phox expression at both doses and catalase expression at 100 mg/kg per day. Histochemistry of diabetic sciatic nerve revealed marked degeneration. nNOS and iNOS immunoreactivities were increased, while S-100 immunoreactivity (Schwann cell marker) was decreased in sciatic nerve. Apocynin treatment reversed these changes dose-dependently. In conclusion, decreased pain threshold of diabetic rats was accompanied by increased NOX and catalase expression in the spinal cord and increased degeneration in the sciatic nerve characterized by increased NOS expression and Schwann cell loss. Apocynin treatment attenuates neuropathic pain by decelerating the increased oxidative stress-mediated pathogenesis in diabetic rats.

Effect of Ceftiofur on Hyperalgesia and Allodynia in a Rat Neuropathic Pain Model: The Role of Immune Processes.

OBJECTIVE: Inflammatory and immune mechanisms play important roles in the pathogenesis of neuropathic pain. Ceftiofur, a third-generation cephalosporin, has anti-inflammatory effects by inhibiting tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, nuclear factor (NF)-κB, and mitogen-activated protein kinase (MAPK) signaling. This study aimed to investigate the effect of ceftiofur on hyperalgesia and allodynia in neuropathic rats and to define the possible contribution of immune mechanisms to this effect. METHODS: A neuropathic pain model was performed by ligating the right sciatic nerve. Mechanic hyperalgesia and allodynia were measured using an analgesia meter and dynamic plantar esthesiometer, respectively. Following sciatic nerve ligation, ceftiofur was administered intraperitoneally (10 and 20 mg/kg/day) for 14 days. The control group received saline. Pain thresholds were recorded pre- and postoperatively on days 3, 7, 10, and 14. Protein was extracted from lumbar spinal cord tissue on day 14, and TNF-α, IL-1ß, p65 NF-κB, p38 MAPK, and inducible nitric oxide synthase (iNOS) were evaluated by Western blotting. RESULTS: Neuropathic rats showed decreased pain thresholds in analgesia meter and esthesiometer measurements. Ceftiofur 20 mg/kg/day significantly alleviated hyperalgesia, but not allodynia, and the increased iNOS and IL-1ß expression was attenuated in neuropathic rats at both doses while decreasing p38 MAPK expression only at 20 mg/kg/day. TNF-α and p65 NF-κB expression remained unchanged 14 days after surgery. CONCLUSIONS: Ceftiofur has anti-inflammatory effects by decreasing iNOS, IL-1ß, and p38 MAPK expression in lumbar spinal cord, and treatment of neuropathic rats with repeated doses of ceftiofur for 14 days results in antihyperalgesic effects.

Macroalgae of Izmir Gulf: Dictyotaceae exhibit high in vitro anti-cancer activity independent from their antioxidant capabilities.

In this study, 24 marine macroalgae collected from the coastline of Izmir Gulf were examined for their antioxidant activities and their effects on cell proliferation. Crude extracts were obtained from samples with cold methanol extraction. Antioxidant activity was evaluated as 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging activity and total phenolic content (TPC); growth inhibitory effects of the extracts were determined by using WST-8. Amongst the species, Polysiphonia denuata (Rhodophyta) and Cystoseira species (Phaeophyceae) have been noticed by their high DPPH radical scavenging activities and TPCs. As expected, there was a strong correlation between these tests. Dictyota dichotoma (Phaeophyceae) showed the highest anti-cancer activity on MCF-7 cells with an IC50 of 17.2 ng mL-1. Flow cytometry analyses demonstrated that D. dichotoma methanolic extract strongly induced apoptosis. This extract exhibited moderate viability inhibition on MCF10A cells (IC50: 49.3 ng mL-1), suggesting a potential use of the extracts or its compounds for cancer therapy. There was no correlation between anti-cancer potential and antioxidant content of the extracts.

Magnesium reduces calcification in bovine vascular smooth muscle cells in a dose-dependent manner.

BACKGROUND: Vascular calcification (VC), mainly due to elevated phosphate levels, is one major problem in patients suffering from chronic kidney disease. In clinical studies, an inverse relationship between serum magnesium and VC has been reported. However, there is only few information about the influence of magnesium on calcification on a cellular level available. Therefore, we investigated the effect of magnesium on calcification induced by ß-glycerophosphate (BGP) in bovine vascular smooth muscle cells (BVSMCs). METHODS: BVSMCs were incubated with calcification media for 14 days while simultaneously increasing the magnesium concentration. Calcium deposition, transdifferentiation of cells and apoptosis were measured applying quantification of calcium, von Kossa and Alizarin red staining, real-time reverse transcription-polymerase chain reaction and annexin V staining, respectively. RESULTS: Calcium deposition in the cells dramatically increased with addition of BGP and could be mostly prevented by co-incubation with magnesium. Higher magnesium levels led to inhibition of BGP-induced alkaline phosphatase activity as well as to a decreased expression of genes associated with the process of transdifferentiation of BVSMCs into osteoblast-like cells. Furthermore, estimated calcium entry into the cells decreased with increasing magnesium concentrations in the media. In addition, higher magnesium concentrations prevented cell damage (apoptosis) induced by BGP as well as progression of already established calcification. CONCLUSIONS: Higher magnesium levels prevented BVSMC calcification, inhibited expression of osteogenic proteins, apoptosis and further progression of already established calcification. Thus, magnesium is influencing molecular processes associated with VC and may have the potential to play a role for VC also in clinical situations.

Apocynin restores endothelial dysfunction in streptozotocin diabetic rats through regulation of nitric oxide synthase and NADPH oxidase expressions.

AIM: Increased production of reactive oxygen species (ROS) in the diabetic vasculature results in the impairment of nitric oxide (NO)-mediated relaxations leading to impaired endothelium-dependent vasodilation. An important source of ROS is nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and the inhibition of this enzyme is an active area of interest. This study aimed to investigate the effects of apocynin, an NADPH oxidase inhibitor, on endothelial dysfunction and on the expression of NO synthase (NOS) and NADPH oxidase in thoracic aorta of diabetic rats. METHOD: Streptozotocin (STZ)-diabetic rats received apocynin (16 mg/kg per day) for 4 weeks. Endothelium-dependent and -independent relaxations were determined in thoracic aortic rings. Western blotting and RT-PCR analysis were performed for NOSs and NADPH oxidase in the aortic tissue. RESULTS: Acetylcholine-induced relaxations and l-NAME-induced contractions were decreased in diabetic aorta. The decrease in acetylcholine and l-NAME responses were prevented by apocynin treatment without a significant change in plasma glucose levels. Endothelial NOS (eNOS) protein and mRNA expression exhibited significant decrease in diabetes, while protein and/or mRNA expressions of inducible NOS (iNOS) as well as p22(phox) and gp91(phox) subunits of NADPH oxidase were increased, and these alterations were markedly prevented by apocynin treatment. CONCLUSION: NADPH oxidase expression is increased in diabetic rat aorta. NADPH oxidase-mediated oxidative stress is accompanied by the decreased eNOS and increased iNOS expressions, contributing to endothelial dysfunction. Apocynin effectively prevents the increased NADPH oxidase expression in diabetic aorta and restores the alterations in NOS expression, blocking the vicious cycle leading to diabetes-associated endothelial dysfunction.