Identification of antidiabetic effect of iridoid glycosides and low molecular weight polyphenol fractions of Corni Fructus, a constituent of Hachimi-jio-gan, in streptozotocin-induced diabetic rats.
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In our previous study, Corni Fructus (Cornus officinalis SIEB. et ZUCC.), a component crude drug of the Chinese prescription Hachimi-jio-gan, was reported to reduce glucotoxicities, up-regulate renal function, and consequently ameliorate glycation-associated renal damage as well as Hachimi-jio-gan. Based upon these facts, we prepared Corni Fructus fractions and evaluated which fraction contained the effective components against diabetes, using one iridoid glycoside and three polyphenol fractions, which were expected to possess stronger activities than Corni Fructus, administered orally at a dose of 20 mg/kg body weight/d for 10 d, respectively. As a result, iridoid glycosides and low molecular weight polyphenol fractions could reduce the pathogenesis of diabetic renal damage, each having different mechanisms, i.e., iridoid glycosides successfully decreased the hyperglycemic state and affected renal advanced glycation end-product (AGE) accumulation, such as N(epsilon)-(carboxyethyl)lysine and N(epsilon)-(carboxymethyl)lysine, while low molecular weight polyphenol fractions could reduce renal lipid peroxidation, the receptor for AGE, and inducible nitric oxide synthase. Overall, these data suggest that iridoid glycosides and low molecular weight polyphenols purified from Corni Fructus improve metabolic parameters associated with the development of diabetic renal damage. The main active components of these fractions are discussed. (+info)
Cornuside suppresses cytokine-induced proinflammatory and adhesion molecules in the human umbilical vein endothelial cells.
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Cornuside is a bisiridoid glucoside compound isolated from the fruit of Cornus officinalis SIEB. et ZUCC. The present study was designed to examine the effects of cornuside on expression levels of cytokine-induced proinflammatory and adhesion molecules in the human umbilical vein endothelial cells (HUVECs). Cornuside treatment attenuated tumor necrosis factor-alpha (TNF-alpha)-induced nuclear factor-kappa B (NF-kappaB) p65 translocation in HUVECs. In addition, cornuside suppressed the expression levels of endothelial cell adhesion molecules including intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) induced by TNF-alpha. TNF-alpha-induced monocyte chemoattractant protein 1 (MCP-1) expression was also attenuated by treatment of cornuside. These inhibitory effects of cornuside on proinflammatory and adhesion molecules were not due to decreased HUVEC viability as assessed by MTT test. Taken together, the present study suggests that cornuside suppresses expression levels of cytokine-induced proinflammatory and adhesion molecules in the human endothelial cells. (+info)
Dynamics of bioluminescence by Armillaria gallica, A. mellea and A. tabescens.
(11/28)
Although fungal bioluminescence is well documented, the ecological significance is poorly understood. We examined bioluminescence by three sympatric species of Armillaria wood decay fungi, differing in parasitic ability. Luminescence by mycelia of four genets of A. gallica, A. mellea and A. tabescens was examined in response to environmental illumination or mechanical disturbance. Luminescence dynamics were assessed in a time series of measurements every 2 min for 72 h for mycelia growing on malt agar or on Cornus florida root wood. Luminescence by the necrotrophic species A. gallica was enhanced by environmental illumination and mechanical disturbance of mycelia. In contrast luminescence by the more parasitic A. mellea and A. tabescens was quenched by prolonged exposure to environmental illumination and less responsive to mechanical disturbance. With environmental illumination absent, all mycelia representing six genets of each Armillaria species were constitutively luminescent. The temporal dynamics of luminescence by all mycelia were complex with no evidence of the previously reported diurnal periodicity. Differences among Armillaria spp. in bioluminescence expression might reflect differences in ecological context as well. (+info)
Protective effects of morroniside isolated from Corni Fructus against renal damage in streptozotocin-induced diabetic rats.
(12/28)
In our previous study, we reported the renoprotective effect of Hachimi-jio-gan, a Chinese traditional prescription consisting of eight medicinal plants, and also reported the effect of Corni Fructus (Cornus officinalis SIEB. et ZUCC.), a component of Hachimi-jio-gan, on diabetic nephropathy using diabetic rats. In this study, we investigated the effects of morroniside isolated from Corni Fructus on renal damage in streptozotocin-treated diabetic rats. Oral administration of morroniside at a dose of 20 or 100 mg/kg body weight/d for 20 d to diabetic rats resulted in significant decreases in increasing serum glucose and urinary protein levels. Moreover, the decreased levels of serum albumin and total protein in diabetic rats were significantly increased by morroniside administration at a dose of 100 mg/kg body weight/d. In addition, morroniside significantly reduced the elevated serum urea nitrogen level and showed a tendency to reduce creatinine clearance. Morroniside also significantly reduced the enhanced levels of serum glycosylated protein, and serum and renal thiobarbituric acid-reactive substances. Protein expressions related to the advanced glycation endproduct (AGE) level and actions, oxidative stress such as N(epsilon)-(carboxyethyl)lysine, as well as receptors for AGE and heme oxygenase-1 were increased in diabetic rats, but the levels were also significantly decreased by the administration of morroniside. This suggests that morroniside exhibits protective effects against diabetic renal damage by inhibiting hyperglycemia and oxidative stress. These results indicate that morroniside is one component partly responsible for the protective effects of Corni Fructus and Hachimi-jio-gan against diabetic renal damage. (+info)
7-O-galloyl-D-sedoheptulose is a novel therapeutic agent against oxidative stress and advanced glycation endproducts in the diabetic kidney.
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Diabetes is the leading cause of end-stage renal failure, since glucose-dependent metabolic factors are synergistically activated within the diabetic kidney. Accordingly, in Japan, there is much debate over the health benefits of natural therapies to reduce these risk factors. In our previous study, we reported that Cornus officinalis SIEB. et ZUCC. possessed an antidiabetic effect via ameliorating glucose-mediated metabolic disorders as well as aminoguanidine, an inhibitor of advanced glycation endproduct (AGE) formation, with a renoprotective effect. The aim of the present study was to investigate the effect of 7-O-galloyl-D-sedoheptulose (GS) against diabetic oxidative stress and AGE formation. Streptozotocin-induced diabetic rats were orally administered GS for 20 d, and the changes in serum glucose levels, as well as those of body weight every 10 d were evaluated. In addition, glucose, fluorescent AGE, methylglyoxal, glycolaldehyde (GA), and immunoblotting analyses for heme oxygenase-1, receptor for AGE, N(epsilon)-(carboxymethyl)lysine, N(epsilon)-(carboxyethyl)lysine, and GA-pyridine were performed in the kidney at the end of the experiment. The results obtained in this study demonstrated that 20 d of treatment with GS had beneficial effects on hypoglycemic and renal metabolic abnormalities, including renal glucose, oxidative stress, and AGE formation. Together, our data help to elucidate its potential therapeutic value against diabetic kidney disease. (+info)
Effect of three herbal extracts on NO and PGE2 production by activated mouse macrophage-like cells.
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Three Chinese herbal extracts, Drynaria baronii, Angelica sinensis and Cornus officinalis Sieb. et Zucc (referred to as DB, AS, CO, respectively), were investigated for their possible anti-inflammatory activity. DB, AS and CO inhibited nitric oxide (NO) production by lipopolysaccharide (LPS)-activated mouse macrophage-like RAW264.7 cells. Western blot and RT-PCR analyses demonstrated that this was due to the inhibition of inducible NO synthase (iNOS) expression at both protein and mRNA levels. Electron-spin resonance spectroscopy showed that DB, AS and CO dose-dependently scavenged the NO radical produced by NOC-7 in the presence of carboxy-PTIO. In order to confirm the anti-inflammatory potency, effects on prostaglandin (PG) E(2) production and the expression of enzymes involved in the arachidonic acid pathway were next investigated. DB and CO effectively inhibited the PGE(2) production by LPS-stimulated RAW264.7 cells, although the extent of inhibition of PGE(2) production was slightly lower than that of NO production. AS only marginally inhibited the LPS-stimulated PGE(2) production. DB, AS and CO inhibited cyclooxygenase (COX)-2 expression at both protein and mRNA levels, but to much lesser extents as compared with that for iNOS expression. These data further substantiate the anti-inflammatory potency of DB, AS and CO. (+info)
The beneficial effects of morroniside on the inflammatory response and lipid metabolism in the liver of db/db mice.
(15/28)
The effect of morroniside on lipid metabolism and the inflammatory response in the liver of type 2 diabetes model mice was investigated in this study. Male C57BLKS/J db/db mice were divided into the three groups: control (vehicle), morroniside 20, or 100 mg/kg body weight-treated mice. The elevated serum triglyceride and alanine aminotransferase levels as well as hepatic glucose and lipids contents in db/db mice were significantly decreased by the 8-week oral administration of morroniside in a dose-dependent manner. The generations of hepatic thiobarbituric acid-reactive substances and reactive oxygen species induced by hyperglycemia and dyslipidemia were also significantly decreased by the administration of morroniside. In addition, the barometer of an antioxidative state, the oxidized to reduced glutathione ratio, in the liver of db/db mice was markedly increased by morroniside treatment. From protein analysis, the elevated expressions of nuclear factor-kappaBp65, cyclooxygenase-2, inducible nitric oxide synthase, and sterol regulatory element binding proteins (SREBP-1 and SREBP-2) were down-regulated in the liver of db/db mice. On the other hand, the administration of morroniside significantly increased hepatic peroxisome proliferator activated receptor alpha expression. These results suggest that morroniside would act as a regulator of hepatic inflammatory reactions and lipid metabolism in db/db mice. (+info)
Architectural strategies of Cornus sericea, a native but invasive shrub of Southern Quebec, Canada, under an open or a closed canopy.
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