Effect of Momordica grosvenori on oxidative stress pathways in renal mitochondria of normal and alloxan-induced diabetic mice. Involvement of heme oxygenase-1

Understanding consumer preferences to develop dahi using pineapple pomace powder and monk-fruit extract

Consumer preferences refer to the subjective assessments of products and services expressed by individuals. The objective of this investigation aims to examine the preferences of consumers regarding dahi, followed by the development of a corresponding product. The initial phase of the experimental design involves understanding the interests of consumers and the variables that influence their purchasing intentions through the administration of a questionnaire. The subsequent phase entails the development of dahi in accordance with consumer preferences, followed by an assessment of its nutritional value, sensory acceptability, and storage study. Subsequently, a significant proportion of consumers (91%) expressed an interest for the introduction of a pineapple-flavour (61.5%) spoon-able dahi (77%) containing natural sugar (65%) and packaged in a cup (71.5%) within the market. To adjust the sweetness intensity of monk fruit, a series of preliminary experiments were carried out to regulate the concentration to a level that can be considered sensory acceptable, specifically 05 g/100 ml. Afterwards, dahi was prepared by altering the concentration of FPP (freeze-dried pine-apple pomace powder) within the range of 0.5 to 2.5 g/100 ml. Prepared dahi were further subjected to sensory evaluation and storage study. Based on the obtained results and sensory analyst feedback, we conclude that the dahi formulation TPM2 exhibits considerable organoleptic acceptance and also has the potential for industrial-scale production to cater wider consumer demands.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05919-5.

A comprehensive review of Siraitia grosvenorii (Swingle) C. Jeffrey: chemical composition, pharmacology, toxicology, status of resources development, and applications

Siraitia grosvenorii (Swingle) C. Jeffrey (S. grosvenorii), a perennial indigenous liana from the Cucurbitaceae family, has historically played a significant role in southern China's traditional remedies for various ailments. Its dual classification by the Chinese Ministry of Health for both medicinal and food utility underscores its has the potential of versatile applications. Recent research has shed light on the chemical composition, pharmacological effects, and toxicity of S. grosvenorii. Its active ingredients include triterpenoids, flavonoids, amino acids, volatile oils, polysaccharides, minerals, vitamins, and other microconstituents. Apart from being a natural sweetener, S. grosvenorii has been found to have numerous pharmacological effects, including alleviating cough and phlegm, preventing dental caries, exerting anti-inflammatory and anti-allergic effects, anti-aging and anti-oxidative, hypoglycemic, lipid-lowering, anti-depression, anti-fatigue, anti-schizophrenic, anti-Parkinson, anti-fibrotic, and anti-tumor activities. Despite its versatile potential, there is still a lack of systematic research on S. grosvenorii to date. This paper aims to address this gap by providing an overview of the main active components, pharmacological efficacy, toxicity, current status of development and application, development dilemmas, and strategies for intensive exploitation and utilization of S. grosvenorii. This paper aims to serve as a guide for researchers and practitioners committed to exploiting the biological resources of S. grosvenorii and further exploring its interdisciplinary potential.

The impact of oxidative stress-induced mitochondrial dysfunction on diabetic microvascular complications

Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycaemia, with absolute insulin deficiency or insulin resistance as the main cause, and causes damage to various target organs including the heart, kidney and neurovascular. In terms of the pathological and physiological mechanisms of DM, oxidative stress is one of the main mechanisms leading to DM and is an important link between DM and its complications. Oxidative stress is a pathological phenomenon resulting from an imbalance between the production of free radicals and the scavenging of antioxidant systems. The main site of reactive oxygen species (ROS) production is the mitochondria, which are also the main organelles damaged. In a chronic high glucose environment, impaired electron transport chain within the mitochondria leads to the production of ROS, prompts increased proton leakage and altered mitochondrial membrane potential (MMP), which in turn releases cytochrome c (cyt-c), leading to apoptosis. This subsequently leads to a vicious cycle of impaired clearance by the body's antioxidant system, impaired transcription and protein synthesis of mitochondrial DNA (mtDNA), which is responsible for encoding mitochondrial proteins, and impaired DNA repair systems, contributing to mitochondrial dysfunction. This paper reviews the dysfunction of mitochondria in the environment of high glucose induced oxidative stress in the DM model, and looks forward to providing a new treatment plan for oxidative stress based on mitochondrial dysfunction.

Enhancing the Antioxidant Ability of Momordica grosvenorii Saponin to Resist Gastrointestinal Stresses via Microcapsules of Sodium Alginate and Chitosan and Its Application in Beverage

Momordica grosvenorii saponin (MGS), as a promising dietary supplement with remarkable biological properties, has poor stability under acidic conditions and thus hinders its application in functional foods. In this study, capsules of chitosan and sodium alginate were successfully prepared to enhance the stability of MGS. The optimized parameters for preparing MGS capsules were established. Sodium alginate of 20.8 mg/mL and triplication of MGS powder were added to chitosan of 4 mg/mL and calcium chloride of 10 mg/mL at a volume ratio of 3:1, stirring at 1000 r/min for 30 min to form the capsules. In this case, the fresh particles averaged 1687 μm with an encapsulation efficiency (EE) of 80.25% MGS. The capsule tolerated acidic environments better, and in vitro MGS could be controlled to release in a stimulated gastrointestinal tract system. The antioxidant activity and delayed release of MGS could be achieved by microencapsulation of chitosan/sodium alginate. Moreover, one drink containing 19 mg/mL MGS was successfully developed for the fruit.

Physicochemical analysis, proteolysis activity and exopolysaccharides production of herbal yogurt fortified with plant extracts

Yogurt production with starter culture at 41 °C in the presence of plant water extracts (Momordica grosvenori, Psidium guajava, Lycium barbarum or Garcinia mangostana) were studied to examine the effects on acidification, physicochemical properties, microbial growth, proteolytic activity, and exopolysaccharide (EPS) content. All plant-based yogurt reached a pH of 4.5 faster (300–330 min) than plain-yogurt (360 min). All plant water extracts stimulated Lactobacillus spp. (∼7.4 log10 CFU/mL) and Streptococcus thermophilus (8.20–8.50 log10 CFU/mL) growth except for G. mangostana which marginally inhibited Lactobacillus spp. growth (7.21 log10 CFU/mL). M. grosvenori, L. barbarum, and G. mangonstana were significantly affected proteolysis of milk proteins (46.2 ± 0.8, 39.9 ± 0.5, & 35.8 ± 0.1 µg/mL; respectively) compared to plain-yogurt (26.3 ± 0.4 µg/mL). The presence of G. mangostana and L. barbarum resulted in an increase (p < 0.05) of total solids content (∼15.0%) and water holding capacity in yogurt (28.1 ± 1.2 & 26.5 ± 0.3%; respectively; p < 0.05). In addition, M. grosvenori water extract enhanced (p < 0.05) syneresis of yogurt (1.78 ± 0.30%). L. barbarum yogurt showed the highest EPS concentration (220.9 ± 12.4 µg/L) among yogurt samples. In conclusion, the presence of plant water extracts positively altered yogurt fermentation, enhanced proteolysis of milk protein, and induced EPS production.

Pyrrolidine dithiocarbamate reduces alloxan-induced kidney damage by decreasing nox4, inducible nitric oxide synthase, and metalloproteinase-2

We examined the effect of the NFκB inhibitor pyrrolidine-1-carbodithioic acid (PDTC) on inducible nitric oxide synthase (iNOS), matrix metalloproteinase-2 (MMP-2) activity, and oxidative and inflammatory kidney damage in alloxan-induced diabetes. Two weeks after diabetes induction (alloxan-130 mg/kg), control and diabetic rats received PDTC (100 mg/kg) or vehicle for 8 weeks. Body weight, glycemia, urea, and creatinine were measured. Kidney changes were measured in hematoxylin/eosin sections and ED1 by immunohistochemistry. Kidney thiobarbituric acid reactive substances (TBARS), superoxide anion (O2-), and nitrate/nitrite (NOx) levels, and catalase and superoxide dismutase (SOD) activities were analyzed. Also, kidney nox4 and iNOS expression, and NFkB nuclear translocation were measured by western blot, and MMP-2 by zymography. Glycemia and urea increased in alloxan rats, which were not modified by PDTC treatment. However, PDTC attenuated kidney structural alterations and macrophage infiltration in diabetic rats. While diabetes increased both TBARS and O₂^- levels, PDTC treatment reduced TBARS in diabetic and O₂^- in control kidneys. A decrease in NO_x levels was found in diabetic kidneys, which was prevented by PDTC. Diabetes reduced catalase activity, and PDTC increased catalase and SOD activities in both control and diabetic kidneys. PDTC treatment reduced MMP-2 activity and iNOS and p65 NFκB nuclear expression found increased in diabetic kidneys. Our results show that the NFκB inhibitor PDTC reduces renal damage through reduction of Nox4, iNOS, macrophages, and MMP-2 in the alloxan-induced diabetic model. These findings suggest that PDTC inhibits alloxan kidney damage via antioxidative and anti-inflammatory mechanisms.

The protective effects of Mogroside V and its metabolite 11-oxo-mogrol of intestinal microbiota against MK801-induced neuronal damages

RATIONALE

Animal models, notably with non-competitive NMDA receptor antagonist MK801, are commonly used to investigate the mechanisms of schizophrenia and to pursue its mechanism-related drug discoveries.

OBJECTIVES

In the current study, we have extensively examined the protective effects of MogrosideV (MogV), a plant-derived three terpene glucoside known to exhibit anti-oxidative and anti-inflammatory activities.

METHODS AND RESULTS

Here, we investigated its protective effects against neuronal damages elicited by MK-801 treatment. Our behavioral experimental results showed that MK-801-induced PPI deficits and social withdrawal were prevented by MogV treatment. Moreover, the cellular and neurochemical responses of MK-801 in medial prefrontal cortical cortex (mPFC) were also ameliorated by MogV treatment. Also, profiling metabolites assay through artificial intestinal microbiota was performed to identify bioactive components of MogV. An in vitro study of primary neuronal culture demonstrated that MogV and its metabolite 11-oxo-mogrol treatment prevented the MK-801-induced neuronal damages through the mechanisms of promoting neurite outgrowth, inhibiting cell apoptosis, and [Ca²⁺]_i release. Additionally, 11-oxo-mogrol reversed inactivation of phosphorylation levels of AKT and mTOR induced by MK801.

CONCLUSIONS

These results suggest therapeutic potential of MogV for schizophrenia.

Blood levels of heme oxygenase-1 versus bilirubin in patients with coronary artery disease

OBJECTIVE

Heme oxygenase-1 (HO-1) degrades heme to CO, iron, and biliverdin/bilirubin. Although serum bilirubin levels were often reported in patients with coronary artery disease (CAD), HO-1 levels in patients with CAD and the association between HO-1 and bilirubin levels have not been clarified.

METHODS

We measured plasma HO-1 and serum total bilirubin levels in 262 patients undergoing coronary angiography.

RESULTS

HO-1 levels were higher in patients with CAD than without CAD (median 0.46 vs. 0.35 ng/mL, P < 0.01), but bilirubin were lower in patients with CAD than without CAD (0.69 vs. 0.75 mg/dL, P < 0.02). Notably, HO-1 levels in CAD(-), 1-vessel, 2-vessel, and 3-vessel disease were 0.35, 0.51, 0.45, and 0.44 ng/mL, and were highest in 1-vessel disease (P < 0.05). Bilirubin levels in CAD(-), 1-vessel, 2-vessel, and 3-vessel disease were 0.75, 0.70, 0.68, and 0.66 mg/dL (P = NS). No correlation was found between HO-1 and bilirubin levels. In multivariate analysis, HO-1 levels were a significant factor for CAD independent of atherosclerotic risk factors and bilirulin levels. Odds ratio for CAD was 2.32 (95%CI = 1.29-4.17) for high HO-1 (>0.35 ng/mL).

CONCLUSIONS

Patients with CAD were found to have high HO-1 and low bilirubin levels in blood, but no correlation was found between HO-1 and bilirubin levels.

Association of serum FAM19A5 with metabolic and vascular risk factors in human subjects with or without type 2 diabetes

OBJECTIVES

A recent experimental study revealed that family with sequence similarity 19 [chemokine (C-C motif)-like] member A5 (FAM19A5), a novel secreted adipokine, has inhibitory effects on vascular smooth muscle cell proliferation and migration, and on neointima formation in injured arteries. We investigated the associations between serum FAM19A5 concentration and cardio-metabolic risk factors for the first time in human subjects.

METHODS

Circulating FAM19A5 concentrations and their associations with cardio-metabolic risk factors were explored in 223 individuals (45 without diabetes and 178 with type 2 diabetes).

RESULTS

Serum FAM19A5 concentrations (pg/mL) were greater in patients with type 2 diabetes [median (interquartile range), 172.70 (116.19, 286.42)] compared with non-diabetic subjects [92.09 (70.32, 147.24)] (p < 0.001). Increasing serum FAM19A5 tertile was associated with trends of increasing waist-to-hip ratio, fasting plasma glucose, glycated haemoglobin and mean brachial-ankle pulse wave velocity. Serum FAM19A5 was positively correlated with waist circumference, waist-to-hip ratio, alanine aminotransferase, fasting plasma glucose, glycated haemoglobin and mean brachial-ankle pulse wave velocity. Multiple stepwise regression analyses identified waist-to-hip ratio, low-density lipoprotein cholesterol and brachial-ankle pulse wave velocity as determining factors for log-transformed serum FAM19A5 concentration (R² = 0.0689).

CONCLUSION

A novel adipokine FAM19A5 was related to various metabolic and vascular risk factors in humans, suggesting its potential as a biomarker of cardio-metabolic disease.

The Protective Role of Heme Oxygenase-1 in Atherosclerotic Diseases

Heme oxygenase-1 (HO-1) is an intracellular enzyme that catalyzes the oxidation of heme to generate ferrous iron, carbon monoxide (CO), and biliverdin, which is subsequently converted to bilirubin. These products have anti-inflammatory, anti-oxidant, anti-apoptotic, and anti-thrombotic properties. Although HO-1 is expressed at low levels in most tissues under basal conditions, it is highly inducible in response to various pathophysiological stresses/stimuli. HO-1 induction is thus thought to be an adaptive defense system that functions to protect cells and tissues against injury in many disease settings. In atherosclerosis, HO-1 may play a protective role against the progression of atherosclerosis, mainly due to the degradation of pro-oxidant heme, the generation of anti-oxidants biliverdin and bilirubin and the production of vasodilator CO. In animal models, a lack of HO-1 was shown to accelerate atherosclerosis, whereas HO-1 induction reduced atherosclerosis. It was also reported that HO-1 induction improved the cardiac function and postinfarction survival in animal models of heart failure or myocardial infarction. Recently, we and others examined blood HO-1 levels in patients with atherosclerotic diseases, e.g., coronary artery disease (CAD) and peripheral artery disease (PAD). Taken together, these findings to date support the notion that HO-1 plays a protective role against the progression of atherosclerotic diseases. This review summarizes the roles of HO-1 in atherosclerosis and focuses on the clinical studies that examined the relationships between HO-1 levels and atherosclerotic diseases.

Taurine Have Neuroprotective Activity against Oxidative Damage-Induced HT22 Cell Death through Heme Oxygenase-1 Pathway

Glutamate-induced oxidative neurotoxicity plays a part role in neuronal degeneration on the disorders of central nervous system (CNS). The expression of heme oxygenase (HO)-1 mediated by Inducible nuclear factor-E2-related factor 2 (Nrf2) functions as an anti-oxidants that is able to play an important role in the pathogenesis of several neuronal disorders. In the present study, taurine showed the inhibitory effect against reactive oxygen species (ROS) induction and protective effects against neurotoxicity induced by glutamate- and H2O2 through induction of HO-1 expression in HT22 cells. Moreover, taurine promoted the Nrf2 nuclear translocation in HT22 cells. We also verified the oxidative stress-mediated cell death of HT22 cells was significantly repressed by taurine, using tin protoporphyrin (SnPP) as an HO activity inhibitor. In addition, we found that treatment of the cells with p38 inhibitor (SB203580) suppressed taurine-induced HO-1 expression and cytoprotection, but inhibitors of c-Jun NH2 terminal kinase (JNK) (SP600125) or extracellular signal regulated kinase (ERK) (PD98059) did not. These results suggest that taurine improves the resistance against oxidative damages induced by glutamate in HT22 cells via the p38/Nrf2-dependent HO-1 expression. Our results demonstrated the potential application of taurine as a therapeutic agent for neurodegenerative diseases.

Plasma Heme Oxygenase-1 Levels in Patients with Coronary and Peripheral Artery Diseases

Aims

Heme oxygenase-1 (HO-1) is an intracellular enzyme that catalyzes the oxidation of heme to generate CO, biliverdin, and iron. Since these products have antiatherogenic properties, HO-1 may play a protective role against the progression of atherosclerosis. However, plasma HO-1 levels in patients with atherosclerotic diseases, such as coronary artery disease (CAD) and peripheral artery disease (PAD), have not been clarified yet.

Methods

We investigated plasma HO-1 levels by ELISA in 410 consecutive patients undergoing elective coronary angiography who also had an ankle-brachial index (ABI) test for PAD screening.

Results

Of the 410 study patients, CAD was present in 225 patients (55%) (1-vessel (1-VD), n = 91; 2-vessel (2-VD), n = 66; 3-vessel disease (3-VD), n = 68). PAD (ABI < 0.9) was found in 36 (9%) patients. Plasma HO-1 levels did not differ between 225 patients with CAD and 185 without CAD (median 0.44 versus 0.35 ng/mL), but they were significantly lower in 36 patients with PAD than in 374 without PAD (0.27 versus 0.41 ng/mL, P < 0.02). After excluding the 36 patients with PAD, HO-1 levels were significantly higher in 192 patients with CAD than in 182 without CAD (0.45 versus 0.35 ng/mL, P < 0.05). HO-1 levels in 4 groups of CAD(−), 1-VD, 2-VD, and 3-VD were 0.35, 0.49, 0.44, and 0.44 ng/mL, respectively, and were highest in 1-VD (P < 0.05). In the multivariate analysis, HO-1 levels were inversely associated with PAD, whereas they were also associated with CAD. The odds ratios for PAD and CAD were 2.12 (95% CI = 1.03–4.37) and 0.65 (95% CI = 0.42–0.99) for the HO-1 level of <0.35 ng/mL, respectively.

Conclusions

Plasma HO-1 levels were found to be low in patients with PAD, in contrast to high levels in patients with CAD.

Protective effects of Momordica grosvenori extract against lipid and protein oxidation-induced damage in dried minced pork slices

The experiment was conducted to assess the protective effects of Momordica grosvenori extract (MGE) against lipid and protein oxidation-induced damage in vacuum-packed dried minced pork slices stored at room temperature for 21days. Antioxidant activity of MGE was evaluated by measuring its radical scavenging activities and reducing power with progressive concentrations from 40 to 200g/L. MGE was added to the dried minced pork slices at 7, 10 or 15g/100g. Results showed that inclusion of MGE in dried minced pork slice significantly delayed the formation of hexanal, thiobarbituric acid-reactive substances and carbonyls and reduced the sulfhydryl loss in a dose-dependent manner (P<0.05), indicating that MGE exerted a protective effect against lipids and protein oxidation. Concomitantly, an intense increase of redness and loss of lightness and yellowness was found to take place (P<0.05), though it exhibited little negative effects on the sensory properties of slices. Mogrosides, the main bioactive components in M. grosvenori, decreased primarily during processing while they were relatively stable during storage under vacuum condition, room temperature. All these results demonstrated MGE had great potential as a natural antioxidant used in meat products.

Increment of serum bilirubin as an independent marker predicting new-onset type 2 diabetes mellitus in a Korean population

BACKGROUND AND AIMS

Several cross-sectional studies reported that serum bilirubin concentrations had an inverse association with type 2 diabetes mellitus (T2DM) prevalence. The aim of the current study was to investigate the relationship between percentage change in bilirubin levels (PCB) and incident risk of T2DM using a longitudinal model.

METHODS AND RESULTS

22,084 participants who received regular health check-ups between 2006 and 2012 were enrolled. Multivariable-adjusted Cox regression models were used to determine the hazard ratio (HR) of incident T2DM based on PCB. PCB was determined by subtracting baseline serum bilirubin level (BB) from the bilirubin level at the end of follow-up or a year before the last date of diagnosis, dividing by BB and multiplying by 100. Compared to non-diabetics, BB was lower in the diabetic group at the initial visit. There were 20,098 participants without T2DM at the initial visit; 1253 new cases occurred during follow-up. As PCB increased, T2DM incidence also increased (P < 0.001). After adjusting for confounders, the HR of incident T2DM in the highest PCB quartile was 2.08 (95% confidence interval [CI] 1.76-2.46). This trend remained significant when PCB was analyzed as a continuous variable (HR for 1-SD increment, 1.25; 95% CI 1.19-1.31). Additional analysis comparing the rate of PCB during the follow-up period revealed that the serum bilirubin level of the Incident T2DM group increased before T2DM development and decreased rapidly thereafter compared to others (P < 0.001).

CONCLUSIONS

Bilirubin level increment over time is associated with T2DM development.

Serum bilirubin levels and risk of type 2 diabetes: results from two independent cohorts in middle-aged and elderly Chinese

Serum bilirubin is a potent endogenous antioxidant and has been identified as cardiovascular risk in cohort studies, while the relation to type 2 diabetes (T2D) in the elderly remains unclear. We investigated both cross-sectional and prospective associations between serum bilirubin levels and T2D risk in the Dongfeng-Tongji (DFTJ) cohort, and replicated the prospective findings in a nested case-control study (509 cases and 509 controls) within the Singapore Chinese Health Study (SCHS). In the cross-sectional analysis of DFTJ cohort (15,575 participants with 2,532 diabetes cases), serum bilirubin levels (total, direct and indirect) increased in new on-set diabetes and decreased with the diabetic duration. In the longitudinal analysis of DFTJ cohort (772 incident diabetes cases during 4.5 years of follow-up among 12,530 diabetes-free participants at baseline), positive association was found between direct bilirubin and T2D risk comparing extreme quartiles, similar results were observed in the nested case-control study within SCHS. Total and indirect bilirubin levels were not significantly associated with T2D in either cohort. In conclusion, our findings do not support the protective association between serum bilirubin levels and incident T2D in the middle-aged and elderly adults; instead, direct bilirubin levels were associated with increased risk of T2D.

Change in Serum Bilirubin Level as a Predictor of Incident Metabolic Syndrome

Aim

Serum bilirubin level was negatively associated with the prevalence of metabolic syndrome (MetS) in previous cross-sectional studies. However, bilirubin variance preceding the development of MetS has yet to be investigated. We aimed to determine the effect of change in bilirubin concentration on the risk of incident MetS in healthy Korean adults.

Methods

We conducted a retrospective longitudinal study of subjects who had undergone at least four yearly health check-ups between 2006 and 2012. Of 24,185 total individuals who received annual check-ups, 11,613 non-MetS participants with a baseline bilirubin level not exceeding 34.2 μmol/l were enrolled. We evaluated the association between percent change in bilirubin and risk of incident MetS.

Results

During 55,407 person-years of follow-up, 2,439 cases of incident MetS developed (21.0%). Baseline serum bilirubin level clearly showed no association with the development of MetS in men but an independent significant inverse association in women which attenuated (hence may be mediated) by elevated homeostatic model assessment index 2 for insulin resistance (HOMA2-IR). However, increased risk for incident MetS was observed in higher percent change in bilirubin quartiles, with hazard ratios of 2.415 (95% CI 2.094–2.785) in men and 2.156 (95% CI 1.738–2.675) in women in the fourth quartile, compared to the lowest quartile, after adjusting for age, smoking status, medication history, alanine aminotransferase, uric acid, estimated glomerular filtration rate, fasting glucose, baseline diabetes mellitus prevalence, systolic blood pressure, waist circumference, and body mass index. The hazard ratios per one standard deviation increase in percent change in bilirubin as a continuous variable were 1.277 (95% CI 1.229–1.326) in men and 1.366 (95% CI 1.288–1.447) in women.

Conclusions

Increases in serum bilirubin concentration were positively associated with a higher risk of incident MetS. Serum bilirubin increment might be a sensitive marker for the development of MetS.

Carnosine ameliorates cognitive deficits in streptozotocin-induced diabetic rats: Possible involved mechanisms

Diabetic patients are at increased risk to develop cognitive deficit and senile dementia. This study was planned to assess the benefits of chronic carnosine administration on prevention of learning and memory deterioration in streptozotocin (STZ)-diabetic rats and to explore some of the involved mechanisms. Rats were divided into 5 groups: i.e., control, carnosine100-treated control, diabetic, and carnosine-treated diabetics (50 and 100mg/kg). Carnosine was injected i.p. at doses of 50 or 100mg/kg for 7 weeks, started 1 week after induction of diabetes using streptozotocin. Treatment of diabetic rats with carnosine at a dose of 100mg/kg at the end of the study lowered serum glucose, improved spatial recognition memory in Y maze, improved retention and recall in elevated plus maze, and prevented reduction of step-through latency in passive avoidance task. Furthermore, carnosine at a dose of 100mg/kg reduced hippocampal acetylcholinesterase (AChE) activity, lowered lipid peroxidation, and improved superoxide dismutase (SOD) activity and non-enzymatic antioxidant defense element glutathione (GSH), but not activity of catalase. Meanwhile, hippocampal level of nuclear factor-kappaB (NF-κB), tumor necrosis factor α (TNF-α), and glial fibrillary acidic protein (GFAP) decreased and level of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase 1 (HO-1) increased upon treatment of diabetic group with carnosine at a dose of 100mg/kg. Taken together, chronic carnosine treatment could ameliorate learning and memory disturbances in STZ-diabetic rats through intonation of NF-κB/Nrf2/HO-1 signaling cascade, attenuation of astrogliosis, possible improvement of cholinergic function, and amelioration of oxidative stress and neuroinflammation.

S-allyl cysteine ameliorates cognitive deficits in streptozotocin-diabetic rats via suppression of oxidative stress, inflammation, and acetylcholinesterase

Diabetes mellitus (DM) is associated with learning, memory, and cognitive deficits. S-allyl cysteine (SAC) is the main organosulfur bioactive molecule in aged garlic extract with anti-diabetic, antioxidant, anti-inflammatory and nootropic property. This research was conducted to evaluate the efficacy of SAC on alleviation of learning and memory deficits in streptozotocin (STZ)-diabetic rats and to explore involvement of toll-like receptor 4 (TLR4), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), nuclear factor-kappa B (NF-κB), and heme oxygenase 1 (HO-1) signaling cascade. Male Wistar rats were divided into control, diabetic, SAC-treated diabetic, and glibenclamide-treated diabetic (positive control) groups. SAC was administered at a dose of 150mg/kg for seven weeks. Treatment of diabetic rats with SAC lowered serum glucose, improved spatial recognition memory in Y maze, discrimination ratio in novel object recognition task, and restored step-through latency (STL) in passive avoidance paradigm. In addition, SAC reduced acetylcholinesterase activity, lipid peroxidation marker malondialdehyde (MDA) and augmented antioxidant defensive system including superoxide dismutase (SOD), catalase and reduced glutathione (GSH) in hippocampal lysate. Meanwhile, SAC lowered hippocampal NF-kB, TLR4, and TNFα and prevented reduction of Nrf2 and heme oxygenase-1 (HO-1) in diabetic rats. Taken together, chronic SAC treatment could ameliorate cognitive deficits in STZ-diabetic rats through modulation of Nrf2/NF-κB/TLR4/HO-1, and acetylcholinesterase and attenuation of associated oxidative stress and neuroinflammation.

Antioxidant Capacities of Hot Water Extracts and Endopolysaccharides of Selected Chinese Medicinal Fruits

Fruits are a rich source of antioxidants and traditional Chinese fruits have been studied for their chemopreventive and chemotherapeutic properties against cancers and other diseases. The total phenol and flavonoid contents of eleven Chinese fruits extracts were determined. Total phenolic and flavonoid contents were estimated by both the Folin-Ciocalteau and aluminium chloride methods. The antioxidant activities were evaluated by four assays: a biological assay using Saccharomyces cerevisiae, DPPH radical scavenging activity, chelating ability for ferrous ions and ferric reducing antioxidant power (FRAP). The phenols and flavonoids contents of the hot water extracts were in the range of 17.7 to 94.7 mg/g and 12.3 to 295.4 mg/g, whereas the endopolysaccharides lie in the range of 4.5 to 77.4 mg/g and 22.7 to 230.0 mg/g. Significant amounts of phenols and flavonoids were present in the majority of the fruit extracts and showed strong antioxidant activities. The antioxidant properties of the fruit extracts of Crataegus pinnatifida, Illicium verum, Ligustrum lucidum, Momordica grosvenori and Psoralea corylifolia as determined by the DPPH and FRAP methods, were significant compared to other fruit extracts. In the present study, we found that significant amounts of phenolic and flavonoid compounds were present in these fruit extracts and may contribute to in vitro antioxidant activities.

Adiponectin ameliorates hyperglycemia-induced cardiac hypertrophy and dysfunction by concomitantly activating Nrf2 and Brg1

Hyperglycemia-induced oxidative stress is implicated in the development of cardiomyopathy in diabetes that is associated with reduced adiponectin (APN) and heme oxygenase-1 (HO-1). Brahma-related gene 1 (Brg1) assists nuclear factor-erythroid-2-related factor-2 (Nrf2) to activate HO-1 to increase myocardial antioxidant capacity in response to oxidative stress. We hypothesized that reduced adiponectin (APN) impairs HO-1 induction which contributes to the development of diabetic cardiomyopathy, and that supplementation of APN may ameliorate diabetic cardiomyopathy by activating HO-1 through Nrf2 and Brg1 in diabetes. Control (C) and streptozotocin-induced diabetic (D) rats were untreated or treated with APN adenovirus (1×10(9) pfu) 3 weeks after diabetes induction and examined and terminated 1 week afterward. Rat left ventricular functions were assessed by a pressure-volume conductance system, before the rat hearts were removed to perform histological and biochemical assays. Four weeks after diabetes induction, D rats developed cardiac hypertrophy evidenced as increased ratio of heart weight to body weight, elevated myocardial collagen I content, and larger cardiomyocyte cross-sectional area (all P<0.05 vs C). Diabetes elevated cardiac oxidative stress (increased 15-F2t-isoprostane, 4-hydroxynonenal generation, 8-hydroxy-2'-deoxyguanosine, and superoxide anion generation), increased myocardial apoptosis, and impaired cardiac function (all P<0.05 vs C). In D rats, myocardial HO-1 mRNA and protein expression were reduced which was associated with reduced Brg1 and nuclear Nrf2 protein expression. All these changes were either attenuated or prevented by APN. In primarily cultured cardiomyocytes (CMs) isolated from D rats or in the embryonic rat cardiomyocytes cell line H9C2 cells incubated with high glucose (HG, 25 mM), supplementation of recombined globular APN (gAd, 2μg/mL) reversed HG-induced reductions of HO-1, Brg1, and nuclear Nrf2 protein expression and attenuated cellular oxidative stress, myocyte size, and apoptotic cells. Inhibition of HO-1 by ZnPP (10μM) or small interfering RNA (siRNA) canceled all the above gAd beneficial effects. Moreover, inhibition of Nrf2 (either by the Nrf2 inhibitor luteolin or siRNA) or Brg1 (by siRNA) canceled gAd-induced HO-1 induction and cellular protection in CMs and in H9C2 cells incubated with HG. In summary, our present study demonstrated that APN reduced cardiac oxidative stress, ameliorated cardiomyocyte hypertrophy, and prevented left ventricular dysfunction in diabetes by concomitantly activating Nrf2 and Brg1 to facilitate HO-1 induction.

The duration of diabetes is inversely associated with the physiological serum bilirubin levels in patients with type 2 diabetes

OBJECTIVE

The aim of this study was to assess the relationship between the duration of diabetes and the physiological serum bilirubin concentration in association with antioxidant properties in patients with type 2 diabetes.

METHODS

A total of 1,746 patients with type 2 diabetes were investigated in this cross-sectional study. An analysis of covariance was performed after adjusting for other covariates. Simple correlation analyses and a multivariate regression model were used to assess the association between the duration of diabetes and the serum bilirubin concentration.

RESULTS

The mean total bilirubin value differed significantly according to the tertile of diabetes duration (<5 years, 12.38 μmol/L, 95% confidence interval (CI) 12.02-12.76; 5-11.9 years, 12.33 μmol/L, 95% CI 11.97-12.69; ≥12 years, 11.73 μmol/L, 95% CI 11.35-12.11; p for trend =0.033), after adjustment for other covariates. In addition, an inverse correlation was found between the serum bilirubin concentration and diabetes duration (ρ=-0.211, p<0.001). According to a multivariate model, the association between the diabetes duration and serum bilirubin concentration remained significant, even after adjustment for confounding factors (β=-0.074, p=0.008).

CONCLUSION

The duration of diabetes is inversely associated with a serum bilirubin concentration within the physiologic range in patients with type 2 diabetes.

Inhibitory effects of Momordica grosvenori Swingle extracts on 12-O-tetradecanoylphorbol 13-acetate-induced skin inflammation and tumor promotion in mouse skin

Our previous data showed that the Momordica grosvenori Swingle extract (MSE) exhibited the anti-inflammatory effect through markedly suppressed LPS-induced up-regulation of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2) and ODC (ornithine decarboxylase) gene expression in RAW 264.7 cells. Regarding the link between inflammation and carcinogenesis, we further investigated the bio-molecular mechanisms of both anti-inflammatory and anti-tumor activities in vivo using a TPA (12-O-tetradecanoyl phorbol 13-acetate)-stimulated mouse skin model. Pretreatment with MSE in mouse skin has led to the reduction of TPA-induced nuclear translocation of the nuclear factor-κB (NFκB) subunits as well as phosphorylation of IκBα and p65 subsequent reduction of IκBα degradation. In addition, the MSE inhibitory effect on upstream of NFκB was found to involve the transcriptional effects of MAPK signaling as indicated by strong suppression on TPA-induced activation of extracellular signal regulate kinase (ERK)1/2, p38 mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNK)1/2, phosphatidylinositol 3-kinase (PI3K) and Akt. Moreover, MSE significantly inhibited 7,12-dimethylbenz[a]anthracene (DMBA)-TPA-induced skin tumor formation in mice measured by the tumor multiplicity of papillomas at 20 weeks. The results suggested that MSE contained promising functional ingredients capable of preventing inflammation-associated tumorigenesis.

Cucurbitane glycosides derived from mogroside IIE: structure-taste relationships, antioxidant activity, and acute toxicity

Mogroside IIE is a bitter triterpenoid saponin which is the main component of unripe Luo Han Guo fruit and a precursor of the commercially available sweetener mogroside V. In this study, we developed an enzymatic glycosyl transfer method, by which bitter mogroside IIE could be converted into a sweet triterpenoid saponin mixture. The reactant concentration, temperature, pH and buffer system were studied. New saponins with the α-glucose group were isolated from the resulting mixtures, and the structures of three components of the extract were determined. The structure-taste relationships of these derivatives were also studied together with those of the natural mogrosides. The number and stereoconfiguration of glucose groups present in the mogroside molecules were found to be the main factor to determine the sweet or bitter taste of a compound. The antioxidant and food safety properties were initially evaluated by their radical scavenging ability and via 7 day mice survival tests, respectively. The results showed that the sweet triterpenoid saponin mixture has the same favorable physiological and safety characteristics as the natural mogrosides.

Chromium, selenium, and zinc multimineral enriched yeast supplementation ameliorates diabetes symptom in streptozocin-induced mice

Chromium, selenium, and zinc malnutrition has been implicated in the pathogenesis of diabetic mellitus. This study aims to investigate the effects of novel multiminerals-enriched yeast (MMEY) which are minerals supplementation containing elevated levels of chromium, selenium, and zinc simultaneously in a diabetic animal model. Streptozocin-induced diabetic male Balb/c mice (n = 80) were randomly divided into diabetes control group and three treatment groups. They were administrated oral gavages with low, medium, or high doses of MMEY, respectively. Meanwhile, healthy male Balb/c mice (n = 40) of the same body weight were randomly assigned into normal control group and high dose of MMEY control group. After 8 weeks duration of treatment, the animals were sacrificed by cervical dislocation. Serum glucose concentrations, lipid profiles, oxidative/antioxidant, and immunity status were determined. No significant adverse effects were observed in the high-dose MMEY control group. Treatment of the diabetic mice with medium- or high-dose MMEY significantly decreased serum glucose, triglyceride, total cholesterol, and malondialdehyde and increased high-density lipoprotein cholesterol, glutathione, and the activities of superoxide dismutase and glutathione peroxidase. In addition, MMEY ameliorated the pathological damage of the pancreatic islets, elevated the thymus or spleen coefficient, and increased the expressions of interleukin-2 and -4 in spleen lymphocytes compared with unsupplemented diabetic mice. In conclusion, these results indicate that supplemental MMEY inhibits hyperglycemia, abates oxidative stress, modulates disorders of lipid metabolism, and reduces the impairment of immune function in diabetic mice; especially notable are the protective effects of medium doses of MMEY on the islet cells of diabetic mice.

Preventive effects of North American ginseng (Panax quinquefolium) on diabetic nephropathy

PURPOSE

Ginseng has been used as an herbal medicine and nutritional supplement in East Asia for thousands of years and gained popularity in the west because of its various pharmacological properties. Panax ginseng (Asian ginseng) and Panax quinquefolium (North American ginseng) both are reported to possess antihyperglycemic properties. The aim of the present study is to evaluate the preventive effects of North American ginseng on diabetic nephropathy (DN) and the underlying mechanisms of such effects.

METHODS

Models of both type 1 (C57BL/6 mice with STZ-induced diabetes) and type 2 diabetes (db/db mice) and age- and sex-matched controls were examined. Alcoholic ginseng root (200mg/kgbodywt, daily oral gavage) extract was administered to the diabetic mice (type 1 and type 2) for two or four months in order to evaluate its effects on DN.

RESULTS

Dysmetabolic state in the diabetic mice was significantly improved by ginseng treatment. In the kidneys of diabetic animals, ginseng significantly prevented oxidative stress and reduced the NF-κB (p65) levels. Diabetes-induced up-regulations of ECM proteins and vasoactive factors in the kidneys were significantly diminished by ginseng administration. Furthermore, albuminuria and mesangial expansion in the diabetic mice were prevented by ginseng therapy.

CONCLUSION

North American ginseng has preventive effects on DN and it works through a combination of mechanisms such as antihyperglycemic and antioxidant activities.

Anti-inflammatory activities of mogrosides from Momordica grosvenori in murine macrophages and a murine ear edema model

Momordica grosvenori (Luo Han Guo), grown primarily in Guangxi province in China, has been traditionally used for thousands of years by the Chinese to make hot drinks for the treatment of sore throat and the removal of phlegm. The natural noncaloric sweetening triterpenoid glycosides (mogrosides) contained in the M. grosvenori fruits are also antioxidative, anticarcinogenic, and helpful in preventing diabetic complications. The aim of this study was to assess the anti-inflammatory properties of mogrosides in both murine macrophage RAW 264.7 cells and a murine ear edema model. The results indicate that mogrosides can inhibit inflammation induced by lipopolysaccharides (LPS) in RAW 264.7 cells by down-regulating the expression of key inflammatory genes iNOS, COX-2, and IL-6 and up-regulating some inflammation protective genes such as PARP1, BCL2l1, TRP53, and MAPK9. Similarly, in the murine ear edema model, 12-O-tetradecanoylphorbol-13-acetate-induced inflammation was inhibited by mogrosides by down-regulating COX-2 and IL-6 and up-regulating PARP1, BCL2l1, TRP53, MAPK9, and PPARδ gene expression. This study shows that the anticancer and antidiabetic effects of M. grosvenori may result in part from its anti-inflammatory activity.

Increased expression of the multidrug resistance-associated protein 1 (MRP1) in kidney glomeruli of streptozotocin-induced diabetic rats

Oxidative stress has been linked to the podocytopathy, mes-angial expansion and progression of diabetic nephropathy. The major cell defence mechanism against oxidative stress is reduced glutathione (GSH). Some ABC transporters have been shown to extrude GSH, oxidised glutathione or their conjugates out of the cell, thus implying a role for these transporters in GSH homeostasis. We found a remarkable expression of mRNA for multidrug resistance-associated proteins (MRP/ABCC) 1, 3, 4 and 5 in rat glomeruli. Three weeks after induction of diabetes in glomeruli of streptozotocin-treated rats, we observed a decline in reduced GSH levels and an increase in the expression and activity of MRP1 (ABCC1). These lower GSH levels were improved by ex vivo treatment with pharmacological inhibitors of MRP1 activity (MK571). We conclude that increased activity of MRP1 in diabetic glomeruli is correlated with an inadequate adaptive response to oxidative stress.

Plasma heme oxygenase-1 concentration is elevated in individuals with type 2 diabetes mellitus

Background

Circulating concentrations of heme oxygenase-1 (HO-1) have been recently reported to be elevated in several chronic disorders. However, no study has ever examined the association between circulating HO-1 concentrations and type 2 diabetes mellitus (T2DM).

Methods and Findings

581 cases with newly-diagnosed T2DM (New-T2DM) and 611 comparison controls were recruited in this two-phase case-control study, comprising 420 cases and 429 controls collected in the first phase study and 161 cases and 182 controls in the second phase replication study. Analyses, using both separated data and combined data from the two-phase studies, show that plasma HO-1 concentrations were significantly increased in New-T2DM cases compared to controls (P<0.001). Plasma HO-1 concentrations were significantly correlated with plasma glucose concentrations, HOMA-beta and HOMA-IR (P<0.001). After adjustment for age, sex, BMI and family history of diabetes, the ORs for New-T2DM in the highest quartile of plasma HO-1 concentrations, compared with the lowest, was 8.23 (95% CI 5.55–12.21; P for trend <0.001). The trend remained significant after additional adjustment for fasting plasma glucose/insulin, HOMA-beta/HOMA-IR, TC/TG, smoking, drinking and history of hypertension, and even in further stratification analysis by age, sex, BMI, smoking, drinking and history of hypertension.

Conclusions

Elevated plasma HO-1 concentrations are associated with higher ORs for New-T2DM, which add more knowledge regarding the important role of oxidative stress in T2DM. More consequent studies were warranted to confirm the clinical utility of plasma HO-1, especially in diagnosis and prognosis of T2DM and its complications.

Association between heme oxygenase-1 gene promoter polymorphisms and type 2 diabetes in a Chinese population

The authors aimed to determine whether 2 functional polymorphisms in the heme oxygenase-1 (HO-1) gene promoter are associated with type 2 diabetes mellitus (T2DM). A Chinese case-control study involving 1,103 newly diagnosed T2DM patients, 371 patients with impaired glucose regulation (IGR), and 1,615 controls was performed (December 2004-December 2007). A (GT)(n) microsatellite polymorphism and a single nucleotide polymorphism, T(-413)A, were genotyped, and their functional relevance was evaluated by examining the level of HO-1 protein expression. For the (GT)(n) microsatellite polymorphism, genotypes with the L (GT)(n) allele (>or=25 GT repeats) were associated with increased odds of IGR or T2DM compared with the S/S genotype (<25 GT repeats) (S/L genotype: odds ratio (OR) = 1.35, P = 0.048; L/L genotype: OR = 1.65, P = 0.006). Subsequent haplotype analysis showed that haplotype TL contributed to increased odds of IGR or T2DM compared with haplotype TS (OR = 1.56, P = 0.003). In functional analyses, HO-1 expression level was significantly reduced in persons with IGR and T2DM carrying the L/L (GT)(n) genotype compared with persons with the S/S genotype. Further haplotype combination assay confirmed the functional dominance of the (GT)(n) microsatellite polymorphism over the T(-413)A single nucleotide polymorphism. These results support an association between the HO-1 (GT)(n) microsatellite polymorphism, HO-1 expression levels, and the odds of T2DM.

Heme oxygenase-1 accelerates cutaneous wound healing in mice

Heme oxygenase-1 (HO-1), a cytoprotective, pro-angiogenic and anti-inflammatory enzyme, is strongly induced in injured tissues. Our aim was to clarify its role in cutaneous wound healing. In wild type mice, maximal expression of HO-1 in the skin was observed on the 2(nd) and 3(rd) days after wounding. Inhibition of HO-1 by tin protoporphyrin-IX resulted in retardation of wound closure. Healing was also delayed in HO-1 deficient mice, where lack of HO-1 could lead to complete suppression of reepithelialization and to formation of extensive skin lesions, accompanied by impaired neovascularization. Experiments performed in transgenic mice bearing HO-1 under control of keratin 14 promoter showed that increased level of HO-1 in keratinocytes is enough to improve the neovascularization and hasten the closure of wounds. Importantly, induction of HO-1 in wounded skin was relatively weak and delayed in diabetic (db/db) mice, in which also angiogenesis and wound closure were impaired. In such animals local delivery of HO-1 transgene using adenoviral vectors accelerated the wound healing and increased the vascularization. In summary, induction of HO-1 is necessary for efficient wound closure and neovascularization. Impaired wound healing in diabetic mice may be associated with delayed HO-1 upregulation and can be improved by HO-1 gene transfer.

Suppressive effect of Siraitia grosvenorii extract on dicyclanil-promoted hepatocellular proliferative lesions in male mice

Dicyclanil (DC) generates reactive oxygen species (ROS) due to Cyp1a1 induction, and DNA damage caused by oxidative stress is probably involved in hepatocarcinogenesis in mice. To clarify the modifying effect of the Siraitia grosvenorii extract (SGE), which has antioxidative properties, we employed a 2-stage liver carcinogenesis model in partially hepatectomized male ICR mice. Mice maintained on diet containing DC at a concentration of 1,500 ppm for 9 weeks after a single intraperitoneal injection of diethylnitrosamine (DEN) at a dose of 30 mg/kg and they were given water containing 2,500 ppm of SGE for 11 weeks including 2 weeks as pre-administration on DC. SGE inhibited the induction of gamma-glutamyltranspeptidase-positive hepatocytes, lipid peroxidation, and gene expression of Cyp1a1, all of which were caused by DC. To examine whether SGE indirectly inhibits Cyp1a1 expression induced by inhibition of aryl hydrocarbon receptor (Ahr)-mediated signal transduction caused by DC, mice with high (C57BL/6J mice) and low affinities (DBA/2J mice) to Ahr were given DC-containing diet and/or SGE-containing tap water for 2 weeks. Cyp1a1 gene expression was significantly lower in C57BL/6J mice administered DC + SGE than in C57BL/6J mice administered DC alone; there was no difference in the Cyp1a1 expression between DBA/2J mice administered DC + SGE and DC alone. These results suggest that SGE suppresses the induction of Cyp1a1, leading to inhibition of ROS generation and consequently inhibited hepatocarcinogenesis, probably due to suppression of Ahr activity.