Effects of carnosine supplementation on markers for the pathophysiological development of metabolic dysfunction-associated steatotic liver disease in a diet-induced model.

Consumption of diets high in sugar and fat is related to the development of Metabolic dysfunction-associated steatotic liver disease (MASLD). Carnosine (CAR) is a dipeptide with antioxidant and anti-inflammatory action and has been studied for treating diseases. This work aimed to evaluate the effects of CAR on diet-induced MASLD in rats. Male Wistar rats were distributed into 2 groups (17 weeks): normocaloric (Co, n = 12), and hypercaloric diet rich in lipids and simple carbohydrates (MASLD, n = 12). After, the animals were redistributed to begin the treatment with CAR (4 weeks): Co (n = 6), Co + CAR (n = 6), MASLD (n = 6), and MASLD + CAR (n = 6), administered intraperitoneally (250 mg/kg). Evaluations included nutritional, hormonal and metabolic parameters; hepatic steatosis, inflammatory and oxidative markers. MASLD group had a higher adiposity index, systolic blood pressure, glucose, plasma and liver triglycerides and cholesterol, insulin, hepatic steatosis, oxidative markers, and lower PPAR-α (Peroxisome Proliferator-activated receptor α), compared to the Co. CAR attenuated plasma and hepatic triglyceride and cholesterol levels, hepatic steatosis, CD68+ macrophages, and hepatic oxidative markers, in addition to increasing HDL cholesterol levels and PPAR-α, compared to the untreated MASLD group. CAR acts in importants pathophysiological processes of MASLD and may be a therapeutic compound to control the disease.

Carnosine supplementation and retinal oxidative parameters in a high-calorie diet rat model.

BACKGROUND: To assess oxidative effects induced by a high-calorie diet on the retina of Wistar rats and test the antioxidative effects of carnosine supplementation. METHODS: Wistar rats were randomly divided into the following groups: standard diet (SD), high-calorie diet (HcD), standard diet + carnosine (SD + Car), and high-calorie diet + carnosine (HcD + Car). The body weight, adiposity index, plasma glucose, total lipids, high-density lipoprotein (HDL), low-density lipoprotein (LDL), uric acid, creatinine, and triglycerides of the animals were evaluated. The retinas were analyzed for markers of oxidative stress. Hydrogen peroxide production was assessed by 2',7'-dichlorodihydrofluorescein diacetate (DCF) oxidation. The total glutathione (tGSH), total antioxidant capacity (TAC), protein carbonyl, and sulfhydryl groups of the antioxidant system were analyzed. RESULTS: TAC levels increased in the retinas of the SD + Car group compared to the SD group (p < 0.05) and in the HcD + Car group compared to the HcD group (p < 0.05). The levels of GSH and the GSSH:GSSG ratio were increased in the HcD + Car group compared to the SD + Car group (p < 0.05). An increase in the retinal carbonyl content was observed in the HcD group compared to the SD group (p < 0.05) and in the HcD + Car group compared to the SD + Car group (p < 0.05). A high-calorie diet (HcD) was also associated with a decrease in retinal sulfhydryl-type levels compared to the SD group (p < 0.05). CONCLUSION: The results suggest that feeding a high-calorie diet to rats can promote an increase in carbonyl content and a reduction in sulfhydryl groups in their retinas. The administration of carnosine was not effective in attenuating these oxidative markers. TRIAL REGISTRATION: Animal Ethics Committee of Botucatu Medical School - Certificate number 1292/2019.

Targeting Nrf2 and NF-κB Signaling Pathways in Inflammatory Pain: The Role of Polyphenols from Thinned Apples.

Diet can modulate the different stages of inflammation due to the presence of bioactive compounds such as polyphenols. Apples are a great source of phenolic compounds that show anti-inflammatory and antioxidant properties, and these might be used as a dietary supplement and/or functional element in the treatment of chronic inflammatory illnesses. The aim of our study was to evaluate the anti-inflammatory and antioxidant actions of thinned apple polyphenol (TAP) extracts in a model of paw edema. The experimental model was induced in rats via subplantar injections of 1% λ-Carrageenan (CAR) in the right hind leg, and TAP extract was administered via oral gavage 30 min before and 1 h after the CAR injection at doses of 5 mg/kg and 10 mg/kg, respectively. The inflammatory response is usually quantified by the increase in the size of the paw (edema), which is maximal about 5 h after the injection of CAR. CAR-induced inflammation generates the release of pro-inflammatory mediators and reactive oxygen species (ROS). Furthermore, the inflammatory state induces the pain that involves the peripheral nociceptors, but above all it acts centrally at the level of the spinal cord. Our results showed that the TAP extracts reduced paw histological changes, neutrophil infiltration, mast cell degranulation, and oxidative stress. Additionally, the oral administration of TAP extracts decreased thermal and mechanical hyperalgesia, along with a reduction in spinal microglia and the markers of nociception. In conclusion, we demonstrate that TAP extract is able to modulate inflammatory, oxidative, and painful processes, and is also useful in the treatment of the symptoms associated with paw edema.

Treatment with bergamot (Citrus bergamia) leaves extract attenuates leptin resistance in obese rats.

Low-grade chronic inflammation in obesity is associated with leptin resistance. In order to alleviate this pathological condition, bioactive compounds capable of attenuating oxidative stress and inflammation have been researched, and bergamot (Citrus bergamia) presents these properties. The aim was to evaluate the effect of bergamot leaves extract on leptin resistance in obese rats. Animals were divided into 2 groups: control diet (C, n = 10) and high sugar-fat diet (HSF, n = 20) for 20 weeks. After detecting hyperleptinemia, animals were divided to begin the treatment with bergamot leaves extract (BLE) for 10 weeks: C + placebo (n = 7), HSF + placebo (n = 7), and HSF + BLE (n = 7) by gavage (50 mg/kg). Evaluations included nutritional, hormonal and metabolic parameters; adipose tissue dysfunction; inflammatory, oxidative markers and hypothalamic leptin pathway. HSF group presented obesity, metabolic syndrome, adipose tissue dysfunction, hyperleptinemia and leptin resistance compared to control group. However, the treated group showed a decrease in caloric consumption and attenuation of insulin resistance. Moreover, dyslipidemia, adipose tissue function, and leptin levels showed an improvement. At the level of the hypothalamus, the treated group showed a reduction of oxidative stress, inflammation and modulation of leptin signaling. In conclusion, BLE properties were able to improve leptin resistance through recovery of the hypothalamic pathway.

Bergamot (Citrus bergamia) leaf extract improves metabolic, antioxidant and anti-inflammatory activity in skeletal muscles in a metabolic syndrome experimental model.

Metabolic Syndrome (MetS), inflammation and oxidative stress contribute to impairment of skeletal muscle function. Bergamot (Citrus bergamia) leaf extract (BLE) has shown protective effects against comorbidities associated with MetS through its anti-inflammatory and antioxidant effects. The aim of this work was to elucidate the antioxidant and anti-inflammatory activity of BLE in skeletal muscles in an experimental model of MetS. Once metabolic syndrome was diagnosed, animals were divided into groups receiving different treatments for 10 weeks, including control diet (n = 10), control + BLE (n = 10), High Sugar-fat diet (HSF) (n = 10), HSF + BLE (n = 10). Evaluation included nutritional, metabolic and hormonal analyses, along with measurements of inflammatory status and oxidative stress in soleus and extensor digitorum longus (EDL) muscles. BLE showed positive metabolic effects, with a reduction of plasma triglycerides and insulin resistance and an increase in high-density lipoprotein cholesterol, and protective activity against oxidative stress and inflammation in Soleus and EDL muscles in animals with MetS.

An integrated metabolomic and proteomic approach for the identification of covalent inhibitors of the main protease (Mpro) of SARS-COV-2 from crude natural extracts.

Mpro represents one of the most promising drug targets for SARS-Cov-2, as it plays a crucial role in the maturation of viral polyproteins into functional proteins. HTS methods are currently used to screen Mpro inhibitors, and rely on searching chemical databases and compound libraries, meaning that they only consider previously structurally clarified and isolated molecules. A great advancement in the hit identification strategy would be to set-up an approach aimed at exploring un-deconvoluted mixtures of compounds such as plant extracts. Hence, the aim of the present study is to set-up an analytical platform able to fish-out bioactive molecules from complex natural matrices even where there is no knowledge on the constituents. The proposed approach begins with a metabolomic step aimed at annotating the MW of the matrix constituents. A further metabolomic step is based on identifying those natural electrophilic compounds able to form a Michael adduct with thiols, a peculiar chemical feature of many Mpro inhibitors that covalently bind the catalytic Cys145 in the active site, thus stabilizing the complex. A final step consists of incubating recombinant Mpro with natural extracts and identifying compounds adducted to the residues within the Mpro active site by bottom-up proteomic analysis (nano-LC-HRMS). Data analysis is based on two complementary strategies: (i) a targeted search applied by setting the adducted moieties identified as Michael acceptors of Cys as variable modifications; (ii) an untargeted approach aimed at identifying the whole range of adducted peptides containing Cys145 on the basis of the characteristic b and y fragment ions independent of the adduct. The method was set-up and then successfully tested to fish-out bioactive compounds from the crude extract of Scutellaria baicalensis, a Chinese plant containing the catechol-like flavonoid baicalin and its corresponding aglycone baicalein which are well-established inhibitors of Mpro. Molecular dynamics (MD) simulations were carried out in order to explore the binding mode of baicalin and baicalein, within the SARS-CoV-2 Mpro active site, allowing a better understanding of the role of the nucleophilic residues (i.e. His41, Cys145, His163 and His164) in the protein-ligand recognition process.

Achillea moschata Wulfen: From Ethnobotany to Phytochemistry, Morphology, and Biological Activity.

A multidisciplinary investigation on Achillea moschata Wulfen (Asteraceae) is outlined herein. This work, part of the European Interreg Italy-Switzerland B-ICE project, originated from an ethnobotanical survey performed in Chiesa in Valmalenco (Sondrio, Lombardy, Northern Italy) in 2019-2021 which highlighted this species' relevance of use in folk medicine to treat gastrointestinal diseases. In addition, this contribution included analyses of the: (a) phytochemical profile of the aqueous and methanolic extracts of the dried flower heads using LC-MS/MS; (b) morpho-anatomy and histochemistry of the vegetative and reproductive organs through Light, Fluorescence, and Scanning Electron Microscopy; (c) biological activity of the aqueous extract concerning the antioxidant and anti-inflammatory potential through cell-based in vitro models. A total of 31 compounds (5 phenolic acids, 13 flavonols, and 13 flavones) were detected, 28 of which included in both extracts. Covering and secreting trichomes were observed: the biseriate 10-celled glandular trichomes prevailing on the inflorescences represented the main sites of synthesis of the polyphenols and flavonoids detected in the extracts, along with volatile terpenoids. Finally, significant antioxidant and anti-inflammatory activities of the aqueous extract were documented, even at very low concentrations; for the first time, the in vitro tests allowed us to formulate hypotheses about the mechanism of action. This work brings an element of novelty due to the faithful reproduction of the traditional aqueous preparation and the combination of phytochemical and micromorphological research approaches.

Bergamot leaf extract treats cardiorenal metabolic syndrome and associated pathophysiological factors in rats fed with a high sugar fat diet.

Bergamot citrus (Citrus bergamia Risso et Poiteau), have been used as a strategy to prevent or treat comorbidities associated with metabolic syndrome parameters, such as cardiorenal metabolic syndrome (CRMS). The aim was to test the effect of bergamot leaf extract on CRMS and associated pathophysiological factors in rats fed with a high sugar-fat diet. Animals were divided into two experimental groups with control diet (Control, n = 30) and high sugar-fat diet (HSF, n = 30) for 20 weeks. Once CRMS was detected, animals were redivided to begin the treatment with Bergamot Leaf Extract (BLE) by gavage (50 mg/kg) for 10 weeks: control diet + placebo (Control, n = 09), control diet + BLE (Control + BLE, n = 09), HSF diet + placebo (HSF, n = 09), HSF + BLE (n = 09). Evaluation included nutritional, metabolic and hormonal analysis; and renal and cardiac parameters. HSF groups presented obesity, dyslipidemia, hypertension, hyperglycemia, hyperinsulinemia, insulin resistance. BLE showed protection against effects on hypertriglyceridemia, insulin resistance, renal damage, and structural and functional alterations of the heart. Conclusion: Bergamot leaf extract shows potential as a therapeutic to treat CRMS in animals fed with a high sugar-fat diet.

Cyclo(His-Pro) Exerts Protective Carbonyl Quenching Effects through Its Open Histidine Containing Dipeptides.

Cyclo(His-Pro) (CHP) is a cyclic dipeptide which is endowed with favorable pharmacokinetic properties combined with a variety of biological activities. CHP is found in a number of protein-rich foods and dietary supplements. While being stable at physiological pH, CHP can open yielding two symmetric dipeptides (His-Pro, Pro-His), the formation of which might be particularly relevant from dietary CHP due to the gastric acidic environment. The antioxidant and protective CHP properties were repeatedly reported although the non-enzymatic mechanisms were scantly investigated. The CHP detoxifying activity towards α,ß unsaturated carbonyls was never investigated in detail, although its open dipeptides might be effective as already observed for histidine containing dipeptides. Hence, this study investigated the scavenging properties of TRH, CHP and its open derivatives towards 4-hydroxy-2-nonenal. The obtained results revealed that Pro-His possesses a marked activity and is more reactive than l-carnosine. As investigated by DFT calculations, the enhanced reactivity can be ascribed to the greater electrophilicity of the involved iminium intermediate. These findings emphasize that the primary amine (as seen in l-carnosine) can be replaced by secondary amines with beneficial effects on the quenching mechanisms. Serum stability of the tested peptides was also evaluated, showing that Pro-His is characterized by a greater stability than l-carnosine. Docking simulations suggested that its hydrolysis can be catalyzed by serum carnosinase. Altogether, the reported results evidence that the antioxidant CHP properties can be also due to the detoxifying activity of its open dipeptides, which might be thus responsible for the beneficial effects induced by CHP containing food.

The ergogenic effect of acute carnosine and anserine supplementation: dosing, timing, and underlying mechanism.

Background: Recent studies suggest that acute-combined carnosine and anserine supplementation has the potential to improve the performance of certain cycling protocols. Yet, data on optimal dose, timing of ingestion, effective exercise range, and mode of action are lacking. Three studies were conducted to establish dosing and timing guidelines concerning carnosine and anserine intake and to unravel the mechanism underlying the ergogenic effects. Methods: First, a dose response study A was conducted in which 11 men randomly received placebo, 10, 20, or 30 mg.kg-1 of both carnosine and anserine. They performed 3x maximal voluntary isometric contractions (MVC), followed by a 5 x 6 s repeated cycling sprint ability test (RSA), once before the supplement and 30 and 60 minutes after. In a second study, 15 men performed 3x MVCs with femoral nerve electrical stimulation, followed by an RSA test, once before 30 mg.kg-1 carnosine and anserine and 60 minutes after. Finally, in study C, eight men performed a high intensity cycling training after randomly ingesting 30 mg.kg-1 of carnosine and anserine, a placebo or antihistamines (reduce post-exercise blood flow) to investigate effects on muscle perfusion. Results: Study A showed a 3% peak power (p = 0.0005; 95% CI = 0.07 to 0.27; ES = 0.91) and 4.5% peak torque (p = 0.0006; 95% CI = 0.12 to 0.50; ES = 0.87) improvement on RSA and MVC, with 30 mg.kg-1 carnosine + anserine ingestion 60 minutes before the performance yielding the best results. Study B found no performance improvement on group level; however, a negative correlation (r = -0.54; p = 0.0053; 95% CI = -0.77 to -0.19) was found between carnosinase enzyme activity (responsible for carnosine and anserine breakdown) and performance improvement. No effect of the supplement on neuromuscular function nor on muscle perfusion was found. Conclusions: These studies reveal that acute ingestion of 30 mg.kg-1 of both carnosine and anserine, 60 minutes before a high intensity exercise, can potentially improve performance, such as short cycling sprints or maximal muscle contractions. Subjects with lower carnosinase activity, and thus a slower breakdown of circulating dipeptides, appear to benefit more from this ergogenic effect. Finally, neither the involvement of a direct effect on neuromuscular function, nor an indirect effect on recovery through increased muscle perfusion could be confirmed as potential mechanism of action. The ergogenic mechanism therefore remains elusive.

PHoral: Effects of carnosine supplementation on quantity/quality of oral salivae in healthy volunteer and in subjects affected by common oral pathologies.

BACKGROUND: Diseases of the oral cavity (OC) with an infectious trigger such as caries and periodontal disease are extremely common in the general population and can also have effects at the cardiovascular level. The oral salivary flow, with its buffering capacity, is able to regulate the pH of the OC and, therefore, significantly contribute to the ecological balance of the microenvironment in which the oral microbiome (OM) develops. On the other side, when the quality/quantity of salivary flow is altered it is supposed the disruption of this balance with the potential increase in oral pathogens and triggered diseases. Among the endogenous substances able to exert a significant effect on the salivary flow and its characteristics, carnosine (Car), a dipeptide originally isolated in skeletal muscle, represents, thanks to the known buffering properties, a promising principle. METHODS: We aimed this protocol to evaluate the quantitative/qualitative characteristics of the salivary flow in healthy volunteer subjects (n = 20) and in subjects suffering from common OC pathologies (n = 40), before and after 7 days of supplementation with SaliflussTM (Metis Healthcare srl, Milan, Italy), a Class I medical device on the market as 400 mg mucoadhesive oral tablets that has Car as the main ingredient. DISCUSSION: Combining the characteristics of saliva with the OM and comparing them with OC pathologies, we expect to clarify their reciprocal relationship and, using quantitative proteomics techniques, to help clarify the mechanism of action of Car.

Profiling Vaccinium macrocarpon components and metabolites in human urine and the urine ex-vivo effect on Candida albicans adhesion and biofilm-formation.

The aim of this work was to profile, by using an HPLC-MS/MS method, cranberry compounds and metabolites found in human urine after ingestion of a highly standardized cranberry extract (Anthocran®). Two different strategies were adopted for the data analysis: a targeted and an untargeted approach. These strategies allowed the identification of 42 analytes including cranberry components, known metabolites and metabolites hitherto unreported in the literature, including six valerolactones/valeric acid derivatives whose presence in urine after cranberry consumption has never been described before. Absolute concentrations of 26 over 42 metabolites were obtained by using pure available standards. Urine collected at different time points after the last dosage of Anthocran® were tested on the reference strain C. albicans SC5314, a biofilm-forming strain. Fractions collected after 12 h were found to significantly reduce the adhesion and biofilm formation compared to the control (p < 0.05). A similar effect was then obtained by using Anthocran™ Phytosome™, the lecithin formulation containing 1/3 of standardized cranberry extract and formulated to enhance the absorption of the cranberry components. The urinary profile of cranberry components and metabolites in the urine fractions collected at 1 h, 6 h and 12 h after the last capsule intake were then reproduced by using the pure standards at the concentration ranges found in the urine fraction, and tested on C. albicans. Only the mixture mimicking the urinary fraction collected at 12 h and containing as main components, quercetin and 5-(3',4'-dihydroxyphenyl)-γ-valerolactone was found effective thus confirming the ex-vivo results.

Development and validation of a HPLC method for the direct separation of carnosine enantiomers and analogues in dietary supplements.

The chiral purity of some molecules such as nutraceuticals is fundamental to ensure their beneficial activities and it must be checked during quality control analysis. Carnosine is a natural histidine dipeptide used as ingredient for food supplements, but only his L-enantiomer is absorbed and active. Despite of this feature, a method for the separation of carnosine enantiomers without derivatization has only recently been published. Herein, we validated a method based on a Chirobiotic T column and an UV detector for the direct quantification of carnosine enantiomers, following ICH guideline. Moreover, we demonstrated that elution with water containing 0.1% formic acid and 20-40% ensures stereo-, chemo- and regio-selectivity for the separation and the identification of carnosine enantiomers and natural analogues. Moreover, the method allows a direct hyphenation with electrospray mass spectrometry to increase detection selectivity and sensitivity. As far as we know, this is the first method allowing the simultaneous identification and quantification of natural analogues of carnosine, which can be important for application such as the identification of enantiomeric impurities or adulteration that can occur during the storage or the preparation of foods or food supplements containing histidine dipeptides.

Development of a direct ESI-MS method for measuring the tannin precipitation effect of proline-rich peptides and in silico studies on the proline role in tannin-protein interactions.

Tannins are a heterogeneous class of polyphenols that are present in several plants and foods. Their ability to interact and precipitate proline-rich proteins leads to different effects such as astringency or antidiarrheal activity. Thus, evaluation of the tannin content in plant extracts plays a key role in understanding their potential use as pharmaceuticals and nutraceuticals. Several methods have been proposed to study tannin-protein interactions but few of them are focused on quantification. The purpose of the present work is to set up a suitable and time efficient method able to quantify the extent of tannin protein precipitation. Bradykinin, chosen as a model, was incubated with increasing concentrations of 1,2,3,4,6-penta-O-galloyl-ß-d-glucose and tannic acid selected as reference of tannic compounds. Bradykinin not precipitated was determined by a mass spectrometer TSQ Quantum Ultra Triple Quadrupole (direct infusion analysis). The results were expressed as PC50, which is the concentration able to precipitate 50% of the protein. The type of tannin-protein interaction was evaluated also after precipitate solubilisation. The involvement of proline residues in tannin-protein interactions was confirmed by repeating the experiment using a synthesized peptide (RR-9) characterized by the same bradykinin sequence, but having proline residues replaced by glycine residues: no interaction occurred between the peptide and the tannins. Moreover, modelling studies on PGG-BK and PGG-RR-9 were performed to deeply investigate the involvement of prolines: a balance of hydrophobic and H-bond contacts stabilizes the PGG-BK cluster and the proline residues exert a crucial role thus allowing the PGG molecules to elicit a sticking effect.

Colostrum from cows immunized with a veterinary vaccine against bovine rotavirus displays enhanced in vitro anti-human rotavirus activity.

Human rotaviruses represent a major cause of severe diarrheal disease in infants and young children. The limited impact of oral vaccines on global estimates of rotavirus mortality and the suboptimal use of oral rehydration justify the need for alternative prophylactic and therapeutic strategies, especially for immunocompromised hosts. The protective effects of colostrum-the first milk produced during the initial 24 to 48 h after parturition-are well documented in the literature. In particular, the ingestion of hyperimmune bovine colostrum has been proposed as an alternative preventive approach against human rotavirus gastroenteritis. Although the immunization of pregnant cows with human rotavirus boosts the release of specific immunoglobulin G in bovine colostrum, it raises regulatory and safety issues. In this study, we demonstrated that the conventional bovine rotavirus vaccine is sufficient to enhance the anti-human rotavirus protective efficacy of bovine colostrum, thus providing a conservative approach to produce hyperimmune bovine colostrum, making it exploitable as a functional food.

Ripe and Raw Pu-Erh Tea: LC-MS Profiling, Antioxidant Capacity and Enzyme Inhibition Activities of Aqueous and Hydro-Alcoholic Extracts.

Herein, we reported a detailed profiling of soluble components of two fermented varieties of Chinese green tea, namely raw and ripe pu-erh. The identification and quantification of the main components was carried out by means of mass spectrometry and UV spectroscopy, after chromatographic separation. The antioxidant capacity towards different radical species, the anti-microbial and the enzyme inhibition activities of the extracts were then correlated to their main constituents. Despite a superimposable qualitative composition, a similar caffeine content, and similar enzyme inhibition and antimicrobial activities, raw pu-erh tea extract had a better antioxidant capacity owing to its higher polyphenol content. However, the activity of raw pu-erh tea seems not to justify its higher production costs and ripe variety appears to be a valid and low-cost alternative for the preparation of products with antioxidant or antimicrobial properties.

Phenolic profiles and anti-inflammatory activities of sixteen table grape (Vitis vinifera L.) varieties.

Several studies have shown that fresh grape and its derivatives contain phenolic compounds exhibiting antioxidant and health promoting effects, particularly in relation to the cardiovascular system. In this study, two methods were developed to characterize sixteen varieties of table and wine grapes: (1) a LC-MS method to identify major and minor phenolic compounds; and (2) a HPLC-DAD method to quantify the most representative compounds. Sixty-seven molecules belonging to different classes of phenolic compounds were identified: anthocyanins, flavan-3-ols, flavonols, stilbenes and organic acids. In parallel, the free radical scavenging activity and anti-inflammatory activities of the 16 grape varieties were evaluated. The results showed a good correlation between the total phenolic content and the biological activity. Extracts from Exalta and Albarossa grape varieties were the most active in reducing IL-8 release by gastric epithelial cells (IC50 = 8.48 µg mL-1 and 6.68 µg mL-1, respectively), a biomarker of inflammatory processes. The observed biological activities were mainly associated with skin and seed extracts/portions. The interest in studying table grapes and their non-fermented derivatives as sources of healthy compounds has increased in the last few years and our findings suggest that table grapes and their fresh derivatives, in addition to wine, could be involved in the health promoting effects of the Mediterranean diet.

Carnosine supplementation reduces plasma soluble transferrin receptor in healthy overweight or obese individuals: a pilot randomised trial.

Abnormalities of iron homeostasis have been linked to insulin resistance, type 2 diabetes and cardiovascular disease. Carnosine, an over-the-counter food supplement with chelating properties, has been shown to decrease serum iron and improve glucose metabolism in diabetic rodents. We have previously demonstrated that carnosine supplementation prevented worsening of glucose metabolism in healthy overweight and obese middle-aged adults. Yet, the impact of carnosine on markers of iron metabolism in humans has not been investigated. We aimed to determine whether carnosine supplementation has an effect on iron parameters in overweight and obese, otherwise healthy adults. We included 26 participants, who were randomly allocated to receive 1 g carnosine (n = 14) or identical placebo (n = 12) twice daily for 12 weeks. Iron parameters including iron, ferritin, transferrin, soluble transferrin receptor, total iron binding capacity and iron saturation were measured in serum or plasma by standard commercial assays. Carnosine supplementation decreased plasma soluble transferrin receptor compared to placebo (mean change difference ± standard error: - 0.07 ± 0.03 mg/l, p = 0.04). None of the other iron parameters were different between carnosine and placebo groups. At follow-up, soluble transferrin receptor was associated inversely with urinary carnosine concentrations and positively with serum carnosinase-1 activity (both p < 0.02). Our findings suggest that carnosine may modulate iron metabolism in high-risk groups which could ameliorate insulin resistance and prevent type 2 diabetes. Larger human clinical trials are required to confirm our results.

Carnosine Supplementation Improves Serum Resistin Concentrations in Overweight or Obese Otherwise Healthy Adults: A Pilot Randomized Trial.

Adipokines play an important role in the regulation of glucose metabolism. We have previously shown that carnosine supplementation in overweight or obese non-diabetic individuals improves glucose metabolism but does not change adiponectin concentrations. However, its effect on other adipokines has not been investigated. Herein we further determined the effect of carnosine supplementation on serum adipsin, resistin and leptin. Twenty-two overweight or obese otherwise healthy adults were randomly assigned to receive either 2 g of carnosine (n = 13) or identically looking placebo (n = 9) for 12 weeks. Serum adipsin, leptin and resistin were analyzed using a bead-based multiplex assay. Carnosine supplementation decreased serum resistin concentrations compared to placebo (mean change from baseline: -35 ± 83 carnosine vs. 35 ± 55 ng/mL placebo, p = 0.04). There was a trend for a reduction in serum leptin concentrations after carnosine supplementation (-76 ± 165 ng/mL carnosine vs. 20 ± 28 ng/mL placebo, p = 0.06). The changes in leptin and resistin concentrations were inversely related to the change in concentration for urinary carnosine (r = -0.72, p = 0.0002; r = -0.67, p = 0.0009, respectively), carnosine-propanal (r = -0.56, p = 0.005; r = -0.63, p = 0.001, respectively) and carnosine-propanol (r = -0.61, p = 0.002; r = -0.60, p = 0.002, respectively). There were no differences between groups in change in adipsin concentrations. Our findings show carnosine supplementation may normalize some, but not all, of the serum adipokine concentrations involved in glucose metabolism, in overweight and obese individuals. Further clinical trials with larger samples are needed to confirm these results.

Isotopic labelling for the characterisation of HNE-sequestering agents in plant-based extracts and its application for the identification of anthocyanidins in black rice with giant embryo.

Reactive carbonyl species (RCS) are cytotoxic molecules that originate from lipid peroxidation and sugar oxidation. Natural derivatives can be an attractive source of potential RCS scavenger. However, the lack of analytical methods to screen and identify bioactive compounds contained in complex matrices has hindered their identification. The sequestering actions of various rice extracts on RCS have been determined using ubiquitin and 4-hydroxy-2-nonenal (HNE) as a protein and RCS model, respectively. Black rice with giant embryo extract was found to be the most effective among various rice varieties. The identification of bioactive compounds was then carried out by an isotopic signature profile method using the characteristic isotopic ion cluster generated by the mixture of HNE: 2H5-HNE mixed at a 1:1 stoichiometric ratio. An in-house database was used to obtain the structures of the possible bioactive components. The identified compounds were further confirmed as HNE sequestering agents through HPLC-UV analysis.