An in vitro comparison of a new vinyl chalcogenide and sodium selenate on adenosine deaminase activity of human leukocytes

In vitro and in vivo ameliorative effects of polyphenols from purple potato leaves on renal injury and associated inflammation induced by hyperuricemia

In the present study, the ameliorative effects of polyphenols from purple potato leaves (PSPLP) on hyperuricemia were investigated. HPLC-MS analysis showed that PSPLP was mainly composed of caffeoylquinic acid derivatives (84%). PSPLP inhibited the levels of cytokines (IL-1β, IL-6, and TNF-α) in monosodium urate-induced RAW264.7 cells. In vivo, PSPLP significantly inhibited the level of uric acid in hyperuricemia mice from 209.6 to 166.6 μM, and significantly interfered with the activities of xanthine oxidase (XOD) and adenosine deaminase in liver, the activity of XOD decreased from 13.5 to 11.6 U/gprot. PSPLP can decrease serum creatinine level from 105 to 59 μM, and urea nitrogen level from 21.9 to 14.1 mM, which can effectively protect kidney. These results provide a reference for future research and application of PSPLP as a functional food to intervene hyperuricemia and associated inflammation. PRACTICAL APPLICATIONS: This study evaluated the effect of polyphenols from purple potato leaves (PSPLP) on hyperuricemia. The results suggested that PSPLP has an important role in the intervention of hyperuricemia and hyperuricemic-related inflammation or renal injury, and can be used in the application of functional foods. These results provided a basis for further study on the biological activities of polyphenols from purple sweet potato leaves.

Effects of epigallocatechin-3-gallate combined with ascorbic acid and glycerol on the stability and uric acid-lowering activity of epigallocatechin-3-gallate

CONTEXT

Epigallocatechin-3-gallate (EGCG) is unstable and easily oxidized, which limits its applications. Ascorbic acid (Vc) is a natural antioxidant.

OBJECTIVE

The effects of EGCG combined with Vc and glycerol on stability and uric acid-lowering activity of EGCG were examined.

MATERIALS AND METHODS

EGCG (aqueous solution), EGCG + Vc (aqueous solution), EGCG (glycerol solution) and EGCG + Vc (glycerol solution) were prepared and incubated under different conditions in vitro. The recovery rate of EGCG was calculated by HPLC. Kunming mice were randomly divided into normal control group, model group, allopurinol (5 mg/kg), EGCG (10 mg/kg), EGCG + Vc (both 10 mg/kg), EGCG (10 mg/kg) + glycerol (60%), and EGCG (10 mg/kg) + Vc (10 mg/kg) + glycerol (60%) (n = 6). Allopurinol was injected intraperitoneally to mice, others were administered intragastrically to (2 cases) mice. All mice were continuously administrated for 7 days, once a day.

RESULTS

EGCG recovery rates of EGCG group and EGCG + Vc + glycerol group respectively reached to 32.34 ± 1.86% and 98.90 ± 0.64% when they were incubated for 4 h at 80 °C. EGCG recovery rates reached to 91.82 ± 5.13% (incubated for 6 h at pH 8) and 88.85 ± 2.63% (incubated for 4 h in simulated intestinal fluid) when EGCG incubated with Vc and glycerol. Compared with the model group, UA values of EGCG + Vc + glycerol group reduced by 43.49% while EGCG group reduced by 25.63%. The activities of xanthine oxidase (XOD, 31.41 U/gprot) and adenosine deaminase (ADA, 10.05 U/mgprot), and the mRNA expression levels of glucose transporter 9 (GLUT9, 1.03) and urate transporter 1 (URAT1, 0.44) in EGCG + Vc + glycerol group were notably lower than those of EGCG group (38.12 U/gprot, 13.16 U/mgprot, 1.54, and 0.55). The mRNA expression levels of ATP-binding cassette superfamily G member 2 (ABCG2, 1.39) and organic anion transport 1/2 (OAT1/2, 2.34, 2.53) in EGCG + Vc + glycerol group were notably higher than those of EGCG group (0.57, 1.13, and 1.16).

DISCUSSION AND CONCLUSIONS

Our findings suggest that when EGCG used in combination with Vc and glycerol could effectively increase its biology activities and can be generalized to the broader pharmacological studies. This sheds light on the development and application of EGCG in the fields of food and medicine.

Meyer-Schuster-Type Rearrangement of Propargylic Alcohols into α-Selenoenals and -enones with Diselenides

We describe a mild and broadly applicable protocol for the preparation of a diverse array of multisubstituted α-selenoenals and -enones from readily accessible propargylic alcohols and diselenides. The transformation proceeds via the Selectfluor-promoted selenirenium pathway, which enables selenenylation/rearrangement of a variety of propargylic alcohols. Gram-scale experiments showed the potential of this synergistic protocol for practical application.

Bovine milk exosomes attenuate the alteration of purine metabolism and energy status in IEC-6 cells induced by hydrogen peroxide

Evidence suggests that dietary depletion of bovine milk exosomes and their cargos causes a loss of circulating microRNAs and a series of health problems. The aim of the current study was to determine whether bovine milk exosomes affect purine nucleotide metabolism and energy metabolism in oxidatively stressed intestinal crypt epithelial cells (IEC-6). Cells were pretreated with exosomes, followed by H₂O₂ to induce oxidative stress. Reactive oxidative species (ROS) levels, purine nucleotides, purine metabolic key enzyme activities, cell energy status, and AMPK protein expression were analysed. Exosome pretreatment reduced ROS level and the activities of adenosine deaminase and xanthine oxidase induced by H₂O₂ in cells. Total adenine nucleotides and energy charge were increased with exosome pretreatment, while the AMPK phosphorylation level was downregulated. The results indicated that bovine milk exosomes could attenuate purine nucleotide catabolism and improve energy status in oxidatively stressed IEC-6 cells and exerted protective effects against oxidative stress.

Comparative effects of green and black tea extracts on lowering serum uric acid in hyperuricemic mice

CONTEXT

Tea (Camellia sinensis (L.) Kuntze [Theaceae]) is used to induce urination and inducing nervous excitation. Green and black teas have multifarious physiological functions. The different effects of green and black tea aqueous extracts (GTEs and BTEs) on hyperuricemia are not definitely reported.

OBJECTIVE

The different effects of GTEs and BTEs on lowering serum uric acid (UA) in hyperuricemic mice were determined.

MATERIALS AND METHODS

Kunming mice were divided into nine groups (n = 6/each group). GTEs and BTEs at the doses of 0.5, 1 and 2 g/kg were orally administrated to mice for seven days, respectively. Hepatic xanthine oxidase (XOD) and adenosine deaminase (ADA) activities as mechanisms of actions were assessed.

RESULTS

Research indicated that the LD₅₀ of tea extract is greater than 2 g/kg in mice. UA levels were suppressed significantly with dose-dependent treatment of 0.5, 1 and 2 g/kg BTEs (up to 25.5%, 28.7% and 29.8%, respectively); the serum UA levels were decreased by GTEs but not significant. The activities of XOD and ADA in high dose (2 g/kg) groups of both GTEs and BTEs were notably lower than those of the model group.

DISCUSSION AND CONCLUSIONS

The results suggested that both GTEs and BTEs have hypouricaemic and renal protective effects on hyperuricemic mice and the latter one was better. Our study sheds light on the research and development of anti-hyperuricemic functional foods and drugs from tea.

Chronic alcohol administration affects purine nucleotide catabolism in vivo

AIMS

To investigate the relationship between chronic alcohol administration and purine nucleotide metabolism in vivo.

MAIN METHODS

Rat models of alcohol dependence and withdrawal were used. The concentrations of uric acid (UAC), urea nitrogen (UREA), creatinine (CREA), and beta-2-microglobulin (β2-M) and creatinine clearance rate (CCR) in plasma were measured. The PLC method was used to detect the absolute content of purine nucleotides in different tissues. Enzymatic activities of adenosine deaminase (ADA), xanthine oxidase (XO), ribose 5-phosphate pyrophosphokinase (RPPPK), glutamine phosphoribosylpyrophosphate amidotransferase (GPRPPAT), hypoxanthine-guanine phosphate ribose transferase (HGPRT), and adenine phosphoribosyltransferase (APRT) in the tissues were analyzed. Real-time PCR was used to determine the relative level of ADA and XO.

KEY FINDINGS

The renal function of rats with alcohol dependence was normal. Further, the content of purine nucleotides (GMP, AMP, GTP, and ATP) in tissues of the rats was decreased, which indicated that the increased uric acid should be derived from the decomposition of nucleotides in vivo. The activity of XO and ADA increased, and their mRNA expression was enhanced in the alcohol dependence group, but there was no significant difference in the activity of RPPPK and GPRPPAT in the liver, small intestine, and muscle; furthermore, no significant difference in the activity of HGPRT and APRT was observed in the brain.

SIGNIFICANCE

These results indicate that chronic alcohol administration might enhance the catabolism of purine nucleotides in tissues by inducing gene expression of ADA and XO, leading to elevation of plasma uric acid levels.

Differential effects of organic and inorganic selenium compounds on adenosine deaminase activity and scavenger capacity in cerebral cortex slices of young rats

Selenium (Se) has anti-inflammatory and antioxidant properties and is necessary for the development and normal function of the central nervous system. This study was aimed to compare the in vitro effects of 3-methyl-1-phenyl-2-(phenylseleno)oct-2-en-1-one (C21H2HOSe; organoselenium) and sodium selenate (inorganic Se) on adenosine deaminase (ADA) activity, cell viability, lipid peroxidation, scavenger of nitric oxide (NO) and nonprotein thiols (NP-SH) content in the cerebral cortex slices of the young rats. A decrease in ADA activity was observed when the slices were exposed to organoselenium at the concentrations of 1, 10 and 30 µM. The same compound showed higher scavenger capacity of NO than the inorganic compound. Inorganic Se was able to protect against sodium nitroprusside-induced oxidative damage and increased the NP-SH content. Both the compounds displayed distinctive antioxidant capacities and were not cytotoxic for the cerebral cortex slices in the conditions tested. These findings are likely to be related to immunomodulatory and antioxidant properties of this compound.