Assessment of anti-hyperglycemic and anti-hyperlipidemic effects of thiazolidine-2,4-dione derivatives in HFD-STZ diabetic animal model

Type 2 diabetes mellitus (T2DM) is a chronic endocrine/metabolic disorder characterized by elevated postprandial and fasting glycemic levels that result in disturbances in primary metabolism. In this study, we evaluated the metabolic effects of thiazolidine-2,4-dione derivatives in Wistar rats and Swiss mice that were fed a high-fat diet (HFD) for 4 weeks and received 90 mg/kg of streptozotocin (STZ) intraperitoneally as a T2DM model. The HFD consisted of 17% carbohydrate, 58% fat, and 25% protein, as a percentage of total kcal. The thiazolidine-2,4-dione derivatives treatments reduced fasting blood glucose (FBG) levels by an average of 23.98%-50.84%, which were also improved during the oral starch tolerance test (OSTT). Treatment with thiazolidine-2,4-dione derivatives also improved triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), and total cholesterol levels (P < 0.05). The treatment intake has also shown a significant effect to modulate the altered hepatic and renal biomarkers. Further treatment with thiazolidine-2,4-dione derivatives for 28 days significantly ameliorated changes in appearance and metabolic risk factors, including favorable changes in histopathology of the liver, kidney, and pancreas compared with the HFD/STZ-treated group, suggesting its potential role in the management of diabetes. Thiazolidine-2,4-dione derivatives are a class of drugs that act as insulin sensitizers by activating peroxisome proliferator-activated receptor-gamma (PPAR-γ), a nuclear receptor that regulates glucose and lipid metabolism. The results of this study suggest that thiazolidine-2,4-dione derivatives may be a promising treatment option for T2DM by improving glycemic control, lipid metabolism, and renal and hepatic function.

miR-196a provides antioxidative neuroprotection via USP15/Nrf2 regulation in Huntington's disease

Huntington's disease (HD) is a devastating neurodegenerative disorder characterized by the accumulation of mutant Huntingtin protein (mHTT) and oxidative stress-induced neuronal damage. Based on previous reports, microRNA-196a (miR-196a) has emerged as a potential therapeutic target due to its neuroprotective effects in various neurodegenerative diseases. However, whether miR-196a functions through antioxidative effects is still unknown. In this study, we demonstrated that HD models, both in vitro and in vivo, exhibit elevated levels of reactive oxygen species (ROS) and increased neuronal death, and miR-196a mitigates ROS levels and reduces cell death in HD cells. Moreover, we elucidated that miR-196a facilitates the translocation of nuclear factor erythroid 2 (Nrf2) into the nucleus, enhancing the transcription of antioxidant genes, including heme oxygenase-1 (HO-1). We further identified ubiquitin-specific peptidase 15 (USP15), a direct target of miR-196a related to the Nrf2 pathway, and USP15 exacerbates mHTT aggregate formation while partially counteracting miR-196a-induced reductions in mHTT levels. Taken together, these findings shed light on the multifaceted role of miR-196a in HD, highlighting its potential as a therapeutic avenue for ameliorating oxidative stress and neurodegeneration in this debilitating disease.

Hepatoprotective functions of jujuboside B

Jujuboside B (JB) found in the seeds of Zizyphi Spinosi Semen possesses pharmacological functions, such as anti-inflammatory, antiplatelet aggregation, and antianxiety potentials. This study evaluated the effect of JB on liver failure in cecal ligation and puncture (CLP)-induced sepsis. First, we observed histopathological changes in the liver by optical microscopy and the activity of enzymes in serum such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST). We further measured the levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, nitric oxide (NO), and antioxidative parameters in liver homogenate. The expression of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), and glucocorticoid receptor (GR) in the liver was observed by Western blotting. CLP enhanced the migration of inflammatory cells, ALT and AST concentrations, and necrosis, which were reduced by JB. In addition, JB reduced 11β-HSD2 expression and levels of inflammatory mediators (TNF-α, IL-1β, and NO) in the liver, increased GR expression, enhanced endogenous antioxidative capacity. These results further suggest that JB may protect the liver against CLP-induced damage by regulating anti-inflammatory responses, downregulating 11β-HSD2 expression and antioxidation, and up-regulating GR expression.

Antioxidative and anti-inflammatory activity of psiguadial B and its halogenated analogues as potential neuroprotective agents

Psiguadial B (8), and its fluoro- (8a), chloro- (8b), and bromo- (8c) derivatives were synthesized using a sodium acetate-catalyzed single step coupling of three components: β-caryophyllene (5), diformylphloroglucinol (11), and benzaldehyde (12). These compounds efficiently and dose-dependently decreased H₂O₂-induced cell death, a quantitative marker of cell death, in primary cultures of mouse cortical neurons. Psiguadial B also decreased neuronal death and accumulation of ROS induced by FeCl₂ in cortical cultures. The in vitro effects of these compounds in lipopolysaccharide (LPS)-induced expression of nitric oxide (NO), and TNF-α and IL-6 by suppressing the NF-κB pathway in immune cells demonstrated their antioxidative and anti-inflammatory activity. The present findings warrant further research on the development of psiguadial B-based neuroprotective agents for the treatment of neurodegenerative diseases, acute brain injuries and immunological disorders.

Hydrogen sulfide ameliorates disorders in the parafacial respiratory group region of neonatal rats caused by prenatal cigarette smoke exposure via an antioxidative effect

We previously found that hydrogen sulfide (H₂S) ameliorated the dysfunction of central chemoreception caused by prenatal cigarette smoke exposure (CSE). In the present study, we further explored whether the parafacial respiratory group (pFRG) is involved in the protection of central chemoreception by H₂S against prenatal CSE-induced injury. We found that NaHS, a donor of H₂S, restored the expression of Phox2b, which was downregulated by prenatal CSE, in the pFRG region of neonatal rats. NaHS also relieved the prenatal CSE-induced excitatory synapse disturbance in the pFRG region of neonatal rats. Additionally, NaHS prevented the increase in the malondialdehyde level and suppression of antioxidase activity in the pFRG region of neonatal rats induced by prenatal CSE. Furthermore, NaHS prevented the downregulation of the expression of antioxidases and Nrf2 in the pFRG region of neonatal rats with prenatal CSE. These results suggest that H₂S can protect the pFRG of neonatal rats against prenatal CSE-induced injury via an antioxidative effect.

Molecular cloning and characterization of two genes encoding peroxiredoxins from freshwater bivalve Anodonta woodiana: Antioxidative effect and immune defense

Members of Prx family function as an important players in host defense against oxidative stress, and modulate immune responses. In the current study, two complete Prx sequences were isolated from bivalve Anodonta woodiana and respectively named AwPrx4a and AwPrx4b. Regulative characterizations of AwPrx4a and AwPrx4b derived from perfluorooctanesulfonate (PFOS), perfluoroocanoic acid (PFOA), lipopolysaccharide (LPS) and polyinosinic:polycytidylic (Poly I:C) challenge in hepatopancreas, gill and hemocytes were measured by quantitative real-time PCR, respectively. The full-length cDNA of AwPrx4a had an open reading frame ORF of 588 bp encoding 196 amino acids. Two highly conserved Prxs signature motifs were observed in deduced amino acid sequence, one was FYPLDFTFACPTEI, and the other was GEVCPA. Complete cDNA sequence of AwPrx4b was comprised of a 5' untranslated region (UTR) of 120 nucleotides, a 426 bp ORF which was encoded 142 amino acids, and a long 3'-UTR of 412 nucleotides. Expressions of AwPrx4a and AwPrx4b showed a significant up-regulation pattern in groups at lower concentration treatment of PFOS and PFOA, a biphasic profile in groups with a higher concentration treatment. Compared with that of control group, expressions of AwPrx4a and AwPrx4b were significantly induced by LPS and Poly I:C treatment in the hepatopancreas, gill and hemocytes. These results indicate up-regulations of AwPrx4a and AwPrx4b expression are associated with eliminating oxidative stress derived from PFOS and PFOA administration as well as enhancing immune defense against LPS and Poly I:C challenge.

Comparative study on anti-oxidative and anti-inflammatory properties of hydroponic ginseng and soil-cultured ginseng

Hydroponic ginseng (HPG) and soil-cultured ginseng (SCG) were extracted in 70% methanol to quantify relative content of 8 ginsenosides and polyphenolic compounds, and flavonoids to compare their antioxidative effects. Level of nitric oxide and inflammatory targets produced in LPS-stimulated RAW 264.7 cells were measured. 2-year-old HPG shoots contained highest levels of ginsenoside Rb2, Rb3, Rd, Re, and F1. Total polyphenol content was highest in shoots of HPG, followed by roots of HPG and SCG. HPG shoots had high radical scavenging activity and an elevated ability to inhibit linoleic acid oxidation. 2-year-old HPG shoots reduced nitric oxide production in RAW 264.7 cells by 47%, whereas 6-year-old SCG roots reduced it by only 21%. HPG also significantly lowered mRNA expression of iNOS, TNF-α, IL-1β, and IL-6, as determined by RT-PCR, compared to SCGs. Therefore, HPG may have potential for utilization as an alternative to SCG, because of superior antioxidant and anti-inflammatory properties.

Rapid preparation of functional polysaccharides from Pyropia yezoensis by microwave-assistant rapid enzyme digest system

This study describes a simple preparation of functional polysaccharides from Pyropia yezoensis using a microwave-assistant rapid enzyme digest system (MAREDS) with various carbohydrases, and evaluates their antioxidative effects. Polysaccharide hydrolysates were prepared using MAREDS under different hydrolytic conditions of the carbohydrases and microwave powers. Polysaccharides less than 10kDa (Low molecular weight polysaccharides, LMWP, ≤10kDa) were efficiently obtained using an ultrafiltration (molecular weight cut-off of 10kDa). MAREDS increases AMG activation via an increased degree of hydrolysis; the best AMG hydrolysate was prepared using a 10:1 ratio of substrate to enzyme for 2h in MAREDS with 400W. LMWP consisted of galactose (27.3%), glucose (64.5%), and mannose (8.3%) from the AMG hydrolysate had stronger antioxidant effects than the high molecular weight polysaccharides (>10kDa). We rapidly prepared functional LMWPs by using MAREDS with carbohydrases, and suggest that LMWP might be potentially a valuable algal polysaccharide antioxidant.

Nano-TiO2 induces autophagy to protect against cell death through antioxidative mechanism in podocytes

Autophagy is a cellular pathway involved in degradation of damaged organelles and proteins in order to keep cellular homeostasis. It plays vital role in podocytes. Titanium dioxide nanoparticles (nano-TiO₂) are known to induce autophagy in cells, but little has been reported about the mechanism of this process in podocytes and the role of autophagy in podocyte death. In the present study, we examined how nano-TiO₂ induced authophagy. Besides that, whether autophagy could protect podocytes from the damage induced by nano-TiO₂ and its mechanism was also investigated. Western blot assay and acridine orange staining presented that nano-TiO₂ significantly enhanced autophagy flux in podocytes. In addition, AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) were involved in such process. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that upregulated level of autophagy induced by rapamycin in high concentration nano-TiO₂-treated podocytes could significantly reduce the level of oxidative stress and alleviate podocyte death. Downregulating the level of autophagy with 3-methyladenine had the opposite effects. These findings indicate that nano-TiO₂ induces autophagy through activating AMPK to inhibit mTOR in podocytes, and such autophagy plays a protecting role against oxidative stress on the cell proliferation. Changing autophagy level may become a new treatment strategy to relieve the damage induced by nano-TiO₂ in podocytes.

Dermal quercetin smartCrystals®: Formulation development, antioxidant activity and cellular safety

Flavonoids are natural plant pigments, which possess high antioxidative and antiradical activities. However, their poor water solubility led to a limited bioavailability. To overcome this major hurdle, quercetin nanocrystals were produced implementing smartCrystals® technology. This process combines bead milling and subsequent high-pressure homogenization at relatively low pressure (300bar). To test the possibility to develop a dermal formulation from quercetin smartCrystals®, quercetin nanosuspensions were admixed to Lutrol® F127 and hydroxythylcellulose nonionic gels. The physicochemical properties (morphology, size and charge), saturation solubility, dissolution velocity and the antioxidant properties (DPPH assay) as well as the cellular interaction of the produced quercetin smartCrystals® were studied and compared to crude quercetin powder. Quercetin smartCrystals® showed a strong increase in the saturation solubility and the dissolution velocity (7.6 fold). SmartCrystals® loaded or not into gels proved to be physically stable over a period of three months at 25°C. Interestingly, in vitro DPPH assay confirmed the preservation of quercetin antioxidative properties after nanonization. In parallel, the nanocrystalline form did not display cellular toxicity, even at high concentration (50μg/ml), as assayed on an epithelial cell line (VERO cells). In addition, the nanocrystalline form confirmed a protective activity for VERO cells against hydrogen peroxide induced toxicity in vitro. This new formulation presents a promising approach to deliver quercetin efficiently to skin in well-tolerated formulations.

Isolation and structural elements of a water-soluble free radical scavenger from Nyctanthes arbor-tristis leaves

The leaves of Nyctanthes arbor-tristis L. (Oleaceae) are used in Ayurvedic medicine for the management of a range of diseases, but reports on its phytochemicals and pharmacological properties are inadequate. Herein, we report purification of an antioxidative polysaccharide (F2) extracted from its leaves by water. The presence of a highly branched polysaccharide (75 kDa) containing esterified phenolic acids was revealed by chemical, chromatographic and spectroscopic analyses. Particularly, ESMS analysis of per acetylated oligomeric fragments derived by Smith degradation provides important structural information on a spectrum of glycerol tagged oligosaccharides. This polysaccharide showed dose dependent free radical scavenging capacity as evidenced by DPPH and Ferric reducing power assay. This pharmacologically active compound (F2) formed a water soluble complex with bovine serum albumin over pH 4.0-7.4. Accordingly, traditional aqueous extraction method provides a molecular entity that induces a pharmacological effect: this could epitomize a smart approach in phytotherapeutic management.

Antioxidative effect of folate-modified chitosan nanoparticles

OBJECTIVE

To evaluate the potency of carboxymethyl chitosan-2, 2' ethylenedioxy bis-ethylamine-folate (CMC-EDBE-FA) on tissue injury, antioxidant status and glutathione system in tissue mitochondria and serum against nicotine-induced oxidative stress in mice.

METHODS

CMC-EDBE-FA was prepared on basis of carboxymethyl chitosan tagged with folic acid by covalently linkage through 2, 2' ethylenedioxy bis-ethylamine. Animals were divided into four groups, i.e., control, nicotine (1 mg/kg bw/day), CMC-EDBE-FA (1 mg/kg bw/day) and nicotine (1 mg/kg bw/day) and CMC-EDBE-FA (1 mg/kg bw/day) for 7 days. Levels of lipid peroxidation, oxidized glutathione level, antioxidant enzyme status and DNA damage were observed and compared.

RESULTS

The significantly increase of lipid peroxidation, oxidized glutathione levels and DNA damage was observed in nicotine treated group as compared with control group; those were significantly reduced in CMC-EDBE-FA supplemented group. Moreover, significantly reduced antioxidant status in nicotine treated group was effectively ameliorated by the supplementation of CMC-EDBE-FA. Only CMC-EDBE-FA treated groups showed no significant change as compared with control group; rather than it repairs the tissue damage of nicotine treated group.

CONCLUSIONS

These findings suggest that CMC-EDBE-FA is non-toxic and ameliorates nicotine-induced toxicity.

Nitric oxide mediated Staphylococcus aureus pathogenesis and protective role of nanoconjugated vancomycin

OBJECTIVE

To test the survival of Staphylococcus aureus (S. aureus) inside lymphocyte that contributes to the pathogenesis of infection and possible anti-inflammatory and antioxidative effect of nanoconjugated vancomycin against in vivo S. aureus infection in a dose and duration dependent manner.

METHODS

5×10(6) CFU/mL vancomycin-sensitive S. aureus (VSSA) and vancomycin-resistive S. aureus (VRSA) were challenged in Swiss male mice for 3 days, 5 days, 10 days and 15 days, respectively. Bacteremia and inflammatory parameters were observed to evaluate the duration for development of VSSA and VRSA infection. 100 mg/kg bw/day and 500 mg/kg bw/day nanoconjugated vancomycin were administrated to VSSA and VRSA infected group for 5 days. Bacteremia, inflammatory parameters and oxidative stress related parameters were tested to observe the effective dose of nanoconjugated vancomycin against VSSA and VRSA infection. Nanoconjugated vancomycin was treated at a dose of 100 mg/kg bw/day and 500 mg/kg bw/day, respectively, to VSSA and VRSA infected group for successive 5 days, 10 days and 15 days. Bacteremia, inflammatory parameters and oxidative stress related parameters were observed to assess the effective duration of nanoconjugated vancomycin against VSSA and VRSA infection.

RESULTS

The result revealed that in vivo VSSA and VRSA infection developed after 5 days of challenge by elevating the NO generation in lymphocyte and serum inflammatory markers. Administration with nanoconjugated vancomycin to VSSA and VRSA infected group at a dose of 100 mg/kg bw/day and 500 mg/kg bw/day, respectively, for successive 10 days eliminated bacterimia, decreased NO generation in lymphocyte, serum inflammatory markers and increased antioxidant enzyme status.

CONCLUSIONS

These findings suggest, in vivo challenge of VSSA and VRSA for 5 days can produce the highest degree of damage in lymphocyte which can be ameliorated by treatment with nanoconjugated vancomycin for 10 successive days.