Chemical characterisation, hypoglycaemic and renoprotective effects of aqueous leaf extract of Limoniastrum guyonianum on fructose-induced metabolic syndrome in rats

In the present study, we chemically characterised the aqueous leaf extract of Limoniastrum guyonianum by HPLC-TOF/MS and evaluated its effects on fructose-induced metabolic syndrome (MetS) in Wistar rats. MetS groups were given (10% w/v) fructose solution to drink ad libitum for 9 weeks, whereas, normal animals received ordinary water. LG extract was administrated to treated groups by gavage for the last 6 weeks of the experimental period. Fructose feeding as a liquid solution increased body weight, reduced insulin sensitivity, raised blood glucose level and provoked atherogenic dyslipidemia associated with renal oxidative stress and structural damage. Treating MetS rats with LG extract at doses of 100, 200 and 300 mg/kg b.w./day considerably ameliorated the fructose-induced alterations. From this study, it was concluded that aqueous leaf extract of L. guyonianum possesses hypoglycaemic, hypolipidemic, antioxidant and renoprotective abilities against fructose-induced metabolic syndrome in rats.

Artemisia herba-alba aqueous extract improves insulin sensitivity and hepatic steatosis in rodent model of fructose-induced metabolic syndrome

CONTEXT

Fructose consumption is associated with the development of obesity and metabolic syndrome (MetS) in human and animal models.

OBJECTIVE

This study investigates the ability of an aqueous extract of Artemisia herba-alba Asso (AH) to ameliorate fructose-induced MetS in Male Wistar rats.

METHODS

AH extract at doses of 100, 200 and 400 mg/kg b.w./day was administered for six weeks to MetS animals.

RESULTS

Liquid fructose (10% w/v) intake did not vary total animal body weight, whereas, it produced moderate hyperglycemia associated with metabolic and histological alterations. Treating MetS rats with AH extract improved insulin sensitivity, alleviated atherogenic dyslipidaemia and decreased lipid deposition in their hepatic tissues. Additionally, AH extract was found to raise GSH level and antioxidant enzymes (GPx, GST and CAT) activities in rat livers homogenates.

CONCLUSION

The results here reported demonstrated, for the first time, that A. herba-alba have therapeutic proprieties against fructose-induced MetS in rodent model.

Epigenetic modifiers 5-aza-2'-deoxycytidine and valproic acid differentially change viability, DNA damage and gene expression in metastatic and non-metastatic colon cancer cell lines

DNA methylation and histone modifications are major components of cellular epigenetic pattern determining gene expression. Cancer cells have their own epigenetic array, which can be different in cells of primary and metastatic tumors. In the present work we investigated effects of 1 mM valproic acid (VPA), a histone deacetylase inhibitor and 0.2 μM 5-aza-2'-deoxycytidine (5-aza-dC), a DNA demethylation agent, singly or in combination in two colorectal cancer cell lines Caco-2 (non-metastatic) and LoVo (metastatic). Cell viability, DNA damage and the mRNA expression of the CDC25C (cell division cycle 25C), CDKN1A (cyclin dependent kinase inhibitor 1A) and CHEK1 (checkpoint kinase 1), SQSTM1 (sequestosome 1) and ULK1 (unc-51 like autophagy activating kinase 1), RELA (RELA proto-oncogene, NF-κB subunit) and TP53BP1 (tumor protein p53 binding protein 1) genes important in cell cycle regulation, autophagy and cancer progression were investigated. Both drugs induced a moderate decrease in cell viability and significant DNA damage in both cell lines. LoVo cells were more sensitive to VPA and combined treatment than Caco-2. LoVo cells also showed higher expression of genes that are often associated with more aggressive tumors than Caco-2 cells and treatment with the modifiers increased this difference. In conclusion, 5-aza-dC and VPA can induce different effects in metastatic and non-metastatic cancer cell lines and this may be important in determination of epigenetic profile responsible for metastatic properties of cancer cells.

Protective activity of Hertia cheirifolia extracts against DNA damage, lipid peroxidation and protein oxidation

CONTEXT

Hertia cheirifolia L. (Asteraceae), a perennial shrub widely distributed in Northern Africa, is traditionally used to treat inflammatory disorders.

OBJECTIVE

The protective effect of methanol (Met E) and aqueous (Aq E) extracts of Hertia cheirifolia against DNA, lipid and protein oxidation was investigated.

MATERIALS AND METHODS

Different concentrations (50-1000 μg/mL) of Hertia cheirifolia aerial part extracts were examined against DNA, lipid and protein oxidation induced by H₂O₂+ UV, FeSO₄, and Fe³⁺/H₂O₂-ascorbic acid, respectively. The DPPH^•, metal ion chelating, reducing power and β-carotene bleaching tests were conducted.

RESULTS

Both extracts were rich in polyphenols, flavonoids and tannins, and were able to scavenge DPPH^• with IC₅₀ values of 138 and 197 μg/mL, respectively. At 300 μg/mL, Aq E exerted stronger chelating effect (99%) than Met E (69%). However, Met E reducing power (IC₅₀=61 μg/mL) was more than that of Aq E (IC₅₀=193 μg/mL). Both extracts protected from β-carotene bleaching by 74% and 94%, respectively, and inhibited linoleic acid peroxidation. The inhibitory activity of Aq E extract (64%) was twice more than that of Met E (32%). Interestingly, both extracts protected DNA against the cleavage by about 96-98%. At 1 mg/mL, Met E and Aq E restored protein band intensity by 94-99%.

CONCLUSIONS

Hertia cheirifolia exhibits potent antioxidant activity and protects biomolecules against oxidative damage; hence, it may serve as potential source of natural antioxidant for pharmaceutical applications and food preservation. This is the first report on the protective activity of this plant against biomolecule oxidation.

Phytochemical screening and anti-inflammatory properties of Algerian Hertia cheirifolia methanol extract

CONTEXT

Hertia cheirifolia L. (Asteraceae) is traditionally used in Northern Africa to treat various inflammatory infections. However, few studies on this plant have been reported.

OBJECTIVE

The anti-inflammatory activity of methanol extract of H. cheirifolia leaves was investigated using different experimental models.

MATERIALS AND METHODS

Phytochemical analysis was performed to determine phenolic compounds. Acute toxicity of the extract (2000 mg/kg) was examined in Swiss albino mice for 14 days, before croton oil-induced ear oedema in mice, carrageenan-induced paw oedema in Swiss albino rats, cotton pellet-induced granuloma in rats and carrageenan-induced air pouch in mice were conducted. The IL-1β and TNF-α release from concanavalin A-stimulated monocytes was measured by ELISA.

RESULTS

Methanol extract of H. cheirifolia is rich in polyphenols and flavonoids. Cinnamic acid and rutin represent the major constituents. Methanol extract up to 2000 mg/kg did not produce any toxic effects. Topical application of 2 mg/ear of the extract produced 78.7% of inhibition on ear swilling. Oral pre-treatment of rats with 200 and 400 mg/kg of the extract inhibited paw oedema by 70% and 89%, respectively. At 200 mg/kg, granuloma dry and wet weights were reduced by 41.85% and 61.72%, respectively. Moreover, the treatment with methanol extract at 1 mg/kg exerted 62.7% of inhibition on leucocytes migrated into the ear pouch. TNF-α and IL-1β release was reduced by 69% and 78%, respectively, with 1 μg/mL of the extract.

CONCLUSION

Methanol extract of H. cheirifolia possesses a strong anti-inflammatory activity and may be considered an interesting source of effective anti-inflammatory compounds.

Immunomodulatory effects of Santolina chamaecyparissus leaf extracts on human neutrophil functions

CONTEXT

Santolina chamaecyparissus L. (Asteraceae) is an aromatic plant wide spread in the Mediterranean region. It is used in folk medicine for its anti-inflammatory properties.

OBJECTIVE

The effects of S. chamaecyparissus aqueous extract (SCAE) and polyphenolic extract (SCPE) on human polymorphonuclear neutrophil (PMN) degranulation, chemotaxis, phagocytosis, and microbicidal capacity were examined in vitro.

MATERIALS AND METHODS

Aqueous and polyphenolic extracts were prepared from S. chamaecyparissus leaves. The elastase release was used as a marker for measuring PMN degranulation, while chemotaxis was performed using a 48-microwell chemotaxis chamber. The phagocytosis and the microbicidal capacity were evaluated using fresh cultures of Candida albicans.

RESULTS

The treatment of neutrophils with different concentrations (10-200 µg/ml) of SCAE and SCPE caused a significant (p < 0.001) and dose-dependent inhibitory effect on elastase release in fMLP/Cytochalasin B (CB)-stimulated neutrophils. Indeed, 100 µg/ml of SCAE exerted an inhibitory effect of 51.97 ± 6.2%, whereas SCPE at the same concentration abolished completely PMN degranulation. Moreover, both extracts inhibited markedly (p < 0.01) fMLP-induced chemotactic migration. At 200 µg/ml, SCAE and SCPE exerted an inhibitory effect of 54.61 ± 7.3% and 57.71 ± 7.44%, respectively. In addition, a decline in both phagocytosis and microbicidal capacity against Candida albicans was observed when PMNs were exposed to 100 and 200 µg/ml of SCAE or SCPE.

CONCLUSION

The exerted effects on neutrophil functions support the anti-inflammatory activity and show new mechanisms of action and effectiveness of S. chamaecyparissus leaf extracts. This plant may be considered as an interesting source of anti-inflammatory and immunomodulatory agents.

Phosphorylation of p47phox is required for receptor-mediated NADPH oxidase/NOX2 activation in Epstein-Barr virus-transformed human B lymphocytes

The phagocyte NADPH oxidase (NOX2) is known to be expressed in Epstein-Barr virus (EBV)-transformed human B lymphocytes. Phosphorylation of the NOX2 cytosolic subunit p47phox is required for phorbol myristate acetate (PMA)-induced NOX2 activation in EBV-transformed B lymphocytes, however the role of this process in receptor-mediated NOX2 activation is not known. Here, we used pansorbin which acts by cross linking cell surface IgG and transfected cells with mutated p47phox to address if the phosphorylation of this subunit is required for receptor-mediated NOX2 activation. We show that pansorbin induced NOX2 activation in a time and concentration-dependent manner, albeit at levels only of 20% of those induced by PMA. GF109203X, a PKC selective inhibitor, inhibited pansorbin as well as PMA-induced NOX2 activation. Using specific anti-phospho serine antibodies we showed that pansorbin induced p47phox phosphorylation on Ser304, 315, 320, 328, and 345 and kinetics of these phosphorylations preceed NOX2 activation. To determine whether the phosphorylation of p47phox is required for pansorbin-induced NOX2 activation, we transfected EBV-transformed lymphocytes deficent in p47phox with a plasmid expressing wild type p47phox or p47phox with all the phosphorylated serines mutated to alanines, p47phoxS(303-379)A. Results show that pansorbin-induced NOX2 activation was greatly decreased in lymphocytes expressing the mutant as compared to the wild-type p47phox. These results show that pansorbin induced p47phox phosphorylation on multiple sites in EBV-transformed B lymphocytes and this process is required for pansorbin-induced NADPH oxidase activation in these cells.

Anti-inflammatory, free radical-scavenging, and metal-chelating activities of Malva parviflora

CONTEXT

Malva parviflora L. (Malvaceae) is widely distributed throughout Africa. It has several uses in traditional medicinal practice. Leaves of this plant are used in the treatment of some inflammatory disorders.

OBJECTIVE

The anti-inflammatory and the antioxidant activities of the methanol extract (Met. E) and aqueous extract (Aq. E) of M. parviflora leaves were investigated.

MATERIALS AND METHODS

Croton oil-induced ear edema and acetic acid-induced vascular permeability were applied as acute inflammatory models to evaluate the anti-inflammatory activity of the extracts. The antioxidant effects were evaluated using the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical assay and the measurement of the metal-chelating activity.

RESULTS

Results demonstrated that Met. E inhibited the croton oil-induced ear edema by 57%. In contrast, the Aq. E did not show any activity. Furthermore, Met. E and Aq. E inhibited significantly the acetic acid-induced vascular permeability by 36 and 40%, respectively. However, Met. E and Aq. E exerted a strong scavenging activity with IC(50) values of 89.03 ± 2.65 and 76.67 ± 0.29 µg/mL, respectively. Moreover, Met. E and Aq. E were able to chelate ferrous ions in a concentration-dependent manner.

DISCUSSION AND CONCLUSION

These findings demonstrate that M. parviflora leaf extracts possess anti-inflammatory and antioxidant activities and thus have great potential as an interesting source for natural health products.

Prion protein protects against zinc-mediated cytotoxicity by modifying intracellular exchangeable zinc and inducing metallothionein expression

PrPC contains several octapeptide repeats sequences toward the N-terminus which have binding affinity for divalent metals such as copper, zinc, nickel and manganese. However, the link between PrPC expression and zinc metabolism remains elusive. Here we studied the relationship between PrPC and zinc ions intracellular homeostasis using a cell line expressing a doxycycline-inducible PrPC gene. No significant difference in 65Zn2+ uptake was observed in cells expressing PrPC when compared with control cells. However, PrPC-expressing cells were more resistant to zinc-induced toxicity, suggesting an adaptative mechanism induced by PrPC. Using zinquin-ethyl-ester, a specific fluorophore for vesicular free zinc, we observed a significant re-localization of intracellular exchangeable zinc in vesicles after PrPC expression. Finally, we demonstrated that PrPC expression induces metallothionein (MT) expression, a zinc-upregulated zinc-binding protein. Taken together, these results suggest that PrPC modifies the intracellular localization of zinc rather than the cellular content and induces MT upregulation. These findings are of major importance since zinc deregulation is implicated in several neurodegenerative disorders. It is postulated that in prion diseases the conversion of PrPC to PrPSc may deregulate zinc homeostasis mediated by metallothionein.

Prion protein protects against DNA damage induced by paraquat in cultured cells

Exposure of cells to paraquat leads to production of superoxide anion (O2*-). This reacts with hydrogen peroxide to give the hydroxyl radical (*OH), leading to lipid peroxidation and cell death. In this study, we investigated the effects of cellular prion protein (PrPC) overexpression on paraquat-induced toxicity by using an established model system, rabbit kidney epithelial A74 cells, which express a doxycycline-inducible murine PrPC gene. PrPC overexpression was found to significantly reduce paraquat-induced cell toxicity, DNA damage, and malondialdehyde acid levels. Superoxide dismutase (total SOD and CuZn-SOD) and glutathione peroxidase activities were higher in doxycycline-stimulated cells. Our findings clearly show that PrPC overexpression plays a protective role against paraquat toxicity, probably by virtue of its superoxide dismutase-like activity.