Differential Molecular Targets for Neuroprotective Effect of Chlorogenic Acid and its Related Compounds Against Glutamate Induced Excitotoxicity and Oxidative Stress in Rat Cortical Neurons.

The present study has been designed to explore the molecular mechanism and signaling pathway targets of chlorogenic acid (CGA) and its main hydrolysates, caffeic (CA) and quinic acid in the protective effect against glutamate-excitotoxicity. For this purpose 8-DIV cortical neurons in primary culture were exposed to 50 µM L-glutamic acid plus 10 µM glycine, with or without 10-100 µM tested compounds. Chlorogenic acid and caffeic acid via their antioxidant properties inhibited cell death induced by glutamate in dose depended manner. However, quinic acid slightly protects neurons at a higher dose. DCF, JC-1 and Ca2+sensitive fluorescent dye fura-2, were used to measure intracellular ROS accumulation, mitochondrial membrane potential integration and intracellular calcium concentration [Ca2+] i . Results indicate that similarly, CGA acts as a protective agent against glutamate-induced cortical neurons injury by suppressing the accumulation of endogenous ROS and restore the mitochondrial membrane potential, activate the enzymatic antioxidant system by the increase levels of SOD activity and modulate the rise of intracellular calcium levels by increasing the rise of intracellular concentrations of Ca2+caused by glutamate overstimulation. PKC signaling cascade appear to be engaged in this protective mechanism. Interseling, CGA and CA also exhibit antiapoptotic properties against glutamate-induced cleaved activation of pro-caspases; caspase 1,8 and 9 and calpain (PD 150606,Calpeptin and MDL 28170).These data suggest that neuroprotective activity of CGA ester may occurs throught its hydrolysate,the caffeic acid and its interaction with intracellular molecules suggesting that CGA exert its neuroprotection via its caffeoly acid group that might potentially be used as a therapeutic agent in neurodegeneratives disorders associated with glutamate excitotoxicity.

Morus alba leaf extract mediates neuroprotection against glyphosate-induced toxicity and biochemical alterations in the brain.

Recent studies demonstrate that glyphosate exposure is associated with oxidative stress and some neurological disorders such as Parkinson's pathology. Therefore, phytochemicals, in particular phenolic compounds, have attracted increasing attention as potential agents for neuroprotection. In the present study, we investigate the impact of glyphosate on the rat brain following i.p. injection and the possible molecular target of neuroprotective activity of the phenolic fraction from Morus alba leaf extract (MALE) and its ability to reduce oxidative damage in the brain. Wistar rats from 180 to 240 g were i.p. treated with a single dose of glyphosate (100 mg kg-1 b.w.) or MALE (100 µg mL-1 kg-1 b.w.) for 2 weeks. Brain homogenates were used to evaluate neurotoxicity induced by the pesticide. For this, biochemical parameters were measured. Data shows that MALE regulated oxidative stress and counteracted glyphosate-induced deleterious effects and oxidative damage in the brain, as it abrogated LDH, protein carbonyls, and malonyldialdehyde. MALE also appears to be able to scavenge H2O2 levels, maintain iron and Ca2+ homeostasis, and increase SOD activity. Thus, in vivo results showed that mulberry leaf extract is a potent protector against glyphosate-induced toxicity, and its protective effect could result from synergism or antagonism between the various bioactive phenolic compounds in the acetonic fraction from M. alba leaf extract.

Pomegranate and mint syrup addition to green tea beverage stabilized its polyphenolic content and biofunctional potentials during refrigerated storage.

The chemical stability of the green tea (GT) preparation during refrigerated storage was investigated following the addition of mint (MS) or pomegranate (PS) syrups, a common habit in the Mediterranean countries that improves the savor of this popular beverage. The supernatants recovered by centrifuging GT supplemented or not with mint (GTMS) or pomegranate (GTPS) syrup were examined for their polyphenolic profiles using the high performance liquid chromatography with diode array detection and electrospray ionization-mass spectrometry. Following storage at 4 °C for 15 days, not-supplemented GT showed a significant decrease (≈92 %) of its phenolic content. However, the decrease was relatively lesser in GTPS (≈36 %) and in GTMS (≈40 %). The observed slight increase of the extractable polyphenolics in PS and MS during the storage might explain in part the relatively limited decrease of GTPS and GTMS total phenolic content. However, chromatographic examination proved that some tea compounds, particularly caffeine, were preserved following PS and MS supplementation. Likewise, syrups'addition to GT significantly (P < 0.5) limited the reduction of its antioxidant capacity as revealed by the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis-(3-ethylbenz-thialzoline-6-sulfonic acid)) assays. As expected, the antimicrobial trials showed that Gram (+) Staphylococcus aureus and Staphylococcus epidermidis were the most sensitive strains to tea polyphenols. The syrups supplementation noticeably preserved the tea bacteriostatic and bactericide activities during storage. The obtained analytical results demonstrate that MS or PS addition to green tea beverage stabilized its polyphenolic content and biofunctional properties during refrigerated storage, thus, scientifically supporting this popular practice in the Mediterranean countries.

Comparative analysis of Tunisian wild Crataegus azarolus (yellow azarole) and Crataegus monogyna (red azarole) leaf, fruit, and traditionally derived syrup: phenolic profiles and antioxidant and antimicrobial activities of the aqueous-acetone extracts.

Quantitative and qualitative analyses of the yellow and red azarole phenolic extracts prepared from leaf, fruit peel/pulp, and syrup were comparatively investigated. The yellow azarole was found significantly richer in polyphenols than the red-fruit species. Hyperoside was the main phenolic in both yellow and red azarole leaves and only in yellow fruits, whereas procyanidin B2 was the major compound in red fruits. Yellow azarole leaf and fruit peel extracts exhibited the strongest antioxidant activities using DPPH (≈168 and 79 µmol TEAC/g fw, respectively) and FRAP (≈378 and 161 µmol Fe(2+)/g fw, respectively) assays. The highest antibacterial activities were recorded for the yellow azarole leaf and fruit peel extracts, especially against Staphylococcus aureus and Streptococcus faecalis . The low phenolic content of the syrups contrasted with their significant antioxidant and antimicrobial potentials, which were correlated to their hydroxymethylfurfural (HMF) (furan derivative amounts) content.