Effects of Ginkgo biloba extract (EGb 761) and quercetin on lipopolysaccharide-induced release of nitric oxide

Heat Shock Protein 70 Is a Potential Virulence Factor in MurineToxoplasmaInfection Via Immunomodulation of Host NF-κB and Nitric Oxide

“…A potential limitation of the protocols used in this study to inhibit HSP70 expression by T. gondii (i.e., the combination of transient transfection with antisense oligonucleotides and quercetin) is that quercetin and other related flavonoids are known to induce multiple changes in the cells exposed to them (32)(33)(34)(35). The complex nature of the relationship between flavonoid compounds such as quercetin, heat shock proteins, and the immune response obviously requires further characterization, but it should be emphasized that, in this study, only parasites were treated with quercetin; the host cells that were used to examine the effects of parasite HSP70 on various parameters of the immune response were not exposed directly to quercetin at any time.…”

Antimicrobial, Antioxidant, and Anti-Inflammatory Activities of Essential Oils from Five Selected Herbs

“…To determine NO radical-scavenging activity, various concentrations of the various essential oils, and -tocopherol were mixed individually with 0.1 mL of sodium nitroprusside (100 mM) and phosphate buffer solution (pH 7.4), yielding a final volume of 1 mL. After 2.5 h of incubation at 20 C, 0.05 mL of the mixture was added to 0.05 mL of Griess reagent over 10 min at 25 C. The absorbance was determined at 540 nm, 19) and NO radical scavenging activity was calculated by the following formula: % NO radical scavenging ¼ ðA blank À A sample Þ=A blank  100:…”

Inhibition of 5-Lipoxygenase Product Synthesis by Natural Compounds of Plant Origin

“…In fact, the flavonoid quercetin 11 that suppresses 5-LO product synthesis also blocks the ERK1/2 and p38 MAPK pathway [58], [59], and plantderived tyrosine kinase inhibitors such as genistein reduced 5-LO activation in HL60 cells [47]. Moreover, agents that cause elevation of cAMP (e. g., ginkgetin 25 from Ginkgo biloba, a potent inhibitor of cellular 5-LO product synthesis [40], [60]) and thus stimulation of PKA may suppress 5-LO activity and translocation by such mechanisms.…”