Synergistic Effect Of Quercetin Research Articles

Potential from synergistic effect of quercetin and paclitaxel co-encapsulated in the targeted folic–gelatin–pluronic P123 nanogels for chemotherapy

Dual-drug delivery systems for anticancer therapy have recently attracted substantial attention due to their potency to overcome limitations of conventional anti-cancer drugs, tackle drug resistance problems, as well as improve the therapeutic efficacy. In this study, we introduced a novel nanogel based on folic acid-gelatin-pluronic P123 (FA-GP-P123) conjugate to simultaneously deliver quercetin (QU) and paclitaxel (PTX) to the targeted tumor. The results indicated that the drug loading capacity of FA-GP-P123 nanogels was significantly higher than that of P123 micelles. The kinetic release profiles of QU and PTX from the nanocarriers were governed by Fickian diffusion and swelling behavior, respectively. Notably, FA-GP-P123/QU/PTX dual-drug delivery system induced higher toxicity to MCF-7 and Hela cancer cells than either QU or PTX individual delivery system, and the non-targeted dug delivery system (GP-P123/QU/PTX), indicating the synergistic combination of dual drugs and FA positive targeting effect. Furthermore, FA-GP-P123 could effectively deliver QU and PTX to tumors in vivo after administration into MCF-7 tumor-bearing mice, which resulted in 94.20 ± 5.90 % of tumor volume reduced at day 14. Moreover, the side effects of the dual-drug delivery system were significantly reduced. Overall, we suggest FA-GP-P123 as potential nanocarrier for dual-drug delivery for targeted chemotherapy.

Synergistic Effect of Quercetin on Antibacterial Activity of Florfenicol Against Aeromonas hydrophila In Vitro and In Vivo.

The overuse or abuse of antimicrobial drugs in aquaculture, aggravates the generation of drug-resistant bacteria, which has caused potential risks to human health and the aquaculture industry. Flavonoid–antibiotic combinations have been shown to suppress the emergence of resistance in bacteria, and sometimes even reverse it. Here, the antibacterial activity of florfenicol in combination with quercetin, a potential drug to reverse multidrug resistance, was tested against Aeromonas hydrophila (A. hydrophila). Of eleven selected antimicrobial agents, quercetin and florfenicol showed the strongest bactericidal effect, and fractional inhibitory concentration (FIC) indices were 0.28, showing a highly synergistic effect. Then, the antibacterial activities of quercetin and florfenicol against A. hydrophila were further tested in vitro and in vivo. Bacterial viability of A. hydrophila decreased in a florfenicol dose-dependent manner, about 16.3–191.4-fold lower in the presence of 15 μg/mL quercetin and 0.156 to 1.25 μg/mL florfenicol than in the absence of quercetin, respectively. The cell killing was maximum at 45 μg/mL quercetin in the dose range tested plus 0.156 μg/mL florfenicol. The viability decreased over time during the combined treatment with quercetin and florfenicol by 60.5- and 115-fold in 0.156 μg/mL florfenicol and 0.625 μg/mL florfenicol, respectively. Additionally, the synergistic effect was confirmed by the bacterial growth curve. Furthermore, quercetin and florfenicol had an obvious synergistic activity in vivo, reducing the bacterial load in the liver, spleen and kidney tissues of Cyprinus carpio up to 610.6-fold compared with the florfenicol group, and improving the survival rate of infected fish from 10% in the control group to 90% in drug combinations group. These findings indicated that quercetin could potentiate the antibacterial activity of florfenicol against A. hydrophila infection and may reduce the use of antimicrobial drugs and improve the prevention and control capability of bacterial resistance.

Synergistic effect of quercetin and cobalt ferrite-graphene oxide-based hyperthermia to inhibit expression of heat shock proteins and induce apoptosis in breast cancer cells

Background: Combinatorial medicine includes promising therapeutic methods for diseases such as cancer, whereby various biochemical and physical agents are simultaneously used to remove tumors. For example, the effectiveness of hyperthermia as a new technique for cancer therapy, can be enhanced, if it is combined with chemical compounds. Herein, the influence of quercetin as a heat shock protein (HSP) inhibitor on the efficiency of cobalt ferrite-graphene oxide (CoFe2O4-GO) nanoparticles- based hyperthermia was investigated in an in vitro study. Methods: Firstly, the surface of graphene sheets was decorated with CoFe2O4 nanoparticles (5-8 nm) and assayed using transmission electron microscopy (TEM), vibrating-sample magnetometer (VSM) and X-ray diffraction (XRD) methods. The cytotoxic effect of the corresponding co-implementation was then examined in MCF7 cell line with or without hyperthermia by (3-(4,5-dimethyl thiazolyl-2)-2,5-diphenyltetrazolium bromide) (MTT) test for 24, 48 and 72 hrs. In addition, the expression of Bax, Bcl2 and HSP70 genes and the production of radicals were evaluated by Real-Time PCR and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays respectively. Results: The study showed that the doses associated with the IC50 points for quercetin and the CoFe2O4-GO nanocomposite were 0.02 mg/ml and 0.001 g/ml, respectively. The results showed that the simultaneous treatment of the cancer cells with quercetin, the nanocomposite, and hyperthermia significantly improves the cytotoxicity effect, increases the expression of Bax gene and down-regulates HSP70 and Bcl2 genes. In addition, the greatest attenuation of DPPH free radicals was observed in the corresponding group. Conclusion: The hybrid treatment of quercetin and the nanoparticle in the presence of hyperthermia could be considered as a promising approach for cancer therapy with minor side effects.

Effects of quercetin and low-level laser on oxidative and inflammatory factors among patients with type 2 diabetes mellitus and mild cognitive impairment

Background: Unmanaged type 2 diabetes mellitus has dangerous consequences, such as neuropathy. Oxidative stress and inflammatory factors play an important role in the development of diabetic neuropathy. Diabetics are prone to mild cognitive impairment, which is a neurological disease. The aim of this study was to investigate the effects of quercetin as a functional food and oxidative agents and inflammatory factors of low-level laser.Methods: In this study, 60 elderly volunteers were selected: 30 normal as a control group and 30 with type 2 diabetes mellitus and mild cognitive impairment. The average age was 75 years old. Groups of diabetic patients were examined for changes in glucose levels, oxidants, antioxidants and inflammatory factors before and after treatment with quercetin and low-level laser therapy–green laser diode with a wavelength of 532 nm at 100 mw and compared with the control group. Changes in the levels of biochemical parameters were performed according to the instructions of the relevant kits. Results: The results of the obtained data analysis showed that there was a significant difference (P value < 0.05) in the levels of glucose, hydrogen peroxide, advanced glycation end-products, malondialdehyde, oxidized-low density lipoprotein, paraoxonase, lipoprotein lipase, and inflammatory factors including TNF-α, interleukin-1 alpha and interleukin-1 beta between diabetic samples before and after treatment with quercetin and laser from control subject samples. There was no significant difference (P value > 0.05) in inflammatory factors between quercetin-treated, laser-treated and both quercetin and laser treated groups. The synergistic effect of quercetin and laser between the quercetin and laser treated group and the untreated group on changes in the levels of biochemical parameters was observed significantly only in advanced glycation end-products, malondialdehyde, oxidized-low density lipoprotein, and paraoxonase.Conclusion: The results showed that quercetin, laser, and their synergistic effect can play a role in reducing some oxidant factors.Keywords: Quercetin, Low-level laser, Inflammatory factors, Oxidative factors, Diabetes mellitus

Mechanism of Anti-Inflammatory and Antibacterial Effects of QingXiaoWuWei Decoction Based on Network Pharmacology, Molecular Docking and In Vitro Experiments.

Background and Aim: QingXiaoWuWei Decoction (QXWWD) is a traditional Chinese medicine that is commonly used in clinical settings to treat inflammatory and bacterial diseases. However, there is still a lot to learn about its molecular mechanism. A network pharmacology approach was applied to investigate the pharmacological mechanisms of QXWWD in inflammation treatment. Methods: The basic mechanisms involved in the anti-inflammatory and antibacterial potentials of QXWWD were identified using network pharmacology and molecular docking. The principal components of QXWWD were identified by the HPLC-Q-Exactive-MS method. The antibacterial bioactivity of QXWWD was further investigated using the Kirby-Bauer disc diffusion method and the determination of the minimum inhibitory concentration. The anti-inflammatory activity of QXWWD was evaluated using mice ear swelling test, RAW264.7 cell culture, and pro-inflammatory cytokines measurement. Skin irritation and HE staining were employed to evaluate the safety of QXWWD topical use and to depict the drug’s potential therapeutic function. The hub genes and signaling pathways associated with inflammatory and bacterial diseases were validated by western blot in addition to biochemical and pathological markers. Results: Our findings revealed that the ethanolic extract of QXWWD had a strong inhibitory effect against Staphylococcus aureus, Enterococcus faecalis, and Streptococcus pneumoniae. Meanwhile, QXWWD was potentially effective in suppressing ear swelling, elevated white blood cell counts, and the TNF-α, IL-1, and IL-6 levels. According to skin irritation, QXWWD was found to be safe when tested for topical application. The results of HE staining showed that the possible therapeutic role of QXWWD was related to the change in skin microstructure. Also, the network pharmacology, molecular docking as well as Q-Exactive-MS and HPLC analysis suggested that the synergistic effect of quercetin, luteolin and other ingredients could serve as main contributor of QXWWD for its anti-inflammatory and antibacterial activities. Moreover, the JUN, MAPK1, RELA, NFKBIA, MYC, and AKT1 were the potential identified key targets, and MAPK/PI3K/Akt was among the possibly involved signaling pathways in the anti-inflammatory and antibacterial activities of QXWWD. Conclusions: From a therapeutic standpoint, QXWWD may be a promising antibacterial and anti-inflammatory agent for the treatment of bacterial, acute, and chronic dermatitis.

Solvent controlled synthesis of quercetin loaded CuS nanostructure: A versatile treatment against harmful bacteria and carcinogenic organic moiety in water

The present work demonstrates the successful synthesis of solvent controlled copper sulfide nanoparticles (CuS NP's) and nanotubes (CuS NT's) using a facile and green microwave irradiation method. Ethylene glycol and a mixture of water and ethylene glycol (1:1) were used as solvents for the preparation of CuS NT's and NP's, respectively. The catalytic and bactericidal attributes of the fabricated nano structures were measured and compared vividly. The formation of CuS nano structures was monitored using simple techniques like UV–visible absorption spectroscopy, IR spectroscopy, XRD and then finally confirmed by TEM analysis. After complete structural elucidation, biologically active quercetin molecule was successfully loaded into both nano-modules and confirmed using UV, TGA and IR techniques. The respective loading efficiency in CuS NP's and NT's was estimated to be 9.59 ± 3% and 12.5 ± 3%. The release of quercetin drug using both CuS nano-modules at two different pH conditions (pH 2.2 and 7.4) was further investigated. Owing to the inherent bactericidal properties of nanostructures and quercetin, the synergistic effect of quercetin and CuS was also examined. Further, the catalytic efficiency of CuS NP's and NT's were tested on the removal of toxic carcinogenic dyes (Methyl orange and crystal violet) in solar light. The catalytic degradation study of methyl orange demonstrated 91.72% degradation ability with CuS NP's and 96.62% with CuS NT's in 30 min. Moreover, the percentage degradation of crystal violet with CuS NP's and NT's was found to be 96.92 and 97.23%, respectively.

ANTI-COAGULANT PROPERTIES OF FLAVONOID COMPOUNDS: POTENTIAL STRUCTURE-FUNCTIONAL RELATIONSHIP

Objective: Flavonoids, naturally-occurring compounds in fruits and vegetables, possess anti-coagulant property. However, a very few studies wereattempted to understand how flavonoid structure influences its anti-coagulation property, such as clotting time. In this study, we investigatedstructurally similar flavonoid compounds which differ in the number of hydroxyl groups and compared their anti-coagulation properties.Methods: We selected and evaluated five flavonoid compounds, that is, chrysin, apigenin, luteolin, kaempferol, and quercetin, for their anti-coagulantproperties using in vitro prothrombin time (PT) assays and activated partial thromboplastin time (APTT) assay.Results: Our findings suggested that quercetin, kaempferol, and luteolin showed a significant anti-coagulant effect on APTT (p<0.05) in a dosedependentmanner. The dose of 500 μM quercetin showed potent prolong APTT with 37.43±1.60 s, followed by 500 μM of kaempferol and luteolin(34.63±1.29 s and 4.83±1.56 s, respectively). Furthermore, a combination of 500 μM of quercetin with 0.25 U/ml of heparin demonstrated prolongAPTT (52.16±5.18 s) when compared with individual effects of either 0.25 U/ml heparin (33.4±0.50 s) or 500 μM quercetin (37.43±1.62 s) alone.Conclusion: Our results demonstrated that numbers of the hydroxyl group on flavonoid compounds influence anti-coagulation properties. Inaddition, the prolonged APTT assay results suggested that quercetin, kaempferol, and luteolin could affect factors VIII, IX, XI, and XII of intrinsicpathway. Moreover, the synergistic effect of quercetin further enhances the heparin anti-coagulation effect. Based on our findings, we recommendthat the consumption of vegetables and fruits rich in quercetin, luteolin, and kaempferol could help prevent thrombotic stroke in high-risk patients.

Synergistic Effect of Quercetin and Vitamin C Against COVID-19: Is a Possible Guard for Front Liners

Background: While waiting for vaccine, hygiene measures, social distance and personal protective equipment are the only basic protection against Novel Coronavirus. However, these are not sufficient to protect healthcare workers.This study aimed to evaluate if quercetin and vitamin C could be protective against Novel Coronavirus.Methods: In prophylaxis group supplementation containing 500mg of quercetin, 500mg of vitamin C and 50mg of bromelain (QCB) was initiated daily in 2 divided doses for 71 healthcare workers working in areas with high risk of COVID-19, whereas 42 were determined as control group without using supplements.A maximum period of follow-up was determined as 120 days.Termination of use of QCB earlier or having a Coronavirus infection was considered as final point.At the end rapid diagnostic test used to detect immunoglobulin positivity.Results: A total of 113 persons included. No significant difference detected between groups in terms of other features.Mean age of QCB group was 39.0 ± 8.8 years and control group was 32.9 ± 8.7.Average follow-up period for the QCB group was 113 days, and for the control group, 118, during follow-up period, 1 healthcare worker in QCB group and 9 out of 42 in control group had COVID-19.One of cases was asymptomatic, while others were not.Transmission risk hazard ratio whose did not receive QCB was 12.04 (95% Confidence interval= 1.26-115.06, P = 0.031).No significant effect of gender, smoking, antihypertensive medication exposure and having chronic disease on rate of transmission.Conclusion: This study revealed that QCB was protective for healthcare workers.Trial registration NCT04377789Funding: None to discloseDeclaration of Interest: None to discloseEthical Approval Statement: This study was approved by the ethical approval team at Kanuni Sultan Süleyman Eğitim ve Araştırma Hastanesi.

Potential synergistic activity of quercetin with antibiotics against multidrug-resistant clinical strains of Pseudomonas aeruginosa.

Development of drug resistance in opportunistic pathogens is one of the major healthcare challenges associated with infection management. Combination therapy has many advantages due to the simultaneous action of two drugs on two separate cellular targets. However, selection of the drugs should offer safety and synergistic interaction against most of the strains. Here, the efficacy of antibiotics in combination with quercetin, a natural flavonoid capable of targeting quorum sensing was tested against biofilm-forming Pseudomonas aeruginosa strains previously isolated from catheter associated urinary tract infection. Based on the antibiotic susceptibility pattern, synergistic effect of quercetin with selected antibiotics (levofloxacin, ceftriaxone, gentamycin, tobramycin and amikacin) was tested at the fractional concentrations of MIC by the checkerboard method and the fractional inhibitory concentration index (FICi) was calculated to estimate the synergistic effect. Effect of the synergistic combinations were further tested using time-kill assay, and against biofilm formation and biofilm cell viability. Cytotoxicity assays were performed using Human Embryonic Kidney 293T cells (HEK-293T) using the effective drug combinations with respective controls. The biofilm formation and biofilm cell viability were drastically affected with quercetin and selected antibiotics combinations with ≥80% inhibition. In vitro infection studies showed that all the strains could exert significant cell killing (68 to 85%) and the drug combinations decreased the infection rate significantly by reducing the cell killing effect of P. aeruginosa (p<0.05). The synergistic effect of quercetin is attributed to its quorum sensing inhibitory properties. These findings indicate that quercetin along with existing antibiotics can potentiate the treatment against P. aeruginosa infection and may reduce the selection pressure due to antibiotic overuse.

Side Effects of Chemotherapy on the Molecular Structure of rat’s retina and the Possible Protective Role of Antioxidants

Ifosfamide is an alkylating oxazaphosphorine antitumor prodrug. Although it is an effective chemotherapeutic agent, it has been shown to induce many side effects. The objective of the present study, therefore, was to investigate the possible protective roles of lecithin and quercetin either singly or combined against ifosfamide-induced molecular structure changes in retina of female rats using Fourier transform infrared spectroscopy (FTIR). Seventy female albino rats were randomly divided into seven groups. Ifosfamide (Ifo; 80mg/kg b.wt.) was administrated for five consecutive days intraperitoneally (i.p.), while quercetin (50mg/kg b.wt.) and lecithin (100mg/kg b.wt) were given orally either singly or in-combination with IFO for six consecutive days. Our results indicate that Ifosfamide was affected on the lipid components of the retina, NH-OH region changes revealed unusual interface/binding mechanism that related to different surrounding environment due to ifosfamide intraperitoneal injection. The co-administration of Lec+Que with the intraperitoneal injection of Ifosfamide preventing the side effect of Ifosfamide. We suggest that synergistic effect of quercetin and lecithin in the combined therapy results in marked neuroprotective effect in part through its antioxidant properties and down regulation of molecular structure in retina.

Synergistic Effect of Quercetin in Combination with Sulfamethoxazole as New Antibacterial Agent: In Vitro and In Vivo Study

The present study was aimed at creating a combination between lower dose of sulfamethoxazole (S) as a broad-spectrum synthetic antibiotic and quercetin (Q), a natural polyphenol to decrease the antibiotic side effects and increase its antioxidant activity. Staphylococcus aureus infected animal model was studied both in vitro and in vivo in comparison to doxycycline (Dox) as standard antibiotic. The in vitro test results indicated that Q exhibited activity alone and in combination with S against tested bacterial strains, while S in low concentration was inactive. The in vivo results revealed that the S+Q combination in mice showed significant improvements in the liver and kidney functions as compared to those in the infected group or S- and Dox-treated groups. Moreover, malondialdehyde level was significantly decreased, while superoxide dismutase and catalase activities were significantly increased in the sera of (S+Q)-treated group in comparison to other treated groups. The spleen recovery in the (S+Q)-treated group was observed with the disappearance of S. aureus colonies as compared to the infected mice. In conclusion, the in vivo treatment of S. aureus infection with S+Q combination decreased the sulfamethoxazole side effects while increasing its antibacterial activity, which supported the therapeutic use of this combination in humans.

Functionalized graphene oxide as a nanocarrier for dual drug delivery applications: The synergistic effect of quercetin and gefitinib against ovarian cancer cells.

Graphene Oxide (GO) has been extensively studied in the field of biomedical sciences as one of the most promising biomaterials due to its exceptional physiochemical properties. Experts have long favored anticancer drug cocktails over single drugs, given that the former may provide a more balanced molecular basis for novel chemotherapeutic strategies. Here, we investigated a combinatorial anticancer drug treatment involving the well-proven anticancer drugs quercetin and gefitinib and compared it with gefitinib and quercetin loaded separately onto polyvinylpyrrolidone (PVP)-functionalized graphene oxide (GO-PVP). The loading and cancer cell cytotoxicity of the individual drug systems and their combined loading onto GO-PVP nanovehicles were investigated in PA-1 ovarian cancer cells and compared to their effects on IOSE-364 ovarian epithelial cells. In this report, the combined drug system loaded on the GO-PVP nanovehicle was found to be significantly more toxic than the individual drug loaded systems, as well as the free drugs, toward PA-1 cells compared to the toxicity toward IOSE-364 cells. The combined drug system loaded on the GO-PVP nanovehicle is likely to be more successful than individual drug therapy, given the stronger impact of the combinatorial approach and the efficiency of chemotherapeutic delivery.

Synergistic Effect of Quercetin and Vitamin C in Reducing Acute Toxicity and Improving Antitumor Activity of Liposomal Doxorubicin

This article attempts to reduce the acute toxicity of doxorubicin while preserving its antitumor effects. For this purpose, a long-circulating liposomal doxorubicin was PEGylated to treat tumor-bearing Kunming mice, and quercetin and vitamin C were orally administered simultaneously to further suppress toxicity. Quercetin is a fat-soluble flavonoid that scavenges free radicals in cell membranes, whereas vitamin C is a water-soluble vitamin capable of neutralizing free radicals in the cytoplasm. Doxorubicin concentrations in the plasma and in the different organs of the mice were compared, and the detoxication effects of different combinations of reagents are discussed in detail. The results show that quercetin and vitamin C can synergistically reduce the acute toxicity of long-circulating liposomal doxorubicin and further improve its antitumor effect.

Synergistic Effect of Quercetin and α-Lipoic Acid on Aluminium Chloride Induced Neurotoxicity in Rats.

Objectives The present study was carried out to study the protective effects of quercetin and α-lipoic acid alone and in combination against aluminum chloride induced neurotoxicity in rats. Materials and Methods The study consisted of eight groups, namely, Group 1: control rats, Group 2: rats receiving aluminium chloride 7 mg/kg body weight intraperitoneal route (i.p) for two weeks, Group 3: rats receiving quercetin 50 mg/kg body weight i.p. for two weeks, Group 4: rats receiving quercetin 50 mg/kg body weight followed by aluminium chloride 7 mg/kg body weight i.p. for two weeks, Group 5: rats receiving α-lipoic acid 20 mg/kg body weight i.p. for two weeks, Group 6: rats receiving lipoic acid 20 mg/kg body weight followed by aluminium chloride 7 mg/kg body weight i.p. for two weeks, Group 7: rats receiving α-lipoic acid 20 mg/kg body weight and quercetin 50 mg/kg body weight i.p. for two weeks, and Group 8: rats receiving α-lipoic acid 20 mg/kg body weight and quercetin 50 mg/kg body weight followed by aluminium chloride 7 mg/kg body weight i.p. for two weeks. The animals were killed after 24 hours of the last dose by cervical dislocation. Results Aluminium chloride treatment of rats resulted in significant increases in lipid peroxidation, protein carbonyl levels, and acetylcholine esterase activity in the brain. This was accompanied with significant decreases in reduced glutathione, activities of the glutathione reductase, and superoxide dismutase. Pretreatment of AlCl3 exposed rats to either quercetin or α-lipoic acid also restored altered lipid peroxidation and superoxide dismutase to near normal levels. Quercetin or α-lipoic acid pretreatment of AlCl3 exposed rats improved the protein carbonyl and reduced glutathione, glutathione reductase, and acetylcholine esterase activities in rat brains towards normal levels. Combined pretreatment of AlCl3 exposed rats with quercetin and α-lipoic acid resulted in a tendency towards normalization of most of the parameters. Conclusions Quercetin and α-lipoic acid complemented each other in protecting the rat brain against oxidative stress induced by aluminium chloride.

Synergistic effect of quercetin and pH-responsive DEAE-chitosan carriers as drug delivery system for breast cancer treatment

Amphiphilic chitosans, which may self-assemble in aqueous solution to form nanoaggregates with different conformations depending to the environmental pH, can be used as drug transport and delivery agents, when the target pH differs from the delivery medium pH. In this study, quercetin, a bioactive flavonoid, was encapsulated in a pH-responsive system based on amphiphilic chitosan. The hydrophilic reagent 2-chloro-N,N-diethylethylamine hydrochloride (DEAE), also known to inhibit the proliferation of cancer cells, was used as a grafting agent. Drug loading experiments (DL ∼5%) showed a quercetin entrapment efficiency of 73 and 78% for the aggregates. The sizes of blank aggregates measured by dynamic light scattering (DLS) varied from 169 to 263nm and increased to ∼410nm when loaded with quercetin. The critical aggregation concentration, zeta potential and morphology of the aggregates were determined. pH had a dominant role in the release process and Fickian diffusion was the controlling factor in drug release according to the Korsmeyer-Peppas mathematical model. In vitro studies indicated that the DEAE-modified chitosan nanoaggregates showed a synergistic effect with quercetin on the control of the viability of MCF-7 cells. Therefore, DEAE-modified chitosan nanoaggregates with pH-sensibility can be used as optimized nanocarriers in cancer therapy.

Evaluation of the protective role of quercetin and lecithin on Ifosfamide neurotoxicity in rats

Objective: The present study aimed to contribute the ability of quercetin and /or lecithin to attenuate ifosfamide neurotoxicity. Seventy female albino rats were randomly divided into seven groups. Ifosfamide (IFO; 80mg/kg b.wt.) was administrated for fiv e consecutive days intraperitoneally (i.p.), while quercetin (50mg/kg b.wt.) and lecithin (100mg/kg b.wt) were given orally either singly or in-combination with IFO for six consecutive days. Results: Ifosfamide induce neural toxicity as indicated by decreased GSH/GSSG ratio and elevated NO level in different brain areas. As well as altering neurotransmitters levels accompanied by inhibition of choline esterase activity in serum. Also, it stimulates an apoptotic signaling program by up-regulation of caspase-3 and assimilation of Bcl-2 gene expression in all tested brain areas. Pretreatment with quercetin and lecithin singly or in combination could attenuate ifosfamide neurotoxicity by variable degrees of improvement. This improvement seems to be a parameter selective among different brain areas. Conclusion: The present study concludes that pretreatment with combined therapy showed more pronounced effect compared to singular one. Therefore, we suggested that the synergistic effect of quercetin and lecithin in the combined treatment results in marked neuroprotective effect in part through their antioxidant properties and intervening in apoptotic pathways.

Synergistic effect of quercetin and 6-gingerol treatment in streptozotocin induced type 2 diabetic rats and poloxamer P-407 induced hyperlipidemia

Ginger and quercetin have been reported to have significant antidiabetic effects.

Compatibility and synergistic effect of Quercetin and Indomethacin combination

The previous study of indomethacin-​quercetin (IM-​QRT) compatibility by thermal anal. was continued in presence of different ratios of QRT to investigate the effect of QRT on the polymorphic structure of IM. Thermal anal. results revealed that the compatibility of phys. mixts. and co-​ppts. were at all ratios and slight formation of polymorph II of IM in all ratios of co-​ppts. Also, UV-​spectra investigated the compatibility and possibility of quant. anal. of IM in presence of QRT. The synergistic effects of QRT on IM were studied using hot plate and p-​benzoquinone methods for analgesic activity in mice and yeast-​induced inflammation for anti-​inflammatory effect in rats. QRT was found to have the ability to increase the duration of analgesic activity of IM. Also, the reaction time of IM-​QRT combination increased significantly to reach the max. after 4 h.