Quercetin supplementation attenuates cisplatin induced myelosuppression in mice through regulation of hematopoietic growth factors and hematopoietic inhibitory factors.

The present study investigated the effects of quercetin on cisplatin (CDDP)-induced common side effect, myelosuppression, and the possible mechanisms in Balb/c mice. The mice were randomly treated with CDDP alone or in combination with quercetin for 14 days. Quercetin was given by intraperitoneal injection (10 mg/kg, 3 times a week; IQ) or by a diet containing 0.1% or 1% quercetin (LQ and HQ, respectively). We found that quercetin supplementation especially HQ and IQ, significantly restored the decrease in number of bone marrow cells, total white blood cells, red blood cells and platelets, and the body weight in mice exposed to CDDP (P≤.05). Similar trends were observed in the number of neutrophils, lymphocytes and monocytes in the plasma. HQ and IQ also increased the levels of hematopoietic growth factors (HGFs), especially in granulocyte-macrophage-colony stimulating factor and IL-9 (P<.05), but decreased the levels of hematopoietic inhibitory factors (HIFs) and oxidative stress in the plasma and the bone marrow in CDDP-exposed mice. Furthermore, both quercetin and quercetin-3-O-glucuronide (Q3G) significantly increase cell viability and inhibited apoptosis at 48 or 72 h (P≤.05), accompanied by increasing HGF levels and decreasing HIF levels in the cultured medium in 32D cells exposed to CDDP. IL-9 siRNA transfection suppressed the effects of quercetin and Q3G on cell viability (P≤.05) in32D cells. In conclusion, our results indicate that quercetin attenuates CDDP-induced myelosuppression through the mechanisms associated with regulation of HGFs and HIFs.

Enzyme-Digested Peptides Derived from Lates calcarifer Enhance Wound Healing after Surgical Incision in a Murine Model.

Surgical wounds are common injuries of skin and tissues and usually become a clinical problem. Until now, various synthetic and natural peptides have been widely explored as potential drug candidates for wound healing. Inhibition of the TNF-α signaling pathway and promotion of angiogenesis are suggested to be involved in their effects. Angiogenesis at the wound site is one of the essential requisites for rapid healing. In the present study, a novel peptide extract derived from the natural source Lates calcarifer, commonly known as sea bass or barramundi, was evaluated for its wound healing property. The specific acidic and enzymatic approaches were employed for producing sea bass extract containing small size peptides (molecular weight ranging from 1 kD to 5 kD). The cytotoxicity of the extract was examined in HaCaT and NIH3T3. After this, the effects of enzyme digested peptide extracts of sea bass on wound healing in mice were investigated. The peptide extracts (660 and 1320 mg/kg/day) and control protein (1320 mg/kg/day) was orally given to the wounded mice, respectively, for 12 days. The surgical method was improved by implanting a silicone ring at the wound site. The ring avoided the contracting effect in murine wounds, making it more closely related to a clinical condition. The results showed promising improvement at the wound site in mice. Sea bass peptide extracts accelerated the wound healing process and enhanced the microvessel formation at the wound site. The remarkable effects of this novel sea bass peptide extract in healing traumatic injuries revealed a new option for developing wound management.

Quercetin attenuates cisplatin-induced fat loss.

PURPOSE: The major aim of the present study was to determine the effects of quercetin, a well-known flavonoid, on attenuating cisplatin (CDDP)-induced fat loss and the possible mechanisms. METHODS: Tumor-bearing nude mice and tumor-free BALB/c mice were administrated with CDDP alone or in combination with quercetin by a diet containing 0.1% or 1% quercetin (LQ or HQ) or by intraperitoneal injection (IQ) to determine the effects of quercetin on the anticancer effect of CDDP or CDDP-induced fat loss. The effects of quercetin on fat accumulation in CDDP-exposed 3T3-L1 cells were also determined. RESULTS: We first showed that HQ and IQ significantly enhanced the anticancer effect of CDDP by upregulating p53- and p21-associated pathways, while tended to attenuate CDDP-induced fat loss in tumor-bearing nude mice. The study in 3T3-L1 cells showed that CDDP decreased the fat accumulation accompanied by strong upregulation of the expression of six genes which are associated with fat metabolism, while quercetin completely suppressed such an effect. The tumor-free BALB/c mice study consistently showed a protective effect of HQ on CDDP-induced body weight and epididymal fat loss. HQ also increased the fat levels in liver and muscle tissues. In epididymal fat tissues, HQ consistently attenuated CDDP-induced changes in fat metabolism-associated gene expression. However, CDDP alone or in combination with HQ did not affect the food intake. CONCLUSIONS: This study demonstrates that quercetin possesses the potential to suppress CDDP-induced fat loss may partly through the regulation of the fat metabolism-associated gene expression.

Discovery of Antibacterials That Inhibit Bacterial RNA Polymerase Interactions with Sigma Factors.

Formation of a bacterial RNA polymerase (RNAP) holoenzyme by a catalytic core RNAP and a sigma (σ) initiation factor is essential for bacterial viability. As the primary binding site for the housekeeping σ factors, the RNAP clamp helix domain represents an attractive target for novel antimicrobial agent discovery. Previously, we designed a pharmacophore model based on the essential amino acids of the clamp helix, such as R278, R281, and I291 (Escherichia coli numbering), and identified hit compounds with antimicrobial activity that interfered with the core-σ interactions. In this work, we rationally designed and synthesized a class of triaryl derivatives of one hit compound and succeeded in drastically improving the antimicrobial activity against Streptococcus pneumoniae, with the minimum inhibitory concentration reduced from 256 to 1 µg/mL. Additional characterization of antimicrobial activity, inhibition of transcription, in vitro pharmacological properties, and cytotoxicity of the optimized compounds demonstrated their potential for further development.

Quercetin enhances the antitumor activity of trichostatin A through up-regulation of p300 protein expression in p53 null cancer cells.

In the present study, we investigated the p53-independent mechanism by which quercetin (Q) increased apoptosis in human lung cancer H1299 cells exposed to trichostatin A (TSA), a histone deacetylase inhibitor. We also investigated the role of Q in increasing the acetylation of histones H3 and H4 and the possible mechanism. Q at 5 µM significantly increased apoptosis by 88% in H1299 cells induced by TSA at 72 h. Q also significantly increased TSA-induced death receptor 5 (DR5) mRNA and protein expression as well as caspase-10/3 activities in H1299 cells. Transfection of DR5 siRNA into H1299 cells significantly diminished the enhancing effects of Q on TSA-induced apoptosis. Furthermore, TSA in combination with Q rather than TSA alone significantly increased p300 expression. Transfection of p300 siRNA in H1299 cells significantly diminished the increase of histone H3/H4 acetylation, DR5 protein expression, caspase-10/3 activity and apoptosis induced by Q. In addition, similar effects of Q were observed when Q was combined with vorinostat, another FDA-approved histone deacetylase inhibitor. These data suggest that the up-regulation of p300 expression, which in turn increases histone acetylation and DR5 expression, plays an important role in the enhancing effect of Q on TSA/vorinostat- induced apoptosis in H1299 cells.

Quercetin and chrysin inhibit nickel-induced invasion and migration by downregulation of TLR4/NF-κB signaling in A549 cells.

Nickel exposure promotes the invasive potential of human lung cancer cells. Polyphenols such as quercetin, curcumin, chrysin, apigenin, and luteolin, present in many plant foods may suppress the development of cancers. However, whether these compounds inhibit the promoting effects of Nickel on cancer cell invasion and migration as well as the possible mechanisms are unclear. In the present study, we first showed that quercetin, curcumin, chrysin, apigenin, and luteolin at 5 µM, significantly suppressed the promoting effects of NiCl2 (Ni) on migration and invasion in H1975 and A549 human lung cancer cells. The five phytochemicals also significantly suppressed the secretion of cytokines, IL-1ß, IL-6, TNF-α and IL-10, induced by Ni in A549 cells. The overall efficiency of quercetin was the best, followed by chrysin and the other compounds. Furthermore, we found that quercetin and chrysin suppressed the mRNA and protein expression of TLR4 and Myd88. Consistently, quercetin and chrysin also decreased the phosphorylation of IKKß and IκB, the nuclear level of p65 (NF-κB) as well as the expression of MMP-9 in A549 cells exposed to Ni. In conclusion, these results suggest the potential preventive effects of the five phytochemicals on the promoting effect of Ni on human lung cancer cell invasion. In addition, the preventive effects are associated with downregulation of the TLR4/NF-κB signaling pathway, especially for quercetin and chrysin.

Quercetin enhances the antitumor effect of trichostatin A and suppresses muscle wasting in tumor-bearing mice.

Quercetin, a flavonol, displays anti-inflammatory and anti-cancer properties. This study aimed to investigate whether a diet containing 0.1% or 1% quercetin (LQ and HQ, respectively) enhances the anti-tumor effects of trichostatin A (TSA) and prevents muscle wasting induced by TSA. The positive control group received quercetin intraperitoneally (IQ). Three weeks after injecting A549 cells, nude mice were given TSA alone or in combination with quercetin administered orally or intraperitoneally for 16 weeks. Tumor volumes as well as body, muscle and epididymal fat weights were determined during or after the experiment. Quercetin given as a diet supplement dose-dependently enhanced the anti-tumor potency of TSA (p < 0.05). The enhancing effect of HQ was similar to that of IQ. HQ also significantly increased the expression of p53, a tumor suppressor, in tumor tissues compared with the TSA alone group. In addition, TSA-induced loss of gastrocnemius muscle weight was inhibited by oral quercetin in a dose dependent manner; the efficiencies of LQ and HQ were similar to or better than IQ. Moreover, both LQ and HQ decreased TSA-induced activation of Forkhead box O1 (FOXO1), a crucial transcription factor that regulates muscle wasting associated genes. Consistently, LQ and HQ suppressed muscle wasting associated proteins atrophy gene-1 and muscle ring-finger protein-1 expression as well as increased the myosin heavy chain level in the gastrocnemius muscles. Besides, quercetin attenuated TSA-increased oxidative damage and proinflammatory cytokines (p < 0.05). These findings demonstrate that a diet containing 0.1% or 1% quercetin enhances the antitumor effect of TSA and prevents TSA-induced muscle wasting.

Combination of ß-carotene and quercetin against benzo[a]pyrene-induced pro-inflammatory reaction accompanied by the regulation of antioxidant enzyme activity and NF-κB translocation in Mongolian gerbils.

PURPOSE: We have previously shown that quercetin modulates the proinflammatory effect of ß-carotene (BC) induced by oral benzo[a]pyren (Bap) partly through the regulation of the JNK pathway. In the present study, we determined whether the combination of BC and quercetin regulates the antioxidant enzymes and the activation of NF-κB in Mongolian gerbils exposed to Bap. We also compared the combined effects of BC+ quercetin with that of BC+ ascorbic acid (C)+ α-tocopherol (E). METHODS: The gerbils were given BC (10 mg/kg) alone or in combination with quercetin (50 or 100 mg/kg) or C (13 mg/kg)+E (92 mg/kg) by gavage 3 times/week for 6 months. During the first 2 months, the gerbils were exposed to Bap by intratracheal instillation once/week. The levels of proinflammatory cytokines, thiobarbituric acid reactive substances, antioxidant enzymes and NF-κB activation in the plasma or the lungs were determined. RESULTS: Bap increased the level of proinflammatory cytokines and oxidative stress in the plasma or lungs, while it decreased the antioxidant systems. Bap also increased nuclear NF-κB levels in the lungs. BC partly recovered the Bap-induced decrease in antioxidant activity, antioxidant enzyme activities and glutathione levels but had no effect on proinflammatory cytokines and NF-κB translocation. BC in combination with quercetin or C+E suppressed all the harmful effects induced by Bap. All the effects of quercetin at 100 mg/kg were similar to the effect of C+E. CONCLUSION: BC in combination with quercetin or C+E rather than BC alone similarly suppresses the Bap-induced inflammatory reaction that was accompanied by the regulation of antioxidant enzymes and the translocation of NF-κB in vivo.

Oral and intraperitoneal administration of quercetin decreased lymphocyte DNA damage and plasma lipid peroxidation induced by TSA in vivo.

Our previous study showed that quercetin enhances the anticancer effect of trichostatin A (TSA) in xenograft mice given quercetin intraperitoneally (10 mg/kg, 3 times/week). Herein, we investigate whether quercetin administered orally exerts such an effect and prevents the cytotoxic side effects of TSA. We found that quercetin given orally (20 and 100 mg/kg, 3 times/week) failed to enhance the antitumor effect of TSA although it increased the total quercetin concentration more than quercetin administered intraperitoneally in the plasma. The compound quercetin-3-glucuronide (Q3G) increased the most. However, quercetin administered intraperitoneally increased the total quercetin level in tumor tissues more than oral quercetin. Oral and intraperitoneal administration of quercetin similarly decreased lymphocyte DNA damage and plasma lipid peroxidation level induced by TSA. Furthermore, we found that the enhancing effect of Q3G on the antitumor effect of TSA and the incorporation of Q3G was less than that of quercetin in A549 cells. However, we found that A549 cells possessed the ability to convert Q3G to quercetin. In conclusion, different from quercetin administered intraperitoneally, quercetin administered orally failed to enhance the antitumor effect of TSA because of its metabolic conversion. However, it prevented TSA-induced DNA damage and lipid peroxidation.

Quercetin enhances the antitumor activity of trichostatin A through upregulation of p53 protein expression in vitro and in vivo.

This study investigated the effects of quercetin on the anti-tumor effect of trichostatin A (TSA), a novel anticancer drug, in vitro and in vivo and the possible mechanisms of these effects in human lung cancer cells. We first showed that quercetin (5 µM) significantly increased the growth arrest and apoptosis in A549 cells (expressing wild-type p53) induced by 25 ng/mL of (82.5 nM) TSA at 48 h by about 25% and 101%, respectively. However, such enhancing effects of quercetin (5 µM) were not significant in TSA-exposed H1299 cells (a p53 null mutant) or were much lower than in A549 cells. In addition, quercetin significantly increased TSA-induced p53 expression in A549 cells. Transfection of p53 siRNA into A549 cells significantly but not completely diminished the enhancing effects of quercetin on TSA-induced apoptosis. Furthermore, we demonstrated that quercetin enhanced TSA-induced apoptosis through the mitochondrial pathway. Transfection of p53 siRNA abolished such enhancing effects of quercetin. However, quercetin increased the acetylation of histones H3 and H4 induced by TSA in A549 cells, even with p53 siRNA transfection as well as in H1299 cells. In a xenograft mouse model of lung cancer, quercetin enhanced the antitumor effect of TSA. Tumors from mice treated with TSA in combination with quercetin had higher p53 and apoptosis levels than did those from control and TSA-treated mice. These data indicate that regulation of the expression of p53 by quercetin plays an important role in enhancing TSA-induced apoptosis in A549 cells. However, p53-independent mechanisms may also contribute to the enhancing effect of quercetin.

Quercetin supplementation suppresses the secretion of pro-inflammatory cytokines in the lungs of Mongolian gerbils and in A549 cells exposed to benzo[a]pyrene alone or in combination with ß-carotene: in vivo and ex vivo studies.

In vitro studies have shown that quercetin modulates the effects of ß-carotene induced by stimulants. Whether these reactions happen in vivo, however, is unclear. Thus, we investigated whether quercetin supplementation suppresses the harmful effects of benzo[a]pyrene (BaP) alone or combined with ß-carotene in the lungs of Mongolian gerbils. The gerbils were given quercetin (100 mg/kg body wt, 3 times/week), ß-carotene (10 mg/kg body wt, 3 times/week), and BaP (8 mmol, 2 times/week) alone or in combination by gavage for 6 months. ß-Carotene supplementation enhanced the pro-inflammatory effects of BaP in the lungs of gerbils. In contrast, quercetin supplementation significantly decreased the infiltration of inflammatory cells as well as the levels of TNF-α and IL-1ß in the bronchoalveolar lavage fluid and plasma of gerbils exposed to BaP or BaP+ß-carotene (P<.05). Such effects of quercetin supplementation were accompanied by a down-regulation of the expression of phospho-c-Jun and phospho-JNK induced by BaP or BaP+ß-carotene in the lungs of gerbils. Furthermore, in the ex vivo study, we found that quercetin-metabolite-enriched plasma (QP) obtained from gerbils acted like a JNK inhibitor to significantly suppress the secretion of pro-inflammatory cytokines induced by BaP or BaP+ß-carotene in A549 cells (P<.05). QP also suppressed the activation of the JNK pathway in the A549 cells. These results suggest that supplemental quercetin suppress the pro-inflammatory effect of ß-carotene induced by BaP in vivo and ex vivo. The regulation of the JNK pathway by the metabolites of quercetin contributes, at least in part, to such effects of quercetin in vivo.

Effects of quercetin metabolites on the enhancing effect of ß-carotene on DNA damage and cytochrome P1A1/2 expression in benzo[a]pyrene-exposed A549 cells.

A549 cells were pre-incubated with ß-carotene (BC) alone or in combination with quercetin or three major quercetin metabolites in human plasma, quercetin 3-glucuronide (Q3G), quercetin 3'-sulphate (Q3'S) and isorhamnetin, followed by incubation with benzo[a]pyrene (BaP), to investigate the effects of these compounds on the BaP-induced harmful effects of BC. All the quercetin metabolites at 10µM inhibited BaP+BC-induced cell death. Q3'S, Q3G and isorhamnetin also significantly decreased BaP±BC-induced DNA damage by 64%, 60% and 24%, respectively. In a similar order, these compounds suppressed BaP+BC-induced cytochrome P450 (CYP)1A1/1A2 expression by 10-50%. Q3G and Q3'S significantly decreased the intracellular reactive oxygen species formation induced by BaP+BC; however, Q3G had the best effect on decreasing the loss of BC induced by Fe/NTA. The combined effects of quercetin metabolites were additive. This study indicates that quercetin metabolites decrease the BaP-induced harmful effect of ß-carotene in A549 cells by downregulating the expression of CYP1A1/1A2, at least in part.

Plasma rich in quercetin metabolites induces G2/M arrest by upregulating PPAR-γ expression in human A549 lung cancer cells.

In this study, we incubated human A549 lung cancer cells with quercetin-metabolite-enriched plasma (QMP) obtained from Mongolian gerbils 2 h after quercetin feeding (100 mg/kg body wt/week). We investigated the effects of QMP on the growth of A549 cells and the possible mechanisms for these effects. We found that QMP but not control plasma (CP) reduced the cell growth in A549 cells. QMP led to cell cycle arrest at the G (2)/M phase by downregulating the expression of cdk1 and cyclin B. QMP but not CP or quercetin itself significantly increased PPAR- γ expression (p < 0.05), which was accompanied by an increase of phosphatase and tensin homologue deleted on the chromosome ten level and a decrease of phosphorylation of Akt. Furthermore, quercetin-3-glucuronide and quercetin-3'-sulfate also significantly increased PPAR- γ expression in A549 cells. GW9662, a PPAR- γ antagonist, significantly suppressed the effects of 10 % QMP on cell proliferation and on the expression of cyclin B and cdk1. Taken together, these data suggest that the activation of PPAR- γ plays an important role, at least in part, in the antiproliferative effects of quercetin metabolites.

Inhibition of ICAM-1 gene expression, monocyte adhesion and cancer cell invasion by targeting IKK complex: molecular and functional study of novel alpha-methylene-gamma-butyrolactone derivatives.

The transcription factor nuclear factor-kappaB (NF-kappaB) is a regulator related to cellular inflammation, immune responses and carcinogenesis. Therefore, components of the NF-kappaB-activating singnaling pathways are frequent targets for the anti-inflammatory and anticancer agents. In this study, CYL-19 s and CYL-26z, two synthetic alpha-methylene-gamma-butyrolactone derivatives, were shown to inhibit the tumor necrosis factor-alpha (TNF-alpha)-induced intercellular adhesion molecule-1 (ICAM-1) expression in human A549 alveolar epithelial cells and the adhesion of U937 cells to these cells. RT-PCR analysis also demonstrated their inhibitory effects on TNF-alpha-induced ICAM-1 mRNA expression. TNF-alpha-induced ICAM-1 and NF-kappaB-dependent promoter activities were attenuated by CYL-19 s and CYL-26z. ICAM-1 promoter activities induced by the over-expression of wild-type NF-kappaB-inducing kinase and IkappaB kinase beta (IKKbeta) were also inhibited by both compounds. Furthermore, CYL-19 s and CYL-26z inhibited the TNF-alpha-induced phosphorylation and degradation of IkappaBalpha and NF-kappaB-specific DNA-protein binding activity via targeting IKK complex directly, without any effect on the activations of other kinases such as ERK1/2 and p38. In addition to ICAM-1 expression, CYL-19 s and CYL-26z also suppressed other NF-kappaB-mediated gene expressions such as matrix metalloproteinase-9 (MMP-9) mRNA and cyclooxygnease-2 (COX-2) protein. In Matrigel assays, ICAM-1 and COX-2 expressions induced by TNF-alpha elicited A549 and NCI-H292 cell invasion, respectively, and these effects were inhibited by both compounds. In summary, our data demonstrated that CYL-19 s and CYL-26z down-regulate the TNF-alpha-induced inflammatory genes expression through suppression of IKK activity and NF-kappaB activation. These agents may be effective in the anti-inflammatory and anticancer therapy.