Preventive effect of the flavonoid, quercetin, on hepatic cancer in rats via oxidant/antioxidant activity: molecular and histological evidences

Can Compounds of Natural Origin Be Important in Chemoprevention? Anticancer Properties of Quercetin, Resveratrol, and Curcumin-A Comprehensive Review

Malignant tumors are the second most common cause of death worldwide. More attention is being paid to the link between the body's impaired oxidoreductive balance and cancer incidence. Much attention is being paid to polyphenols derived from plants, as one of their properties is an antioxidant character: the ability to eliminate reactive oxygen and nitrogen species, chelate specific metal ions, modulate signaling pathways affecting inflammation, and raise the level and activity of antioxidant enzymes while lowering those with oxidative effects. The following three compounds, resveratrol, quercetin, and curcumin, are polyphenols modulating multiple molecular targets, or increasing pro-apoptotic protein expression levels and decreasing anti-apoptotic protein expression levels. Experiments conducted in vitro and in vivo on animals and humans suggest using them as chemopreventive agents based on antioxidant properties. The advantage of these natural polyphenols is low toxicity and weak adverse effects at higher doses. However, the compounds discussed are characterized by low bioavailability and solubility, which may make achieving the blood concentrations needed for the desired effect challenging. The solution may lie in derivatives of naturally occurring polyphenols subjected to structural modifications that enhance their beneficial effects or work on implementing new ways of delivering antioxidants that improve their solubility and bioavailability.

Impact of anthocyanin on genetic stability in mammary adenocarcinoma-induced mice treated with methotrexate

Background

Genetic instability leads to genome mutations, changes in nucleotide sequences, rearrangements, and gains or losses of part of the chromosomes. This instability can initiate and develop cancer. This study evaluated genomic stability in methotrexate and anthocyanin-treated mammary adenocarcinoma model. Seventy albino mice were divided into seven groups: negative control, anthocyanin, methotrexate, Ehrlich’s solid tumor; Ehrlich’s solid tumor and methotrexate; Ehrlich’s solid tumor and anthocyanin; and Ehrlich’s solid tumor, methotrexate, and anthocyanin groups.

Results

Tumor weight and size were evaluated. Serum arylesterase activity was low in all the induced tumors and those treated with anthocyanin, methotrexate, or both. Poly[adenosine diphosphate (ADP)-ribose] polymerase activity was high, and glutathione S-transferase activity was low in the tumors treated with anthocyanin, methotrexate, or both, compared with that of the untreated tumor. There was an increase in DNA damage in the mice with solid tumors and those injected with methotrexate or methotrexate and anthocyanin, compared with that in the untreated mice.

Conclusions

There was a decrease in genetic instability and DNA damage in the tumor-bearing mice treated with anthocyanin, with a concomitant increase in nuclear poly[adenosine diphosphate (ADP)-ribose] polymerase activity, compared with those of the untreated group. Anthocyanin exerted positive effects in the treatment of mammary adenocarcinoma.

A Comprehensive Analysis and Anti-Cancer Activities of Quercetin in ROS-Mediated Cancer and Cancer Stem Cells

Reactive oxygen species (ROS) induce carcinogenesis by causing genetic mutations, activating oncogenes, and increasing oxidative stress, all of which affect cell proliferation, survival, and apoptosis. When compared to normal cells, cancer cells have higher levels of ROS, and they are responsible for the maintenance of the cancer phenotype; this unique feature in cancer cells may, therefore, be exploited for targeted therapy. Quercetin (QC), a plant-derived bioflavonoid, is known for its ROS scavenging properties and was recently discovered to have various antitumor properties in a variety of solid tumors. Adaptive stress responses may be induced by persistent ROS stress, allowing cancer cells to survive with high levels of ROS while maintaining cellular viability. However, large amounts of ROS make cancer cells extremely susceptible to quercetin, one of the most available dietary flavonoids. Because of the molecular and metabolic distinctions between malignant and normal cells, targeting ROS metabolism might help overcome medication resistance and achieve therapeutic selectivity while having little or no effect on normal cells. The powerful bioactivity and modulatory role of quercetin has prompted extensive research into the chemical, which has identified a number of pathways that potentially work together to prevent cancer, alongside, QC has a great number of evidences to use as a therapeutic agent in cancer stem cells. This current study has broadly demonstrated the function-mechanistic relationship of quercetin and how it regulates ROS generation to kill cancer and cancer stem cells. Here, we have revealed the regulation and production of ROS in normal cells and cancer cells with a certain signaling mechanism. We demonstrated the specific molecular mechanisms of quercetin including MAPK/ERK1/2, p53, JAK/STAT and TRAIL, AMPKα1/ASK1/p38, RAGE/PI3K/AKT/mTOR axis, HMGB1 and NF-κB, Nrf2-induced signaling pathways and certain cell cycle arrest in cancer cell death, and how they regulate the specific cancer signaling pathways as long-searched cancer therapeutics.

Function and Application of Flavonoids in the Breast Cancer

Breast cancer is one of the top causes of death, particularly among women, and it affects many women. Cancer can also be caused by various factors, including acquiring genetic alteration. Doctors use radiation to detect and treat breast cancer. As a result, breast cancer becomes radiation-resistant, necessitating a new strategy for its treatment. The approach discovered by the researchers is a flavonoid, which is being researched to see if it might help treat radiation-resistant breast cancer more safely than an approved medicine already being used in the field. As a result, this study focuses on the role of flavonoids in breast cancer suppression, breast cancer gene anomalies, and the resulting apoptotic mechanism.

Antidiabetic efficacy of Trifolium alexandrinum extracts hesperetin and quercetin in ameliorating carbohydrate metabolism and activating IR and AMPK signaling in the pancreatic tissues of diabetic rats

Diabetes is a metabolic disease that is mainly characterized by hyperglycemia. The present work investigated the efficacy of the flavanones hesperetin (HES) and quercetin (Q) extracted from Trifolium alexandrinum (TA) to treat type 2 diabetic rats. Wistar albino rats were supplemented with a high fat diet (HFD) for 2 weeks and then administered streptozotocin to induce diabetes. Diabetic rats were orally treated with Q, HES, and TA extract at concentrations of 40, 50, and 200 mg/kg BW, respectively, for 4 weeks. Various biochemical, molecular, and histological analysis were performed to evaluate the antidiabetic effects of these treatments. Q, HES, and TA extract treatments all significantly improved diabetic rats' levels of serum glucose, insulin, glucagon, liver function enzymes, hepatic glycogen, α-amylase, lipase enzymes, lipid profiles, oxidative stress indicators, and antioxidant enzymes as compared with control diabetic untreated rats. In addition, supplementation with Q, HES, and TA extract attenuated the activities of glucose-6-phosphate; fructose-1,6-bisphospahate; 6-phosphogluconate dehydrogenase; glucose-6-phosphate dehydrogenase; glucokinase; and hexokinase in pancreatic tissue, and they improved the levels of glucose transporter 2 and glucose transporter 4. Furthermore, these treatments modulated the expressions levels of insulin receptor (IR), phosphoinositide 3-kinase (PI3K), AMP-activated protein kinase (AMPK), caspase-3, and interleukin-1β (IL-1β). Enhancement of the histological alterations in pancreatic tissues provided further evidence of the ability of Q, HES, and TA extract to exert antidiabetic effects. Q, HES, and TA extract remedied insulin resistance by altering the IR/PI3K and AMPK signaling pathways, and they attenuated type 2 diabetes by improving the antioxidant defense system.

Application of Quercetin in the Treatment of Gastrointestinal Cancers

Many cellular signaling pathways contribute to the regulation of cell proliferation, division, motility, and apoptosis. Deregulation of these pathways contributes to tumor cell initiation and tumor progression. Lately, significant attention has been focused on the use of natural products as a promising strategy in cancer treatment. Quercetin is a natural flavonol compound widely present in commonly consumed foods. Quercetin has shown significant inhibitory effects on tumor progression via various mechanisms of action. These include stimulating cell cycle arrest or/and apoptosis as well as its antioxidant properties. Herein, we summarize the therapeutic effects of quercetin in gastrointestinal cancers (pancreatic, gastric, colorectal, esophageal, hepatocellular, and oral).

LC-DAD-ESI-MS/MS analysis and cytotoxic and antiproliferative effects of chlorogenic acid derivative rich extract from Nerium oleander L. pink flowers

Nerium oleander L. is a widely used medicinal plant for pharmaceutical purposes. In this work, an extract of the pink flowers of this plant (FE) was characterized in terms of phenolic composition by LC-DAD-ESI-MS/MS and bioactivity, namely, antioxidant and antiproliferative effects. A total of 20 compounds from different classes, including derivatives of phenolic acids and flavonoid glycosylated derivatives, were identified in FE. Chlorogenic acid was the dominant phenolic compound in the extract (62.28 ± 1.74 μg mg^-1 of dry extract). The antioxidant activity was assessed by ORAC assay, and FE showed an ability to reduce peroxyl radicals (ORAC value of 791.26 μmol TEAC per g DE). Additionally, the FE inhibited the proliferation of a colorectal cancer cell line (HT29 cells, EC₅₀ = 11.72 ± 0.02 μg mL^-1) and showed no cytotoxicity to confluent Caco-2 cells, a model of human intestinal epithelium. These results provide new information about the phenolic composition of Nerium oleander pink flowers and the bioactivity of the extracts.

Plant-Derived Natural Products in Cancer Research: Extraction, Mechanism of Action, and Drug Formulation

Cancer is one of the main causes of death globally and considered as a major challenge for the public health system. The high toxicity and the lack of selectivity of conventional anticancer therapies make the search for alternative treatments a priority. In this review, we describe the main plant-derived natural products used as anticancer agents. Natural sources, extraction methods, anticancer mechanisms, clinical studies, and pharmaceutical formulation are discussed in this review. Studies covered by this review should provide a solid foundation for researchers and physicians to enhance basic and clinical research on developing alternative anticancer therapies.

Antioxidant Phytoconstituents From Onosma bracteata Wall. (Boraginaceae) Ameliorate the CCl4 Induced Hepatic Damage: In Vivo Study in Male Wistar Rats

Onosma bracteata Wall. (Boraginaceae) is a highly valuable medicinal herb that is used for the treatment of fever, bronchitis, asthma, rheumatism, stomach irritation, and other inflammatory disorders. The present study aims to explore the hepatoprotective potential of ethanolic extract (Obeth) from O. bracteata aerial parts against carbon tetrachloride (CCl₄) which causes hepatic damage in the male Wistar rats. Obeth showed effective radical quenching activity with an EC₅₀ of 115.14 and 199.33 µg/mL in superoxide radical scavenging and lipid peroxidation analyses respectively along with plasmid DNA protective potential in plasmid nicking assay. The Obeth modulated mutagenicity of 2 Aminofluorine (2AF) in the pre-incubation mode of investigation (EC₅₀ 10.48 µg/0.1 mL/plate) in TA100 strain of Salmonella typhimurium. In in vivo studies, pretreatment of Obeth (50, 100, and 200 mg/kg) had the potential to normalize the biochemical markers aggravated by CCl₄ (1mL/kg b.wt.) including liver antioxidative enzymes. Histopathological analysis also revealed the restoration of CCl₄-induced liver histopathological alterations. Immunohistochemical studies showed that the treatment of Obeth downregulated the expression levels of p53 and cyclin D in hepatocytes. and downregulation in the Western blotting analysis revealed the downregulation of p-NF-kB, COX-2, and p53. HPLC data analysis showed the supremacy of major compounds namely, catechin, kaempferol, epicatechin, and Onosmin A in Obeth. The present investigation establishes the hepatoprotective and chemopreventive potential of O. bracteata against CCl₄-induced hepatotoxicity via antioxidant defense system and modulation of the expression of proteins associated with the process of carcinogenesis in hepatic cells.

Phenolic compounds from Nerium oleander leaves: microwave assisted extraction, characterization, antiproliferative and cytotoxic activities

A microwave-assisted extraction (MAE) method was used for the extraction of phenolic compounds from Nerium oleander leaves. The influence of variables such as ethanol concentration, microwave power, irradiation time and liquid/solid ratio on polyphenol extraction was modelled using a second-order regression equation based on response surface methodology (RSM). The optimal conditions for MAE were: extraction solvent 35% ethanol concentration, 500 W microwave power, 60 s irradiation time and a solvent/material ratio of 20 mL g^-1. Under optimal MAE conditions, the recovery of TPC was 25.752 mg GAE per g dw. 19 compounds have been identified by HPLC-ESI-MS/MS analysis; the main compounds identified were chlorogenic acid, rutin and quinic acid esters, such as caffeoylquinic acids and dicaffeoylquinic acids. Additionally, the optimized extract demonstrated potential to inhibit HT29 colorectal cancer cell growth (EC₅₀ = 2.432 μg mL^-1) without presenting cytotoxicity in confluent Caco-2 cells, a model of human intestinal epithelium. These results supply new information about the phenolic composition of Nerium oleander leaves and their antiproliferative effect.

Quercetin attenuated oxidative DNA damage through NRF2 signaling pathway in rats with DMH induced colon carcinogenesis

Accumulating recent studies have demonstrated the preventive and therapeutic effects of polyphonic compounds such as quercetin in colorectal cancer. Therefore, we aimed to evaluate the underlying mechanisms for positive effects of quercetin in rats with 1,2-dimethylhydrazine (DMH)- induced colorectal cancer. For this purpose, male Wistar rats were classified as 6 groups, including group 1 without any intervention, group 2 as quercetin received rats (50 mg/kg), groups 3 as DMH received rats (20 mg/kg) group 4-6 DMH and quercetin received rats. DNA damage, DNA repair, the expression levels and activities of enzymic antioxidants, non-enzymic antioxidants, and NRF2/Keap1 signaling were evaluated in colon tissues of all groups. Our results showed significant suppression of DNA damage and induction of DNA repair in DMH + Quercetin groups, particularly in entire-period in comparison to other groups (p < .05). The expression levels and activities of enzymic and non-enzymic antioxidants were increased in DMH + Quercetin groups (p < .05). Lipid and protein peroxidation were significantly suppressed in DMH + Quercetin groups (p < .05). In addition, quercetin also modulated NRF2/Keap1 signaling and its targets, detoxifying enzymes in DMH + Quercetin groups. Our finding demonstrated that quercetin supplementation effectively reversed DMH-mediated oxidative stress and DNA damage through targeting NRF2/Keap1 signaling pathway.

Assessment of the Antitumor Potentiality of Newly Designed Steroid Derivatives: Pre-Clinical Study

Cancer is recognized as one of the most prevalent contributors to mortality in several nations and it remains one of the common health issues globally. In particular, hepatocellular carcinoma (HCC) has become a public health problem along with the increase of hepatitis B (HBV) and hepatitis C (HCV) virus infections. Based on this fact, our study goaled to synthesize newly hybrid drugs containing heterocyclic rings incorporated to steroid moiety and to examine the potential antitumor activity of the newly designed heterosteroid derivatives against HCC induced in animal model. Several heterocyclic steroids were synthesized 2-7 and confirmed via the analytical and spectral data (IR, ¹H NMR¹³C NMR and Mass spectroscopy). Compounds 3, 4, and 5 were chosen to be investigated as anticancer agents in HCC rat model by means of validated biomarkers (alfa –fetoprotein, endoglin, lipocali-2 and heat shock protein-70). Following administration of compounds 3, 4 or 5, availability of the active tumor marker molecules was significantly dropped and a substantial decrease of the angiogenic and inflammatory mediators was also evident. These findings were supported by the histological examination of liver tissue. Taken together, this study indicates the potential anticancer activity of the newly synthesized heterosteroid derivatives against HCC in vivo. The antitumor activity of these compounds was likely attributable to modulating some signal transduction pathways involved in tumorigenesis, angiogenesis and inflammation.

Cranberry: A Promising Natural Source of Potential Nutraceuticals with Anticancer Activity

Studies have shown that cranberry and its components may exert anticancer properties. The present study aims to critically summarise the existing experimental studies evaluating the potential effects of cranberry on cancer prevention and treatment. PubMed database was searched to identify relevant studies. Current in vitro studies have indicated that cranberry and/or its components may act as chemopreventive agents, diminishing the risk for cancer by inhibiting cells oxidation and inflammatory-related processes, while they may also exert chemotherapeutic effects by inhibiting cell proliferation and angiogenesis, inducing cell apoptosis and attenuating the ability of tumour cells to invade and metastasis. Limited in vivo studies have further documented potential anticancer activity. Cranberry could be considered as a conglomeration of potential effective anticancer druglike compounds.

Quercetin shows anti-tumor effect in hepatocellular carcinoma LM3 cells by abrogating JAK2/STAT3 signaling pathway

Objective

Hepatocellular carcinima is one of the most common tumors in clinic and also one of the leading causes of death from cancer worldwide. Quercetin shows significant effects on blocking the development of various cancers.

Methods

We used the human hepatocellular carcinoma LM3 and nude mice tumor model to assess the effects of quercetin in hepatocellular carcinoma and clarify its mechanism of action. We collected LM3 cell line treated with different doses of quercetin at different time periods and determined the vital indexes. The liver tissues of mice were collected and used for western boltting (WB), Hematoxylin and Eosin (H&E) and TUNEL staining.

Results

Results indicated that quercetin suppressed the Hepatocellular carcinoma (HCC) growth both in vivo and in vitro. Quercetin could disturb LM3 cells proliferation and cell cycle distribution, thus inducing apoptosis. At the same time, quercetin inhibited LM3 cells migration and invasion and promoted HCC autophagy. These effects at least partly depended on the down‐regulation of the activation of JAK2 and STAT3 by quercetin.

Conclusion

Quercetin inhibited hepatocellular carcinoma progression by modulating cell apoptosis, migration, invasion, and autophagy; and its effects were at least partly related with the JAK2/STAT3 signaling pathway.

In Vitro Cytotoxic and Antiproliferative Activity of Cydonia oblonga flower petals, leaf and fruit pellet ethanolic extracts. Docking simulation of the active flavonoids on anti-apoptotic protein Bcl-2

This study aimed to compare in vitro cell cytotoxicity and antiproliferative potency of three standardized ethanolic extracts (5mg GAE/mL sample) from quince flower petals, leaves and fruit pellet on four cell lines (L-929, and HepG2, Caco-2 and BT-20 respectively). Comparative analytical qualitative studies (HPTLC) indicated that if quince leaf extracts (Col40) mainly contain quercetin and kaempferol derivates, the flower petal extracts (Cof40) contain caffeoylquinic acid derivates, while the fruit pellet extracts (Cop40) are comprised of quercetin and caffeoylquinic acid derivates. Pharmacological studies demonstrated the lack of toxicity of test extracts; the most important antiproliferative effects were observed on the hepatic cancer cell line HepG2 (up to 75%, 53% and 70% inhibition in the case of Col40, Cof40 and Cop40 test extracts), followed by the colon cancer cell line Caco-2 (up to 69%, 77% and 40% inhibition) and breast cancer cell line BT-20 (up to 54%, 61% and 19% inhibition). The docking simulations on hyperoside, isoquercitrin, astragalin, and quercetin and kaempferol compared to the synthetic co-crystallized LI0 A1000 ligand (a strong inhibitor of anti-apoptotic protein Bcl-2) indicated astragalin as the most feasible protein inhibitor, but quercetin and kaempferol respected all the parameters involved in the Lipinski rule, making them the most promising antiproliferative candidates.

Impact of heavy metal bioaccumulation on antioxidant activities and DNA profile in two earthworm species and freshwater prawn from Ogun River

The use of freshwater invertebrates as bioindicator of heavy metal pollution is an important tool for environmental biomonitoring. This study investigated antioxidant activities and DNA profile in two limicolous earthworms (Alma millsoni and Libyodrilus violaceus) and freshwater prawns (Macrobrachium vollenhovenii) at selected points of Ogun River, Abeokuta. Heavy metal concentrations and DNA profile in the earthworms and prawn tissues were measured using standard procedures. Zn concentration was higher than other heavy metals in A. millsoni (685.83±114.42mg/kg), L. violaceus (1913.3±1098.7mg/kg) and M. vollenhovenii (134.7±13.61mg/kg). Superoxide dismutase activity ranged from 62.44±7.16-79.82±11.18U/g tissues, 60.26±11.18-71.07±7.54U/g tissues and 74.07±16.69-87.79±8.50U/g tissues in A. millsoni, L. violaceus and M. vollenhovenii respectively. RAPD-PCR revealed varying DNA profile among the earthworms samples; the UPGMA dendrogram formed two distinct clusters at genetic similarity coefficient of 0.15-0.2 with one cluster consisting of Alma millsoni and Libyodrilus violaceus from Sokori, Enugada and Iberekodo sampling points and the second cluster forming two distinct sub-clusters comprising Arakanga and Ago-ika's L. violaceus in one and A. millsoni in the other. High genetic variability was recorded among the earthworm species while the freshwater prawn showed no variability. Antioxidant activities and genetic variability in earthworms could serve as biomarkers of heavy metal pollution in freshwater environment.

Ellagic Acid Holds Promise Against Hepatocellular Carcinoma in an Experimental Model: Mechanisms of Action

This research work was initiated to explore the efficacy of ellagic acid in mitigation of hepatocarcinogenesis in rats. Rats were distributed into 4 groups; negative control, hepatocellular carcinoma (HCC), doxorubicin and ellagic acid. Serum alpha-fetoprotein (AFP), glypican-3 (GPC-3), signal transducer and activator of transcription 3 (STAT3) and suppressors of cytokine signaling 3 (SOCS3) levels were assayed by ELISA. Immunohistochemical examination of hepatic VEGF expression was also conducted, along with histological procedures for examination of liver tissue sections. Significant elevation in serum AFP, GPC-3 and STAT3 levels with a significant drop in SOCS3 were observed in the HCC group. In contrast, the treated groups showed significant decline in serum AFP, GPC-3 and STAT3 levels and significant increase in SOCS3. Additionally, the HCC group declared mild positive immunoreaction for VEGF in hepatocytes while treatment with doxorubicin or ellagic acid was associated with a negative immunoreaction for VEGF. These results were supported by histological examination of liver tissue. The obtained findings suggested that ellagic acid may have beneficial chemopreventive role against hepatocarcinogenesis through its apoptotic, antiangiogenic and antiproliferative activities.

Quercetin improves endothelial function in diabetic rats through inhibition of endoplasmic reticulum stress-mediated oxidative stress

Endoplasmic reticulum (ER) stress attributes a crucial role in diabetes-induced endothelial dysfunction. The present study investigated the effects of quercetin, a potent antioxidant on the attenuation of ER stress-modulated endothelial dysfunction in streptozotocin (STZ)-induced diabetic rats. Oral administration of quercetin for six weeks to diabetic rats dose-dependently reduced the blood glucose levels and improved insulin secretion. Histopathological examination of pancreatic tissues in diabetic rats showed pathological changes such as shrunken islets, reduction in islet area and distorted β-cells, which were found to be restored by quercetin treatment. In addition, quercetin reduced the pancreatic ER stress-induced endothelial dysfunction as assessed by immunohistochemical analysis of C/ERB homologous protein (CHOP) and endothelin-1 (ET-1). Moreover, quercetin administration progressively increased the expression of vascular endothelial growth factor (VEGF) and its receptor, VEGFR2 in diabetes rats. Quercetin-mediated decrease in the nitric oxide (NO∙) and cyclic 3',5'- guanosine monophosphate (cGMP) levels were also observed in the diabetic rats. Quercetin treatment reduced the lipid peroxidation in the diabetic rats, meanwhile increased the total antioxidant capacity in the pancreas from diabetic rats. Altogether, these results demonstrated the vasoprotective effect of quercetin against STZ-induced ER stress in the pancreas of diabetic rats.

New insights for the use of quercetin analogs in cancer treatment

AIM

Quercetin (Q1) is a flavonoid widely present in plants and endowed with several pharmacological properties mostly due to its antioxidant potential. Q1 shows anticancer activity and could be useful in cancer prevention. On the other hand, Q1 is poorly soluble in water and unstable in physiological systems, and its bioavailability is very low.

METHODS

A small set of Q1 derivatives (Q2-Q9) has been synthesized following opportunely modified chemical procedures previously reported. Anticancer activity has been evaluated by MTT assay. Human Topoisomerases inhibition has been performed by direct enzymatic assays. Apoptosis has been evaluated by TUNEL assay. ROS production and scavenging activity have been determined by immunofluorescence.

RESULTS

The anticancer profile of a small library of Q1 analogues, in which the OH groups were all or partially replaced with hydrophobic functional groups, has been evaluated. Two of the studied compounds demonstrated an interesting cytotoxic profile in two breast cancer models showing the capability to inhibit human Topoisomerases.

CONCLUSION

The studied compounds represent suitable leads for the development of innovative anticancer drugs. [Formula: see text].

Cytotoxicity, Oxidative Stress, Cell Cycle Arrest, and Mitochondrial Apoptosis after Combined Treatment of Hepatocarcinoma Cells with Maleic Anhydride Derivatives and Quercetin

The inflammatory condition of malignant tumors continually exposes cancer cells to reactive oxygen species, an oxidizing condition that leads to the activation of the antioxidant defense system. A similar activation occurs with glutathione production. This oxidant condition enables tumor cells to maintain the energy required for growth, proliferation, and evasion of cell death. The objective of the present study was to determine the effect on hepatocellular carcinoma cells of a combination treatment with maleic anhydride derivatives (prooxidants) and quercetin (an antioxidant). The results show that the combination of a prooxidant/antioxidant had a cytotoxic effect on HuH7 and HepG2 liver cancer cells, but not on either of two normal human epithelial cell lines or on primary hepatocytes. The combination treatment triggered apoptosis in hepatocellular carcinoma cells by activating the intrinsic pathway and causing S phase arrest during cell cycle progression. There is also clear evidence of a modification in cytoskeletal actin and nucleus morphology at 24 and 48 h posttreatment. Thus, the current data suggest that the combination of two anticarcinogenic drugs, a prooxidant followed by an antioxidant, can be further explored for antitumor potential as a new treatment strategy.

CS-PEG decorated PLGA nano-prototype for delivery of bioactive compounds: A novel approach for induction of apoptosis in HepG2 cell line

PURPOSE

Polymer-based nanoparticles are used as vectors for cancer drug delivery. The bioactive compounds (quercetin, ellagic acid and gallic acid) are well known to be not only antioxidants but also chemopreventive candidates against various types of cancers. To circumvent the low bioavailability and the short half-life time obstacles, we hypothesized a novel PLGA nano-platform functionalized with CS and PEG to encapsulate these phytochemicals. This encapsulation will protect the compounds from the phagocytic uptake and deliver PLGA-CS-PEG nano-prototype with high biodegradability and biosafety.

MATERIALS AND METHODS

Three consequent types of PLGA-based nanocomposites were prepared and characterized. Furthermore, we investigated the newly synthesized nano-formulations against human hepatocellular carcinoma (HepG2) and colorectal cancer (HCT 116) cell lines using cell growth inhibition assays, followed by apoptosis and necrosis assays using flow cytometry to detect the underlying mechanism of HepG2 cell death.

RESULTS

Through Malvern Zeta Sizer, we recorded that the average diameters of the nano-prototypes ranged from 150 to 300nm. The cytotoxic activity of quercetin, ellagic acid, and gallic acid-encapsulated PLGA, PLGA-CS, and PLGA-CS-PEG nano-prototypes it has been found that they reduce the IC50s of the HepG2 cells values by 2.2, 2.9, 2.8-folds, 1, 1.5, 2.7-folds, and 0.9, 0.7, 1.5-folds, respectively. Mechanistically, the nano-platforms of quercetin seem to be dependent on both apoptosis and necrosis, while those of ellagic acid and gallic acid are mainly dependent on apoptosis.

CONCLUSIONS

CS-PEG-blended PLGA nano-delivery system of quercetin, ellagic acid and gallic acid can potentiate apoptosis-mediated cell death in HepG2 cell line.

Gallic acid against hepatocellular carcinoma: An integrated scheme of the potential mechanisms of action from in vivo study

The global burden of hepatocellular carcinoma is increasing; actually, it is estimated as 750,000 new cases annually. This study was initiated to emphasize the possibility that gallic acid could alleviate hepatocarcinogenesis in vivo. In this study, 40 rats were enrolled and distributed as follows; group 1 was set as negative control, while all of groups 2, 3, and 4 were orally received N-nitrosodiethylamine for hepatocellular carcinoma induction. Group 2 was left untreated, whereas groups 3 and 4 were orally treated with gallic acid and doxorubicin, respectively. The current data indicated that gallic acid administration in hepatocellular carcinoma bearing rats yielded significant decline in serum levels of alpha-fetoprotein, glypican-3, and signal transducer and activator of transcription 3 along with significant enhancement in serum suppressors of cytokine signaling 3 level. Also, gallic acid-treated group displayed significant downregulation in the gene expression levels of hepatic gamma glutamyl transferase and heat shock protein gp96. Intriguingly, treatment with gallic acid remarkably ameliorated the destabilization of liver tissue architecture caused by N-nitrosodiethylamine intoxication as evidenced by histopathological investigation. In conclusion, this study demonstrates that the hepatocarcinogenic effect of N-nitrosodiethylamine can be abrogated by gallic acid supplementation owing to its affinity to regulate signal transducer and activator of transcription 3 signaling pathway through its outstanding bioactivities including antioxidant, anti-inflammatory, apoptotic, and antitumor effects.

Quercetin Reverses Rat Liver Preneoplastic Lesions Induced by Chemical Carcinogenesis

Quercetin is a flavonoid widely studied as a chemopreventive agent in different types of cancer. Previously, we reported that quercetin has a chemopreventive effect on the liver-induced preneoplastic lesions in rats. Here, we evaluated if quercetin was able not only to prevent but also to reverse rat liver preneoplastic lesions. We used the modified resistant hepatocyte model (MRHM) to evaluate this possibility. Treatment with quercetin was used 15 days after the induction of preneoplastic lesions. We found that quercetin reverses the number of preneoplastic lesions and their areas. Our results showed that quercetin downregulates the expression of EGFR and modulates this signaling pathway in spite of the activated status of EGFR as detected by the upregulation of this receptor, with respect to that observed in control rats. Besides, quercetin affects the phosphorylation status of Src-1, STAT5, and Sp-1. The better status of the liver after the treatment with quercetin could also be confirmed by the recovery in the expression of IGF-1. In conclusion, we suggest that quercetin reversed preneoplastic lesions by EGFR modulation and the activation state of Src, STAT5, and Sp1, so as the basal IGF-1.

Hepatoprotective activity of Butea monosperma bark against thioacetamide-induced liver injury in rats

For thousands of years, the plant-based natural products have been a source of curative agents for various ailments. Butea monosperma (Fabaceae) has an important place in Indian traditional system of medicine for curing number of disorders. The present study deals with evaluation of hepatoprotective properties of ethyl acetate fraction (Beac) from B. monosperma bark in rat model. In preliminary antioxidant studies, Beac demonstrated pronounced superoxide scavenging (IC₅₀ 88.85μg/ml) and anti-lipid peroxidation (IC₅₀ 131.66μg/ml) potential. In animal studies, Beac showed protective effect against thioacetamide-induced pathophysiology in liver of male Wistar rats. The levels of different parameters related to hepatic functions were altered by thioacetamide treatment (300mg/g bw) in rats. The pre-treatment of rats with Beac (50, 100 and 200mg/kg bw) was able to normalize the biochemical markers viz. serum bilirubin, SGOT, SGPT, albumin and ALP along with liver antioxidative molecules viz. SOD, CAT, GSH and GR. Results of histopathological and colorimetric studies revealed that Beac treatment also restored the markers of fibrosis i.e. collagen and hydroxyproline towards normal level. Beac considerably inhibited thioacetamide-induced expression of p-PI3K, p-Akt and p-mTOR in hepatocytes as revealed from immunohistochemical studies. This finding is the first evidence of inhibitory action of B. monosperma bark on these pro-carcinogenic proteins. HRMS analysis revealed the presence of quercetin, buteaspermin B and ononin in Beac fraction of Butea monosperma. From the results, it can be concluded that B. monosperma bark is a rich source of phytochemicals with in vitro and in vivo protective activities which deserves further mechanistic studies for its use as a hepatoprotective agent in the prevention of hepatic inflammation and its related malignancies.

Spectroscopic study of molecular structure, antioxidant activity and biological effects of metal hydroxyflavonol complexes

Flavonols with varied hydroxyl substitution can act as strong antioxidants. Thanks to their ability to chelate metals as well as to donate hydrogen atoms they have capacity to scavenge free radicals. Their metal complexes are often more active in comparison with free ligands. They exhibit interesting biological properties, e.g. anticancer, antiphlogistic and antibacterial. The relationship between molecular structure and their biological properties was intensively studied using spectroscopic methods (UV-Vis, IR, Raman, NMR, ESI-MS). The aim of this paper is review on spectroscopic analyses of molecular structure and biological activity of hydroxyflavonol metal complexes.

Anticancer Efficacy of Polyphenols and Their Combinations

Polyphenols, found abundantly in plants, display many anticarcinogenic properties including their inhibitory effects on cancer cell proliferation, tumor growth, angiogenesis, metastasis, and inflammation as well as inducing apoptosis. In addition, they can modulate immune system response and protect normal cells against free radicals damage. Most investigations on anticancer mechanisms of polyphenols were conducted with individual compounds. However, several studies, including ours, have indicated that anti-cancer efficacy and scope of action can be further enhanced by combining them synergistically with chemically similar or different compounds. While most studies investigated the anti-cancer effects of combinations of two or three compounds, we used more comprehensive mixtures of specific polyphenols and mixtures of polyphenols with vitamins, amino acids and other micronutrients. The mixture containing quercetin, curcumin, green tea, cruciferex, and resveratrol (PB) demonstrated significant inhibition of the growth of Fanconi anemia head and neck squamous cell carcinoma and dose-dependent inhibition of cell proliferation, matrix metalloproteinase (MMP)-2 and -9 secretion, cell migration and invasion through Matrigel. PB was found effective in inhibition of fibrosarcoma HT-1080 and melanoma A2058 cell proliferation, MMP-2 and -9 expression, invasion through Matrigel and inducing apoptosis, important parameters for cancer prevention. A combination of polyphenols (quercetin and green tea extract) with vitamin C, amino acids and other micronutrients (EPQ) demonstrated significant suppression of ovarian cancer ES-2 xenograft tumor growth and suppression of ovarian tumor growth and lung metastasis from IP injection of ovarian cancer A-2780 cells. The EPQ mixture without quercetin (NM) also has shown potent anticancer activity in vivo and in vitro in a few dozen cancer cell lines by inhibiting tumor growth and metastasis, MMP-2 and -9 secretion, invasion, angiogenesis, and cell growth as well as induction of apoptosis. The presence of vitamin C, amino acids and other micronutrients could enhance inhibitory effect of epigallocatechin gallate (EGCG) on secretion of MMPs. In addition, enrichment of NM with quercetin (EPQ mix) enhanced anticancer activity of NM in vivo. In conclusion, polyphenols, especially in combination with other polyphenols or micronutrients, have been shown to be effective against multiple targets in cancer development and progression, and should be considered as safe and effective approaches in cancer prevention and therapy.

A possible therapeutic potential of quercetin through inhibition of μ-calpain in hypoxia induced neuronal injury: a molecular dynamics simulation study

The neuroprotective property of quercetin is well reported against hypoxia and ischemia in past studies. This property of quercetin lies in its antioxidant property with blood-brain barrier permeability and anti-inflammatory capabilities. µ-Calpain, a calcium ion activated intracellular cysteine protease causes serious cellular insult, leading to cell death in various pathological conditions including hypoxia and ischemic stroke. Hence, it may be considered as a potential drug target for the treatment of hypoxia induced neuronal injury. As the inhibitory property of µ-calpain is yet to be explored in details, hence, in the present study, we investigated the interaction of quercetin with µ-calpain through a molecular dynamics simulation study as a tool through clarifying the molecular mechanism of such inhibition and determining the probable sites and modes of quercetin interaction with the µ-calpain catalytic domain. In addition, we also investigated the structure-activity relationship of quercetin with μ-calpain. Affinity binding of quercetin with µ-calpain had a value of -28.73 kJ/mol and a Ki value of 35.87 µM that may be a probable reason to lead to altered functioning of µ-calpain. Hence, quercetin was found to be an inhibitor of µ-calpain which might have a possible therapeutic role in hypoxic injury.

Quercetin induces cell death by caspase-dependent and p38 MAPK pathway in EGFR mutant lung cancer cells

Objectives The aim of this study was whether quercetin induces cell death by caspase and MAPK signaling pathway in EGFR mutant lung cancer cells Methods PC-9 cells, EGFR mutant lung cancer cells, were treated various times and concentrations of quercetin and harvested and measured using MTT assay, DNA fragmentation, Western blotting, and FACS analysis. Results Treatment with quercetin in PC-9 cells resulted in inhibition of cell growth through apoptosis. Quercetin-induced apoptosis was associated with caspase-dependent manner. Quercetin also significantly increased levels of phosphor-p38 and decreased levels of phosphor-ERK, indicating that quercetin induces p38 MAPK signaling pathway in PC-9 cells. Quecetin treatment also generated the release of cytochrome c in PC-9 cells; however, pretreatment with rotenone or z-LEHD-fmk, significantly attenuated quercetin-induced apoptosis. Conclusions Our data indicate that quercetin exhibits EGFR mutant lung cancer effects through apoptosis by caspase dependent and mitochondrial pathway.

New Approach for Treatment of Primary Liver Tumors: The Role of Quercetin

Hepatocellular carcinoma (HCC) is the most common primary liver tumor (PLT), with cholangiocarcinoma (CC) being the second most frequent. Glucose transporter 1 (GLUT-1) expression is increased in PLTs and therefore it is suggested as a therapeutic target. Flavonoids, like quercetin, are GLUT-1 competitive inhibitors and may be considered as potential therapeutic agents for PLTs. The objective of this study was evaluation of quercetin anticancer activity in three human HCC cell lines (HepG2, HuH7, and Hep3B2.1-7) and in a human CC cell line (TFK-1). The possible synergistic effect between quercetin and sorafenib, a nonspecific multikinase inhibitor used in clinical practice in patients with advanced HCC, was also evaluated. It was found that in all the cell lines, quercetin induced inhibition of the metabolic activity and cell death by apoptosis, followed by increase in BAX/BCL-2 ratio. Treatment with quercetin caused DNA damage in HepG2, Hep3B2.1-7, and TFK-1 cell lines. The effect of quercetin appears to be independent of P53. Incubation with quercetin induced an increase in GLUT-1 membrane expression and a consequent reduction in the cytoplasmic fraction, observed as a decrease in (18)F-FDG uptake, indicating a GLUT-1 competitive inhibition. The occurrence of synergy when sorafenib and quercetin were added simultaneously to HCC cell lines was noticed. Thus, the use of quercetin seems to be a promising approach for PLTs through GLUT-1 competitive inhibition.

Significance of Rumex vesicarius as anticancer remedy against hepatocellular carcinoma: a proposal-based on experimental animal studies

Rumex vesicarius is an edible herb distributed in Egypt and Saudi Arabia. The whole plant has significant value in folk medicine and it has been used to alleviate several diseases. Hepatocellular carcinoma (HCC), the major primary malignant tumor of the liver, is one of the most life-threatening human cancers. The goal of the current study was to explore the potent role of Rumex vesicarius extract against HCC induced in rats. Thirty adult male albino rats were divided into 3 groups: (I): Healthy animals received orally 0.9% normal saline and served as negative control group, (II): HCC group in which rats were orally administered N-nitrosodiethylamine NDEA, (III): HCC group treated orally with R. vesicarius extract in a dose of 400 mg/kg b.wt daily for two months. ALT and AST, ALP and γ-GT activities were estimated. CEA, AFP, AFU, GPC-3, Gp-73 and VEGF levels were quantified. Histopathological examination of liver tissue sections was also carried out. The results of the current study showed that the treatment of the HCC group with R. vesicarius extract reversed the significant increase in liver enzymes activity, CEA, AFP, AFU, glypican 3, golgi 73 and VEGF levels in serum as compared to HCC-untreated counterparts. In addition, the favorable impact of R. vesicarius treatment was evidenced by the marked improvement in the histopathological features of the liver of the treated group. In conclusion, the present experimental setting provided evidence for the significance of R. vesicarius as anticancer candidate with a promising anticancer potential against HCC. The powerful hepatoprotective properties, the potent antiangiogenic activity and the effective antiproliferative capacity are responsible for the anticancer effect of this plant.

Hydrophobic Interactions Are a Key to MDM2 Inhibition by Polyphenols as Revealed by Molecular Dynamics Simulations and MM/PBSA Free Energy Calculations

p53, a tumor suppressor protein, has been proven to regulate the cell cycle, apoptosis, and DNA repair to prevent malignant transformation. MDM2 regulates activity of p53 and inhibits its binding to DNA. In the present study, we elucidated the MDM2 inhibition potential of polyphenols (Apigenin, Fisetin, Galangin and Luteolin) by MD simulation and MM/PBSA free energy calculations. All polyphenols bind to hydrophobic groove of MDM2 and the binding was found to be stable throughout MD simulation. Luteolin showed the highest negative binding free energy value of -173.80 kJ/mol followed by Fisetin with value of -172.25 kJ/mol. It was found by free energy calculations, that hydrophobic interactions (vdW energy) have major contribution in binding free energy.

Coexistence of Aflatoxicosis with Protein Malnutrition Worsens Hepatic Oxidative Damage in Rats

To investigate the effects of the coexistence of aflatoxin B1 (AFB1) and protein malnutrition in rat liver, weanling rats were fed either normal protein diet (20% protein), low-protein (PEM) diet (5%), normal protein diet + 40 ppb AFB1, or low-protein diet + 40 ppb AFB1. After 8 weeks, biomarkers of hepatic functions and oxidative stress, caspase-3 activity, and tumor suppressor protein 53 (p53) were determined spectrophotometrically. Randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) was employed to determine genomic alterations among the groups. Coexistence of aflatoxicosis and PEM significantly decreased glutathione, glutathione-S-transferase, glutathione peroxidase, and superoxide dismutase, while it increased peroxidase and catalase. RAPD-PCR showed genomic alterations that were associated with significant increases in p53 level and caspase-3 activity in rats fed PEM diet + AFB1. In conclusion, the coexistence of aflatoxicosis and protein malnutrition induced oxidative stress with concomitant genomic alterations in the liver of weanling rats.

Quercetin and Tryptanthrin: Two Broad Spectrum Anticancer Agents for Future Chemotherapeutic Interventions

The idea and practice of developing or identifying compounds capable of eliminating the transformed cells or cancer cells without being nontoxic to their normal counterparts deserves much importance. Since ages, plants have been considered and proven to be repertoires of chemicals possessing immense therapeutic potential. A proportion of these plant-derived compounds or phytochemicals were shown to be highly competent anticancer agents besides being effective against many other diseases. Representative compounds of different classes of phytochemicals are in clinical use against cancer. In this chapter, we discuss the anticancer potential of two compounds: quercetin, a flavonoid and tryptanthrin, an indoloquinazoline alkaloid, and the mechanisms behind their cytotoxic effects on cancers of different origin. The chapter also gives a brief mention of their properties that make them effective against cancer.

Protective effect of quercetin on melphalan-induced oxidative stress and impaired renal and hepatic functions in rat

One major challenge with the use of anticancer agents is the phenomenon of drug-induced toxicity. Melphalan (MPLN) is an alkylating anticancer agent, while quercetin (QCT) is an antioxidant. We investigated the protective role of quercetin against MPLN-induced toxicity. Twenty-five male Wistar rats (160-170 g) were randomized into five treatment groups; (I) control, (II) MPLN (0.2 mg/kg b.w.), (III) pre-treated with QCT (20 mg/kg b.w.) for 7 days followed by MPLN (0.2 mg/kg b.w.) for 7 days, (IV) cotreated with QCT (20 mg/kg b.w.) and MPLN (0.2 mg/kg b.w.) for 7 days, and (V) QCT (20 mg/kg b.w.) alone. MPLN caused a significant increase in plasma bilirubin, urea, and creatinine by 122.2%, 102.3%, and 188%, respectively (P < 0.05). Similarly, plasma ALP, ALT, AST, and γ-GT activities increased significantly by 57.9%, 144.3%, 71.3%, and 307.2%, respectively, relative to control. However, pre or cotreatment with QCT ameliorated the levels of renal and hepatic function indices. Hepatic ascorbic acid and GSH and activities of glutathione-S-transferase, SOD, and catalase decreased significantly by 36.2%, 188%, 46.5%, 34.4%, and 55.2%, respectively, followed by increase in MDA content by 46.5% relative to control. Pre- and cotreatment with QCT reestablished the hepatic antioxidant status and lipid peroxidation. Overall, quercetin protected against MPLN-induced renal and hepatic toxicity in rats.

Kolaviron and L-ascorbic Acid attenuate chlorambucil-induced testicular oxidative stress in rats

Chlorambucil (4-[4-[bis(2-chloroethyl)amino]phenyl]butanoic acid) is an alkylating agent, indicated in chronic lymphocytic leukaemia. Kolaviron (KV), a biflavonoid complex from Garcinia kola, and L-ascorbic acid (AA) are known to protect against oxidative damage in vivo. This study evaluates the protective capacity of KV and AA on chlorambucil-induced oxidative stress in the testes of rat. Twenty male Wistar rats (180–200 g) were randomized into four groups: I: control, II: chlorambucil (0.2 mg/kg b.w.), III: 0.2 mg/kg chlorambucil and 100 mg/kg KV, and IV: 0.2 mg/kg chlorambucil and 100 mg/kg AA. After 14 days of treatments, results indicated that chlorambucil caused significant reduction (P < 0.05) in testicular vitamin C and glutathione by 32% and 39%, respectively, relative to control. Similarly, activities of testicular GST, SOD, and CAT reduced significantly by 48%, 47%, and 49%, respectively, in chlorambucil-treated rats relative to control. Testicular MDA and activities of ALP, LDH, and ACP were increased significantly by 53%, 51%, 64%, and 70%, respectively, in the chlorambucil-treated rat. However, cotreatment with KV and AA offered protection and restored the levels of vitamin C, GSH, and MDA as well as SOD, CAT, GST, ACP, ALP, and LDH activities. Overall, kolaviron and L-ascorbic acid protected against chlorambucil-induced damage in the testes of the rat.