Inhibition of azoxymethane-induced colon cancer by orange juice

Virtual screening indicates potential inhibitors of the P2X7 receptor

Anti-inflammatory agents can be synthetic or natural compounds and are often used to attenuate different levels of inflammation. Inflammatory diseases, due to the involvement of multiple systems, are becoming difficult to treat, involve long durations of therapy where applicable, have a high cost of management and have a deleterious impact on public health. The search for natural and synthetic compounds with anti-inflammatory activity is an important strategy in drug design. Bioactive synthetic drugs may be repurposed for other pharmacological applications, and natural product chemical structures offer unlimited opportunities for new drug discoveries due to the unparalleled availability of chemical diversity. Virtual screening of 2774 molecules on the mouse P2X7 protein showed that potential ligands are composed of five flavonoids (narirutin, diosmin, complanatuside, hesperidin, and oroxin B) and other drugs such as velpatasvir, itacitinib and lifitegrast. In vitro studies in mouse cells confirmed the inhibitory activity of the indicated ligands on the P2X7 receptor by applying virtual screening. The behavior of protein bonded to the ligands was verified by analysis of the molecular dynamic simulation trajectories for four of the most potent inhibitor compounds, indicating that the ligands velpatasvir, itacitinib, lithospermic acid and narirutin remained in the binding site indicated by molecular docking.

Investigation of the Genotoxicological Profile of Aqueous Betula pendula Extracts

Betula pendula belongs to the Betulaceae family and is most common in the northern hemisphere. Various birch species have exhibited antimicrobial, antioxidant and anticancer properties. In the present study, we investigated the genotoxic and cytotoxic activity as well as the antigenotoxic potential against the mutagenic agent mitomycin-C (MMC) of two commercial products, i.e., a Betula pendula aqueous leaf extract product (BE) and a Betula pendula product containing aqueous extract of birch leaves at a percentage of 94% and lemon juice at a percentage of 6% (BP) using the cytokinesis block micronucleus (CBMN) assay. The most prevalent compounds and elements of BE and BP were identified using UHPLC-MS and ICP-MS/MS, respectively. All mixtures of BE with MMC demonstrated a decrease in the MN frequencies, with the lowest and highest concentrations inducing a statistically significant antigenotoxic activity. BP lacked genotoxic potential, while it was cytotoxic in all concentrations. Its mixtures with MMC demonstrated statistically significant antigenotoxic activity only at the lowest concentration. UHPLC-MS and ICP-MS/MS showed the presence of various elements and phytochemicals. Our results reveal antigenotoxic and cytotoxic potential of both BE and BP, while the variations observed could indicate the importance of the interactions among different natural products and/or their compounds.

Phytochemicals in Chemoprevention: A Cost-Effective Complementary Approach

Cancer is one of the leading causes of death across the world. Although conventional cancer treatments such as chemotherapy and radiotherapy have effectively decreased cancer progression, they come with many dose-limiting side-effects. Phytochemicals that naturally occur in spices, fruits, vegetables, grains, legumes, and other common foods are surprisingly effective complements to conventional cancer treatments. These biologically active compounds demonstrate anticancer effects via cell signaling pathway interference in cancerous cells. In addition, phytochemicals protect non-cancerous cells from chemotherapy-induced side-effects. This paper addresses the not only the potential of phytochemicals quercetin, isoflavones, curcumin, catechins, and hesperidin in terms of cancer treatment and protection against side-effects of chemotherapy, but also methods for increasing phytochemical bioavailability.

A comparative metabolomics analysis of the halophyte Suaeda salsa and Salicornia europaea

Suaeda salsa and Salicornia europaea are both annual herbaceous species belonging to the Chenopodiaceae family, and often grow together through our observations in the Yellow River Delta Nature Reserve, and could be used as raw material to produce food and beverages in food industry due to its high nutritional value. In this study, we adopted widely targeted metabolomics to identify 822 and 694 metabolites in the leaves of S. salsa and S. europaea, respectively, to provide a basic data for the future development and utilization of these two species. We found that these two plants were rich in metabolic components with high medical value, such as flavonoids, alkaloids and coumarins. The high contents of branched chain amino acid in these two species may be an important factor for their adaptation to saline-alkali environments. In addition, the contents of glucosamine (FC = 7.70), maltose (FC = 9.34) and D-(+)-sucrose (FC = 7.19) increased significantly, and the contents of D-(+)-glucose, 2-propenyl (sinigrin) and fructose 1-phosphate were significantly increased in the leaves of S. salsa compared to S. europaea, indicating that some certain compounds in different plants have different sensitivity to salt stress. Our work provides new perspectives about important second metabolism pathways in salt tolerance between these two plants, which could be helpful for studying the tolerance mechanisms of wetland plants.

Use of Nanovesicles from Orange Juice to Reverse Diet-Induced Gut Modifications in Diet-Induced Obese Mice

We have determined whether orange juice-derived nanovesicles (ONVs) could be used for the treatment of obesity-associated intestinal complications. ONVs were characterized by lipidomic, metabolomic, electron microscopy. In vitro, intestinal barriers (IBs = Caco-2+HT-29-MTX) were treated with ONVs and co-cultured with adipocytes to monitor IB fat release. In vivo, obesity was induced with a high-fat, high-sucrose diet (HFHSD mice) for 12 weeks. Then, half of HFHSD mice were gavaged with ONVs. One-month ONV treatment did not modify HFHSD-induced insulin resistance but reversed diet-induced gut modifications. In the jejunum, ONVs increased villi size, reduced triglyceride content, and modulated mRNA levels of genes involved in immune response (tumor necrosis factor [TNF]-α and interleukin [IL]-1β), barrier permeability (CLDN1, OCLN, ZO1), fat absorption, and chylomicron release. ONVs targeted microsomal triglyceride transfer protein (MTP) and angiopoietin-like protein-4 (ANGPTL4), two therapeutic targets to reduce plasma lipids and inflammation in gastrointestinal diseases. Interestingly, ONV treatment did not aggravate liver steatosis, as MTP mRNA was increased in the liver. Therefore, ONVs protected both intestine and the liver from fat overload associated with the HFHSD. As ONVs concentrated amino acids and bioactive lipids versus orange juice, which are deficient in obese patients, the use of ONVs as a dietary supplement could bring physiological relevant compounds in the jejunum to accelerate the restoration of intestinal functions during weight loss in obese patients.

Chemopreventive effect of hesperidin, a citrus bioflavonoid in two stage skin carcinogenesis in Swiss albino mice

The cancer-protective ability of hesperidin was investigated on 7, 12-dimethylbenz[a]anthracene (DMBA) and 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced skin carcinogenesis in Swiss albino mice. Topical application of DMBA+TPA on mice skin led to 100% tumour incidence and rise in average number of tumours. Administration of different doses of hesperidin (HPD) before (pre) or after (post) and continuous (pre and post) DMBA application significantly reduced tumour incidence and average number of tumours in comparison to DMBA+TPA treatment alone. Topical application of DMBA+TPA increased oxidative stress as shown by significantly increased TBARS values and reduced glutathione contents, and glutathione-S-transferase, superoxide dismutase and catalase activities. Hesperidin treatment significantly reduced TBARS values and elevated glutathione concentration and glutathione-S-transferase, superoxide dismutase and catalase activities in the skin/tumors of mice treated with HPD+DMBA+TPA, HPD+DMBA+TPA+HPD or DMBA+TPA+HPD when compared to DMBA+TPA application alone. The study of molecular mechanisms showed that hesperidin suppressed expression of Rassf7, Nrf2, PARP and NF-κB in a dose dependent manner with a maximum inhibition at the level of 300 mg/kg body weight hesperidin. In conclusion, oral administration of hesperidin protected mice against chemical carcinogenesis by increasing antioxidant status, reducing DMBA+TPA induced lipid peroxidation and inflammatory response, and repressing of Rassf7, Nrf2, PARP and NF-κB levels.

Synthesis of hesperetin-loaded PLGA nanoparticles by two different experimental design methods and biological evaluation of optimized nanoparticles

Hesperetin was effectively encapsulated into poly (d,l-lactic-co-glycolic acid) nanoparticles by using experimental design methods. A seven-factor Plackett-Burman design was used in order to determine the major process parameters. A significant linear equation, which shows the effect of each process parameter on encapsulation efficiency was developed, and then the most effective factors were determined. Further investigation and optimization was carried out by applying the three-factor three-level Box-Behnken design. Significant second-order mathematical models were developed by regression analysis of the experimental data for both responses: encapsulation efficiency and nanoparticle size. The two step experimental design allowed the synthesis of the desired nanoparticle formulations with maximum encapsulation efficiency (80.5 ± 4.9%) and minimum particle size (260.2 ± 16.5 nm) at optimum process conditions: 0.5% polyvinyl alcohol (PVA) concentration, 5.13 water:organic phase ratio, and 3.59 ml min^-1 flow rate of the emulsified solution into 0.1% PVA. Furthermore, the biological activity of these optimized nanoparticles were determined with antimicrobial activity and cytotoxicity studies; results were then compared to the free hesperetin. The cytotoxicity result revealed that hesperetin and hesperetin-loaded nanoparticles were biocompatible with normal cell line L929 fibroblast cells up to 184.83 and 190.88 μg ml^-1 for 24 h, and up to 133.24 and 134.80 μg ml^-1 for 48 h, respectively. In the antimicrobial study, the optimized nanoparticle showed inhibition activity (minimal inhibitory concentration (MIC) values were 125 μg ml^-1 for Escherichia coli, and 200 μg ml^-1 for Staphylococcus aureus), while the free hesperetin did not demonstrate activity in both strains (MIC value >200 μg ml^-1). These in vitro results may provide useful information for the investigation of hesperetin-loaded nanoparticles in diagnostic and therapeutic applications.

Citrus fruits intake and oral cancer risk: A systematic review and meta-analysis

OBJECTIVE

To quantify the relationship between Citrus intake and risk of cancer of the oral cavity and pharynx.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Ovid MEDLINE, EMBASE, and Web of Science were searched until September 2017. Search terms included Citrus, Citrus aurantifolia, Citrus sinensis, Citrus paradisi, Citrus fruits, Citrus fruits extract, Citrus oil, fruits, oral cancer, mouth cancer, mouth neoplasm.

STUDY SELECTION

The selection of studies and the systematic review were carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A pre-defined inclusion checklist resulted in the inclusion of articles which were (i) published in peer-reviewed scientific journals; (ii) English language; (iii) and included a measure of Citrus fruit intake and risk of oral and pharyngeal cancer. Studies were excluded if (i) preparations derived from other fruits were used, (ii) Citrus intake was combined with intake of other fruits; (iii) in vitro or animal models were used. We also excluded reviews, systematic reviews, meta-analyses, letters, personal opinions, conference abstracts and book chapters.

DATA EXTRACTION

Three reviewers independently performed the extraction of data from studies included.

RESULTS

Seventeen studies met our inclusion criteria and were included in the final review. Pooled analyses showed that those with the highest Citrus fruit intake compared to the lowest intake had a 50% reduction in risk of oral cavity and pharyngeal cancer (OR 0.50; 95% CI 0.43-0.59).

CONCLUSION

The studies included in this review and meta-analysis showed an inverse association between Citrus fruit intake and oral cancer.

Protective effect of bioaccessible fractions of citrus fruit pulps against H2O2-induced oxidative stress in Caco-2 cells

Fruit pulps from Navel (N) and Cara Cara (CC) oranges, and Clementine mandarin freshly harvested (M) and refrigerated stored (M12) were used to evaluate the cytoprotective effect of their bioaccessible fractions (BF) against H₂O₂-induced oxidative stress in Caco-2 cells. BF of samples preserved viability vs. H₂O₂ treated cells, reaching values similar to controls. Lipid peroxidation was reduced to levels of control cells, but M did not reach control values. ROS and mitochondrial membrane potential changes (Δψ_m) values were reduced compared with H₂O₂ treated cells, but without achieving control levels. A significant reduction in cell proportions in G1 phase and a significant increase in sub-G1 phase (apoptosis) of cell cycle was shown in H₂O₂ treated cells, and BF allowed a recovery close to control levels. Thus, BF of samples protect the cells from oxidative stress by preserving cell viability, mitochondrial membrane potential and correct cell cycle progression, and diminishing lipid peroxidation and ROS.

Anticancer Potential of Citrus Juices and Their Extracts: A Systematic Review of Both Preclinical and Clinical Studies

Background: During the last decades, a huge body of evidence has been accumulated suggesting that Citrus fruits and their juices might have a role in preventing many diseases including cancer.

Objective: To summarize the numerous evidences on the potential of Citrus juices and their extracts as anticancer agents.

Data sources: A systematic review of articles written in English using MEDLINE (1946-present), EMBASE (1974-present) and Web of Sciences (1970-present) was performed independently by two reviewers. Search terms included Citrus, Citrus aurantifolia, Citrus sinensis, Citrus paradisi, Citrus fruits, Citrus fruits extract, cancer, neoplasm, neoplasia, tumor, metastasis, carcinogenesis, proliferation. The last search was performed on March 16th, 2017.

Study selection: Study selection and systematic review were carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Prior to the beginning of the review, Authors defined a checklist for inclusion criteria, thus including articles which meet the following: (i) published on peer-reviewed scientific journals; (ii) Citrus juice used alone; (iii) extracts derived from Citrus juice; (iii) for preclinical studies, an exposure time to Citrus juices and their extracts more than 24 h. Reviews, meta-analyses, conference abstracts and book chapters were excluded.

Data extraction: Three reviewers independently performed the extraction of articles.

Data synthesis: 22 papers met our inclusion criteria and were eligible for inclusion in the final review. According to the kind of study, the selected ones were further divided in preclinical (n = 20) and observational (n = 2) studies.

Conclusion: The studies discussed in this review strongly corroborate the role of Citrus juices and their derivatives as potential resource against cancer.

Chemopreventive Agents and Inhibitors of Cancer Hallmarks: May Citrus Offer New Perspectives?

Fruits and vegetables have long been recognized as potentially important in the prevention of cancer risk. Thus, scientific interest in nutrition and cancer has grown over time, as shown by increasing number of experimental studies about the relationship between diet and cancer development. This review attempts to provide an insight into the anti-cancer effects of Citrus fruits, with a focus on their bioactive compounds, elucidating the main cellular and molecular mechanisms through which they may protect against cancer. Scientific literature was selected for this review with the aim of collecting the relevant experimental evidence for the anti-cancer effects of Citrus fruits and their flavonoids. The findings discussed in this review strongly support their potential as anti-cancer agents, and may represent a scientific basis to develop nutraceuticals, food supplements, or complementary and alternative drugs in a context of a multi-target pharmacological strategy in the oncology.

Chemopreventive Actions of Blond and Red-Fleshed Sweet Orange Juice on the Loucy Leukemia Cell Line

BACKGROUND

Red-fleshed sweet orange juice (ROJ) comes from a new variety of citrus cultivated in Brazil that contains high levels of β-carotene and lycopene, and similar amounts of hesperidin (HSP) and nutrients, equivalently to blond orange juice (BOJ). Such bioactive compounds are associated with chemopreventive actions in several cancer cell lines. The purpose of this study was to examine the cytotoxicity, cell cycle, apoptosis, and cytokine secretion after BOJ, ROJ, and HSP treatment of a novel T acute lymphoblastic leukemia cell line, Loucy.

MATERIALS AND METHODS

Loucy cells were incubated for 24-h with BOJ, ROJ, and HSP, and the viability was measured using trypan blue. Cell cycling and apoptosis were assessed by propidium iodide (PI) and annexin V-FITC/PI flow cytometry, respectively. Secretion of cytokines IL-1α, IL1-β, IL-2, IL-4, IL-6, IL-10, IL-17A, IFNγ, TNFα, TGFβ, MIPα, and MIPβ was determined by ELISA array.

RESULTS

BOJ and ROJ treatments promoted Loucy cell cytotoxicity. Additionally, BOJ induced cell cycle arrest in the G0/G1 phase, and decreased the cell accumulation in the G2/M. ROJ decreased only the G0/G1 fraction, while HSP did not change the cell cycle. BOJ led to apoptosis in a different fashion of ROJ, while the first treatment induced apoptosis by increase of late apoptosis and primary necrotic fractions, the second increased early and late apoptosis, and primary necrotic fraction compared to positive controls. HSP had no effect on apoptosis. IL-6 and IL-10 were abrogated by all treatments.

CONCLUSIONS

Taking together, these results suggest potential chemopreventive effects of BOJ and ROJ on Loucy cells.

Physical properties and biological activities of hesperetin and naringenin in complex with methylated β-cyclodextrin

The aim of this work is to improve physical properties and biological activities of the two flavanones hesperetin and naringenin by complexation with β-cyclodextrin (β-CD) and its methylated derivatives (2,6-di-O-methyl-β-cyclodextrin, DM-β-CD and randomly methylated-β-CD, RAMEB). The free energies of inclusion complexes between hesperetin with cyclodextrins (β-CD and DM-β-CD) were theoretically investigated by molecular dynamics simulation. The free energy values obtained suggested a more stable inclusion complex with DM-β-CD. The vdW force is the main guest–host interaction when hesperetin binds with CDs. The phase solubility diagram showed the formation of a soluble complex of A_L type, with higher increase in solubility and stability when hesperetin and naringenin were complexed with RAMEB. Solid complexes were prepared by freeze-drying, and the data from differential scanning calorimetry (DSC) confirmed the formation of inclusion complexes. The data obtained by the dissolution method showed that complexation with RAMEB resulted in a better release of both flavanones to aqueous solution. The flavanones-β-CD/DM-β-CD complexes demonstrated a similar or a slight increase in anti-inflammatory activity and cytotoxicity towards three different cancer cell lines. The overall results suggested that solubilities and bioactivities of both flavanones were increased by complexation with methylated β-CDs.

Oxidative stress and cancer; the role of hesperidin, a citrus natural bioflavonoid, as a cancer chemoprotective agent

Cancer is the third cause of death worldwide, with complex etiology, and is defined as an uncontrolled growth of cells. A high proportion of cancer incidence and deaths are due to different environmental and genetic factors such as high body mass index, low fruit and vegetable intake, lack of physical activity, tobacco use, alcohol consumption, exposure to radiation, chronic infections, and heredity also. In addition, oxidative stress plays a crucial role in the pathophysiology of different types of cancer. Hence, screening and testing of more effective compounds with minimum side effects for the prevention and treatment of cancers started a few decades ago. Regarding this, much attention has been paid to natural antioxidants as a novel prevention and treatment strategy for cancer. Flavonoids are one of the most important ingredients in vegetables and fruits, especially in the genus Citrus. Hesperidin is a flavonone glycoside, belonging to the flavonoid family, which is widely found in Citrus species and acts as a potent antioxidant and anticancer agent. In the present review, we attempt to provide an overview and summarize the scientific literature about the cancer chemoprotective effects of hesperidin with an emphasis on its relation to the protection roles against oxidative stress.

Effect of Citrus bergamia juice on human neuroblastoma cells in vitro and in metastatic xenograft models

Neuroblastoma is the most common extracranial pediatric solid tumor with poor prognosis in children with disseminated stage of disease. A number of studies show that molecules largely distributed in commonly consumed fruits and vegetables may have anti-tumor activity. In this study we evaluate the effect of Citrus bergamia (bergamot) juice (BJ) in vitro and in a spontaneous metastatic neuroblastoma SCID mouse model. Qualitative and quantitative characterizations of BJ flavonoid fractions were performed by RP-HPLC/PDA/MS. We show that BJ significantly affects SK-N-SH and LAN-1 cell proliferation in vitro, but fails to reduce primary tumor weight in vivo. Moreover, BJ reduced cell adhesiveness and invasion of LAN-1 and SK-N-SH cells in vitro and the number of pulmonary metastases under consideration of the number of tumor cells in the blood in mice inoculated with LAN-1 cells in vivo. These effects without any apparent sign of systemic toxicity confirm the potential clinical interest of BJ and lay the basis for further investigation in cancer.

Metabolic engineering of β-carotene in orange fruit increases its in vivo antioxidant properties

Orange is a major crop and an important source of health-promoting bioactive compounds. Increasing the levels of specific antioxidants in orange fruit through metabolic engineering could strengthen the fruit's health benefits. In this work, we have afforded enhancing the β-carotene content of orange fruit through blocking by RNA interference the expression of an endogenous β-carotene hydroxylase gene (Csβ-CHX) that is involved in the conversion of β-carotene into xanthophylls. Additionally, we have simultaneously overexpressed a key regulator gene of flowering transition, the FLOWERING LOCUS T from sweet orange (CsFT), in the transgenic juvenile plants, which allowed us to obtain fruit in an extremely short period of time. Silencing the Csβ-CHX gene resulted in oranges with a deep yellow ('golden') phenotype and significant increases (up to 36-fold) in β-carotene content in the pulp. The capacity of β-carotene-enriched oranges for protection against oxidative stress in vivo was assessed using Caenorhabditis elegans as experimental animal model. Golden oranges induced a 20% higher antioxidant effect than the isogenic control. This is the first example of the successful metabolic engineering of the β-carotene content (or the content of any other phytonutrient) in oranges and demonstrates the potential of genetic engineering for the nutritional enhancement of fruit tree crops.

Immunomodulatory activities of Yoyo bitters: recommended dose precipitated inflammatory responses in male Wistar rats

This study investigated the immunomodulatory capabilities of the sub-chronic administration of Yoyo bitters in male Wistar rats. Eighteen rats weighing 86.2 +/- 4.43 g were randomly picked into three equal groups. The rats were acclimatized for 14 days, after which 0.308 and 0.462 mL kg(-1) b.wt. of Yoyo bitters were administered once daily to groups B and C respectively for 56 days, while group A received distilled water. The feed intake, body weight, blood glucose, interleukin 2 (IL-2), interleukin 6 (IL-6), tumour necrosis factor alpha (TNF-alpha), haematological parameters, serum lipid profile and uric acid, liver reduced glutathione and malodialdehyde were determined. The feed intake, body weight and blood glucose concentrations were reduced (p < 0.05) at the doses. No changes were recorded in the concentration of serum IL-2 (p > 0.05), but IL-6 decreased (p < 0.05) in group B and increased (p < 0.05) in group C, while TNF-alpha were increased (p < 0.05) dose dependent. The haematological parameters were decreased at all the doses (p < 0.05), except the ESR, WBC and lymphocytes that were increased (p < 0.05) and platelets in group C (p < 0.05). The serum total cholesterol, TAG, LDL-C and atherogenic index were decreased (p < 0.05) and HDL-C increased (p < 0.05) in group B only. Serum uric acid was reduced (p < 0.05) in group B, but increased in group C with the concentration of liver MDA (p < 0.05). The study, therefore, established that a dose lower than the manufacturer's recommended dose presented the desired immunomodulatory activities and the habitual use of Yoyo bitters at the adult recommended dose calls for caution.

Mechanisms underlying the anti-tumoral effects of Citrus Bergamia juice

Based on the growing deal of data concerning the biological activity of flavonoid-rich natural products, the aim of the present study was to explore in vitro the potential anti-tumoral activity of Citrus Bergamia (bergamot) juice (BJ), determining its molecular interaction with cancer cells. Here we show that BJ reduced growth rate of different cancer cell lines, with the maximal growth inhibition observed in neuroblastoma cells (SH-SY5Y) after 72 hs of exposure to 5% BJ. The SH-SY5Y antiproliferative effect elicited by BJ was not due to a cytotoxic action and it did not induce apoptosis. Instead, BJ stimulated the arrest in the G1 phase of cell cycle and determined a modification in cellular morphology, causing a marked increase of detached cells. The inhibition of adhesive capacity on different physiologic substrates and on endothelial cells monolayer were correlated with an impairment of actin filaments, a reduction in the expression of the active form of focal adhesion kinase (FAK) that in turn caused inhibition of cell migration. In parallel, BJ seemed to hinder the association between the neural cell adhesion molecule (NCAM) and FAK. Our data suggest a mechanisms through which BJ can inhibit important molecular pathways related to cancer-associated aggressive phenotype and offer new suggestions for further studies on the role of BJ in cancer treatment.

Luteolin induces carcinoma cell apoptosis through binding Hsp90 to suppress constitutive activation of STAT3

Background

Abnormal activity of STAT3 is associated with a number of human malignancies. Hsp90 plays a central role in stabilizing newly synthesized proteins and participates in maintaining the functional competency of a number of signaling transducers involved in cell growth, survival and oncogenesis, such as STAT3. Hsp90 interacts with STAT3 and stabilizes Tyr-phosphorylated STAT3. It has been reported that luteolin possesses anticancer activity through degradation of Tyr⁷⁰⁵-phosphorylated STAT3.

Methodology/Principal Findings

We found that overexpression of Hsp90 inhibited luteolin-induced degradation of Tyr⁷⁰⁵-phosphorylated STAT3 and luteolin also reduced the levels of some other Hsp90 interacting proteins. Results from co-immunoprecipitation and immunoblot analysis demonstrated that luteolin prevented the association between Hsp90 and STAT3 and induced both Tyr⁷⁰⁵- and Ser⁷²⁷-phosphorylated STAT3 degradation through proteasome-dependent pathway. The molecular modeling analysis with CHARMm–Discovery Studio 2.1(DS 2.1) indicated that luteolin could bind to the ATP-binding pocket of Hsp90. SPR technology-based binding assay confirmed the association between luteolin and Hsp90. ATP-sepharose binding assay displayed that luteolin inhibited Hsp90-ATP binding.

Conclusions/Significance

Luteolin promoted the degradation of Tyr⁷⁰⁵- and Ser⁷²⁷-phosphorylated STAT3 through interacting with Hsp90 and induced apoptosis of cancer cells. This study indicated that luteolin may act as a potent HSP90 inhibitor in antitumor strategies.

Flavonoid-deficient mutants in grass pea (Lathyrus sativus L.): genetic control, linkage relationships, and mapping with aconitase and S-nitrosoglutathione reductase isozyme loci

Two flavonoid-deficient mutants, designated as fldL-1 and fldL-2, were isolated in EMS-mutagenized (0.15%, 10 h) M₂ progeny of grass pea (Lathyrus sativus L.). Both the mutants contained total leaf flavonoid content only 20% of their mother varieties. Genetic analysis revealed monogenic recessive inheritance of the trait, controlled by two different nonallelic loci. The two mutants differed significantly in banding patterns of leaf aconitase (ACO) and S-nitrosoglutathione reductase (GSNOR) isozymes, possessing unique bands in Aco 1, Aco 2, and Gsnor 2 loci. Isozyme loci inherited monogenically showing codominant expression in F₂ (1 : 2 : 1) and backcross (1 : 1) segregations. Linkage studies and primary trisomic analysis mapped Aco 1 and fld 1 loci on extra chromosome of trisomic-I and Aco 2, fld 2, and Gsnor 2 on extra chromosome of trisomic-IV in linked associations.

Cancer chemoprevention by citrus pulp and juices containing high amounts of β-cryptoxanthin and hesperidin

β-Cryptoxanthin, a carotenoid, and hesperidin, a flavonoid, possess inhibitory effects on carcinogenesis in several tissues. We recently have prepared a pulp (CHRP) and citrus juices (MJ2 and MJ5) from a satsuma mandarin (Citrus unshiu Mar.) juice (MJ). They contain high amounts of β-cryptoxanthin and hesperidin. We have demonstrated that CHRP and/or MJs inhibit chemically induced rat colon, rat tongue, and mouse lung tumorigenesis. Gavage with CHRP resulted in an increase of activities of detoxifying enzymes in the liver, colon, and tongue rats'. CHRP and MJs were also able to suppress the expression of proinflammatory cytokines and inflammatory enzymes in the target tissues. This paper describes the findings of our in vivo preclinical experiments to develop a strategy for cancer chemoprevention of colon, tongue, and lung neoplasms by use of CHRP and MJs.

Citrus limonin and its glucoside inhibit colon adenocarcinoma cell proliferation through apoptosis

The current study was an attempt to elucidate the mechanism of human colon cancer cell proliferation inhibition by limonin and limonin glucoside (LG) isolated from seeds of Citrus reticulata. The structures of purified compounds were confirmed by NMR and quantified using HPLC. These compounds of more than 95% purity were subjected to proliferation inhibition assay using human colon adenocarcinoma (SW480) cells. The IC50 value of 54.74 and 37.39 μM was observed for limonin and LG, respectively at 72 h. Following confirmation of proliferation inhibition, pattern of DNA fragmentation and activation of caspase-3 of the cells treated with limonoids suggest involvement of apoptosis. Furthermore, reduction in the transcription ratio of bcl2/bax and induction of cytochrome c release from mitochondria to cytosol with treatment of limonoids confirm the activation of intrinsic apoptosis pathway. The activity of Bax and Bcl2 was confirmed through analysis of mitochondrial membrane potential and intracellular calcium in the cells treated with limonin and LG; the net content of caspase-8 was not affected by limonoids. Results of the current study provide compelling evidence on the induction of mitochondria mediated intrinsic apoptosis by both limonin and LG in cultured SW480 cells for the first time.

Identification of the pr1 gene product completes the anthocyanin biosynthesis pathway of maize

In maize, mutations in the pr1 locus lead to the accumulation of pelargonidin (red) rather than cyanidin (purple) pigments in aleurone cells where the anthocyanin biosynthetic pathway is active. We characterized pr1 mutation and isolated a putative F3′H encoding gene (Zmf3′h1) and showed by segregation analysis that the red kernel phenotype is linked to this gene. Genetic mapping using SNP markers confirms its position on chromosome 5L. Furthermore, genetic complementation experiments using a CaMV 35S::ZmF3′H1 promoter–gene construct established that the encoded protein product was sufficient to perform a 3′-hydroxylation reaction. The Zmf3′h1-specific transcripts were detected in floral and vegetative tissues of Pr1 plants and were absent in pr1. Four pr1 alleles were characterized: two carry a 24 TA dinucleotide repeat insertion in the 5′-upstream promoter region, a third has a 17-bp deletion near the TATA box, and a fourth contains a Ds insertion in exon1. Genetic and transcription assays demonstrated that the pr1 gene is under the regulatory control of anthocyanin transcription factors red1 and colorless1. The cloning and characterization of pr1 completes the molecular identification of all genes encoding structural enzymes of the anthocyanin pathway of maize.

Simultaneous determination of flavanones, hydroxycinnamic acids and alkaloids in citrus fruits by HPLC-DAD-ESI/MS

A simple and accurate method has been developed to simultaneously separate and determine 10 bioactive compounds in citrus fruits by high-performance liquid chromatography coupled with diode array detection and electrospray ionisation mass spectrometry (HPLC-DAD-ESI/MS). This HPLC assay was performed on a reversed-phase C18 column with acetonitrile and 0.1% (v/v) aqueous formic acid as mobile phase. DAD has been performed at 273, 283 and 324nm for quantification of the alkaloids, flavanones and hydroxycinnamic acids. MS was also employed to identify the each analyte. Ten analytes (naringin, hesperidin, neohesperidin, ferulic acid, p-coumaric acid, chlorogenic acid, caffeic acid, octopamine, synephrine and tyramine) demonstrated good linearity (r⩾0.9990) in a relatively wide concentration range. The method revealed high average recovery (range, 92.1-97.9%) and good precision with interday and intraday variations with less than 4.71%. The limits of detection (LODs) ranged from 0.02 to 0.11μg/ml, while the limits of quantification (LOQs) were defined in the range of 0.08-0.39μg/ml. The proposed method has been successfully applied to analyse three types of bioactive constituents in eight citrus hybrids pulps and eight citrus hybrids peels, which has been successfully cultivated in China.

Role of citrus juices and distinctive components in the modulation of degenerative processes: genotoxicity, antigenotoxicity, cytotoxicity, and longevity in Drosophila

It is well established that breakfast beverages contain high quantities of Citrus juices. The purpose of the present study was to assess the nutraceutical value of orange and lemon juices as well as two of their active compounds: hesperidin and limonene. Indicator assays were performed at three levels to evaluate different biological health promoter activities: (i) determination of the safety and DNA-damage protecting ability against free radicals by using the somatic mutation and recombination test (SMART) in Drosophila melanogaster, (ii) study of the modulating role for life span in Drosophila melanogaster, and (iii) measurement of the cytotoxic activity against the human tumor cell line HL60. The highest concentrations assayed for lemon juice and limonene (50% v/v and 0.73 mM, respectively) showed genotoxic activity as evidenced from SMART. Orange and lemon juices as well as hesperidin and limonene exhibit antigenotoxic activity against hydrogen peroxide used as an oxidative genotoxin. Life-span experiments revealed that the lower concentrations of orange juice, hesperidin, and limonene exerted a positive influence on the life span of Drosophila. Finally all substances showed cytotoxic activity, with hesperidin being least active. Taking into account the safety, antigenotoxicity, longevity, and cytotoxicity data obtained in the different assays, orange juice may be a candidate as a nutraceutical food as it (1) is not genotoxic, (2) is able to protect DNA against free radicals, and (3) inhibits growth of tumor cells.

Apigenin and naringenin suppress colon carcinogenesis through the aberrant crypt stage in azoxymethane-treated rats

Epidemiological evidence suggests that a diet abundant in fruits and vegetables may protect against colon cancer. Bioactive compounds, including flavonoids and limonoids, have been shown to possess antiproliferative and antitumorigenic effects in various cancer models. This experiment investigated the effects of four citrus flavonoids and one limonoid mixture at the promotion stage of chemically induced colon cancer in rats. Male Sprague-Dawley rats (n = 10 rats/group) were randomly allocated to one of six diets formulated to contain 0.1% apigenin, 0.02% naringenin, 0.1% hesperidin, 0.01% nobiletin, 0.035% limonin glucoside/obacunone glucoside mixture or a control diet (0% flavonoid/limonoid). Rats received experimental diets for 10 weeks and were injected with azoxymethane (15 mg/kg) at weeks 3 and 4. Excised colons were evaluated for aberrant crypt foci (ACF) formation, colonocyte proliferation (proliferating cell nuclear antigen assay), apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labeling assay) and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) (immunoblotting). When compared with the control diet, apigenin lowered the number of high multiplicity ACF (HMACF >4 aberrant crypts/focus) by 57% (P < 0.05), while naringenin lowered both the number of HMACF by 51% (P < 0.05) and the proliferative index by 32% (P < 0.05). Both apigenin and naringenin increased apoptosis of luminal surface colonocytes (78% and 97%, respectively; P < 0.05) when compared with the control diet. Hesperidin, nobiletin and the limonin glucoside/obacunone glucoside mixture did not affect these variables. The colonic mucosal protein levels of iNOS or COX-2 were not different among the six diet groups. The ability of dietary apigenin and naringenin to reduce HMACF, lower proliferation (naringenin only) and increase apoptosis may contribute toward colon cancer prevention. However, these effects were not due to mitigation of iNOS and COX-2 protein levels at the ACF stage of colon cancer.

Effect of hesperetin, a citrus flavonoid, on bacterial enzymes and carcinogen-induced aberrant crypt foci in colon cancer rats: a dose-dependent study

Hesperetin, an important bioactive compound in Chinese traditional medicine, has antioxidant and anticarcinogenic properties. Hesperetin is found in abundance in orange and grape juices (200–590 mg L−1) consumed in the daily diet. We have investigated the effect of different doses of hesperetin on faecal and colonic mucosal bacterial enzymes and aberrant crypt foci (ACF) in 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis in male Wistar rats. The rats were divided into six groups and were fed a modified pellet diet for 16 weeks. Group 1 served as control and group 2 received the modified pellet diet along with hesperetin (30 mg kg−1). The rats in groups 3–6 rats were given a weekly subcutaneous injection of DMH (20 mg kg−1) for the first four weeks. Hesperetin was supplemented orally at different doses (10, 20 or 30 mg kg−1) for a total of 16 weeks. At the end of the experimental period all rats were killed. In DMH-treated rats, the activity of faecal and colonic mucosal bacterial enzymes, such as β-glucuronidase, β-galactosidase, β-glucosidase, nitroreductase, sulfatase and mucinase, were significantly elevated, but in rats supplemented hesperetin along with DMH the activity was significantly lowered (P &lt; 0.05). The total number of aberrant crypts was significantly increased in unsupplemented DMH-treated rats, while hesperetin supplementation to DMH-treated rats significantly reduced the total number of crypts. The results demonstrated that hesperetin supplementation at a dose of 20 mg kg−1 played a potent role in suppressing the formation of aberrant crypt foci and reducing the activity of bacterial enzymes in colon cancer.

Inhibition of P-glycoprotein activity by limonin and other secondary metabolites from Citrus species in human colon and leukaemia cell lines

P-glycoprotein (P-gp), a membrane transporter encoded by the MDR1 gene in human cells, mediates drug efflux from cells and plays a major role in causing multidrug resistance; which is one of the most accepted mechanisms for failure of chemotherapy in cancer treatment. In this study, we investigated the effects of nine naturally occurring compounds isolated from Citrus jambhiri Lush and Citrus pyriformis Hassk (Rutaceae) for their potential to modulate the activity of P-gp in the multidrug-resistant human leukaemia cell line CEM/ADR5000. Limonin, deacetylnomilin, hesperidin, neohesperidin, stigmasterol and ss-sitosterol-O-glucoside inhibited the efflux of the P-gp substrate rhodamine 123 in a concentration-dependent manner. Some of these compounds were more active than verapamil, which was used as a positive control. Treatment of drug-resistant Caco-2 cells with the most active C. jambhiri and C. pyriformis compounds increased their sensitivity to doxorubicin and completely reversed doxorubicin resistance, which agrees with a decreased P-gp activity. Limonin was the most potent P-glycoprotein inhibitor - when it was applied at a non-toxic concentration of 20 microM, it significantly enhanced doxorubicin cytotoxicity 2.98-fold (P<0.001) and 2.2-fold (P<0.001) in Caco2 and CEM/ADR5000 cells, respectively. These isolated Citrus compounds could be considered as good candidates for the development of novel P-gp/MDR1 reversal agents which may enhance the accumulation and efficacy of chemotherapy agents.

Evaluation of equol function on anti- or prooxidant status in vivo

The present study was performed to investigate the effects of equol on oxidative stress and the antioxidant defense system in the livers of mice. Mice were orally administered equol at either 5 or 25 mg/kg body weight/day for 1, 3, or 7 wk. Equol administration significantly inhibited biomarkers of oxidative stress (thiobarbituric acid-reactive substances value, carbonyl content, and serum 8-OH-dG) at all doses and for all durations of administration, and this phenomenon was most pronounced at 3 wk. Moreover, catalase and total superoxide dismutase (SOD) activities and their mRNA expression were significantly increased by equol. Although equol increased the glutathione peroxidase (GSH-px) activity in mice treated with equol for 1 wk, long-term administration of equol (7 wk) caused a decrease in the ratio of reduced/oxidized glutathione (GSH/GSSG) and the activities of GSH-px and glutathione reductase (GR). Taken together, these results suggest that equol may act as an antioxidant through an inhibition of oxidative stress and stimulation of catalase and SOD, but can also cause prooxidant effects such as reduction of the GSH/GSSG ratio, depending on the treatment period.

Exploring the effect of Hesperetin-HSPC complex--a novel drug delivery system on the in vitro release, therapeutic efficacy and pharmacokinetics

Hesperetin is known to exhibit a variety of pharmacological activities in mammalian cell systems. Although it shows appreciable bioavailability when administered orally, its faster elimination from body creates the need of frequent administration to maintain effective plasma concentration. To overcome this limitation, a phospholipid complex of hesperetin was prepared and evaluated for antioxidant activity and pharmacokinetic profile. The hesperetin content of the complex was determined by a spectrophotometer and the surface characteristics of the complex were studied by means of microscope. The antioxidant activity was evaluated in carbon-tetrachloride-intoxicated rats at a dose level of 100 mg/kg body weight, p.o. The complex was studied for in vitro drug release characteristics and effect of complexation on serum concentration of hesperetin in rats was also studied along with main pharmacokinetic parameters. The results showed that the complex has a sustained release property and enhanced antioxidant activity (P < 0.05 and <0.01) as compared to free hesperetin at the same dose level. Pharmacokinetic study depicted that the complex has higher relative bioavailability and acted for a longer period of time. The study therefore suggests that phospholipid complex of hesperetin produced better antioxidant activity than free drug at the same dose level and the effect persisted for a longer period of time, which may be helpful in solving the problems of faster elimination of the molecule.

Orange juice vs vitamin C: effect on hydrogen peroxide-induced DNA damage in mononuclear blood cells

The intake of fruits rich in vitamin C seems to increase the antioxidant defence of the organism. However, it is still not clear whether vitamin C alone is responsible for this effect. The aim of the present investigation was to study the effect of the intake of a single portion of blood orange juice (BOJ, 300 ml, providing 150 mg vitamin C) on mononuclear blood cell (MNBC) DNA damage, compared with a drink supplemented with the same amount of vitamin C (C-drink) or sugars (S-drink). Seven young healthy subjects were randomised in a repeated-measures design in which they received each drink on different occasions, 2 weeks apart. Blood samples were collected at baseline, every hour for 8 h, and at 24 h after the intake of each drink. Vitamin C was analysed at each time point by HPLC, whereas H2O2-induced MNBC DNA damage was evaluated at 0, 3 and 24 h by means of the comet assay. Plasma vitamin C concentration increased similarly following BOJ or C-drink intake and was not affected by the S-drink. DNA damage significantly decreased 3 h after BOJ intake (about 18 %; P < 0.01) and remained constant at 24 h (about 16 %; P < 0.01). No effect of the C-drink and S-drink was observed. In conclusion, the intake of a single portion of BOJ provided an early protection of MNBC against oxidative DNA damage; however, the protective effect of BOJ was not explained by vitamin C alone, thus other phytochemicals could be involved.

Effects of hesperetin on vessel structure formation in mouse embryonic stem (mES) cells

OBJECTIVE

The present study investigated the effects of hesperetin on vessel structure formation in mouse embryonic stem (mES) cells with regard to whether hesperetin acts as an antioxidant or pro-oxidant. Some flavonoids enhance antioxidant systems while increasing oxidative stress in the body.

METHODS

After their differentiation into endothelial-like cells for 10 d, mES cells were treated with 1 to 100 muM of hesperetin for 24 h.

RESULTS

Hesperetin efficiently inhibited the formation of vessel-like tubular structures consisting of platelet-endothelial cell adhesion molecule-1-immunoreactive cells and significantly (P < 0.05) increased the generation of reactive oxygen species in a concentration-dependent manner. Although glutathione (in its reduced and oxidized forms) in mES cells was not affected by hesperetin, the 8-iso-prostaglandin F2(alpha) content was decreased. In addition, cytotoxicity-induced hesperetin was not found; lactate dehydrogenase release and cell viability were determined as an index of cell damage.

CONCLUSION

Taken together, the present study shows that hesperetin inhibits vessel formation by pro-oxidant means and suggests its potential as an antiangiogenic agent.