Effects of dietary flavonoids on major signal transduction pathways in human epithelial cells

Apigenin: Molecular Mechanisms and Therapeutic Potential against Cancer Spreading

Due to its propensity to metastasize, cancer remains one of the leading causes of death worldwide. Thanks in part to their intrinsic low cytotoxicity, the effects of the flavonoid family in the prevention and treatment of various human cancers, both in vitro and in vivo, have received increasing attention in recent years. It is well documented that Apigenin (4',5,7-trihydroxyflavone), among other flavonoids, is able to modulate key signaling molecules involved in the initiation of cancer cell proliferation, invasion, and metastasis, including JAK/STAT, PI3K/Akt/mTOR, MAPK/ERK, NF-κB, and Wnt/β-catenin pathways, as well as the oncogenic non-coding RNA network. Based on these premises, the aim of this review is to emphasize some of the key events through which Apigenin suppresses cancer proliferation, focusing specifically on its ability to target key molecular pathways involved in angiogenesis, epithelial-to-mesenchymal transition (EMT), maintenance of cancer stem cells (CSCs), cell cycle arrest, and cancer cell death.

The Potential Role of Apigenin in Cancer Prevention and Treatment

Cancer is the leading cause of death worldwide. In spite of advances in the treatment of cancer, currently used treatment modules including chemotherapy, hormone therapy, radiation therapy and targeted therapy causes adverse effects and kills the normal cells. Therefore, the goal of more effective and less side effects-based cancer treatment approaches is still at the primary position of present research. Medicinal plants or their bioactive ingredients act as dynamic sources of drugs due to their having less side effects and also shows the role in reduction of resistance against cancer therapy. Apigenin is an edible plant-derived flavonoid that has received significant scientific consideration for its health-promoting potential through modulation of inflammation, oxidative stress and various other biological activities. Moreover, the anti-cancer potential of apigenin is confirmed through its ability to modulate various cell signalling pathways, including tumor suppressor genes, angiogenesis, apoptosis, cell cycle, inflammation, apoptosis, PI3K/AKT, NF-κB, MAPK/ERK and STAT3 pathways. The current review mainly emphases the potential role of apigenin in different types of cancer through the modulation of various cell signaling pathways. Further studies based on clinical trials are needed to explore the role of apigenin in cancer management and explain the possible potential mechanisms of action in this vista.

The effect of immunomodulatory properties of naringenin on the inhibition of inflammation and oxidative stress in autoimmune disease models: a systematic review and meta-analysis of preclinical evidence

BACKGROUND/OBJECTIVE

Naringenin is a member of the flavonoid family that can perform many biological processes to treat a wide range of inflammatory diseases and pathological conditions related to oxidative stress (OS). Naringenin immunomodulatory activities have been the subject of recent research as an effective alternative treatment for autoimmune disorders. The effects of naringenin on the levels of inflammatory biomarkers and OS factors in animal models of autoimmune disorders (ADs) were studied in this meta-analysis.

METHODS

Up until January 2022, electronic databases such as Cochrane Library and EMBASE, PubMed, Web of Science, and Scopus were used to conduct a comprehensive literature search in English language. To evaluate the effect of naringenin on inflammatory mediators, such as TNF-α, IL-6, IL-β, IFN-γ, NF-κB, and nitric oxide, and OS biomarkers, such as CAT, SOD, GPx, GSH and MDA, in AD models, we measured the quality assessment and heterogeneity test using the PRISMA checklist protocol and I² statistic, respectively. A random-effects model was employed based on the heterogeneity test, and then pooled data were standardized as mean difference (SMD) with a 95% confident interval (CI).

RESULTS

We excluded all clinical trials, cell experiment studies, animal studies with different parameters, non-autoimmune disease models, and an inadequate series of studies for quantitative synthesis. Finally, from 627 potentially reports, 12 eligible studies were included in the meta-analysis. Data were collected from several groups. Of these, 153 were in the naringenin group and 149 were in the control group. Our meta-analysis of the pooled data for the parameters of inflammation and OS indicated that naringenin significantly reduced the levels of NF-κB (SMD - 3.77, 95% CI [- 6.03 to - 1.51]; I² = 80.1%, p = 0.002), IFN-γ (SMD - 6.18, 95% CI [- 8.73 to - 3.62]; I² = 53.7%, p = 0.115), and NO (SMD - 3.97, 95% CI [- 5.50 to - 2.45]; I² = 73.4%, p = 0.005), IL-1β (SMD - 4.23, 95% CI [- 5.09 to - 3.37]; I² = 0.0%, p = 0.462), IL-6 (SMD - 5.84, 95% CI [- 7.83 to - 3.85]; I² = 86.5%, p < 0.001), and TNF-α (SMD - 5.10, 95% CI [- 6.34 to - 3.86]; I² = 74.7%, p < 0.001). These findings also demonstrated the efficacy of naringenin on increasing the levels of CAT (SMD 4.19, 95% CI [1.33 to 7.06]; I² = 79.9%, p = 0.007), GSH (SMD 4.58, 95% CI [1.64 to 7.51]; I² = 90.5%, p < 0.001), and GPx (SMD 9.65, 95% CI [2.56 to 16.74]; I² = 86.6%, p = 0.001) and decreasing the levels of MDA (SMD - 3.65, 95% CI [- 4.80 to - 2.51]; I² = 69.4%, p = 0.001) than control groups. However, treatment with naringenin showed no statistically difference in SOD activity (SMD 1.89, 95% CI [- 1.11 to 4.89]; I² = 93.6%, p < 0.001).

CONCLUSION

Overall, our findings revealed the immunomodulatory potential of naringenin as an alternative treatment on inhibition of inflammation and OS in several autoimmune-related diseases. Nevertheless, regarding the limitation of clinical trials, strong preclinical models and clinical settings in the future are needed that address the effects of naringenin on ADs. Before large-scale clinical studies, precise human pharmacokinetic investigations are required to determine the dosage ranges and evaluate the initial safety profile of naringenin.

Combined Metabolome and Transcriptome Analyses Reveal the Flavonoids Changes and Biosynthesis Mechanisms in Different Organs of Hibiseu manihot L

Hibiseu manihot L. (Jinhuakui, JHK), also known as a garden landscape plant, is widely cultivated as a landscape plant having pharmacological effects due to its high flavonoids content. Although flavonoids were the main active pharmaceutical ingredients in JHK, little information was obtained about the content, composition, and accumulation pattern of flavonoids in different tissues. Most studies only identified a few kinds of flavonoids in JHK limited by separation and identification problems. Therefore, combined metabolome and transcriptome analysis was performed to explore the accumulation patterns and biosynthesis mechanisms of flavonoids in JHK. In this study, we identified 160 flavonoids in 15 samples of JHK (flower, leaf, root, stem, and seeds) by using LC-MS/MS. Consistent with the total flavonoid content determination, these flavonoids were significantly accumulated in flowers, followed by leaves, stems, roots, and seeds. Among them, certain flavonoids, with high content, were also identified for the first time in JHK, such as tricetin, catechin, hesperidin, ncyanidin-3-O-sambubioside, astragalin, procyanidin B2/B3/C1, apigenin-5-O-glucoside, etc. Different tissues underwent significantly reprogramming of their transcriptomes and metabolites changes in JHK, particularly in the flavonoid, flavone, and flavonol biosynthesis pathways. We conducted a correlation analysis between RNA-seq and LC-MS/MS to identify the key genes and related flavonoids compounds, rebuild the gene-metabolites regulatory subnetworks, and then identified 15 key genes highly related to flavonoids accumulation in JHK. These key genes might play a fine regulatory role in flavonoids biosynthesis by affecting the gene expression level in different organs of JHK. Our results could be helpful for the improvement of the market/industrial utilization value of different parts of JHK, to pave the way for the regulatory mechanism research of flavonoids biosynthesis, and provide insight for studying the production quality improvement of JHK.

Anticancer activity of flavonoids accompanied by redox state modulation and the potential for a chemotherapeutic strategy

Since researchers began studying the mechanism of flavonoids' anticancer activity, little attention has been focused on the modulation of redox state in cells as a potential chemotherapeutic strategy. However, recent studies have begun identifying that the anticancer effect of flavonoids occurs both in their antioxidative activity which scavenges ROS and their prooxidative activity which generates ROS. Against this backdrop, this study attempts to achieve a comprehensive analysis of the individual and separate study findings regarding flavonoids' modulation of redox state in cancer cells. It focuses on the mechanism behind the anticancer effect, and mostly on the modulation of redox potential by flavonoids such as quercetin, hesperetin, apigenin, genistein, epigallocatechin-3-gallate (EGCG), luteolin and kaempferol in both in vitro and animal models. In addition, the clinical applications of and bioavailability of flavonoids were reviewed to help build a treatment strategy based on flavonoids' prooxidative potential.

Phenolic Constituents of Lamium album L. subsp. album Flowers: Anatomical, Histochemical, and Phytochemical Study

Flos Lamii albi has a high biological activity and is widely used in herbal medicine. The aim of the study was to characterize the secretory structures present in Lamium album subsp. album corolla and the location of phenolic compounds. Additionally, we carried out qualitative phytochemical analyses of flavonoids and phenolic acids. Light, fluorescence, and scanning electron microscopy were used to analyze the structure of the floral organs. The main classes of phenolic compounds and their localization were determined histochemically. Phytochemical analyses were performed with high-performance thin-layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). Six types of glandular trichomes were found which contained flavonoids, phenolic acids, and tannins. The phytochemical studies demonstrated the presence of caffeic, chlorogenic, ferulic, gallic, p-coumaric, protocatechuic, syringic, gentisic, and vanillic phenolic acids as well as rutoside, isoquercetin, and quercetin flavonoids. The corolla in L. album subsp. album has antioxidant properties due to the presence of various polyphenols, as shown by the histo- and phytochemical analyses. The distribution and morphology of trichomes and the content of phenolic compounds in the corolla have taxonomic, pharmacognostic, and practical importance, facilitating the identification of the raw material.

Acacetin, a flavone with diverse therapeutic potential in cancer, inflammation, infections and other metabolic disorders

BACKGROUND

Acacetin is a di-hydroxy and mono-methoxy flavone present in various plants, including black locust, Damiana, Silver birch. Literature information revealed that acacetin exhibits an array of pharmacological potential including chemopreventive and cytotoxic properties in cancer cell lines, prevents ischemia/reperfusion/myocardial infarction-induced cardiac injury, lipopolysaccharide (LPS), 1-methyl-4-phenyl pyridinium ion (MPP+) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP)-induced neuroinflammation, LPS and sepsis-induced lung injury, rheumatoid and collagen-induced arthritis, inhibit the microbial growth, obesity, viral-mediated infections as well as hepatic protection.

PURPOSE

This review highlights the therapeutic potential of acacetin, with updated and comprehensive information on the biological sources, chemistry, and pharmacological properties along with the possible mechanism of action, safety aspects, and future research opportunities.

STUDY DESIGN

The information was retrieved from various search engines, including Pubmed, SciFinder, Science direct, Inxight:drugs, Google scholar, and Meta cyc.

RESULT

The first section of this review focuses on the detailed biological source of acacetin, chromatographic techniques used for isolation, chemical characteristics, the method for the synthesis of acacetin, and the available natural and synthetic derivatives. Subsequently, the pharmacological activities, including anti-cancer, anti-inflammatory, anti-viral, anti-microbial, anti-obesity, have been discussed. The pharmacokinetics data and toxicity profile of acacetin are also discussed.

CONCLUSION

Acacetin is a potent molecule reported for its strong anti-inflammatory and anti-cancer activity, however further scientific evidence is essential to validate its potency in disease models associated with inflammation and cancer. There is limited information available for toxicity profiling of acacetin; therefore, further studies would aid in establishing this natural flavone as a potent candidate for research studies at clinical setup.

Synthesis and Characterization of Quinoline-3-Carboxamide Derivatives as Inhibitors of the ATM Kinase

BACKGROUND

The importance of inhibiting the kinases of the DDR pathway for radiosensitizing cancer cells is well established. Cancer cells exploit these kinases for their survival, which leads to the development of resistance towards DNA damaging therapeutics.

OBJECTIVE

In this article, the focus is on targeting the key mediator of the DDR pathway, the ATM kinase. A new set of quinoline-3-carboxamides, as potential inhibitors of ATM, is reported.

METHODS

Quinoline-3-carboxamide derivatives were synthesized and cytotoxicity assay was performed to analyze the effect of molecules on different cancer cell lines like HCT116, MDA-MB-468, and MDA-MB-231.

RESULTS

Three of the synthesized compounds showed promising cytotoxicity towards a selected set of cancer cell lines. Western Blot analysis was also performed by pre-treating the cells with quercetin, a known ATM upregulator, by causing DNA double-strand breaks. SAR studies suggested the importance of the electron-donating nature of the R group for the molecule to be toxic. Finally, Western-Blot analysis confirmed the down-regulation of ATM in the cells. Additionally, the PTEN negative cell line, MDA-MB-468, was more sensitive towards the compounds in comparison with the PTEN positive cell line, MDA-MB-231. Cytotoxicity studies against 293T cells showed that the compounds were at least three times less toxic when compared with HCT116.

CONCLUSION

In conclusion, these experiments will lay the groundwork for the evolution of potent and selective ATM inhibitors for the radio- and chemo-sensitization of cancer cells.

Apigenin, flavonoid component isolated from Gentiana veitchiorum flower suppresses the oxidative stress through LDLR-LCAT signaling pathway

Flower of Gentiana veitchiorum has traditionally been used as an herbal medicine in Tibet for treatment of variola, respiratory infection, and pneumonia. However, the effective components contained in flower are not identified yet, and the underlying mechanisms for anti-inflammatory, antibacterial, and antioxidative activities remain to be elucidated. Here, we first extracted the flavonoid mixture from G. veitchiorum flower. The mixture was then further isolated and the within compounds was identified through the high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The results showed that apigenin (4',5,7-trihydroxyflavone) was the most abundant flavonoid in G. veitchiorum flower. We next examined the antioxidative activity of the extracted apigenin using the ferric reducing/antioxidant power (FRAP), the 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) assays and found that a positive correlation between apigenin concentration and reactive oxygen species (ROS) scavenging rate. The biochemical assays further revealed that the levels of total cholesterol (TC), triglyceride (TG), and malondialdehyde (MDA) were reduced, while the activity of superoxide dismutase (SOD) was increased after apigenin treatment in hyperlipidemic rats. Moreover, we performed histopathological investigations and found that the lipidic deposition patterns were recovered and the amount of lipid vacuoles was significantly reduced in apigenin-treated hyperlipidemic rat liver. Western blotting assay showed that the expression of low-density lipoprotein receptor (LDLR) and lecithin-cholesterol acyltransferase (LCAT) were up-regulated in the apigenin-treated samples. Overall, our results demonstrated that the apigenin isolated from G. veitchiorum flower exhibited radical scavenging activities, and reversed the high fat diet-induced oxidative damage in rats. Its antioxidative activities are probably achieved via LDLR-LCAT signaling pathway.

HPLC–MS/MS profiling of wild-growing scentless chamomile

Scentless chamomile (Tripleurospermum inodorum = M. inodora) is a plant belonging to Anthemideae tribe of Asteraceae family, with phenotype similar to the common chamomile, a plant used in human consumption in the form of herbal tea infusion. In order to be able to understand possible health-promoting properties and adverse effects of the scentless chamomile's consumption, it is of essence to examine its chemical composition. The aim of the study was to perform phenolic profiling using high-performance liquid chromatography–tandem mass spectroscopy (HPLC–MS/MS), in comparison to the common chamomile. In the investigated extracts, qualitative and quantitative analyses enabled the identification of 66 compounds based on their retention times, mass (MS/MS) spectra, and analysis of their characteristic fragmentation patterns in MS/MS Product Ion Scan experiments. A new HPLC–MS/MS method for quantitation of common plant metabolites was hereby developed, enabling quantitation of 47 compounds. All examined M. inodora samples have relatively high combined phenolic and flavonoid contents (25.2–51.9 mg/g). Apigenin, apigenin-7-O-glucoside, luteolin, luteolin-7-O-glucoside, quinic acid, and 5-O-caffeoyl quinic acid were the compounds with highest concentration in both inodorous and common chamomile. The results obtained hereby represent the first and most detailed chemical profile of scentless chamomile so far.

Hydroponically Grown Sanguisorba minor Scop.: Effects of Cut and Storage on Fresh-Cut Produce

Wild edible plants have been used in cooking since ancient times. Recently, their value has improved as a result of the scientific evidence for their nutraceutical properties. Sanguisorba minor Scop. (salad burnet) plants were hydroponically grown and two consecutive cuts took place at 15 (C1) and 30 (C2) days after sowing. An untargeted metabolomics approach was utilized to fingerprint phenolics and other health-related compounds in this species; this approach revealed the different effects of the two cuts on the plant. S. minor showed a different and complex secondary metabolite profile, which was influenced by the cut. In fact, flavonoids increased in leaves obtained from C2, especially flavones. However, other secondary metabolites were downregulated in leaves from C2 compared to those detected in leaves from C1, as evidenced by the combination of the variable important in projections (VIP score > 1.3) and the fold-change (FC > 2). The storage of S. minor leaves for 15 days as fresh-cut products did not induce significant changes in the phenolic content and antioxidant capacity, which indicates that the nutraceutical value was maintained. The only difference evidenced during storage was that leaves obtained from C2 showed a lower constitutive content of nutraceutical compounds than leaves obtained from C1; except for chlorophylls and carotenoids. In conclusion, the cut was the main influence on the modulation of secondary metabolites in leaves, and the effects were independent of storage.

Synthesis of Daidzein Glycosides, α-Tocopherol Glycosides, Hesperetin Glycosides by Bioconversion and Their Potential for Anti-Allergic Functional-Foods and Cosmetics

Daidzein is a common isoflavone, having multiple biological effects such as anti-inflammation, anti-allergy, and anti-aging. α-Tocopherol is the tocopherol isoform with the highest vitamin E activity including anti-allergic activity and anti-cancer activity. Hesperetin is a flavone, which shows potent anti-inflammatory effects. These compounds have shortcomings, i.e., water-insolubility and poor absorption after oral administration. The glycosylation of bioactive compounds can enhance their water-solubility, physicochemical stability, intestinal absorption, and biological half-life, and improve their bio- and pharmacological properties. They were transformed by cultured Nicotiana tabacum cells to 7-β-glucoside and 7-β-gentiobioside of daidzein, and 3'- and 7-β-glucosides, 3',7-β-diglucoside, and 7-β-gentiobioside of hesperetin. Daidzein and α-tocopherol were glycosylated by galactosylation with β-glucosidase to give 4'- and 7-β-galactosides of daidzein, which were new compounds, and α-tocopherol 6-β-galactoside. These nine glycosides showed higher anti-allergic activity, i.e., inhibitory activity toward histamine release from rat peritoneal mast cells, than their respective aglycones. In addition, these glycosides showed higher tyrosinase inhibitory activity than the corresponding aglycones. Glycosylation of daidzein, α-tocopherol, and hesperetin greatly improved their biological activities.

A review on biological effects of Lamium album (white dead nettle) and its components

Lamium album, commonly known as white dead nettle, is a plant in the family of Lamiaceae. This plant is distributed all over Asia, Europe, and Africa. In the traditional medicine of Asia, it has been used for the treatment of a number of diseases such as trauma, fracture, paralysis, leucorrhoea, hypertension women’s pain, uterine hemorrhage, menorrhagia, vaginal and cervical inflammation. In recent years, L. album has been the subject of intensive experimental studies to evaluate its traditional use to reveal new biological properties. A wide range of pharmacological effects, including antimicrobial, anti-inflammatory, anticancer, and antidiabetic properties have been reported by these studies. This review presents an up-to-date overview of the current literature on the pharmacological and physiological effects of L. album. Also, phytochemical constituents responsible for the biological properties of L. album are presented and discussed.

Discovery of the mechanisms and major bioactive compounds responsible for the protective effects of Gualou Xiebai Decoction on coronary heart disease by network pharmacology analysis

BACKGROUND

Gualou Xiebai decoction (GLXB), a multi-component herbal formula, has been widely used to treat coronary heart disease (CHD) in China for centuries. Several studies have revealed part of its pharmacological activities, whereas its active compounds and mechanisms of action are still unknown because of its complex composition.

PURPOSE

Discover the major active compounds and the pharmacological mechanisms of GLXB by network pharmacology methods.

METHODS

The main candidate target network was constructed by predicting targets of absorbable chemical compounds of GLXB, collecting therapeutic targets of cardiovascular drugs, constructing target network and layers of screening. Community detection and edge-betweenness calculation were applied to analyze the main candidate target network. Cell viability test, Western blot and flow cytometry were performed to validate the predicted results in cardiomyocytes hypoxia/reoxygenation model.

RESULTS

Five clusters and eight cross-talk targets were found in the main candidate target network. Their functions combined together might explain the multifunctional role of GLXB against CHD. Among the cross-talk targets, ESR1 (Estrogen receptor alpha, ERα) and MAPK14 (Mitogen-activated protein kinase 14, p38) were both drug targets and therapeutic targets whose interaction exhibited the greatest edge-betweenness value, suggesting their crucial role in the protective effect of GLXB. The compounds targeting on ESR1 and MAPK14 were identified as apigenin and 25S-macrostemonoside P respectively which were regard as the major bioactive compounds. The predicted results including the major bioactive compounds, their targets and the synergic effects between them were validated.

CONCLUSION

This study screened out major bioactive compounds from GLXB and offered a new understanding of the protection mechanism of GLXB against CHD by network pharmacology method and provides a combination strategy to explore mechanisms of action of multi-component drugs from a holistic perspective.

Bioflavonoids promote stable translocations between MLL-AF9 breakpoint cluster regions independent of normal chromosomal context: Model system to screen environmental risks

Infant acute leukemias are aggressive and characterized by rapid onset after birth. The majority harbor translocations involving the MLL gene with AF9 as one of its most common fusion partners. MLL and AF9 loci contain breakpoint cluster regions (bcrs) with sequences hypothesized to be targets of topoisomerase II inhibitors that promote translocation formation. Overlap of MLL bcr sequences associated with both infant acute leukemia and therapy-related leukemia following exposure to the topoisomerase II inhibitor etoposide led to the hypothesis that exposure during pregnancy to biochemically similar compounds may promote infant acute leukemia. We established a reporter system to systematically quantitate and stratify the potential for such compounds to promote chromosomal translocations between the MLL and AF9 bcrs analogous to those in infant leukemia. We show bioflavonoids genistein and quercetin most biochemically similar to etoposide have a strong association with MLL-AF9 bcr translocations, while kaempferol, fisetin, flavone, and myricetin have a weak but consistent association, and other compounds have a minimal association in both embryonic stem (ES) and hematopoietic stem cell (HSC) populations. The frequency of translocations induced by bioflavonoids at later stages of myelopoiesis is significantly reduced by more than one log. The MLL and AF9 bcrs are sensitive to these agents and recombinogenic independent of their native context suggesting bcr sequences themselves are drivers of illegitimate DNA repair reactions and translocations, not generation of functional oncogenic fusions. This system provides for rapid systematic screening of relative risk, dose dependence, and combinatorial impact of multitudes of dietary and environmental exposures on MLL-AF9 translocations. Environ. Mol. Mutagen. 60: 154-167, 2019. © 2018 Wiley Periodicals, Inc.

The significant impact of apigenin on different aspects of autoimmune disease

Autoimmune diseases are among the highest diseases to diagnose and treat. The current "gold standard" of care for these diseases is immunosuppressive drugs which interfere with overall immune responses; their long-term high-dose treatments would expose the patient to opportunistic, life-threatening and long-term malignant infections. Considering the side effects and toxicity of these drug and also the beneficial effects of herbal compounds among their consumers, the professional investigation on the exact mechanism of the plant's major element has grown much attention in the last years. Apigenin as an extracting compound of plants, such as parsley and celery, which has a variety of biological effects, such as anti-inflammatory, anti-cancer and antioxidant effects. This review is intended to summarize the various effects of Apigenin on several autoimmune diseases which have been worked on so far. The pluralization of the obtained results has revealed Apigenin's effects on pro-inflammatory cytokines such as IL-1β, chemokines such as ICAM-1, immune cells proliferation such as T cells, apoptosis, and various signaling pathways. According to these preclinical findings, we recommend that further robust unbiased studies should be done to use Apigenin as a supplementary or therapeutic element in autoimmune disease.

Apigenin, a dietary flavonoid, induces apoptosis, DNA damage, and oxidative stress in human breast cancer MCF-7 and MDA MB-231 cells

Apigenin is found in several dietary plant foods such as vegetables and fruits. To investigate potential anticancer properties of apigenin on human breast cancer, ER-positive MCF-7 and triple-negative MDA MB-231 cells were used. Moreover, toxicological safety of apigenin towards normal cells was evaluated in human lymphocytes. Cytotoxicity of apigenin towards cancer cells was evaluated by MTT assay whereas further genotoxic and oxidative stress parameters were measured by comet and lipid peroxidation assays, respectively. In order to examine the type of cell death induced by apigenin, several biomarkers were used. Toxicological safety towards normal cells was evaluated by cell viability and comet assays. After the treatment with apigenin, we observed changes in cell morphology in a dose- (10 to 100 μM) and time-dependent manner. Moreover, apigenin caused cell death in both cell lines leading to significant toxicity and dominantly to apoptosis. Furthermore, apigenin proved to be genotoxic towards the selected cancer cells with a potential to induce oxidative damage to lipids. Of great importance is that no significant cytogenotoxic effects were detected in normal cells. The observed cytogenotoxic and pro-cell death activities of apigenin coupled with its low toxicity towards normal cells indicate that this natural product could be used as a future anticancer modality. Therefore, further analysis to determine the exact mechanism of action and in vivo studies on animal models are warranted.

Plant flavone apigenin: An emerging anticancer agent

Research in cancer chemoprevention provides convincing evidence that increased intake of vegetables and fruits may reduce the risk of several human malignancies. Phytochemicals present therein provide beneficial anti-inflammatory and antioxidant properties that serve to improve the cellular microenvironment. Compounds known as flavonoids categorized anthocyanidins, flavonols, flavanones, flavonols, flavones, and isoflavones have shown considerable promise as chemopreventive agents. Apigenin (4', 5, 7-trihydroxyflavone), a major plant flavone, possessing antioxidant, anti-inflammatory, and anticancer properties affecting several molecular and cellular targets used to treat various human diseases. Epidemiologic and case-control studies have suggested apigenin reduces the risk of certain cancers. Studies demonstrate that apigenin retain potent therapeutic properties alone and/or increases the efficacy of several chemotherapeutic drugs in combination on a variety of human cancers. Apigenin's anticancer effects could also be due to its differential effects in causing minimal toxicity to normal cells with delayed plasma clearance and slow decomposition in liver increasing the systemic bioavailability in pharmacokinetic studies. Here we discuss the anticancer role of apigenin highlighting its potential activity as a chemopreventive and therapeutic agent. We also highlight the current caveats that preclude apigenin for its use in the human trials.

Apigenin inhibits renal cell carcinoma cell proliferation

Apigenin, a natural flavonoid found in vegetables and fruits, has antitumor activity in several cancer types. The present study evaluated the effects and mechanism of action of apigenin in renal cell carcinoma (RCC) cells. We found that apigenin suppressed ACHN, 786-0, and Caki-1 RCC cell proliferation in a dose- and time-dependent manner. A comet assay suggested that apigenin caused DNA damage in ACHN cells, especially at higher doses, and induced G2/M phase cell cycle arrest through ATM signal modulation. Small interfering RNA (siRNA)-mediated p53 knockdown showed that apigenin-induced apoptosis was likely p53 dependent. Apigenin anti-proliferative effects were confirmed in an ACHN cell xenograft mouse model. Apigenin treatment reduced tumor growth and volume in vivo, and immunohistochemical staining revealed lower Ki-67 indices in tumors derived from apigenin-treated mice. These findings suggest that apigenin exposure induces DNA damage, G2/M phase cell cycle arrest, p53 accumulation and apoptosis, which collectively suppress ACHN RCC cell proliferation in vitro and in vivo. Given its antitumor effects and low in vivo toxicity, apigenin is a highly promising agent for treatment of RCC.

Pharmacological profile of the aerial parts of Rubus ulmifolius Schott

Background

As aerial parts of Rubus ulmifolius contains phytochemicals like flavonoids and tannins. And whereas flavonoids and tannins have antioxidant and antipyretic activity, hence, current work is carried out to screen crude methanolic extract of aerial parts of Rubus ulmifolius (Ru.Cr) and crude flavonoids rich extract of Rubus ulmifolius (Ru.F) for possible antioxidant and antipyretic activity. Ru.Cr and Ru.F are also tested for brine shrimps lethality bioassay. Ru.F is tested for the first time for possible antioxidant and antipyretic activity.

Methods

Preliminary phytochemical screening of Ru.Cr and Ru.F was performed as it provides rapid finger printing for targeting a pharmacological activity. Acute toxicity and Brine shrimps’ cytotoxicity studies of Ru.Cr and Ru.F were performed to determine its safe dose range. Antioxidant and antipyretic studies were also performed as per reported procedures.

Results

Ru.Cr tested positive for presence of tannins, alkaloids, flavonoids and steroids. Ru.Cr is safe up to 6 g/kg following oral doses for acute toxicity study. Ru.Cr is safe up to 75 μg/kg (p.o), LC₅₀ for Ru.Cr and Ru.F are 16.7 ± 1.4 μg/ml 10.6 ± 1.8 μg/ml, respectively (n = 3). Both Ru.Cr and Ru.F demonstrated comparable antioxidant activity using vitamin C as standard (p ≤ 0.05). In test dose of 300 mg of Ru.Cr, rectal temperature was reduced by 74% (p ≤ 0.05) on 4^th hour of the administration. More, Ru.F produced 72% reduction in pyrexia (p ≤ 0.05) on 4^th hour of administration of paracetamol in Westar rats.

Conclusions

The current work confirms that aerial parts of Rubus ulmifolius contain flavonoids that are safe up to 6 g/kg (p.o). Crude methanolic extract and flavonoids rich fraction of Rubus ulmifolius have significant antioxidant and antipyretic activity. Further work is required to isolate the pharmacologically active substances for relatively safe and effective antipyretics and antioxidants.

Anti-inflammatory effect of apigenin and hydroalcoholic extract of Dracocephalum kotschyi on acetic acid-induced colitis in rats

Colitis is an inflammatory disease of the intestine with unknown etiology involving multiple immune, genetic, and environmental factors. We were interested to examine the effect of total extract from Dracocephalum kotschyi (D. kotschyi) Boiss. on the experimental colitis. D. kotschyi hydroalcoholic extract (10, 20, and 40 mg/kg) or apigenin (5, 10, and 20 mg/kg) were administered orally 2 h prior to induction of colitis which was induced by intrarectal administration of acetic acid (4%) in rats. Prednisolone (4 m/kg) was used as the standard drug for comparison. Biochemical evaluation of inflamed colon was performed by measuring myeloperoxidase (MPO) activity. After 5 days treatment, mucosal ulceration was evaluated. Intrarectal instillation of acetic acid caused significant inflammatory reactions as indicated by macroscopic and microscopic changes. The activity of MPO increased in vehicle treated groups while recovered to normal level by pretreatment of animals with D. kotschyi extract, apigenin, or prednisolone. D. kotschyi and apigenin-treated groups showed significantly lower score values of macroscopic and microscopic characters when compared with the vehicle-treated negative control group. The beneficial effect of apigenin was comparable with that of prednisolone. This research has shown the anti-inflammatory potential of D. kotschyi extract and apigenin in experimentally induced colitis.

Quercetin as an Emerging Anti-Melanoma Agent: A Four-Focus Area Therapeutic Development Strategy

Replacing current refractory treatments for melanoma with new prevention and therapeutic approaches is crucial in order to successfully treat this aggressive cancer form. Melanoma develops from neural crest cells, which express tyrosinase – a key enzyme in the pigmentation pathway. The tyrosinase enzyme is highly active in melanoma cells and metabolizes polyphenolic compounds; tyrosinase expression thus makes feasible a target for polyphenol-based therapies. For example, quercetin (3,3′,4′,5,7-pentahydroxyflavone) is a highly ubiquitous and well-classified dietary polyphenol found in various fruits, vegetables, and other plant products including onions, broccoli, kale, oranges, blueberries, apples, and tea. Quercetin has demonstrated antiproliferative and proapoptotic activity in various cancer cell types. Quercetin is readily metabolized by tyrosinase into various compounds that promote anticancer activity; additionally, given that tyrosinase expression increases during tumorigenesis, and its activity is associated with pigmentation changes in both early- and late-stage melanocytic lesions, it suggests that quercetin can be used to target melanoma. In this review, we explore the potential of quercetin as an anti-melanoma agent utilizing and extrapolating on evidence from previous in vitro studies in various human malignant cell lines and propose a “four-focus area strategy” to develop quercetin as a targeted anti-melanoma compound for use as either a preventative or therapeutic agent. The four areas of focus include utilizing quercetin to (i) modulate cellular bioreduction potential and associated signaling cascades, (ii) affect transcription of relevant genes, (iii) regulate epigenetic processes, and (iv) develop effective combination therapies and delivery modalities/protocols. In general, quercetin could be used to exploit tyrosinase activity to prevent, and/or treat, melanoma with minimal additional side effects.

The consumption of coffee and black tea and the risk of lung cancer

PURPOSE

Coffee and black tea are among the most consumed beverages worldwide. Although their potential role in lung cancer occurrence has been investigated in several studies, results have been inconclusive. We investigated the associations between intake of coffee and black tea with lung cancer in a population-based case-control study in Montreal, Canada.

METHODS

These analyses included 1130 cases and 1483 controls. Adjusted odds ratios (ORs) were estimated between four metrics of coffee and black tea consumption (frequency, average daily amount, duration, and cumulative amount) and lung cancer, using unconditional logistic regression.

RESULTS

The adjusted ORs (95% confidence intervals) for lung cancer comparing daily to never consumers were 0.73 (0.49-1.10) for coffee and 1.05 (0.85-1.31) for black tea. Analyses of other metrics did not reveal any clear patterns of increasing or decreasing risk with increasing amounts or duration of consumption. There was no strong evidence of OR modification by sex or smoking level. The OR estimates did not materially differ by histological subtype for either of the beverages.

CONCLUSION

Our results do not provide strong support for associations between consumption of coffee and black tea and lung cancer.

Advancing toxicology research using in vivo high throughput toxicology with small fish models

Small freshwater fish models, especially zebrafish, offer advantages over traditional rodent models, including low maintenance and husbandry costs, high fecundity, genetic diversity, physiology similar to that of traditional biomedical models, and reduced animal welfare concerns. The Collaborative Workshop on Aquatic Models and 21st Century Toxicology was held at North Carolina State University on May 5-6, 2014, in Raleigh, North Carolina, USA. Participants discussed the ways in which small fish are being used as models to screen toxicants and understand mechanisms of toxicity. Workshop participants agreed that the lack of standardized protocols is an impediment to broader acceptance of these models, whereas development of standardized protocols, validation, and subsequent regulatory acceptance would facilitate greater usage. Given the advantages and increasing application of small fish models, there was widespread interest in follow-up workshops to review and discuss developments in their use. In this article, we summarize the recommendations formulated by workshop participants to enhance the utility of small fish species in toxicology studies, as well as many of the advances in the field of toxicology that resulted from using small fish species, including advances in developmental toxicology, cardiovascular toxicology, neurotoxicology, and immunotoxicology. We alsoreview many emerging issues that will benefit from using small fish species, especially zebrafish, and new technologies that will enable using these organisms to yield results unprecedented in their information content to better understand how toxicants affect development and health.

Characteristic features of cytotoxic activity of flavonoids on human cervical cancer cells

Cervical cancer is the most common gynecologic malignancy worldwide and development of new therapeutic strategies and anticancer agents is an urgent priority. Plants have remained an important source in the search for novel cytotoxic compounds and several polyphenolic flavonoids possess antitumor properties. In this review article, data about potential anticarcinogenic activity of common natural flavonoids on various human cervical cancer cell lines are compiled and analyzed showing perspectives for the use of these secondary metabolites in the treatment of cervical carcinoma as well as in the development of novel chemotherapeutic drugs. Such anticancer effects of flavonoids seem to differentially depend on the cellular type and origin of cervical carcinoma creating possibilities for specific targeting in the future. Besides the cytotoxic activity per se, several flavonoids can also contribute to the increase in efficacy of conventional therapies rendering tumor cells more sensitive to standard chemotherapeutics and irradiation. Although the current knowledge is still rather scarce and further studies are certainly needed, it is clear that natural flavonoids may have a great potential to benefit cervical cancer patients.

Hesperetin induces the apoptosis of hepatocellular carcinoma cells via mitochondrial pathway mediated by the increased intracellular reactive oxygen species, ATP and calcium

Hesperetin, a flavonoid from citrus fruits, has been proved to possess biological activity on various types of human cancers. However, few related studies on hepatocellular carcinoma are available. In this study, we aimed to investigate the effect of hesperetin on hepatocellular carcinoma cells in vitro and in vivo and clarify its potentially specific mechanism. Compared with the control group, the proliferations of hepatocellular carcinoma cells in hesperetin groups were significantly inhibited (P < 0.05), and a dose- and time-dependent inhibition of cell viability was observed. When pretreated with H2O2 (1 mM) or N-acetyl-L-cysteine (5 mM), the inhibition of cell viability by hesperetin was enhanced or reduced, respectively (P < 0.05). Similarly, the levels of intracellular ROS, ATP and Ca(2+) changed in different groups (P < 0.05). The results of Hoechst 33258 staining showed that the percentages of apoptotic cells in hesperetin groups are remarkably higher than that in control group (P < 0.05). And the results of Western blot showed that hesperetin caused an increase in the levels of cytosolic AIF, cytosolic Apaf-1, cytosolic Cyt C, caspase-3, caspase-9 and Bax and a decrease in that of Bcl-2, mitochondrial AIF, mitochondrial Apaf-1 and mitochondrial Cyt C (P < 0.05). Meanwhile, hesperetin significantly inhibited the growth of xenograft tumors. Our study suggests that hesperetin could inhibit the proliferation and induce the apoptosis of hepatocellular carcinoma via triggering the activation of the mitochondrial pathway by increasing the levels of intracellular ROS, ATP and Ca(2+).

Cytotoxicity of dietary flavonoids on different human cancer types

Flavonoids are ubiquitous in nature. They are also in food, providing an essential link between diet and prevention of chronic diseases including cancer. Anticancer effects of these polyphenols depend on several factors: Their chemical structure and concentration, and also on the type of cancer. Malignant cells from different tissues reveal somewhat different sensitivity toward flavonoids and, therefore, the preferences of the most common dietary flavonoids to various human cancer types are analyzed in this review. While luteolin and kaempferol can be considered as promising candidate agents for treatment of gastric and ovarian cancers, respectively, apigenin, chrysin, and luteolin have good perspectives as potent antitumor agents for cervical cancer; cells from main sites of flavonoid metabolism (colon and liver) reveal rather large fluctuations in anticancer activity probably due to exposure to various metabolites with different activities. Anticancer effect of flavonoids toward blood cancer cells depend on their myeloid, lymphoid, or erythroid origin; cytotoxic effects of flavonoids on breast and prostate cancer cells are highly related to the expression of hormone receptors. Different flavonoids are often preferentially present in certain food items, and knowledge about the malignant tissue-specific anticancer effects of flavonoids could be purposely applied both in chemoprevention as well as in cancer treatment.

Site-specific anticancer effects of dietary flavonoid quercetin

Food-derived flavonoid quercetin, widely distributed in onions, apples, and tea, is able to inhibit growth of various cancer cells indicating that this compound can be considered as a good candidate for anticancer therapy. Although the exact mechanism of this action is not thoroughly understood, behaving as antioxidant and/or prooxidant as well as modulating different intracellular signalling cascades may all play a certain role. Such inhibitory activity of quercetin has been shown to depend first of all on cell lines and cancer types; however, no comprehensive site-specific analysis of this effect has been published. In this review article, cytotoxicity constants of quercetin measured in various human malignant cell lines of different origin were compiled from literature and a clear cancer selective action was demonstrated. The most sensitive malignant sites for quercetin revealed to be cancers of blood, brain, lung, uterine, and salivary gland as well as melanoma whereas cytotoxic activity was higher in more aggressive cells compared to the slowly growing cells showing that the most harmful cells for the organism are probably targeted. More research is needed to overcome the issues of poor water solubility and relatively low bioavailability of quercetin as the major obstacles limiting its clinical use.

In vitro action of flavonoids in the canine malignant histiocytic cell line DH82

Cancer is commonly diagnosed in dogs over the age of 10 and is a leading cause of death due to the lack of effective drugs. Flavonoids possess antioxidant, anti-inflammatory and anticarcinogenic properties and have been studied as chemopreventive agents in human cancer therapy. However, the literature on dogs is sparse. In this study, we analyzed the effect of nine flavonoids on cell viability, DNA damage and topoisomerase IIa/IIb gene expression in a canine tumor cell line (DH82). Apigenin, luteolin, trans-chalcone and 4-methoxychalcone showed the highest degree of cytotoxicity in the absence of considerable DNA damage, whereas genistein exhibited low cytotoxicity but induced a high level of DNA damage. These five flavonoids inhibited topoisomerase IIa and IIb gene expression to variable extents and with variable specificity. Genistein exerted a lower inhibitory effect on the two topoisomerases than luteolin and apigenin. trans-Chalcone and 4-methoxychalcone exerted greater inhibition of topoisomerase IIa expression than topoisomerase IIb. The differences in the effects between genistein and luteolin and apigenin might be explained by the position of ring B, whereas the more specific effect of chalcones on topoisomerase IIa might be due to their open chain structure.

Inhibitory effects of apigenin and kaempferol on the essential solute carrier transporters

AIM: To evaluate the inhibitory effects of apigenin and kaempferol on the uptake of several important solute carrier (SLC) transporters.

METHODS: Various SLC transporters including the essential human organic anion transporter 1 (OAT1), OAT2, OAT3 and OAT4 as well as the important organic cation transporter 1 (OCTN1) and OCTN2, were over-expressed in human embryonic kidney (HEK)-293 cells, a well-established cell model of transporter studies. Transport uptake assay was performed 24 h after the transfection. The transport activity was assessed with the uptake of previously determined transporter model substrates and the inhibitory effect of apigenin and kaempferol was evaluated with the substrate uptake in the presence of 10 μmol/L of each compound. Uptake measurements with varying concentrations of inhibitors (ranged from 0.0001 to 50 μmol/L) were performed to further characterize the inhibitory potency of apigenin and kaempferol. The IC₅₀ value (the concentration that inhibits 50% of the transporter function) of each compound was then calculated by the nonlinear regression model of Graphpad Prism 6.0 software.

RESULTS: Our data indicated that apigenin could potently inhibit the uptake of estrone-3-sulfate (ES) mediated by the HEK-293 cells expressing OAT2, OAT3 and OAT4 as well as the L-ergothioneine uptake via OCTN1-expressing HEK-293 cells. Among these transporters, the most prominent inhibition of apigenin was observed in the case of OAT3. Kaempferol showed significant inhibitory effects on the uptake of ES mediated through OAT2 and OAT3. Impaired L-ergothioneine uptake due to the presence of kaempferol was also observed in OCTN1-expressing HEK-293 cells. Similar to apigenin, kaempferol showed the most potent inhibitory effect on OAT3 as well. To further assess the inhibitory potencies of these two compounds on the uptake of ES mediated by OAT3-expressing HEK-293 cells, their IC₅₀ values were then determined. Both chemicals showed pronounced inhibitory potencies on OAT3 with the IC₅₀ values of 1.7 ± 0.1 and 1.0 ± 0.1 μmol/L (P < 0.01) for apigenin and kaempferol, respectively.

CONCLUSION: Both apigenin and kaempferol are potent inhibitors of OAT3; precautions will be necessary when co-administrating them with drugs that are substrates of OAT3.

Investigation on flavonoid composition and anti free radical potential of Sida cordata

BACKGROUND

Sida cordata, a member of Family Malvaceae is used in folk medicine for various ailments including liver diseases. In this study we investigated, its flavonoid constituents, in vitro antioxidant potential against different free radicals and hepatoprotection against carbon tetrachloride (CCl4)-induced liver damage in rat.

METHODS

Dried powder of S. cordata whole plant was extracted with methanol and the resultant (SCME) obtained was fractionated with escalating polarity to obtain n-hexane fraction (SCHE), ethyl acetate fraction (SCEE), n-butanol fraction (SCBE) and the remaining soluble portion as aqueous fraction (SCAE). Diverse in vitro antioxidants assays such as DPPH, H2O2, •OH, ABTS, β-carotene bleaching assay, superoxide radical, lipid peroxidation, reducing power, and total antioxidant capacity were studied to assess scavenging potential of methanol extract and its derived fractions. On account of marked scavenging activity SCEE was selected to investigate the hepatoprotective potential against CCl4 induced toxicity in Sprague-Dawley male rats by assessing the level of serum markers (alkaline phosphatase, alanine transaminase, aspartate transaminase, lactate dehydrogenase, bilirubin, and γ-glutamyltransferase) and of liver antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), glutathione-S-transfers (GST), glutathione reductase (GSR), glutathione peroxidase (GSH-Px), and reduced glutathione (GSH) and lipid peroxidation (TBARS). Histology of the liver was performed to study alteration in histoarchitecture. Existence of active flavonoids was established by thin layer chromatographic studies.

RESULTS

Considerable amount of flavonoid and phenolic contents were recorded in the methanol extract and its derived fractions. Although the extract and all its derived fractions exhibited good antioxidant activities however, the most distinguished scavenging potential was observed for SCEE. Treatment of SCEE decreased the elevated level of serum marker enzymes induced with CCl4 administration whereas increased the activity of hepatic antioxidant enzymes (CAT, SOD, POD, GST, GSR and GSH-Px). Hepatic concentration of GSH was increased while lipid peroxidation was decreased with SCEE administration in CCl4 intoxicated rats. Presence of apigenin with some unknown compounds was observed in SCEE by using thin layer chromatography.

CONCLUSIONS

These results revealed the presence of some bioactive compound in the ethyl acetate fraction, confirming the utility of S. cordata against liver diseases in folk medicine.

Apigenin impairs oral squamous cell carcinoma growth in vitro inducing cell cycle arrest and apoptosis

In the present study, we investigated the effect of apigenin, a flavonoid widely present in fruits and vegetables, on a tongue oral cancer-derived cell line (SCC-25) and on a keratinocyte cell line (HaCaT), with the aim of unveiling its antiproliferative mechanisms. The effect of apigenin on cell growth was evaluated by MTT assay, while apoptosis was investigated by phosphatidyl serine membrane translocation and cell cycle distribution by propidium iodide DNA staining through flow cytometry. In addition the expression of cyclins and cyclin-dependent kinases was evaluated by western blotting. A reduction of apigenin-induced cell growth was found in both cell lines, although SCC-25 cells were significantly more sensitive than the immortalized keratinocytes, HaCaT. Moreover, apigenin induced apoptosis and modulated the cell cycle in SCC-25 cells. Apigenin treatment resulted in cell cycle arrest at both G0/G1 and G2/M checkpoints, while western blot analysis revealed the decreased expression of cyclin D1 and E, and inactivation of CDK1 upon apigenin treatment. These results demonstrate the anticancer potential of apigenin in an oral squamous cell carcinoma cell line, suggesting that it may be a very promising chemopreventive agent due to its cancer cell cytotoxic activity and its ability to act as a cell cycle modulating agent at multiple levels.

Biochemical basis for functional ingredient design from fruits

Functional food ingredients (nutraceuticals) in fruits range from small molecular components, such as the secondary plant products, to macromolecular entities, e.g., pectin and cellulose, that provide several health benefits. In fruits, the most visible functional ingredients are the color components anthocyanins and carotenoids. In addition, several other secondary plant products, including terpenes, show health beneficial activities. A common feature of several functional ingredients is their antioxidant function. For example, reactive oxygen species (ROS) can be oxidized and stabilized by flavonoid components, and the flavonoid radical can undergo electron rearrangement stabilizing the flavonoid radical. Compounds that possess an orthodihydroxy or quinone structure can interact with cellular proteins in the Keap1/Nrf2/ARE pathway to activate the gene transcription of antioxidant enzymes. Carotenoids and flavonoids can also exert their action by modulating the signal transduction and gene expression within the cell. Recent results suggest that these activities are primarily responsible for the health benefits associated with the consumption of fruits and vegetables.

The biochemical and cellular basis for nutraceutical strategies to attenuate neurodegeneration in Parkinson's disease

Future therapeutic intervention that could effectively decelerate the rate of degeneration within the substantia nigra pars compacta (SNc) could add years of mobility and reduce morbidity associated with Parkinson’s disease (PD). Neurodegenerative decline associated with PD is distinguished by extensive damage to SNc dopaminergic (DAergic) neurons and decay of the striatal tract. While genetic mutations or environmental toxins can precipitate pathology, progressive degenerative succession involves a gradual decline in DA neurotransmission/synaptic uptake, impaired oxidative glucose consumption, a rise in striatal lactate and chronic inflammation. Nutraceuticals play a fundamental role in energy metabolism and signaling transduction pathways that control neurotransmission and inflammation. However, the use of nutritional supplements to slow the progression of PD has met with considerable challenge and has thus far proven unsuccessful. This review re-examines precipitating factors and insults involved in PD and how nutraceuticals can affect each of these biological targets. Discussed are disease dynamics (Sections 1 and 2) and natural substances, vitamins and minerals that could impact disease processes (Section 3). Topics include nutritional influences on α-synuclein aggregation, ubiquitin proteasome function, mTOR signaling/lysosomal-autophagy, energy failure, faulty catecholamine trafficking, DA oxidation, synthesis of toxic DA-quinones, o-semiquinones, benzothiazolines, hyperhomocyseinemia, methylation, inflammation and irreversible oxidation of neuromelanin. In summary, it is clear that future research will be required to consider the multi-faceted nature of this disease and re-examine how and why the use of nutritional multi-vitamin-mineral and plant-based combinations could be used to slow the progression of PD, if possible.

Antiproliferative and pro-apoptotic effects of quercetin on human pancreatic carcinoma cell lines EPP85-181P and EPP85-181RDB

Polyphenols are present in several edible plants and for many years induce high interest mainly due to their antioxidative and anti-inflammatory influence. At present, numerous studies are conducted on antineoplastic effects of the compounds. One of most effective biopolyphenols involves the flavonol quercetin. Our studies aimed at evaluation of antiproliferative and pro-apoptotic effects of quercetin alone and in combinations with daunorubicin on cells of human pancreatic carcinoma lines. The experiments were conducted on two cell lines, sensitive to daunorubicin EPP85-181P line, and its resistant variant EPP85-181RDB. Effect of studied substances on cell proliferation was detected using sulphorhodamine B (SRB) protein staining method. Apoptotic damage was estimated using comet and TUNEL techniques. Our data demonstrated that quercetin exerted cytotoxic action on cells of the both neoplastic cell lines in concentration-dependent manner. In the case of EPP85-181RDB cell line, quercetin seemed to sensitize resistant cells to daunorubicin. In parallel, the effect of both substances on the sensitive cell line was synergistic. Results of the studies confirmed that quercetin may probably break resistance of neoplastic cells to chemotherapy. On the other side, studied flavonol augmented action of cytostatic drug in case of sensitive tumour cells what suggest, that it might allow to decrease dosage of cytostatic drugs and reduce negative side effects of the treatment.

Effect of cigarette taxes on the consumption of cigarettes, alcohol, tea and coffee in Taiwan

OBJECTIVES

To analyse whether a health tax of 10 New Taiwan Dollars (NT$) (US$0.3) imposed on cigarettes in 2009 will help to reduce cigarette consumption, and whether or not the cigarette tax will affect consumption of alcohol, coffee and tea.

STUDY DESIGN

Time series data for consumption and retail prices of tobacco, alcohol, tea and coffee were collected and analysed for the period 1973-2007.

METHODS

To establish the Central Bureau of Statistics demand function to estimate the overall demand price elasticities of cigarettes, alcohol, tea and coffee, a seemingly unrelated regression analysis was used. The independent variables were annual consumption of cigarettes, alcohol, tea and coffee. The dependent variables were prices of and expenditures on cigarettes, alcohol, tea and coffee.

RESULTS

The estimated own-price elasticities for cigarettes and alcohol are close to -0.726. The own-price elasticities for tea and coffee are less than those for cigarettes and alcohol. Hence, it is predicted that the NT$10 health tax on cigarettes will reduce cigarette consumption by a significant 13.19%. Analysis of cross-price elasticity reveals that alcohol is complementary to cigarettes.

CONCLUSIONS

Taxation is an effective smoking control policy tool that not only helps to reduce consumption of cigarettes, but also reduces consumption of alcoholic beverages.

Apigenin: a promising molecule for cancer prevention

Apigenin, a naturally occurring plant flavone, abundantly present in common fruits and vegetables, is recognized as a bioactive flavonoid shown to possess anti-inflammatory, antioxidant and anticancer properties. Epidemiologic studies suggest that a diet rich in flavones is related to a decreased risk of certain cancers, particularly cancers of the breast, digestive tract, skin, prostate and certain hematological malignancies. It has been suggested that apigenin may be protective in other diseases that are affected by oxidative process, such as cardiovascular and neurological disorders, although more research needs to be conducted in this regard. Human clinical trials examining the effect of supplementation of apigenin on disease prevention have not been conducted, although there is considerable potential for apigenin to be developed as a cancer chemopreventive agent.

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.

Production of hesperetin glycosides by Xanthomonas campestris and cyclodextrin glucanotransferase and their anti-allergic activities

The production of hesperetin glycosides was investigated using glycosylation with Xanthomonas campestris and cyclodextrin glucanotransferase (CGTase). X. campestris glucosylated hesperetin to its 3'-, 5-, and 7-O-glucosides, and CGTase converted hesperetin glucosides into the corresponding maltosides. The resulting 7-O-glucoside and 7-O-maltoside of hesperetin showed inhibitory effects on IgE antibody production and on O2- generation from rat neutrophils.

Quercetin as a potential modulator of P-glycoprotein expression and function in cells of human pancreatic carcinoma line resistant to daunorubicin

P-glycoprotein (P-gp) is one of the ABC transporters responsible for the resistance of several tumours to successful chemotherapy. Numerous agents are capable of interfering with the P-gp-mediated export of drugs but unfortunately most of them produce serious side effects. Some plant polyphenols, including the flavonol quercetin (Q), manifest anti-neoplastic activity mainly due to their influence on cell cycle control and apoptosis. Reports are also available which show that Q may intensify action of cytostatic drugs and suppress the multidrug resistance (MDR) phenomenon. The study aimed at determination if Q sensitizes cells resistant to daunorubicin (DB) through its effect on P-gp expression and action. The experiments were conducted on two cell lines of human pancreatic carcinoma, resistant to DB EPP85-181RDB and sensitive EPP85-181P as a comparison. Cells of both lines were exposed to selected concentrations of Q and DB, and then membranous expression of P-gp and its transport function were examined. The influence on expression of gene for P-gp (ABCB1) was also investigated. Results of the studies confirmed that Q affects expression and function of P-gp in a concentration-dependent manner. Moreover it decreased expression of ABCB1. Thus, Q may be considered as a potential modulator of P-gp.

Mechanism-based common reactivity pattern (COREPA) modelling of aryl hydrocarbon receptor binding affinity

The aryl hydrocarbon receptor is a ligand-activated transcription factor responsive to both natural and synthetic environmental compounds, with the most potent agonist being 2,3,7,8-tetrachlotrodibenzo-p-dioxin. The aim of this work was to develop a categorical COmmon REactivity PAttern (COREPA)-based structure-activity relationship model for predicting aryl hydrocarbon receptor ligands within different binding ranges. The COREPA analysis suggested two different binding mechanisms called dioxin- and biphenyl-like, respectively. The dioxin-like model predicts a mechanism that requires a favourable interaction with a receptor nucleophilic site in the central part of the ligand and with electrophilic sites at both sides of the principal molecular axis, whereas the biphenyl-like model predicted a stacking-type interaction with the aryl hydrocarbon receptor allowing electron charge transfer from the receptor to the ligand. The current model was also adjusted to predict agonistic/antagonistic properties of chemicals. The mechanism of antagonistic properties was related to the possibility that these chemicals have a localized negative charge at the molecule's axis and ultimately bind with the receptor surface through the electron-donating properties of electron-rich groups. The categorization of chemicals as agonists/antagonists was found to correlate with their gene expression. The highest increase in gene expression was elicited by strong agonists, followed by weak agonists producing lower increases in gene expression, whereas all antagonists (and non-aryl hydrocarbon receptor binders) were found to have no effect on gene expression. However, this relationship was found to be quantitative for the chemicals populating the areas with extreme gene expression values only, leaving a wide fuzzy area where the quantitative relationship was unclear. The total concordance of the derived aryl hydrocarbon receptor binding categorical structure-activity relationship model was 82% whereas the Pearson's coefficient was 0.88.