Cytotoxic effect of plant polyphenols and fat-soluble vitamins on malignant human cultured cells

Phytogenic supplement containing menthol, carvacrol and carvone ameliorates gut microbiota and production performance of commercial layers

Consumer push towards open and free-range production systems makes biosecurity on farms challenging, leading to increased disease and animal welfare issues. Phytogenic products are increasingly becoming a viable alternative for the use of antibiotics in livestock production. Here we present a study of the effects of commercial phytogenic supplement containing menthol, carvacrol and carvone on intestinal microbiota of layer hens, microbial functional capacity, and intestinal morphology. A total of 40,000 pullets were randomly assigned to two sides of the experimental shed. Growth performance, mortality, egg production and egg quality parameters were recorded throughout the trial period (18–30 weeks of age). Microbial community was investigated using 16S amplicon sequencing and functional difference using metagenomic sequencing. Phytogen supplemented birds had lower mortality and number of dirty eggs, and their microbial communities showed reduced richness. Although phytogen showed the ability to control the range of poultry pathogens, its action was not restricted to pathogenic taxa, and it involved functional remodelling the intestinal community towards increased cofactor production, heterolactic fermentation and salvage and recycling of metabolites. The phytogen did not alter the antimicrobial resistance profile or the number of antibiotic resistance genes. The study indicates that phytogenic supplementation can mimic the action of antibiotics in altering the gut microbiota and be used as their alternative in industry-scale layer production.

A Systematic Review of the Preventive and Therapeutic Effects of Naringin Against Human Malignancies

Background: Natural product-based cancer preventive and therapeutic entities, such as flavonoids and their derivatives, are shown to have a noticeable capability to suppress tumor formation and cancer cell growth. Naringin, a natural flavanone glycoside present in various plant species, has been indicated to modulate different signaling pathways and interact with numerous cell signaling molecules, which allows for an extensive variety of pharmacological actions, such as amelioration of inflammation, oxidative stress, metabolic syndromes, bone disorders, and cancer. The purpose of this systematic review is to present a critical and comprehensive assessment of the antitumor ability of naringin and associated molecular targets in various cancers. Methods: Studies were identified through systematic searches of Science Direct, PubMed, and Scopus as well as eligibility checks according to predefined selection criteria. Results: Eighty-seven studies were included in this systematic review. There was strong evidence for the association between treatment with naringin alone, or combined with other drugs and antitumor activity. Additionally, studies showed that naringin-metal complexes have greater anticancer effects compared to free naringin. It has been demonstrated that naringin employs multitargeted mechanisms to hamper cancer initiation, promotion, and progression through modulation of several dysregulated signaling cascades implicated in cell proliferation, autophagy, apoptosis, inflammation, angiogenesis, metastasis, and invasion. Conclusion: The results of our work show that naringin is a promising candidate for cancer prevention and treatment, and might offer substantial support for the clinical application of this phytocompound in the future. Nevertheless, further preclinical and clinical studies as well as drug delivery approaches are needed for designing novel formulations of naringin to realize the full potential of this flavonoid in cancer prevention and intervention.

Antimicrobial Activity of Herbal Mixture Extract Combination on Microorganisms Isolated from Urinary Tract infection

Urinary tract infection (UTI) is the second most common infection after respiratory tract infection. Its prevalence is more in women as compared to men. Approximately 50% of women have an infection of the Urinary tract in their life-time. The bacterial infection is one of the most important bioactivity; using their ability to imitate evanish then distributes international fitness problems into the 21st centenary. Thus a recent study was undertaken to investigate the antibacterial activity of a mixture of three medicinal plants against UTI infectious isolates. The three considered plants were (Aloe vera, Artemisia herba alba and Teucrium polium), which were used in Iraqi medicine for many centuries. The effectiveness of this combination was investigated using in vitro well diffusion method. The extract was tested against four isolated pathogenic bacteria (Staphylococcus aureus, Klebsiella spp, and Proteus spp). The aqueous extract exhibited antibacterial activity against gram-positive and gram-negative bacteria. The mixture extract had the highest effect against S. aureus and Proteus spp, followed by a lower effect on Klebsiella spp. In conclusion, the antibacterial effect of the tested plant extracts confirmed a higher impact on Gram-positive bacteria as compared to Gram-negative bacteria. Therefore, it can be concluded that the usage of these plants as a traditional medicine form can be considered as a strong assistant to regular medicine drugs and treatments.

Tannic acid mediated induction of apoptosis in human glioma Hs 683 cells

Tannic acid (TA), a natural plant compound, is known to induce the death of cancer cells in various types of cancer. The present study was designed with the aim of exploring the effects of tannic acid in vitro on HS 683, a glioma cell line, and to study the mechanism involved in the induction of cytotoxicity and apoptosis by TA. TA exhibited maximum cytotoxic activity against the Hs 683 cell line. Nuclear morphology, 4′,6-diamidino-2-phenylindole staining and annexin V/propidium iodide apoptosis assaying of Hs 683 cells confirmed that cell death was due to the induction of apoptosis by TA. Further mechanistic study of TA on Hs 683 cells revealed that it decreased cell growth with increasing TA concentration, that resulted in the activation of pro-caspase 3 and caspase 9 and the cleavage of poly (ADP-ribose) polymerase, implying the induction of apoptosis cascades. Biochemical evidence of apoptosis resulted from the loss of mitochondrial membrane potential and increased intracellular reactive oxygen species production by TA in a dose-dependent manner. Based on this data, TA may be further investigated as a potential anticancer therapeutic lead.

Butein in health and disease: A comprehensive review

BACKGROUND

The risk of suffering from many chronic diseases seems to have made no improvement despite the advancement in medications available in the modern world. Moreover, the use of synthetic chemicals as medications has proved to worsen the scenario due to the various adverse side effects associated with them.

PURPOSE

Extensive research on natural medicines provides ample evidence on the safety and efficacy of phytochemicals and nutraceuticals against diverse chronic ailments. Therefore, it is advisable to use natural products in the management of such diseases. This article aims to present a comprehensive and critical review of known pharmacological and biological effects of butein, an important chalcone polyphenol first isolated from Rhus verniciflua Stokes, implicated in the prevention and treatment of various chronic disease conditions.

METHODS

An extensive literature search was conducted using PubMed, ScienceDirect, Scopus and Web of Science^TM core collections using key words followed by evaluation of the bibliographies of relevant articles.

RESULTS

Butein has been preclinically proven to be effective against several chronic diseases because it possesses a wide range of biological properties, including antioxidant, anti-inflammatory, anticancer, antidiabetic, hypotensive and neuroprotective effects. Furthermore, it has been shown to affect multiple molecular targets, including the master transcription factor nuclear factor-κB and its downstream molecules. Moreover, since it acts on multiple pathways, the chances of non-responsiveness and resistance development is reduced, supporting the use of butein as a preferred treatment option.

CONCLUSION

Based on numerous preclinical studies, butein shows significant therapeutic potential against various diseases. Nevertheless, well-designed clinical studies are urgently needed to validate the preclinical findings.

Chemistry and pharmacology of Bidens pilosa: an overview

Bidens pilosa L. is an edible herb and has been traditionally used for a wide range of ailments in many countries. The aim of this review is to present comprehensive information of the chemical constituents, nutraceutical and ethnomedical uses as well as the biological and pharmacological effects and toxicity of this plant based on 218 literary sources reported over 40 years. Major chemical constituents (including 301 compounds) belonging to polyacetylenes, polyacetylene glycosides, flavonoids, flavone glycosides, aurones, chalcones, okanin glycosides, phenolic acids, terpenes, pheophytins, fatty acids and phytosterols have been identified or isolated from the different parts of this plant. Many of them have been considered as the bioactive compounds which are potentially responsible for the pharmacological actions. Various types of preparations, extracts and individual compounds derived from this plant have been found to possess biological and pharmacological activities such as anti-malarial, anti-allergy, anti-hypertensive and smooth muscle relaxant, anti-cancerogenic, anti-diabetic, anti-inflammatory, anti-microbial, antioxidant. The results of data analysis on the chemicals, pharmacological and toxicological characteristics of B. pilosa validate the view of its folk worldwide-medicinal uses. This herb has a great beneficial therapeutic property and is possibly used for complement or alternative to pharmaceutical drugs in some specific cases. However, this herb is known as hyperaccumulator and as-excluder; therefore, harvesting the herb for medicinal uses should be judiciously cautioned.

Apoptotic effect of tannic acid on fatty acid synthase over-expressed human breast cancer cells

Breast cancer is one of the most common cancers and is the second leading cause of cancer mortality in women worldwide. Novel therapies and chemo-therapeutic drugs are urgently needed to be developed for the treatment of breast cancer. Increasing evidence suggests that fatty acid synthase (FAS) plays an important role in breast cancer, for the expression of FAS is significantly higher in human breast cancer cells than in normal cells. Tannic acid (TA), a natural polyphenol, possesses significant biological functions, including bacteriostasis, hemostasis, and anti-oxidant. Our previous studies demonstrated that TA is a natural FAS inhibitor whose inhibitory activity is stronger than that of classical FAS inhibitors, such as C75 and cerulenin. This study further assessed the effect and therapeutic potential of TA on FAS over-expressed breast cancer cells, and as a result, TA had been proven to possess the functions of inhibiting intracellular FAS activity, down-regulating FAS expression in human breast cancer MDA-MB-231 and MCF-7 cells, and inducing cancer cell apoptosis. Since high-expressed FAS is recognized as a molecular marker for breast cancer and plays an important role in cancer prognosis, these findings suggest that TA is a potential drug candidate for treatment of breast cancer.

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.

Preventive effect of tannic acid on 2-acetylaminofluorene induced antioxidant level, tumor promotion and hepatotoxicity: a chemopreventive study

Tannic acid, present in almost every food derived from plants, has been widely investigated as a chemopreventive agent because, apart from its use as a food additive, pharmacological studies have demonstrated its many health-promoting properties. In this study, we show the modulatory effect of tannic acid on 2-acetylaminofluorene (2-AAF)-mediated hepatic oxidative stress and cell proliferation in rats. 2-AAF (50 mg/kg body weight) caused reduction in hepatic glutathione content and the activities of hepatic anti-oxidant enzymes and phase-II metabolizing enzymes with an enhancement of xanthine oxidase activity, lipid peroxidation and hydrogen peroxide content. 2-AAF treatment also induced serum oxaloacetate and pyruvate transaminase, lactate dehydrogenase and gamma-glutamyl transpeptidase. Treatment of rats orally with tannic acid (125 and 250 mg/kg body weight) resulted in significant recovery of hepatic glutathione content, antioxidant and phase-II metabolizing enzymes. Also, significant decreases in lipid peroxidation, xanthine oxidase, hydrogen peroxide generation and liver damage marker enzymes were observed. The antiproliferative efficacy of the tannic acid was also evaluated. The promotion parameters induced (ornithine decarboxylase activity and DNA synthesis) by 2-AAF administration in the diet with partial hepatectomy (PH) were also significantly suppressed, dose dependently, by tannic acid. Hence, we propose that tannic acid might suppress the promotion stage via inhibition of oxidative stress and polyamine biosynthetic pathway.

Butein inhibits the proliferation of breast cancer cells through generation of reactive oxygen species and modulation of ERK and p38 activities

Butein (3,4,2',4'-tetrahydroxychalcone) is a polyphenol derived from various natural plants and is capable of inducing several types of death in cancer cells. However, the molecular mechanisms underlying butein-induced breast cancer cell apoptosis remain unknown. The present study aimed to prove that butein inhibits the proliferation of MDA-MB‑231 human breast cancer cells in a dose- and time-dependent manner. Butein markedly induced the generation of reactive oxygen species (ROS), decreased the phosphorylation of extracellular signal-regulated kinase (ERK), increased p38 activity, diminished Bcl-2 expression, induced caspase 3 cleavage and was associated with poly(ADP-ribose) polymerase (PARP) cleavage. Our findings also indicate that ROS may play an important role in butein-induced apoptosis, as pre-treatment with the antioxidant, N-acetyl cysteine (NAC), prevented butein-induced apoptosis. In conclusion, our results demonstrate that butein inhibits the proliferation of breast cancer cells through the generation of ROS and the modulation of ERK and p38 activities. We also demonstrate that these effects may be abrogaged by pre-treatment with NAC. Our results suggest that butein may function as a potential therapeutic agent for the treatment of breast cancer.

Butein induces apoptosis in human uveal melanoma cells through mitochondrial apoptosis pathway

PURPOSE

To study the cytotoxic effects and related signaling pathways of butein on human uveal melanoma cells in vitro.

MATERIALS AND METHODS

Three human uveal melanoma cell lines (M17, SP6.5, and C918), retinal pigment epithelial (RPE) cells and scleral fibroblasts were treated with butein at different dosages. The effects of butein on cell viability were assessed by using the MTT assay. Cell apoptosis was determined using annexin V-FITC/ethidium homodimer III flow cytometry. Mitochondrial transmembrane potential changes were assessed by using the JC-1 fluorescent reader, cytosol cytochrome c levels, and the activities of caspase-3, -8, and -9 were measured by using an enzyme-linked immunosorbent assay or colorimetric assay.

RESULTS

Butein reduced the cell viability of cultured human uveal melanoma cells in a dose-dependent manner (10, 30, and 100 μM), with IC50 at 13.3 μM and 15.8 μM in SP6.5 and M17 cell lines, respectively. Similar effects were also found in a highly aggressive and metastatic C918 cell line (IC50 16.7 μM). Butein at lower concentrations (10-30 μM) selectively reduced the cell viability of uveal melanoma cells, without affecting cell viability of RPE cells and fibroblasts. Butein-induced apoptosis of melanoma cells, increased mitochondrial permeability and the level of cytosol cytochrome c, caspase-9 and -3 activities (but not caspase-8) in a dose-dependent manner.

CONCLUSIONS

Butein has selectively potent pro-apoptotic effects on cultured human uveal melanoma cells via the intrinsic mitochondrial pathway.

Butein inhibits the migration and invasion of SK-HEP-1 human hepatocarcinoma cells through suppressing the ERK, JNK, p38, and uPA signaling multiple pathways

Liver cancer is one of the most commonly diagnosed cancers and the leading cause of death in human populations. Butein, a tetrahydroxychalcone, has been shown to induce apoptosis in many human cancer cells, but the effects of butein on the migration and invasion of human liver cancer cells are not reported. Herein, we found that butein is effective in the suppression of migration and invasion in SK-HEP-1 human hepatocarcinoma cells by using the Matrigel cell migration assay and invasion system. The gelatin zymography assay indicated that butein inhibited the activity of matrix metalloproteinases 2 (MMP-2) and MMP-9. Western blotting analysis indicated that butein decreased the levels of MMP-2, -7, and -9, uPA, Ras, Rho A, ROCK1, ERK1/2, JNK1/2, p-p38, and p-c-Jun in SK-HEP-1 cells. Furthermore, butein inhibited the NF-κB binding activity in SK-HEP-1 cells by electrophoretic mobility shift assay. We also found that butein decreased the ERK, JNK, and p38 in SK-HEP-1 cells by in vitro kinase assay. In conclusion, this is the first study to demonstrate that butein might be a novel anticancer agent for the treatment of hepatocarcinoma through inhibiting migration and invasion.

Effect of methanolic extract of Terminalia arjuna against Helicobacter pylori 26695 lipopolysaccharide-induced gastric ulcer in rats

Helicobacter pylori lipopolysaccharide (HP-LPS) is a potent virulence factor in the causation of gastric ulcer and gastritis. H. pylori-induced gastric pathology is prevalent throughout the world. Herbal medicines are attracting attention because of their traditional values, popularity and belief, as well as for their advantages such as less toxicity, affordability and medicinal value. The present study aimed to evaluate the anti-ulcer effect of a methanolic extract of Terminalia arjuna (TA) against HP-LPS-induced gastric damage in rats. Ulcers were induced with HP-LPS (50 μg per animal) administered orally daily for 3 days. The efficacy of TA on gastric secretory parameters such as volume of gastric juice, pH, free and total acidity, pepsin concentration, and the cytoprotective parameters such as protein-bound carbohydrate complexes in gastric juice and gastric mucosa was assessed. The protective effect of TA was also confirmed by histopathological examination of gastric mucosa. HP-LPS-induced alterations in gastric secretory parameters were altered favourably in rats treated with TA, suggesting that TA has an anti-secretory role. Furthermore, HP-LPS-induced impairments in gastric defence factors were also prevented by treatment with TA. These results suggest that the severe cellular damage and pathological changes caused by HP-LPS are mitigated by TA; these effects are comparable with those of sucralfate. The anti-ulcer effect of TA may reflect its ability to combat factors that damage the gastric mucosa, and to protect the mucosal defensive factors.

Butein sensitizes human leukemia cells to apoptosis induced by tumor necrosis factor-related apoptosis inducing ligand (TRAIL)

Resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) therapy is frequently encountered, requiring combined treatments with sensitizing agents. It is, therefore, important to find nontoxic drugs which can be used together with TRAIL. In this study, we investigated natural compounds that can overcome resistance to TRAIL, and found that butein, a polyphenol, exhibits significant synergism with TRAIL. Treatment with TRAIL in combination with subtoxic concentrations of butein sensitizes TRAIL-resistant human leukemia U937 cells to apoptosis. Butein increased caspase-3 activity and expression of death receptor DR5. The apoptotic cell death induced by combined treatment was significantly reduced by z-DEVD-fmk, a caspase-3 inhibitor, suggesting a critical role of caspase-3 in apoptosis. These results indicate that butein sensitizes TRAIL-resistant U937 cells to TRAIL-induced apoptosis in a caspase-3 dependent manner which might be correlated with upregulation of death receptor DR5. Our data suggests that combined treatment with butein and TRAIL may provide a safe and effective strategy for treating cancer.

Antiproliferative, antioxidant, and antimutagenic activities of flavonoid-enriched extracts from (Tunisian) Rhamnus alaternus L.: combination with the phytochemical composition

A pronounced antiproliferative effect on human leukemia K562 cells was shown with flavonoid-enriched extracts from Rhamnus alaternus roots and leaves, with, respectively, IC(50) values of 165 and 210.73 microg/mL. High DPPH radical-scavenging activity (7.21 and 18.84 microg/mL, respectively) and antioxidative effects using the xanthine oxidase assay (IC(50) values of 83.33 and 103.96 microg/mL, respectively) were detected in the presence of the two tested extracts. Although no mutagenic effect was observed when using the Salmonella typhimurium assay system with TA1535 and TA100 strains, the two tested extracts exhibited a high-level protection toward the direct mutagen, sodium azide-induced response.

Cytotoxic Mannich bases of 6-(3-aryl-2-propenoyl)-2(3H)-benzoxazolones

A series of 12 new Mannich bases with chalcone core structure were synthesized as potential antineoplastic agents, via N-aminomethylation of two parent 6-(3-aryl-2-propenoyl)-2(3H)-benzoxazolones. The newly synthesized compounds as well as the chalcone prototypes were evaluated for cytotoxicity in the human pre-B-cell leukemia cell line BV-173 using the MTT-dye reduction assay. The tested compounds exhibited concentration-dependent cytotoxic effects at low micromolar concentrations. Ten of the Mannich bases characterized by significant activity in BV-173 were further evaluated against the chronic myeloid leukemia cell line K-562 and were found to suppress the growth of these cells at relatively higher concentrations as compared to the former tumor model. Selected Mannich bases induced programmed cell death in BV-173 at a concentration of 2.5muM as evidenced by the encountered DNA-laddering. Taken together our data suggest that the presented heterocyclic chalcone derived Mannich bases necessitate detailed pharmacological evaluation in order to define further the structure activity relationships, in a larger spectrum of tumor models and to elucidate the mechanisms implicated in the observed cytotoxic effects.

Butein, a tetrahydroxychalcone, inhibits nuclear factor (NF)-kappaB and NF-kappaB-regulated gene expression through direct inhibition of IkappaBalpha kinase beta on cysteine 179 residue

Although butein (3,4,2',4'-tetrahydroxychalcone) is known to exhibit anti-inflammatory, anti-cancer, and anti-fibrogenic activities, very little is known about its mechanism of action. Because numerous effects modulated by butein can be linked to interference with the NF-kappaB pathway, we investigated in detail the effect of this chalcone on NF-kappaB activity. As examined by DNA binding, we found that butein suppressed tumor necrosis factor (TNF)-induced NF-kappaB activation in a dose- and time-dependent manner; suppressed the NF-kappaB activation induced by various inflammatory agents and carcinogens; and inhibited the NF-kappaB reporter activity induced by TNFR1, TRADD, TRAF2, NIK, TAK1/TAB1, and IKK-beta. We also found that butein blocked the phosphorylation and degradation of IkappaBalpha by inhibiting IkappaBalpha kinase (IKK) activation. We found the inactivation of IKK by butein was direct and involved cysteine residue 179. This correlated with the suppression of phosphorylation and the nuclear translocation of p65. In this study, butein also inhibited the expression of the NF-kappaB-regulated gene products involved in anti-apoptosis (IAP2, Bcl-2, and Bcl-xL), proliferation (cyclin D1 and c-Myc), and invasion (COX-2 and MMP-9). Suppression of these gene products correlated with enhancement of the apoptosis induced by TNF and chemotherapeutic agents; and inhibition of cytokine-induced cellular invasion. Overall, our results indicated that antitumor and anti-inflammatory activities previously assigned to butein may be mediated in part through the direct inhibition of IKK, leading to the suppression of the NF-kappaB activation pathway.

Ellagic and tannic acids protect newly synthesized elastic fibers from premature enzymatic degradation in dermal fibroblast cultures

Progressive proteolytic degradation of cutaneous elastic fibers, that cannot be adequately replaced or repaired by adult dermal fibroblasts, constitutes a major feature of aging skin. Our present investigations, employing monolayer cultures of human dermal fibroblasts and organ cultures of skin biopsies, were aimed at testing whether the hydrophilic tannic acid (TA) and lipophilic ellagic acid (EA) would protect dermal elastin from exogenous and endogenous enzymatic degradation. Results from both culture systems indicated that dermal fibroblasts, maintained with TA or EA, deposit significantly more elastic fibers than untreated control cultures despite the fact that neither polyphenol enhanced transcription of elastin mRNA or cellular proliferation. Results of a pulse and chase experiment showed that pretreatment with both polyphenols enhanced biostability of tropoelastin and newly deposited elastin. Results of in vitro assays indicated that both polyphenols bound to purified elastin and significantly decreased its proteolytic degradation by elastolytic enzymes belonging to the serine proteinase, cysteine proteinase, and metallo-proteinase families. Importantly, both polyphenols also synergistically enhanced elastogenesis induced by selected elastogenic compounds in cultures of dermal fibroblasts. We propose that EA and TA may be useful for preventing proteolytic degradation of existing dermal elastic fibers and for enhancing more efficient elastogenesis in aged skin.

In vitro bioactivity-guided fractionation and characterization of polyphenolic inhibitory fractions from Acacia nilotica (L.) Willd. ex Del

The present study was undertaken to evaluate antimutagenic and cytotoxic effects of different extracts/fractions of Acacia nilotica prepared by maceration method. The potency order of different extracts was more or less similar in Ames assay as well as in cytotoxic assay. Considering the maximum potential of acetone extract in both the assays, the studies were initiated to fractionate this extract. Two pure fractions, namely AN-1 and AN-2, were obtained from acetone extract, of which AN-2 was found to be of gallic acid and AN-1 fraction is still to be identified. In conclusion, the antimutagenic and cytotoxic activities exhibited by acetone extract may partially be ascribed to the presence of gallic acid and other polyphenols.

Inhibition of cholangiocarcinoma growth by tannic acid

Cholangiocarcinoma is an aggressive malignancy of the biliary tract for which effective treatment is lacking. Tannic acid (TA) is a naturally occurring polyphenolic compound with antioxidant and radical scavenging properties as well as anticarcinogenic effects. TA inhibited proliferation of malignant human cholangiocytes in vitro. Furthermore, the growth rate of Mz-ChA-1 cholangiocarcinoma xenografts in balb/c athymic mice was reduced from 10.9 +/- 1.8 mm(3)/d in mice fed with normal water to 5.5 +/- 1.2 mm(3)/d in mice fed with water containing 0.05% TA. Pretreatment with 50 microg/mL TA for 24 hours before xenograft implantation increased tumor latency by 2.5-fold compared with untreated controls, and decreased subsequent growth rates compared with controls in the absence of TA feeding. TA was not cytotoxic to Mz-ChA-1 cells in vitro, but enhanced sensitivity to camptothecin cytotoxicity. TA potently inhibited cell cycle progression, and increased expression of the cyclin-dependent kinase inhibitor p27(KIP1). In addition, TA (0-50 microg/mL) inhibited proteasomal activity in cholangiocyte cell extracts in a concentration-dependent manner. In conclusion, the growth inhibitory effects of TA may result from dysregulation of cell cycle progression due to altered proteasomal degradation of these cell cycle regulatory proteins. TA warrants evaluation as a candidate for the treatment of human cholangiocarcinoma either by itself or in combination with other chemotherapeutic agents.

Phenolic antioxidants attenuate neuronal cell death following uptake of oxidized low-density lipoprotein

Oxidative stress is implicated in neuronal loss associated with neurodegeneration such as in Parkinson's disease, Alzheimer's disease and age-related cognitive decline. Recent reports indicate that the consumption of flavonoid-rich fruits partly reverses the age-related neuronal and cognitive decline. In this study, cultured striatal neurons were exposed to oxidized lipids in the form of low-density lipoprotein (oxLDL) as a model for the induction of oxidative injury, and the abilities of phenolic antioxidants, flavonoids and hydroxycinnamic acid derivatives, to attenuate this neuronal damage were examined. OxLDL was demonstrated to enter neuronal cells and to be capable of eliciting neurotoxicity in a dose- and time-dependent manner, inducing DNA fragmentation and cell lysis. Flavonoids exert protective effects, which appear to be related to specific structural characteristics, particularly relevant being those defining their reduction potentials and partition coefficients. In summary, these data suggest a possible role for flavonoids in reducing neurodegeneration associated with chronic disorders in which oxidative stress is implicated.

Flavonoids inhibit cell growth and induce apoptosis in B16 melanoma 4A5 cells

We investigated the growth inhibitory activity of several flavonoids, including apigenin, luteolin, kaempherol, quercetin, butein, isoliquiritigenin, naringenin, genistein, and daizein against B16 mouse melanoma 4A5 cells. Isoliquiritigenin and butein, belonging to the chalcone group, markedly suppressed the growth of B16 melanoma cells and induced cell death. The other flavonoids tested showed little growth inhibitory activity and scarcely caused cell death. In cells treated with isoliquiritigenin or butein, condensation of nuclei and fragmentation of nuclear DNA, which are typical phenomena of apoptosis, were observed by Hoechst 33258 staining and by agarose gel electrophoresis of DNA. Flowcytometric analysis showed that isoliquiritigenin and butein increased the proportion of hypodiploid cells in the population of B16 melanoma cells. These results demonstrate that isoliquiritigenin and butein inhibit cell proliferation and induce apoptosis in B16 melanoma cells. Extracellular glucose decreased the proportion of hypodiploid cells that appeared as a result of isoliquiritigenin treatment. p53 was not detected in cells treated with either of these chalcones, however, protein of the Bcl-2 family were detected. The level of expression of Bax in cells treated with either of these chalcones was markedly elevated and the level of Bcl-XL decreased slightly. Isoliquiritigenin did not affect Bcl-2 expression, but butein down-regulated Bcl-2 expression. From these results, it seems that the pathway by which the chalcones induce apoptosis may be independent of p53 and dependent on proteins of the Bcl-2 family. It was supposed that isoliquiritigenin induces apoptosis in B16 cells by a mechanism involving inhibition of glucose transmembrane transport and promotion of Bax expression. On the other hand, it was suggested that butein induces apoptosis via down-regulation of Bcl-2 expression and promotion of Bax expression. This mechanism differs from the isoliquiritigenin induction pathway.

Synthesis and biological evaluation of certain alpha,beta-unsaturated ketones and their corresponding fused pyridines as antiviral and cytotoxic agents

A new series of 3,5-bis(arylidene)-4-piperidones, as chalcone analogues carrying variety of aryl and heteroaryl groups, pyrazolo[4,3-c]pyridines, pyridolo[4,3-c]pyrimidines, and pyrido[4,3-c]-pyridines, carrying an arylidene moiety, and a series of pyrano[3,2-c]pyridines, as flavone and coumarin isosteres, were synthesized and screened for their in vitro antiviral and antitumor activities at the National Cancer Institute (NCI). Compounds 9 and 18 proved to be active against herpes simplex virus-1 (HSV-1), while compound 13 showed moderate activity against human immunodeficiency virus-1 (HIV-1). Compounds 14, 26, 28, 33, and 35 exhibited a broad spectrum antitumor activity. In addition, compounds 26, 33, and 35 proved to be of moderate selectivity toward leukemia cell lines. The pyrano[3,2-c]pyridines heterocyclic system proved to be the most active antitumors among the investigated heterocycles.

Supplementation of Jurkat T cells with green tea extract decreases oxidative damage due to iron treatment

Regular tea consumption has been associated with a reduced risk of cancer. As demonstrated in vitro, green tea contains catechins with antioxidant properties. We evaluated the effect of the supplementation of the Jurkat T-cell line with green tea extract on oxidative damage. Cells grown in medium with or without green tea extract (10 mg/L) were treated with Fe(2+) (100 micromol/L) as an oxidative stimulus for 2 h. Cell membrane lipid peroxidation was evaluated by fatty acids pattern analysis and malondialdehyde production in alpha-linolenic acid-loaded cells. Furthermore, oxidative DNA damage (single strand breaks) was detected in cells by the Comet assay and quantified as relative tail moment (RTM). Supplementation with green tea extract significantly decreased malondialdehyde production (1.6 +/- 0.3 vs. 0.6 +/- 0.1 nmol/mg protein, P < 0.05) and DNA damage (0.32 +/- 0.07 vs. 0.12 +/- 0.04 RTM, P < 0.05) after Fe(2+) oxidative treatment. In control cells, there was no effect on membrane distribution of (n-3) fatty acids due to Fe(2+) treatment. Cell enrichment with alpha-linolenic acid increased total membrane (n-3) fatty acids. However, the oxidative treatment did not modify the distribution of polyunsaturated fatty acids. It is likely that the observed protective effects can be attributed to epigallocatechin gallate, which is present mainly (670 g/kg) in green tea extract; however, we cannot exclude contributions by other catechins. These data support a protective effect of green tea against oxidative damage.

Chemopreventive activity of very low dose dietary tannic acid administration in hepatoma bearing C3H male mice

Tannins are plant polyphenols comprising a heterogeneous group of compounds. Tannic acid is a common tannin found in tea, coffee, immature fruits, etc. and it has also been used as a food additive. An increasing body of experimental evidence supports the hypothesis that tannins exert anticarcinogenic activity in chemically induced cancers in animal models. In the present study, tannic acid was administered in very low doses in the drinking water of C3H male mice divided into three groups (75 mg/l, 150 mg/l and 300 mg/l). These animals carry a genetic defect and show a high incidence of spontaneous liver tumors (> 50%) at an age older than 12 months. The results showed a decrease in the overall incidence of hepatic neoplasms (adenomas plus carcinomas): 53.3% of animals in the control group developed hepatic neoplasms versus 33.3% in the group given a low dose of tannic acid, 26.6% in the group given a medium dose and 13.3% in the high dosage group. The difference was more pronounced in the animals with carcinomas: 4.44% of mice who received tannic acid developed carcinomas versus 33.3% of those in the control group. Tannic acid administration did not affect the PCNA labeling index of normal hepatocytes. It is concluded that tannic acid dietary intake in low doses can exert a strong dose-dependent chemoprotective activity against spontaneous hepatic neoplasm development in C3H male mice, most probably through antipromoting mechanisms.

Tannins, xenobiotic metabolism and cancer chemoprevention in experimental animals

Tannins are plant polyphenolic compounds that are contained in large quantities in food and beverages (tea, red wine, nuts, etc.) consumed by humans daily. It has been shown that various tannins exert broad cancer chemoprotective activity in a number of animal models. This review summarizes the recent literature regarding both the mechanisms involved, and the specific organ cancer models used in laboratory animals. An increasing body of evidence demonstrates that tannins act as both anti-initiating and antipromoting agents. In view of the fact that tannins may be of valid medicinal efficacy in human clinical trials, the present review attempts to integrate results from animal studies, and considers their possible application in humans.

Inhibition of mammary cancer by citrus flavonoids

Double strength orange juice given to the rats in place of drinking water inhibited mammary tumorigenesis induced in female Sprague-Dawley rats by DMBA more effectively than double strength grapefruit juice. This may mean that hesperetin retains its effectiveness in vivo better than naringenin, since the flavonoids are present in the juices at similar levels. It is also possible that orange juice contains other compounds that have anti-cancer activity and that may act synergistically with hesperetin. Citrus flavonoids are effective inhibitors of both estrogen receptor-negative MDA-MB-435 and estrogen receptor-positive MCF-7 human breast cancer cell in vitro. Furthermore, 1:1 combinations of flavonoids with tocotrienols and/or tamoxifen inhibit proliferation of the cells more effectively than the individual compounds. This synergism may be due to the fact that the compounds are exerting their inhibitory effects by different mechanisms.

Glutathione conjugation of chlorambucil: measurement and modulation by plant polyphenols

Chlorambucil (CMB), an anticancer drug, was cytotoxic at concentrations of 5-20 microM to human colon adenocarcinoma cells. It inhibited [14C]thymidine uptake in a dose-dependent manner. Both effects were potentiated by simultaneous exposure of the cells to 10 microM plant polyphenols. In an attempt to explain the possible mechanism of action of the polyphenols in relation to these observations, an HPLC-radiometric method was developed to measure the conjugation of CMB with glutathione in these cells and to monitor the export of monochloromonoglutathionyl CMB (MG-CMB), its main glutathione conjugate. At micromolar concentrations, five polyphenols, namely quercetin, butein, tannic acid, 2'-hydroxychalcone and morin, inhibited the efflux of CMB significantly; an inhibition of 40% was observed with 10 microM quercetin. The glutathione S-transferase (GST) activity of the cancer cells, measured with 1-chloro-2,4-dinitrobenzene, was also inhibited by the polyphenols. Their combined action on GST and on the efflux of MG-CMB conjugate could provide an enhanced positive modulation of sensitivity of the tumour cells to CMB.

Butein (3,4,2',4'-tetrahydroxychalcone) ameliorates experimental anti-glomerular basement membrane antibody-associated glomerulonephritis (3)

The antinephritic effects of butein (3,4,2',4'-tetrahydroxychalcone) on original-type anti-glomerular basement membrane antibody-associated glomerulonephritis in rats were investigated. Butein was given to anti-glomerular basement membrane antibody-associated glomerulonephritic rats for 15 days after the induction of nephritis. Butein prevented proteinuria and histological alterations. The up-regulation of intercellular adhesion molecule-1 (ICAM-1) expression and increase in leukocyte function-associated antigen-1 (LFA-1) positive cells in nephritic glomeruli significantly declined with butein treatment. In the further investigation to clarify the effects of butein on ICAM-1 expression, human umbilical vein endothelial cells were treated with butein in the presence of tumor necrosis factor-alpha (TNF-alpha) or phorbol 12-myristate 13-acetate (PMA). Butein prevented the up-regulation of ICAM-1 expression mediated by TNF-alpha or PMA on human umbilical vein endothelial cells in a dose-dependent manner. When human umbilical vein endothelial cells or neutrophils were treated with butein, the adhesion of neutrophils to human umbilical vein endothelial cells was suppressed. These data suggest that the antinephritic action of butein is due to inhibition of intraglomerular accumulation of leukocytes through the prevention of the up-regulation of ICAM-1 and the inhibition of a function of adhesion molecules on the surface of leukocytes.

Antineoplastic agents 338. The cancer cell growth inhibitory. Constituents of Terminalia arjuna (Combretaceae)

By means of bioassay-guided separation methods, the cancer cell growth inhibitory constituents residing in the bark, stem and leaves of the Mauritius medicinal plant Terminalia arjuna (Combretaceae) were examined. The cancer cell line active components were found to be gallic acid, ethyl gallate, and the flavone luteolin. Only gallic acid was previously known to occur in this plant. Luteolin has a well established record of inhibiting various cancer cell lines and may account for most of the rationale underlying the use of T. arjuna in traditional cancer treatments. Luteolin was also found to exhibit specific activity against the pathogenic bacterium Neisseria gonorrhoeae.

Inhibition of human breast cancer cell proliferation and delay of mammary tumorigenesis by flavonoids and citrus juices

Two citrus flavonoids, hesperetin and naringenin, found in oranges and grapefruit, respectively, and four noncitrus flavonoids, baicalein, galangin, genistein, and quercetin, were tested singly and in one-to-one combinations for their effects on proliferation and growth of a human breast carcinoma cell line, MDA-MB-435. The concentration at which cell proliferation was inhibited by 50% (IC50), based on incorporation of [3H]thymidine, varied from 5.9 to 140 micrograms/ml for the single flavonoids, with the most potent being baicalein. IC50 values for the one-to-one combinations ranged from 4.7 micrograms/ml (quercetin + hesperetin, quercetin + naringenin) to 22.5 micrograms/ml (naringenin + hesperetin). All the flavonoids showed low cytotoxicity (> 500 micrograms/ml for 50% cell death). Naringenin is present in grapefruit mainly as its glycosylated form, naringin. These compounds, as well as grapefruit and orange juice concentrates, were tested for their ability to inhibit development of mammary tumors induced by 7,12-dimethylbenz[a]anthracene (DMBA) in female Sprague-Dawley rats. Two experiments were conducted in which groups of 21 rats were fed a semipurified diet containing 5% corn oil and were given a 5-mg dose of DMBA intragastrically at approximately 50 days of age while in diestrus. One week later, individual groups were given double-strength grapefruit juice or orange juice or fed naringin or naringenin at levels comparable to that provided by the grapefruit juice; in the second experiment, the rats were fed a semipurified diet containing 20% corn oil at that time. As expected, rats fed the high-fat diet developed more tumors than rats fed the low-fat diet, but in both experiments tumor development was delayed in the groups given orange juice or fed the naringin-supplemented diet compared with the other three groups. Although tumor incidence and tumor burden (grams of tumor/rat) were somewhat variable in the different groups, rats given orange juice had a smaller tumor burden than controls, although they grew better than any of the other groups. These experiments provide evidence of anticancer properties of orange juice and indicate that citrus flavonoids are effective inhibitors of human breast cancer cell proliferation in vitro, especially when paired with quercetin, which is widely distributed in other foods.

Butein ameliorates experimental anti-glomerular basement membrane (GBM) antibody-associated glomerulonephritis in rats (1)

Effects of butein on crescentic-type anti-glomerular basement membrane (GBM) nephritis in rats were investigated. When rats were treated with butein from 1 day after i.v. injection of anti-GBM serum, it inhibited the elevation of protein excretion into urine. In the butein-treated rats, cholesterol content in plasma was lower than that of the nephritic control rats. Histological observation demonstrated that this agent suppressed the incidence of crescent formation, adhesion of capillary wall to Bowman's capsule and fibrinoid necrosis in the glomeruli. Furthermore, butein suppressed the accumulation of leukocytes, including CD4-positive cells and CD8-positive cells in the glomeruli. However, butein failed to suppress the production of the antibody against rabbit gamma-globulin and the deposition of rat-IgG on the GBM. These results suggest that butein may be a useful medicine against rapidly progressive glomerulonephritis, which is characterized by severe glomerular lesions with diffuse crescents.

Cytotoxic effect of butein on human colon adenocarcinoma cell proliferation

Several classes of plant polyphenols namely, flavonoids, chalcones and coumarins exhibited varying degrees of inhibition on the cell proliferation of human colon adenocarcinoma cell line 220.1. At the highest concentration tested (100 microM), many of the chalcones showed > 100% growth inhibition and their order of potency was butein > 2'-hydroxychalcone > 2-hydroxychalcone > 2',6'-dihydroxy-4'-methoxychalcone > 2',4-dihydroxychalcone with IC50 values of 1.75, 6.2, 7.5, 17, 23 microM, respectively. Butein (the most potent chalcone) at 2 microM concentration inhibited the incorporation of 14C-labelled thymidine, uridine and leucine into the colon cancer cells whilst 5-fluorouracil (5-FU, a chemotherapeutic drug) at 50 microM concentration could significantly inhibit only the uridine incorporation. The mode of cytotoxic action of butein was different from 5-FU but may be similar to colchicine, a known HeLa cell inhibitor.

Potentiation of beta-adrenoceptor agonist-mediated lipolysis by quercetin and fisetin in isolated rat adipocytes

Quercetin and fisetin, two naturally occurring bioflavonoids mobilized lipids and enzymes in the absence or presence of epinephrine in intact rat adipocytes. Dose-(0-250 microM) and time-(0-2 hr) course studies, showed that they stimulated phosphodiesterase (PDE) activity and simultaneously exert cyclic AMP accumulation. These bioflavonoids when present either singly or together with epinephrine stimulated the membrane-bound PDE but not the cytosolic PDE. The stimulation may act as a feedback mechanism to terminate the cyclic AMP effects. The action of theophylline, a known lipolytic agent (exerting its effects through antagonism of adenosine A1 receptor as well as PDE inhibition) was not potentiated by either fisetin or quercetin. However, the flavonoids potentiated epinephrine or isoproterenol- (a specific beta-adrenoreceptor agonist) induced lipolysis. Their effects were inhibited by propranolol (a beta-receptor antagonist). These results suggest that the flavonoids act synergistically with epinephrine on beta-adrenergic receptor and not through phosphodiesterase inhibition to stimulate adipocyte lipolysis. Increase in membrane phospholipid methylation occurred as a consequence of the epinephrine and/or quercetin/fisetin actions, and it correlated with the cellular accumulation of cyclic AMP.

Effects of gamma-linolenic acid, flavonoids, and vitamins on cytotoxicity and lipid peroxidation

Gamma linolenic acid (GLA), a polyunsaturated fatty acid, promoted lipid peroxidation in Raji lymphoma suspension cultures, in a dose (10 microM-100 microM) and time-dependent (4 h-48 h) manner. The increase in lipid peroxidation could be correlated to an increase in cytotoxicity. The plant flavonoids (quercetin, luteolin, butein, rutin) and the fat-soluble components (retinol, retinoic acid, alpha-tocopherol) by themselves did not affect lipid peroxidation in Raji cells. Quercetin, luteolin, retinol, and alpha-tocopherol were able to inhibit cell proliferation significantly. Although GLA only decreased the cytotoxicity of retinol-treated cells, the latter compound was able to block the prooxidative action of GLA by scavenging the free radicals induced by it. Quercetin at 50 and 100 microM exerted equipotent superoxide anion scavenging effects, but at the higher concentration it had no effect on lipid peroxidation. Although the bioactive test compounds are well known natural antioxidants, interestingly, our data showed that their potent cytotoxic actions do not involve free radicals or lipid peroxidation reactions.

In vitro effects of natural plant polyphenols on the proliferation of normal and abnormal human lymphocytes and their secretions of interleukin-2

The growth of two human lymphoid tissue derived cell lines, IM-9 and Molt-4 cells together with normal lymphocytes was studied in the presence of several plant natural products. Amongst the 11 test compounds studied, the flavonoids (fustin, taxifolin, phloretin) and the polyphenol tannic acid were potent inhibitors. At concentrations ranging from 10-50 microM they exerted varying degrees of inhibition on Molt-4 cell and normal lymphocyte cell proliferation but not on the non-malignant (IM-9) cells. The order of potency was tannic acid > phloretin > taxifolin > fustin. The IL-2 level was also enhanced in the Molt-4 but inhibited in normal lymphocytes. However, its level remained unchanged in the IM-9 cells. The amount of IL-2 secreted could be directly correlated to the percentage cell growth inhibition for only Molt-4 cells. Interestingly, our findings suggest the possibility of exploiting the natural plant polyphenols for their possible use in the treatment of lymphocyte malignancy.

Protective effects of tannic acid and related natural compounds on Crotalus adamenteus subcutaneous poisoning in mice

The plant natural products namely tannic acid and the flavonoids luteolin, kaempferol and apigenin exerted potent inhibition on the hyaluronidase enzyme. They were able to neutralize the haemorrhage induced by Crotalus adamenteus venom in mice dose-dependently from 0.12-2.4 mg/kg subcutaneously. In addition, they were able to antagonize the lethal activity of the venom when injected subcutaneously into mice and the order of potency was: tannic acid >> luteolin = kaempferol > apigenin. Tannic acid (24 mg/kg, subcutaneously) was able to reduce significantly the venom-induced elevation of blood creatine kinase activity. It could also prolong the survival time(s) of mice, when injected immediately after the administration of venom. Experimental evidence is presented for the first time that malondialdehyde in liver and kidney is significantly elevated as a result of rattlesnake venom poisoning and that this effect can be controlled by tannic acid.