Comparative antimutagenic and anticancer activity of three fractions of black tea polyphenols thearubigins

Comparative Study of Bioactivity and Safety Evaluation of Ethanolic Extracts of Zanthoxylum schinifolium Fruit and Pericarp

The fruit and pericarp of Zanthoxylum schinifolium (ZS) have been used in traditional medicine; however, few studies have characterized ZS fruit and pericarp. Therefore, in the present study, we evaluated the safety of ZS fruit (ZSF) and pericarp (ZSP) extracts and compared their bioactivity. To evaluate the safety of ZSF and ZSP, mutagenicity, cytotoxicity, and oxidative stress assays were performed and nontoxic concentration ranges were obtained. ZSP was found to be superior to ZSF in terms of its antimutagenic, antioxidant, and anti-inflammatory activities. In the S9 mix, the mutation inhibition rate of ZSP was close to 100% at concentrations exceeding 625 µg·plate⁻¹ for both the TA98 and TA100 strains. ZSP exhibited efficient DPPH (IC₅₀ = 75.6 ± 6.1 µg·mL⁻¹) and ABTS (IC₅₀ = 57.4 ± 6 µg·mL⁻¹) scavenging activities. ZSP inhibited the release of cytokines, involved in IL-1β (IC₅₀ = 134.4 ± 7.8), IL-6 (IC₅₀ = 262.8 ± 11.2), and TNF-α (IC₅₀ = 223.8 ± 5.8). These results indicate that ZSP contains a higher amount of biochemicals than ZSF, or that ZSP contains unique biochemicals. In conclusion, for certain physiological activities, the use of ZSP alone may be more beneficial than the combined use of ZSF and ZSP.

Preventive Applications of Polyphenols in Dentistry-A Review

Polyphenols are natural substances that have been shown to provide various health benefits. Antioxidant, anti-inflammatory, and anti-carcinogenic effects have been described. At the same time, they inhibit the actions of bacteria, viruses, and fungi. Thus, studies have also examined their effects within the oral cavity. This review provides an overview on the different polyphenols, and their structure and interactions with the tooth surface and the pellicle. In particular, the effects of various tea polyphenols on bioadhesion and erosion have been reviewed. The current research confirms that polyphenols can reduce the growth of cariogenic bacteria. Furthermore, they can decrease the adherence of bacteria to the tooth surface and improve the erosion-protective properties of the acquired enamel pellicle. Tea polyphenols, especially, have the potential to contribute to an oral health-related diet. However, in vitro studies have mainly been conducted. In situ studies and clinical studies need to be extended and supplemented in order to significantly contribute to additive prevention measures in caries prophylaxis.

Theaflavin-Containing Black Tea Extract: A Potential DNA Methyltransferase Inhibitor in Human Colon Cancer Cells and Ehrlich Ascites Carcinoma-Induced Solid Tumors in Mice

Tea is the most popularly consumed beverage in the world. Theaflavin and thearubigins are the key bioactive compounds of black tea that have anticarcinogenic properties as reported in several studies. However, the epigenetic potential of these compounds has not yet been explored. DNA methyltransferase (DNMT) enzymes induce methylation of DNA at cytosine residues and play a significant role in epigenetic regulation and cancer therapy. The present study has explored the role of black tea as a DNMT inhibitor in the prevention of cancer. Herein, the effect of theaflavin has been studied in colon cancer cell line (HCT-116) and EAC-induced solid tumors in mice. It was found that theaflavin prevented cell proliferation and inhibited tumor progression as well. In silico study showed that theaflavin interacted with DNMT1 and DNMT3a enzymes and blocked their activity. Theaflavin also decreased DNMT activity In Vitro and In Vivo as evident from the DNMT activity assay. Results of immunohistochemistry revealed that theaflavin reduced DNMT expression in the tumors of mice. Taken together, our findings showed that theaflavin has a potential role as a DNMT inhibitor in HCT-116 cell line and EAC induced solid tumors in mice.

Effect of fragaria vesca, hamamelis and tormentil on the initial bacterial colonization in situ

OBJECTIVE

The presentin situ study aims to examine the influence of the polyphenolic tea drugs fragaria vesca, hamamelis and tormentil on the initial oral bioadhesion.

DESIGN

Initial biofilm formation was performed on bovine enamel slabs which were carried intraorally by 12 subjects. After 1 min of intraoral pellicle formation, the subjects rinsed with fragaria vesca, tormentil (0.8 mg/8 mL) and hamamelis (0.2 mg/8 mL) for 10 min. Tap water served as negative control, 0.2 % CHX as positive control. The investigations took place on different days (wash-out: 2 days). Afterwards, fluorescence microscopy has been performed per test solution (n = 5) and per subject (n = 12) to visualize bacterial adhesion and glucan formation (8 h oral exposition) with DAPI, ConA and BacLight. Additionally, TEM was used to visualize the pellicle ultrastructure and expectorate samples. Statistical evaluation was carried out using the Kruskal-Wallis- (p < 0.5), Mann-Whitney U test (p < 0.5) and Bonferroni-Holm-correction (p < 0.1).

RESULTS

Rinsing with the polyphenolic tea extracts reduced significantly initial bacterial colonization (DAPI) compared to the negative control. There was no significant difference betweenfragaria vesca, hamamelis and tormentil. All solutions showed a reducing effect on the glucan formation. No significant difference was observed between fragaria vesca and CHX. Considerable alterations of the pellicle's ultrastructure manifested by an increase in thickness and electron density resulted from rinsing with the three polyphenolic aqueous extracts.

CONCLUSIONS

Fragaria vesca, hamamelis and tormentil significantly reduce initial bioadhesion and glucan formation in situ and are therefore recommended as adjuvant antibacterial oral therapeutics.

Research progress of black tea thearubigins: a review

As the most abundant component in black tea, thearubigins (TRs) contribute a lot to black tea's characteristic color, mouthfeel, and potential health benefits. But compared to lower molecular weight black tea polyphenols, there are fewer researches that focus on TRs because of their heterogeneity. This review summarized recent research progress on (1) isolation method of TRs; (2) structure analysis and formation mechanism of TRs; (3) biofunctions of TRs, including antioxidation, antimutagenic and anticancer effects, effects on mitochondrial activation, gastrointestinal motility and skeletal health, to show some future research aspects and prospects of TRs.

The prognostic impact of traditional Chinese medicine monomers on tumor-associated macrophages in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) accounts for 80%-85% of all lung malignancies and good diagnosis and prognosis of NSCLC are critical to the increase of its survival rate. Tumor-associated macrophages (TAM) abundantly present in numerous cancer types, and the role of TAMs in tumor biology and their prognostic value in cancer become major topics of interest. After various stimulations in the tumor microenvironment, TAMs develop into a M1 (tumor-inhibitory) phenotype or M2 (tumor-promoting) phenotype. Recent studies show that traditional Chinese medicine (TCM) monomers have markedly inhibitory actions for NSCLC through M1/M2 modulation. Due to the TCM monomers mainly covered five categories, i.e. terpenoids, flavonoids, polysaccharides, natural polyphenols, and alkaloids. Thus, we will discuss the regulation of TCM monomers on TAM involve in these five parts in this review. In addition, the potential role of TAMs as therapeutic targets will be discussed.

Health Functions and Related Molecular Mechanisms of Tea Components: An Update Review

Tea is widely consumed all over the world. Generally, tea is divided into six categories: White, green, yellow, oolong, black, and dark teas, based on the fermentation degree. Tea contains abundant phytochemicals, such as polyphenols, pigments, polysaccharides, alkaloids, free amino acids, and saponins. However, the bioavailability of tea phytochemicals is relatively low. Thus, some novel technologies like nanotechnology have been developed to improve the bioavailability of tea bioactive components and consequently enhance the bioactivity. So far, many studies have demonstrated that tea shows various health functions, such as antioxidant, anti-inflammatory, immuno-regulatory, anticancer, cardiovascular-protective, anti-diabetic, anti-obesity, and hepato-protective effects. Moreover, it is also considered that drinking tea is safe to humans, since reports about the severe adverse effects of tea consumption are rare. In order to provide a better understanding of tea and its health potential, this review summarizes and discusses recent literature on the bioactive components, bioavailability, health functions, and safety issues of tea, with special attention paid to the related molecular mechanisms of tea health functions.

Inhibitory effect of black tea (Camellia sinensis) theaflavins and thearubigins against HCT 116 colon cancer cells and HT 460 lung cancer cells

Recently, phytochemical-based dietary intervention has gained attention as a preventive and curative strategy against cancers owing to their safety, better tolerance, and economics. Against this background, black tea extract which contains the flavanol-3-ol, theaflavins (TF), and thearubigins (TR) with promising anti-oncogenic activity were assessed to determine its in vitro inhibitory impact on colon cancer (HCT 116) and lung cancer cell lines (HT 460). In a dose-dependent manner, results revealed that TF, TR, and their combinations cause inhibition in cell viability. However, TF imparted a maximum reduction in cell viability of HCT 116 and HT 460. Flow cytometry data revealed that TF, TR, and their combinations exhibited substantial cell arrest at the G2/M phase. The influence was more prominent in lung cancer cells (HT 460) when compared with colon cells (HCT 116). All treatments resulted in apoptosis, however, the combination of TF and TR exhibited the highest apoptotic ability in comparison to individual treatments. TF and TR exhibited a synergistic impact and significantly inhibited cell proliferation of HCT 116 and HT 460 in dose- and time-dependent manners by inducing apoptosis and cell cycle arrest, wherein TF showed a more pronounced impact. PRACTICAL APPLICATIONS: Results from the present study revealed that black tea-isolated polyphenols (TF and TR) exhibited a significant inhibition of lung and colon cancer cell growth. A promising synergistic effect of TF and TR as inhibitors of cancer cells was observed. More clinical work, perhaps on a human subject, is needed before these two isolated compounds can be prescribed as anticancer drugs.

Black Tea (Camellia sinensis) Extract Induced Prenatal and Postnatal Toxicity in Experimental Albino rats

Background

Tea (Camellia sinensis) being the most widely drank beverage and despite having numerous beneficial role toward health and disease, its safety evaluation during pregnancy and prenatal, postnatal developmental period need to be monitored.

Objective

This study was to evaluate the toxicity of black tea extract (BTE) in experimental pregnant rats and on their pups during prenatal and postnatal developmental periods.

Materials and Methods

Pregnant female (120 ± 10 g) Wister albino rats were chosen for this study. Group 1 was control group where pregnant female rats were treated with saline. Group 2 and Group 3 were pregnant female rats treated with 50 mg and 100 mg BTE/kg/day, respectively, throughout prenatal and postnatal periods. All three groups of rats were provided food and drinking water ad libitum. Animals were examined through their urinary and serum parameters, histopathological studies, and biomorphometric studies in pups. All data were expressed as mean ± standard deviation with significance between the controls and the treated groups (n = 6). Collected data were subjected to the analysis of variance and Tukey test; P < 0.05 was considered as statistically significant.

Results

BTE produced significant alterations in urinary calcium, creatinine, and urea during prenatal period; exhibited proteinuria, ketonuria, and histology showed nephrotoxicity during postnatal period, and BTE also showed a significant increase in serum proinflammatory cytokines and decreased anti-inflammatory cytokines level compared to control group. BTE caused significant changes in biomorphometric parameters in the pups as compared with pups of control mothers.

Conclusion

This study confirmed the BTE-induced toxicity in pregnant rats and their pups.

SUMMARY

Black tea (Camellia sinensis) is the most widely drank beverage. This study was to evaluate the toxicity BTE in experimental pregnant rats and on their pups during prenatal and postnatal developmental periods. Animals were examined through their urinary and serum parameters, histopathological studies, and biomorphometric studies in pups. BTE.induced toxicity in pregnant rats and their pups. Abbreviations used: BTE: Black tea extract, IL-1α: Interleukin 1 alpha, IL-1 β: Interleukin 1 beta, IL-6: Interleukin 6, IL-10: Interleukin 10, TNF-α: Tumor necrosis factor alpha.

Oxidative stress-induced diseases and tea polyphenols

Reactive oxide species are the middle products of normal metabolism, and play a crucial role in cell signaling transduction. On the contrary, accumulation of excess reactive oxide species results in oxidative stress that often brings multifarious impairment to cells, including decrease of ATP level in cells, elevation of cytosolic Ca2+, DNA damage, dysfunction of biological function in lipid bilayer and so on. These effects will finally lead to all kinds of diseases. Tea polyphenols are widely considered as a kind of excellent antioxidant agents. It can be antioxidants by directly scavenging reactive oxide species or chelating transition metals, and indirectly upregulating the activity of antioxidant enzymes. In addition, tea polyphenols have also been observed a potent pro-oxidant capacity, which directly leads to the generation of reactive oxide species, and indirectly induces apoptosis and death of cancer cells. The underlying characters of its pro-oxidant activity in some diseases is not well understood. The present review we will discuss the dual character of tea polyphenols, both antioxidant and pro-oxidant properties, in some human diseases induced by oxidative stress.

Valorization of solid wastes from chestnut industry processing: Extraction and optimization of polyphenols, tannins and ellagitannins and its potential for adhesives, cosmetic and pharmaceutical industry

The aim of the current study was to evaluate the potential of chestnut peels to produce pomaces enhanced with tannins to be used in the formulations of wood adhesives, leather tanning or as natural antioxidants in food, cosmetic and pharmaceutical industry. An analytical procedure was planned as 2 factorial design to analyze the influence of solvent (water, Na2SO3 and NaOH at different concentrations of 1, 2, 4, and 8% in water) and extraction time (30, 60, and 120, 240, 480 and 960min) on extraction yield, pH, Stiasny index, and tannins. HPLC-diode array detector equipped with an ionization mass spectrophotometer was used to assess the polyphenol composition. Our results showed that both extraction properties and phytochemicals were significantly affected (P<0.001) by all independent factors. The main tannins identified were the hydrolyzable gallic acid, vescalagin castalagin and ellagic acid, and the condensed epigallocatechin, catechin and epicatechin. The solvent 1% Na2SO3 was more effective to extract the condensed tannins whilst hydrolyzable tannins were extracted efficiently by 1% NaOH. The multivariable analysis and the Pearson's correlation coefficients showed a direct association between Stiasny number and the average levels of condensed tannins.

Antimutagenic and anticancer activity of Darjeeling tea in multiple test systems

Background

Darjeeling tea, a most popular variety of black tea, though consumed by the people in different parts of world but its beneficial health effects have not been investigated in details. In this study, the antimutagenic and anticancer effect of Darjeeling tea extract (DTE) has been evaluated.

Methods

Antimutagenic activity of the DTE was carried out in two different strains of Salmonella typhimurium by AMES test against a known mutagen benzo[a]pyrene (B[a]P) with S9 activation. Moreover, anticlastogenic property of DTE was also measured by micronuclei formation (MN) against B[a]P with S9 activation in human lymphocytes. The anticancer activity of the same was studied on U937 cell line. Here, Human PBMCs were used as the normal cell control to identify selective anticancer activity of the extract against U937 cells.

Results

The results showed significant antimutagenic activity on bacterial strains. A significant decrease in MN was also observed in the DTE treated human lymphocyte cultures pretreated with B[a]P when compared with B[a]P treated cultures alone. The study clearly exhibited anticancer activity of the extract on U937 cell line. Further studies also revealed that apoptosis induction is an important mechanism behind the anticancer effect of DTE.

Conclusion

Overall, this study indicates that DTE has significant antimutagenic and anticancer activities on bacterial and mammalian cells respectively.

Cellular targets for the beneficial actions of tea polyphenols

Green and black teas contain different biologically active polyphenolic compounds that might offer protection against a variety of human diseases. Although promising experimental and clinical data have shown protective effects, limited information is available on how these beneficial effects of tea polyphenols are mediated at the cellular level. Evidence is accumulating that catechins in green tea as well as theaflavins and thearubigins from black tea are the substances responsible for the physiologic effects of tea in vitro. The green tea catechin epigallocatechin-3-gallate (EGCG) is generally considered to be the biologically most active compound in vitro. The changes in the activities of various protein kinases, growth factors, and transcription factors represent a common mechanism involved in cellular effects of tea polyphenols. In addition to modification of intracellular signaling by activation of cellular receptors, it was shown that, at least for EGCG, tea polyphenols can enter the cells and directly interact with their molecular targets within cells. There, they frequently result in opposite effects in primary compared with tumor cells. Although tea polyphenols were long regarded as antioxidants, research in recent years has uncovered their prooxidant properties. The use of high nonphysiologic concentrations in many cell culture studies raises questions about the biological relevance of the observed effects for the in vivo situation. Efforts to attribute functional effects in vivo to specific molecular targets at the cellular level are still ongoing.

Antiproliferative activities of tea and herbal infusions

The consumption of tea and herbal infusions has increased rapidly in recent years. More and more people consume these infusions as daily beverages as well as for health purposes. The aim of this study was to supply new information on the antiproliferative function of these infusions for nutritionists and the general public. The in vitro antiproliferative activities of 60 different tea and herbal infusions on four cancer cell lines were evaluated by MTT assay. The results showed that some infusions strongly inhibited the proliferation of A549 (human lung cancer cells), MCF-7 (human breast cancer cells), HepG2 (human hepatoma cells) and HT-29 (human colon cancer cells), and decreased the viability of these cancer cell lines in a dose-dependent manner. In addition, some bioactive components in the infusions were also separated and determined by HPLC. The results suggested that some tea and herbal infusions may be potential dietary supplements for the prevention and treatment of cancer.