Effect of black and green tea polyphenols on c-jun phosphorylation and H(2)O(2) production in transformed and non-transformed human bronchial cell lines: possible mechanisms of cell growth inhibition and apoptosis induction

Antitumour and anti-angiogenesis efficacy of a multifunctional self-oxygenated active-targeting drug delivery system by encapsulating biological and chemotherapeutic drugs

The hypoxic tumour microenvironment (TME), resulting from abnormal tumour angiogenesis, is a major factor contributing to treatment failure in breast cancer patients. In this study, we present a ZnO2-based oestrone-conjugated PEGylated liposome (ZnO2@EPL-CDDP/EGCG) that incorporates cisplatin (CDDP) and epigallocatechin-3-gallate (EGCG). ZnO2 remains stable in neutral environments but decomposes under mildly acidic conditions, releasing Zn²⁺ and H₂O₂. These byproducts inhibit the electron transport chain, stimulate the endogenous reactive oxygen species production for chemodynamic therapy (CDT), and generate oxygen at tumour sites to alleviate hypoxia and enhance anti-angiogenic efficacy. EGCG inhibits tumour angiogenesis by down-regulating hypoxia-inducible factor-1α (HIF-1α) and its downstream pathways, while also exhibiting synergistic anti-tumour effects with CDDP. Oestrone-conjugated and polyethylene glycol (PEG) modifications facilitate targeted accumulation at tumour sites. Our findings indicate that ZnO2@EPL-CDDP/EGCG significantly improves the therapeutic efficacy of both EGCG and CDDP, remodels tumour vasculature, and alleviates hypoxia within the TME. This self-oxygenated, actively targeted drug delivery system notably extends the survival of healthy ICR mice without observed toxicity. This novel approach, which co-encapsulates ZnO2, EGCG, and CDDP in an active-targeting liposomal formulation for the first time, represents a promising strategy for effective cancer treatment.

Green tea polyphenol epigallocatechin-3-gallate mediates an antioxidant response via Nrf2 pathway in heat-stressed poultry: A review

Heat stress is a critical challenge in the poultry industry. It arises when birds are exposed to elevated ambient temperatures beyond their thermoneutral zone, often exacerbated by high humidity and inadequate ventilation. This condition disrupts the birds' ability to maintain thermal homeostasis, leading to physiological and behavioral changes such as increased panting, reduced feed intake, and elevated water consumption. These responses aim to dissipate heat but often result in energy imbalances, oxidative stress, and impaired immune function. Green tea polyphenols (GTPs) mitigate heat stress in poultry birds by modulating oxidative stress pathways, primarily by scavenging reactive oxygen species (ROS) and enhancing antioxidant defense mechanisms. These pathways play a pivotal role in neutralizing ROS generated during oxidative stress, inflammation, and exposure to electrophilic compounds. This action helps restore cellular balance and enhances overall antioxidant defense mechanisms by converting harmful free radicals into less reactive molecules, such as water and oxygen. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) plays a significant character in the activation of the enzymatic antioxidants network. It translocates to the nucleus upon activation, binds to antioxidant response elements (AREs) in the promoter regions of target genes, and upregulates the expression of key antioxidant enzymes. Therefore, the regulation of Nrf2 is considered a critical molecular marker in mitigating the effects of heat stress, as its activation enhances the expression of antioxidant and detoxification enzymes, protecting against oxidative damage and inflammation induced by elevated temperatures. This exploratory review summarizes the antioxidant mechanisms and anti-oxidative stress effects of GTPs in mitigating heat stress in poultry. It highlights the cytoprotective molecular basis of epigallocatechin-3-gallate (EGCG), particularly its role in modulating Nrf2-mediated cellular pathways, which enhance antioxidant defense systems and protect against oxidative damage.

Epigallocatechin Gallate (EGCG): Pharmacological Properties, Biological Activities and Therapeutic Potential

Epigallocatechin gallate (EGCG), the predominant catechin in green tea, comprises approximately 50% of its total polyphenol content and has garnered widespread recognition for its significant therapeutic potential. As the principal bioactive component of Camellia sinensis, EGCG is celebrated for its potent antioxidant, anti-inflammatory, cardioprotective, and antitumor properties. The bioavailability and metabolism of EGCG within the gut microbiota underscore its systemic effects, as it is absorbed in the intestine, metabolized into bioactive compounds, and transported to target organs. This compound has been shown to influence key physiological pathways, particularly those related to lipid metabolism and inflammation, offering protective effects against a variety of diseases. EGCG's ability to modulate cell signaling pathways associated with oxidative stress, apoptosis, and immune regulation highlights its multifaceted role in health promotion. Emerging evidence underscores EGCG's therapeutic potential in preventing and managing a range of chronic conditions, including cancer, cardiovascular diseases, neurodegenerative disorders, and metabolic syndromes. Given the growing prevalence of lifestyle-related diseases and the increasing interest in natural compounds, EGCG presents a promising avenue for novel therapeutic strategies. This review aims to summarize current knowledge on EGCG, emphasizing its critical role as a versatile natural bioactive agent with diverse clinical applications. Further exploration in both experimental and clinical settings is essential to fully unlock its therapeutic potential.

Camellia sinensis methanolic leaves extract: Phytochemical analysis and anticancer activity against human liver cancer cells

BACKGROUND

The study's primary goal is to ascertain whether there is a relationship between the processed green tea methanolic extract's (GTME) phytochemical components and its potential effectiveness against human liver cancer cells. The GTME's phytochemical composition was identified using gas chromatography-mass spectrometry, and the extract's capacity to lower cellular proliferation and cause apoptosis in HepG2 cancerous liver cell lines was checked.

RESULTS

The findings of the gas chromatography-mass chromatogram showed that GTME included bioactive antioxidants and anticancer substances. Additionally, utilizing the MTT, comet assay, and acridine assay, GTME revealed a selective cytotoxic impact with a significant IC50 value (27.3 µg/ml) on HepG2 cells without any harmful effects on WI-38 healthy cells. Also, compared to untreated cells, the extract-treated HepG2 cells had an upsurge in the proportion of cells that have undergone apoptosis and displayed a comet nucleus, which is a sign of DNA damage. In addition, HepG2 cells treated with GTME revealed a stop in the G1 phase and sub-G1 apoptotic cells (37.32%) in a flow cytometry analysis. Furthermore, reactive oxygen species were shown to be responsible for HepG2 apoptosis, and the tested extract significantly reduced their levels in the treated cells. Lastly, compared to untreated cells in treated HepG2 cells, GTME significantly changed protein expression levels linked with cell cycle arrest in the G1 phase and apoptosis.

CONCLUSION

These findings provided information about the processes through which the GTME inhibited the growth of HepG2. Therefore, it has potential as an effective natural therapy for the treatment of human liver cancer. However, to validate these findings, animal models must be used for in vivo studies.

Polyphenolic Nanomedicine Regulating Mitochondria REDOX for Innovative Cancer Treatment

Cancer remains a highly lethal disease globally. The approach centered on REDOX-targeted mitochondrial therapy for cancer has displayed notable benefits. Plant polyphenols exhibit strong REDOX and anticancer properties, particularly by affecting mitochondrial function, yet their structural instability and low bioavailability hinder their utility. To overcome this challenge, researchers have utilized the inherent physical and chemical characteristics of polyphenols and their derivatives to develop innovative nanomedicines for targeting mitochondria. This review examines the construction strategies and anticancer properties of various types of polyphenol-based biological nanomedicine for regulating mitochondria in recent years, such as polyphenol self-assembly, metal-phenol network, polyphenol-protein, polyphenol-hydrogel, polyphenol-chitosan, and polyphenol-liposome. These polyphenolic nanomedicines incorporate enhanced features such as improved solubility, efficient photothermal conversion capability, regulation of mitochondrial homeostasis, and ion adsorption through diverse construction strategies. The focus is on how these polyphenol nanomedicines promote ROS production and their mechanism of targeting mitochondria to inhibit cancer. Furthermore, it delves into the benefits and applications of polyphenolic nanomedicine in cancer treatments, as well as the challenges for future research.

The physiological levels of epigallocatechin gallate (EGCG) enhance the Cd-induced oxidative stress and apoptosis in CHO-K1 cells

Currently, the increasing pollution of the environment by heavy metals is observed, caused both by natural factors and those related to human activity. They pose a significant threat to human health and life. It is therefore important to find an effective way of protecting organisms from their adverse effects. One potential product showing a protective effect is green tea. It has been shown that EGCG, which is found in large amounts in green tea, has strong antioxidant properties and can therefore protect cells from the adverse effects of heavy metals. Therefore, the aim of the study was to investigate the effect of EGCG on cells exposed to Cd. In the study, CHO-K1 cells (Chinese hamster ovary cell line) were treated for 24 h with Cd (5 and 10 µM) and EGCG (0.5 and 1 µM) together or separately. Cell viability, ATP content, total ROS activity, mitochondrial membrane potential and apoptosis potential were determined. The results showed that, in tested concentrations, EGCG enhanced the negative effect of Cd. Further analyses are needed to determine the exact mechanism of action of EGCG due to the small number of publications on the subject and the differences in the results obtained in the research.

Enhanced Chemoprevention of Prostate Cancer by Combining Arctigenin with Green Tea and Quercetin in Prostate-Specific Phosphatase and Tensin Homolog Knockout Mice

The low bioavailability of most phytochemicals limits their anticancer effects in humans. The present study was designed to test whether combining arctigenin (Arc), a lignan mainly from the seed of Arctium lappa, with green tea (GT) and quercetin (Q) enhances the chemopreventive effect on prostate cancer. We performed in vitro proliferation studies on different cell lines. We observed a strong synergistic anti-proliferative effect of GT+Q+Arc in exposing androgen-sensitive human prostate cancer LNCaP cells. The pre-malignant WPE1-NA22 cell line was more sensitive to this combination. No cytotoxicity was observed in normal prostate epithelial PrEC cells. For an in vivo study, 3-week-old, prostate-specific PTEN (phosphatase and tensin homolog) knockout mice were treated with GT+Q, Arc, GT+Q+Arc, or the control daily until 16 weeks of age. In vivo imaging using prostate-specific membrane antigen (PSMA) probes demonstrated that the prostate tumorigenesis was significantly inhibited by 40% (GT+Q), 60% (Arc at 30 mg/kg bw), and 90% (GT+Q+Arc) compared to the control. A pathological examination showed that all control mice developed invasive prostate adenocarcinoma. In contrast, the primary lesion in the GT+Q and Arc alone groups was high-grade prostatic intraepithelial neoplasia (PIN), with low-grade PIN in the GT+Q+Arc group. The combined effect of GT+Q+Arc was associated with an increased inhibition of the androgen receptor, the PI3K/Akt pathway, Ki67 expression, and angiogenesis. This study demonstrates that combining Arc with GT and Q was highly effective in prostate cancer chemoprevention. These results warrant clinical trials to confirm the efficacy of this combination in humans.

Hydroxyapatite coated titanium with curcumin and epigallocatechin gallate for orthopedic and dental applications

Titanium and its alloy are clinically used as an implant material for load-bearing applications to treat bone defects. However, the lack of biological interaction between bone tissue and implant and the risk of infection are still critical challenges in clinical orthopedics. In the current work, we have developed a novel approach by first 1) modifying the implant surface using hydroxyapatite (HA) coating to enhance bioactivity and 2) integrating curcumin and epigallocatechin gallate (EGCG) in the coating that would induce chemopreventive and osteogenic potential and impart antibacterial properties to the implant. The study shows that curcumin and EGCG exhibit controlled and sustained release profiles in acidic and physiological environments. Curcumin and EGCG also show in vitro cytotoxicity toward osteosarcoma cells after 11 days, and the dual system shows a ~94 % reduction in bacterial growth, indicating their in vitro chemopreventive potential and antibacterial efficacy. The release of both curcumin and EGCG was found to be compatible with osteoblast cells and further promotes their growth. It shows a 3-fold enhancement in cellular viability in the dual drug-loaded implant compared to the untreated samples. These findings suggest that multifunctional HA-coated Ti6Al4V implants integrated with curcumin and EGCG could be a promising strategy for osteosarcoma inhibition and osteoblast cell growth while preventing infection.

Therapeutic Effects of Green Tea Polyphenol (‒)-Epigallocatechin-3-Gallate (EGCG) in Relation to Molecular Pathways Controlling Inflammation, Oxidative Stress, and Apoptosis

(‒)-Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenol in green tea. Thanks to multiple interactions with cell surface receptors, intracellular signaling pathways, and nuclear transcription factors, EGCG possesses a wide variety of anti-inflammatory, antioxidant, antifibrotic, anti-remodelation, and tissue-protective properties which may be useful in the treatment of various diseases, particularly in cancer, and neurological, cardiovascular, respiratory, and metabolic disorders. This article reviews current information on the biological effects of EGCG in the above-mentioned disorders in relation to molecular pathways controlling inflammation, oxidative stress, and cell apoptosis.

Prevention of carcinogen-induced oral cancers by polymeric black tea polyphenols via modulation of EGFR-Akt-mTOR pathway

The overexpression of Epidermal Growth Factor Receptor (EGFR) and dysregulation of its downstream effector pathways are important molecular hallmarks of oral cancers. Present study investigates the chemopreventive potential of polymeric black tea polyphenols (PBPs)/thearubigins (TRs) in the hamster model of oral carcinogenesis as well as determine the effect of PBPs on EGFR and the molecular players in the EGFR pathway. In dose-dependent manner, pre and concurrent treatment with PBPs (1.5%, 5%, 10%) decreased the number and volume of macroscopic tumors as well as the number and area of microscopic lesions. Interestingly, at 10% dose of PBPs, no macroscopic or microscopic tumors were observed. We observed PBPs mediated dose-dependent decrease in oxidative DNA damage (8OHdG); inflammation (COX-2); proliferation (PCNA, Cyclin D1); expression of EGFR, and its downstream signaling kinases (pAkt, Akt, and mTOR); hypoxia (HIF1α) and angiogenesis (VEGF). There was also a PBPs mediated dose-dependent increase in apoptosis (Bax). Thus, our data clearly indicate that the observed chemopreventive potential of PBPs was due to modulation in the EGFR pathway associated with cell proliferation, hypoxia, and angiogenesis. Taken together, our results demonstrate preclinical chemopreventive efficacy of PBPs and give an insight into its mechanistic role in the chemoprevention of experimental oral cancer.

Green Tea Polyphenol (-)-Epigallocatechin-3-Gallate (EGCG): A Time for a New Player in the Treatment of Respiratory Diseases?

(-)-Epigallocatechin-3-gallate (EGCG) is a major polyphenol of green tea that possesses a wide variety of actions. EGCG acts as a strong antioxidant which effectively scavenges reactive oxygen species (ROS), inhibits pro-oxidant enzymes including NADPH oxidase, activates antioxidant systems including superoxide dismutase, catalase, or glutathione, and reduces abundant production of nitric oxide metabolites by inducible nitric oxide synthase. ECGC also exerts potent anti-inflammatory, anti-fibrotic, pro-apoptotic, anti-tumorous, and metabolic effects via modulation of a variety of intracellular signaling cascades. Based on this knowledge, the use of EGCG could be of benefit in respiratory diseases with acute or chronic inflammatory, oxidative, and fibrotizing processes in their pathogenesis. This article reviews current information on the biological effects of EGCG in those respiratory diseases or animal models in which EGCG has been administered, i.e., acute respiratory distress syndrome, respiratory infections, COVID-19, bronchial asthma, chronic obstructive pulmonary disease, lung fibrosis, silicosis, lung cancer, pulmonary hypertension, and lung embolism, and critically discusses effectiveness of EGCG administration in these respiratory disorders. For this review, articles in English language from the PubMed database were used.

Flexion of Nrf2 by tea phytochemicals: A review on the chemopreventive and chemotherapeutic implications

Nuclear factor erythroid 2 [NF-E2]-related factor 2 (Nrf2), the redox-sensitive transcription factor, plays a key role in stress-defense and detoxification. Nrf2 is tightly controlled by its negative regulator cum sensor Kelch-[ECH]-associated protein 1 (Keap1). Nrf2 is well known for its dual nature owing to its cancer preventive and cancer promoting abilities. Modulation of this biphasic nature of Nrf2 signaling by phytochemicals may be a potential cancer preventive and anticancer therapeutic strategy. Phytocompounds may either act as Nrf2-activator or Nrf2-inhibitor depending on their differential concentration and varied cellular environment. Tea is not just the most popular global beverage with innumerable health-benefits but has well-established chemopreventive and chemotherapeutic effects. Various types of tea infusions contain a wide range of bioactive compounds, such as polyphenolic catechins and flavonols, which are endowed with potent antioxidant properties. Despite of their rapid biotransformation and poor bioavailability, regular tea consumption is risk-reductive for several cancer forms. Tea catechins show their dual Nrf2-modulatory effect by directly acting on Nrf2-Keap1 or their upstream regulators and downstream effectors in a highly case-specific manner. In this review, we have tried to present a comprehensive evaluation of the Nrf2-mediated chemopreventive and chemotherapeutic applications of tea in various preclinical cancer models, the Nrf2-modulatory mechanisms, and the limitations which need to be addressed in future research.

Molecular Targets of Natural Compounds with Anti-Cancer Properties

Cancer is the second leading cause of death in humans. Despite rapid developments in diagnostic methods and therapies, metastasis and resistance to administrated drugs are the main obstacles to successful treatment. Therefore, the main challenge should be the diagnosis and design of optimal therapeutic strategies for patients to increase their chances of responding positively to treatment and increase their life expectancy. In many types of cancer, a deregulation of multiple pathways has been found. This includes disturbances in cellular metabolism, cell cycle, apoptosis, angiogenesis, or epigenetic modifications. Additionally, signals received from the microenvironment may significantly contribute to cancer development. Chemical agents obtained from natural sources seem to be very attractive alternatives to synthetic compounds. They can exhibit similar anti-cancer potential, usually with reduced side effects. It was reported that natural compounds obtained from fruits and vegetables, e.g., polyphenols, flavonoids, stilbenes, carotenoids and acetogenins, might be effective against cancer cells in vitro and in vivo. Several published results indicate the activity of natural compounds on protein expression by its influence on transcription factors. They could also be involved in alterations in cellular response, cell signaling and epigenetic modifications. Such natural components could be used in our diet for anti-cancer protection. In this review, the activities of natural compounds, including anti-cancer properties, are described. The influence of natural agents on cancer cell metabolism, proliferation, signal transduction and epigenetic modifications is highlighted.

Tea polyphenols alleviate hydrogen peroxide-induced oxidative stress damage through the Mst/Nrf2 axis and the Keap1/Nrf2/HO-1 pathway in murine RAW264.7 cells

Tea polyphenols (TPs) are the major bioactive extract from green tea that have been extensively reported to prevent and treat oxidative stress damage. In previous studies, TPs have been demonstrated to protect cells against oxidative injury induced by hydrogen peroxide (H₂O₂). However, the underlying mechanism remains unclear. The aim of the current study was to investigate whether the protective and regulatory effects of TPs on oxidative stress damage were dependent on the mammalian STE20-like protein kinase (Mst)/nuclear factor (erythroid-derived 2)-like 2 (Nrf2) axis and the Kelch-like ECH-associated protein 1 (Keap1)/Nrf2/heme oxygenase 1 (HO-1) pathway in RAW264.7 cells, a murine macrophage cell line. Maintaining a certain range of intracellular reactive oxygen species (ROS) levels is critical to basic cellular activities, while excessive ROS generation can override the antioxidant capacity of the cell and result in oxidative stress damage. The inhibition of ROS generation offers an effective target for preventing oxidative damage. The results of the present study revealed that pretreatment with TPs inhibited the production of intracellular ROS and protected RAW264.7 cells from H₂O₂-induced oxidative damage. TPs was also demonstrated to attenuate the production of nitric oxide and malondialdehyde and increase the levels of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase). In addition, following TPs treatment, alterations in Mst1/2 at the mRNA and protein level inhibited the production of ROS and promoted the self-regulation of antioxidation. TPs-induced Keap1 gene downregulation also increased the expression of Nrf2 and HO-1. Collectively, the results of the present study demonstrated that TPs provided protection against H₂O₂-induced oxidative injury in RAW264.7 cells.

The Intrinsic Virtues of EGCG, an Extremely Good Cell Guardian, on Prevention and Treatment of Diabesity Complications

The pandemic proportion of diabesity—a combination of obesity and diabetes—sets a worldwide health issue. Experimental and clinical studies have progressively reinforced the pioneering epidemiological observation of an inverse relationship between consumption of polyphenol-rich nutraceutical agents and mortality from cardiovascular and metabolic diseases. With chemical identification of epigallocatechin-3-gallate (EGCG) as the most abundant catechin of green tea, a number of cellular and molecular mechanisms underlying the activities of this unique catechin have been proposed. Favorable effects of EGCG have been initially attributed to its scavenging effects on free radicals, inhibition of ROS-generating mechanisms and upregulation of antioxidant enzymes. Biologic actions of EGCG are concentration-dependent and under certain conditions EGCG may exert pro-oxidant activities, including generation of free radicals. The discovery of 67-kDa laminin as potential EGCG membrane target has broaden the likelihood that EGCG may function not only because of its highly reactive nature, but also via receptor-mediated activation of multiple signaling pathways involved in cell proliferation, angiogenesis and apoptosis. Finally, by acting as epigenetic modulator of DNA methylation and chromatin remodeling, EGCG may alter gene expression and modify miRNA activities. Despite unceasing research providing detailed insights, ECGC composite activities are still not completely understood. This review summarizes the most recent evidence on molecular mechanisms by which EGCG may activate signal transduction pathways, regulate transcription factors or promote epigenetic changes that may contribute to prevent pathologic processes involved in diabesity and its cardiovascular complications.

From tea to treatment; epigallocatechin gallate and its potential involvement in minimizing the metabolic changes in cancer

As the most abundant bioactive polyphenol in green tea, epigallocatechin gallate (EGCG) is a promising natural product that should be used in the discovery and development of potential drug leads. Due to its association with chemoprevention, EGCG may find a role in the development of therapeutics for prostate cancer. Natural products have long been used as a scaffold for drug design, as their already noted bioactivity can help accelerate the development of novel treatments. Green tea and the EGCG contained within have become associated with chemoprevention, and both in vitro and in vivo studies have correlated EGCG to inhibiting cell growth and increasing the metabolic stress of cancer cells, possibly giving merit to its long utilized therapeutic use in traditional therapies. There is accumulating evidence to suggest EGCG's role as an inhibitor of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin signaling cascade, acting upon major axis points within cancer survival pathways. The purpose of this review is to examine the research conducted on tea along with EGCG in the areas of the treatment of and/or prevention of cancer. This review discusses Camellia sinensis as well as the bioactive phytochemical compounds contained within. Clinical uses of tea are explored, and possible pathways for activity are discussed before examining the evidence for EGCG's potential for acting on these processes. EGCG is identified as being a possible lead phytochemical for future drug design investigations.

Epigallocatechin 3-gallate attenuates arthritis by regulating Nrf2, HO-1, and cytokine levels in an experimental arthritis model

Epigallocatechin 3-gallate (EGCG) is a polyphenol that has been shown to have antioxidant and anti-inflammatory effects. In this study, collagen-induced arthritis (CIA) model, in Wistar albino rats, was used to elucidate the effect of EGCG on pathogenetic pathways in inflammatory arthritis. The levels of serum TNF-α, IL-17, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx); the expression levels of tissue heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2); histopathologically, perisynovial inflammation and cartilage-bone destruction were examined. In the sham group, serum TNF-α, IL-17, and MDA levels increased, while SOD, CAT, GPx levels, and the expressions of Nrf2 and HO-1 decreased. On the other hand, in the EGCG administered groups, serum TNF-α, IL-17, and MDA levels improved, while SOD, CAT, GPx levels and the expressions of Nrf2 and HO-1 increased. Moreover, histopathological analysis has shown that perisynovial inflammation and cartilage-bone destruction decreased in the EGCG administered groups. These results suggest that EGCG has an antiarthritic effect by regulating the oxidative-antioxidant balance and cytokine levels in the CIA model, which is a surrogate experimental model of rheumatoid arthritis.

Synergistic inhibition of lung cancer cells by EGCG and NF-κB inhibitor BAY11-7082

Lung cancer has a poor 5-year survival rate and is the leading cause of cancer-related deaths worldwide. Thus, the development of more efficient therapeutic strategies is urgently needed. Many studies have shown that EGCG, a major polyphenol found in green tea, has potential anticancer effects. The present study aims to investigate the molecular mechanism of EGCG-mediated inhibition of proliferation in lung cancer cells and to explore the effects of combined treatment with EGCG and an NF-κB inhibitor, BAY11-7082, in A549 and H1299 cells both in vitro and in vivo. Our results showed that EGCG inhibits cell proliferation and migration and induces apoptosis in A549 and H1299 cells at relatively high concentrations (IC50=86.4 µM for A549 cells and 80.6 µM for H1299 cells). These effects are partially achieved via inhibition of the NF-κB signaling pathway. Combined treatment with EGCG and BAY11-7082, a potent NF-κB inhibitor, shows significant synergistic effects at relatively low concentrations. The inhibition rate reached approximately 50% in cells treated for 72 h with 20 µM EGCG and 5 µM (A549 cells) or 2.5 µM BAY11-7082 (H1299 cells). This synergistic anti-tumor effect was also observed in a xenograft model. These results indicated that EGCG inhibits lung cancer cell proliferation by suppressing NF-κB signaling. Coadministration of EGCG and BAY11-7082 has a synergistic effect both in vitro and in vivo and may serve as a novel therapeutic strategy for lung cancer.

Biological and toxicological evaluation of Rhus trilobata Nutt. (Anacardiaceae) used traditionally in mexico against cancer

BACKGROUND

Rhus trilobata Nutt. (Anacardiaceae) (RHTR) is a plant of Mexico that is traditionally used as an alternative treatment for several types of cancer. However, the phytochemical composition and potential toxicity of this plant have not been evaluated to support its therapeutic use. Therefore, this study aimed to evaluate the biological activity of RHTR against colorectal adenocarcinoma cells, determine its possible acute toxicity, and analyze its phytochemical composition.

METHODS

The traditional preparation was performed by decoction of stems in distilled water (aqueous extract, AE), and flavonoids were concentrated with C18-cartridges and ethyl acetate (flavonoid fraction, FF). The biological activity was evaluated by MTT viability curves and the TUNEL assay in colorectal adenocarcinoma (CACO-2), ovarian epithelium (CHO-K1) and lung/bronchus epithelium (BEAS-2B) cells. The toxicological effect was determined in female BALB/c mice after 24 h and 14 days of intraperitoneal administration of 200 mg/kg AE and FF, respectively. Later, the animals were sacrificed for histopathological observation of organs and sera obtained by retro-orbital bleeding for biochemical marker analysis. Finally, the phytochemical characterization of AE and FF was conducted by UPLC-MSE.

RESULTS

In the MTT assays, AE and FF at 5 and 18 μg/mL decreased the viability of CACO-2 cells compared with cells treated with vehicle or normal cells (p ≤ 0.05, ANOVA), with changes in cell morphology and the induction of apoptosis. Anatomical and histological analysis of organs did not reveal important pathological lesions at the time of assessment. Additionally, biochemical markers remained normal and showed no differences from those of the control group after 24 h and 14 days of treatment (p ≤ 0.05, ANOVA). Finally, UPLC-MSE analysis revealed 173 compounds in AE-RHTR, primarily flavonoids, fatty acids and phenolic acids. The most abundant compounds in AE and FF were quercetin and myricetin derivates (glycosides), methyl gallate, epigallocatechin-3-cinnamate, β-PGG, fisetin and margaric acid, which might be related to the anticancer properties of RHTR.

CONCLUSION

RHTR exhibits biological activity against cancer cells and does not present adverse toxicological effects during its in vivo administration, supporting its traditional use.

Green tea polyphenols modify gut-microbiota dependent metabolisms of energy, bile constituents and micronutrients in female Sprague-Dawley rats

Our recent metagenomics analysis has uncovered remarkable modifying effects of green tea polyphenols (GTP) on gut-microbiota community structure and energy conversion related gene orthologs in rats. How these genomic changes could further influence host health is still unclear. In this work, the alterations of gut-microbiota dependent metabolites were studied in the GTP-treated rats. Six groups of female SD rats (n=12/group) were administered drinking water containing 0%, 0.5%, and 1.5% GTP (wt/vol). Their gut contents were collected at 3 and 6 months and were analyzed via high performance liquid chromatography (HPLC) and gas chromatography (GC)-mass spectrometry (MS). GC-MS based metabolomics analysis captured 2668 feature, and 57 metabolites were imputatively from top 200 differential features identified via NIST fragmentation database. A group of key metabolites were quantitated using standard calibration methods. Compared with control, the elevated components in the GTP-treated groups include niacin (8.61-fold), 3-phenyllactic acid (2.20-fold), galactose (3.13-fold), mannose (2.05-fold), pentadecanoic acid (2.15-fold), lactic acid (2.70-fold), and proline (2.15-fold); the reduced components include cholesterol (0.29-fold), cholic acid (0.62-fold), deoxycholic acid (0.41-fold), trehalose (0.14-fold), glucose (0.46-fold), fructose (0.12-fold), and alanine (0.61-fold). These results were in line with the genomic alterations of gut-microbiome previously discovered by metagenomics analysis. The alterations of these metabolites suggested the reduction of calorific carbohydrates, elevation of vitamin production, decreases of bile constituents, and modified metabolic pattern of amino acids in the GTP-treated animals. Changes in gut-microbiota associated metabolism may be a major contributor to the anti-obesity function of GTP.

Toxicological effects of Camellia sinensis (green tea): A review

Many scientific articles proved that green tea (GT), Camellia sinensis, has a great potential to manage central nervous system, cardiovascular, and metabolic diseases and treat cancer and inflammatory disorders. However, it is important to consider that "natural" is not always "safe." Some relevant articles reported side effects of GT, detrimental effects on health. The aim of this study is to provide a classified report about the toxicity of GT and its main constituents in acute, subacute, subchronic, and chronic states. Furthermore, it discusses on the cytotoxicity, genotoxicity, mutagenicity, carcinogenicity, and developmental toxicity of GT and its main constituents. The most important side effects have been reported hepatotoxicity and gastrointestinal disorders specially while consumed on an empty stomach. GT and its main components are not major teratogen, mutagen, or carcinogen substances. However, there is limited data in using them during pregnancy, and they should be used with caution in pregnancy, breast-feeding, and susceptible people. Because GT and its main components have a wide variety of drug interactions, consideration should be taken in coadministration of them with narrow therapeutic indexed drugs. Furthermore, they evoke selective cytotoxicity on cancerous cells that could engage them as an adjuvant substance in cancer therapy.

Overexpression of the Anthocyanidin Synthase Gene in Strawberry Enhances Antioxidant Capacity and Cytotoxic Effects on Human Hepatic Cancer Cells

Food fortification through the increase and/or modulation of bioactive compounds has become a major goal for preventing several diseases, including cancer. Here, strawberry lines of cv. Calypso transformed with a construct containing an anthocyanidin synthase (ANS) gene were produced to study the effects on anthocyanin biosynthesis, metabolism, and transcriptome. Three strawberry ANS transgenic lines (ANS L5, ANS L15, and ANS L18) were analyzed for phytochemical composition and total antioxidant capacity (TAC), and their fruit extracts were assessed for cytotoxic effects on hepatocellular carcinoma. ANS L18 fruits had the highest levels of total phenolics and flavonoids, while those of ANS L15 had the highest anthocyanin concentration; TAC positively correlated with total polyphenol content. Fruit transcriptome was also specifically affected in the polyphenol biosynthesis and in other related metabolic pathways. Fruit extracts of all lines exerted cytotoxic effects in a dose/time-dependent manner, increasing cellular apoptosis and free radical levels and impairing mitochondrial functionality.

Are by-products from beeswax recycling process a new promising source of bioactive compounds with biomedical properties?

During the process of beeswax recycling, many industrial derivatives are obtained. These matrices may have an interesting healthy and commercial potential but to date they have not been properly studied. The aim of the present work was to evaluate the proximal and phytochemical composition, the antioxidant capacity and cytotoxic effects of two by-products from beeswax recycling process named MUD 1 and MUD 2 on liver hepatocellular carcinoma. Our results showed that MUD 1 presented the highest (P < .05) fiber, protein, carbohydrate, polyphenol and flavonoid concentration, as well as the highest (P < .05) total antioxidant capacity than the MUD 2 samples. MUD1 exerted also anticancer activity on HepG2 cells, by reducing cellular viability, increasing intracellular ROS levels and affecting mitochondrial functionality in a dose-dependent manner. We showed for the first time that by-products from beeswax recycling process can represent a rich source of phytochemicals with high total antioxidant capacity and anticancer activity; however, further researches are necessary to evaluate their potentiality for human health by in vivo studies.

Green Tea Extracts Epigallocatechin-3-gallate for Different Treatments

Epigallocatechin-3-gallate (EGCG), a component extracted from green tea, has been proved to have multiple effects on human pathological and physiological processes, and its mechanisms are discrepant in cancer, vascularity, bone regeneration, and nervous system. Although there are multiple benefits associated with EGCG, more and more challenges are still needed to get through. For example, EGCG shows low bioactivity via oral administration. This review focuses on effects of EGCG, including anti-cancer, antioxidant, anti-inflammatory, anticollagenase, and antifibrosis effects, to express the potential of EGCG and necessity of further studies in this field.

Research progress on theaflavins: efficacy, formation, and preparation

Background: Theaflavins (TFs) are a category of natural compounds characterized with the benzotropolone skeleton. The prominent benefits of TFs have been well documented. Amount of research were conducted and excellent achievements were disclosed during the past years. However, as far as we know, there is no comprehensive review about TFs. Scope and approach: This review summarized the recent research progress. The activity of TFs on anti-oxidation, anti-mutagenicity, hypolipidemic, anti-inflammatory, anti-cancer, anti-viral effect as well as the epidemiological cure were sorted. Converging pioneer literature and deduction, the underlying formation mechanism of TFs was proposed. Subsequently, acquisition of TFs was pointed out to be the fundament for further research. Accelerated by enzyme, bio-synthesis of TFs were reviewed simultaneously. At the end, employing modern analysis instrument and technology, isolations of TFs were enumerated. Key findings and conclusions: Structure of the skeleton as well as functional groups were paramount related with the bio-activity of TFs. Meanwhile, oxidation pathway of two catechin molecules to form TFs were hypothesized. Also, ascertainment of the several therapeutic efficiency of the family members of TFs would be the next step in the future.

EGCG inhibited bladder cancer SW780 cell proliferation and migration both in vitro and in vivo via down-regulation of NF-κB and MMP-9

Epigallocatechin-3-gallate (EGCG), the bioactive polyphenol in green tea, has been demonstrated to have various biological activities. Our study aims to investigate the antiproliferation and antimigration effects of EGCG against bladder cancer SW780 cells both in vitro and in vivo. Our results showed that treatment of EGCG resulted in significant inhibition of cell proliferation by induction of apoptosis, without obvious toxicity to normal bladder epithelium SV-HUC-1 cells. EGCG also inhibited SW780 cell migration and invasion at 25-100 μM. Western blot confirmed that EGCG induced apoptosis in SW780 cells by activation of caspases-8, -9 and -3, Bax, Bcl-2 and PARP. Besides, animal study demonstrated that EGCG [100 mg/kg, intraperitoneal (i.p.) injection daily for 3 weeks] decreased the tumor volume significantly in mice bearing SW780 tumors, as well as the tumor weight (decreased by 68.4%). In addition, EGCG down-regulated the expression of nuclear factor-kappa B (NF-κB) and matrix metalloproteinase (MMP)-9 in both protein and mRNA level in tumor and SW780 cells. When NF-κB was inhibited, EGCG showed no obvious effect in cell proliferation and migration. In conclusion, our study demonstrated that EGCG was effective in inhibition SW780 cell proliferation and migration, and presented first evidence that EGCG inhibited SW780 tumor growth by down-regulation of NF-κB and MMP-9.

Ethyl acetate extract from Asparagus cochinchinensis exerts anti‑inflammatory effects in LPS‑stimulated RAW264.7 macrophage cells by regulating COX‑2/iNOS, inflammatory cytokine expression, MAP kinase pathways, the cell cycle and anti-oxidant activity

Asparagus cochinchinesis (A. cochinchinesis) is a medicine traditionally used to treat fever, cough, kidney disease, breast cancer, inflammatory disease and brain disease in northeast Asian countries. Although numerous studies of the anti-inflammatory effects of A. cochinchinesis have been conducted, the underlying mechanisms of such effects in macrophages remain to be demonstrated. To investigate the mechanism of suppressive effects on the inflammatory response in macrophages, alterations of the nitric oxide (NO) level, the cell viability, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression levels, inflammatory cytokine expression, the mitogen-activated protein kinase (MAPK) signaling pathway, cell cycle arrest and reactive oxygen species (ROS) levels were measured in lipopolysaccharide (LPS)-activated RAW264.7 cells following treatment with ethyl acetate extract from A. cochinchinesis root (EaEAC). RAW264.7 cells pretreated two different concentrations of EaEAC prior to LPS treatment exhibited no significant toxicity. The concentration of NO was significantly decreased in the EaEAC + LPS treated group compared with the vehicle + LPS treated group. A similar decrease in mRNA transcript level of COX-2, iNOS, pro-inflammatory cytokines [tumor necrosis factor-α and interleukin (IL)-1β] and anti-inflammatory cytokines (IL-6 and IL-10) was detected in the EaEAC + LPS treated group compared with the vehicle + LPS treated group, although the decrease rate varied. Enhancement of the phosphorylation of MAPK family members following LPS treatment was partially rescued in the EaEAC pretreated group, and the cell cycle was arrested at the G2/M phase. Furthermore, the EaEAC pretreated group exhibited a reduced level of ROS generation compared with the vehicle + LPS treated group. Taken together, these results suggest that EaEAC suppresses inflammatory responses through inhibition of NO production, COX-2 expression and ROS production, as well as differential regulation of inflammatory cytokines and cell cycle in RAW264.7 cells. In addition, these results provide strong evidence to suggest that EaEAC may be considered as an important candidate for the treatment of particular inflammatory diseases.

Anti-Inflammatory Effects of Aspalathus linearis and Cyclopia spp. Extracts in a UVB/Keratinocyte (HaCaT) Model Utilising Interleukin-1α Accumulation as Biomarker

Ultraviolet B (UVB) radiation is one of the major predisposing risk factors of skin cancer. The anticancer and photoprotective effects of unoxidized rooibos (Aspalathus linearis) and honeybush (Cyclopia) herbal teas, containing high levels of dihydrochalones and xanthones, respectively, have been demonstrated in skin cancer models in vivo. In the current study, the anti-inflammatory effects of methanol and aqueous extracts of these herbal teas were investigated in a UVB/HaCaT keratinocyte model with intracellular interleukin-1α (icIL-1α) accumulation as a biomarker. Extracts of green tea (Camellia sinensis) served as benchmark. Both extracts of green tea and rooibos, as well as the aqueous extract of C. intermedia, enhanced UVB-induced inhibition of cell viability, proliferation and induction of apoptosis, facilitating the removal of icIL-1α. The underlying mechanisms may involve mitochondrial dysfunction exhibiting pro-oxidant responses via polyphenol-iron interactions. The methanol extracts of honeybush, however, protected against UVB-induced reduction of cell growth parameters, presumably via antioxidant mechanisms that prevented the removal of highly inflamed icIL-1α-containing keratinocytes via apoptosis. The dual antioxidant and/or pro-oxidant role of the polyphenolic herbal tea constituents should be considered in developing preventive strategies against UVB-induced skin carcinogenesis. The indirect removal of UVB damaged keratinocytes by herbal tea extracts via apoptosis may find application in the prevention of photo-induced inflammation.

Epigallocatechin Gallate Nanodelivery Systems for Cancer Therapy

Cancer is one of the leading causes of morbidity and mortality all over the world. Conventional treatments, such as chemotherapy, are generally expensive, highly toxic and lack efficiency. Cancer chemoprevention using phytochemicals is emerging as a promising approach for the treatment of early carcinogenic processes. (−)-Epigallocatechin-3-gallate (EGCG) is the major bioactive constituent in green tea with numerous health benefits including anti-cancer activity, which has been intensively studied. Besides its potential for chemoprevention, EGCG has also been shown to synergize with common anti-cancer agents, which makes it a suitable adjuvant in chemotherapy. However, limitations in terms of stability and bioavailability have hampered its application in clinical settings. Nanotechnology may have an important role in improving the pharmacokinetic and pharmacodynamics of EGCG. Indeed, several studies have already reported the use of nanoparticles as delivery vehicles of EGCG for cancer therapy. The aim of this article is to discuss the EGCG molecule and its associated health benefits, particularly its anti-cancer activity and provide an overview of the studies that have employed nanotechnology strategies to enhance EGCG’s properties and potentiate its anti-tumoral activity.

Characterization of Catechins in Water by Photoemission Yield Spectroscopy in Air

Photoemission yield spectroscopy in air (PYSA) was applied for the characterization of catechins in water in ambient conditions. According to the results of measurements on aqueous solutions of epigallocatechin gallate (EGCg) of various concentrations, the photoemission yield is almost proportional to the concentration of EGCg. Contrarily, the threshold energy of photoemission, EPET, is almost constant at 5.46 ± 0.02 eV. Moreover, we measured aqueous solutions of epicatechin (EC), epigallocatechin (EGC), and epicatechin gallate (ECg). The values of EPET of EC, EGC, ECg were estimated to be 5.72 ± 0.02, 5.68 ± 0.01, and 5.45 ± 0.02 eV, respectively, and a dependence on the molecular structure was found. Furthermore, changes in the photoemission yield spectra of heated EGCg were well explained by molecular orbital calculations on the basis of an assumption of epimerization.

Effects of EGCG content in green tea extract on pharmacokinetics, oxidative status and expression of inflammatory and apoptotic genes in the rat ocular tissues

Green tea extract (GTE) exerts antioxidative activities in ocular tissues of rats, but high levels of (-)-epigallocatechin gallate (EGCG) can induce oxidative stress. In this study, pharmacokinetics, diurnal variation of oxidative status, antioxidation and transcription factors changes in ocular tissues of rats were investigated. Rats were fed intragastrically with GTE and catechin mixtures containing different amounts of EGCG. Plasma and various ocular tissues were taken for pharmacokinetic analysis, oxidation marker testings and gene expression assays. Effects of EGCG on ocular oxidation status were assessed by 8-isoprostane level and reduced/oxidized glutathione ratio. Oxidation, inflammation and apoptosis regulations in retina were evaluated by real-time polymerase chain reaction. Epicatechin, epigallocatechin and EGCG were dominant in various ocular tissues except vitreous humor, where gallocatechin was predominant. Diurnal variation of oxidative status was found in some compartments. GTE caused oxidative stress increase in the plasma, aqueous humor, vitreous humor, cornea and retina but decrease in the lens and choroid-sclera. Catechins mixture containing half dose of EGCG lowered 8-isoprostane in the retina and lens. GTE treatment induced superoxide dismutase 1 and glutathione peroxidase-3 expressions but suppressed catalase in the retina. Our results reveal pro-oxidation of GTE with high EGCG content to the ocular tissues. Optimal EGCG level is needed for protection.

Dietary phytochemicals alter epigenetic events and signaling pathways for inhibition of metastasis cascade: phytoblockers of metastasis cascade

Cancer metastasis is a multistep process in which a cancer cell spreads from the site of the primary lesion, passes through the circulatory system, and establishes a secondary tumor at a new nonadjacent organ or part. Inhibition of cancer progression by dietary phytochemicals (DPs) offers significant promise for reducing the incidence and mortality of cancer. Consumption of DPs in the diet has been linked to a decrease in the rate of metastatic cancer in a number of preclinical animal models and human epidemiological studies. DPs have been reported to modulate the numerous biological events including epigenetic events (noncoding micro-RNAs, histone modification, and DNA methylation) and multiple signaling transduction pathways (Wnt/β-catenin, Notch, Sonic hedgehog, COX-2, EGFR, MAPK-ERK, JAK-STAT, Akt/PI3K/mTOR, NF-κB, AP-1, etc.), which can play a key role in regulation of metastasis cascade. Extensive studies have also been performed to determine the molecular mechanisms underlying antimetastatic activity of DPs, with results indicating that these DPs have significant inhibitory activity at nearly every step of the metastatic cascade. DPs have anticancer effects by inducing apoptosis and by inhibiting cell growth, migration, invasion, and angiogenesis. Growing evidence has also shown that these natural agents potentiate the efficacy of chemotherapy and radiotherapy through the regulation of multiple signaling pathways. In this review, we discuss the variety of molecular mechanisms by which DPs regulate metastatic cascade and highlight the potentials of these DPs as promising therapeutic inhibitors of cancer.

Mechanism of action of (-)-epigallocatechin-3-gallate: auto-oxidation-dependent activation of extracellular signal-regulated kinase 1/2 in Jurkat cells

AIM

(-)-Epigallocatechin-3-gallate (EGCG), a major compound of tea polyphenols, exhibited antitumor activity in previous studies. In these studies, EGCG usually inhibits EGFR, and impairs the ERK1/2 phosphorylation in tumor cells. The aim was to clarify the mechanism of ERK1/2 activation induced by EGCG.

METHOD

Jurkat and 293T cells were treated with EGCG in different culture conditions. Western Blotting (WB) was employed to analyze ERK1/2 and MEK phosphorylation. Cetuximab and FR180204 were used to inhibit cell signaling. The stability of EGCG was assessed by HPLC. The concentration of hydrogen peroxide generated by the auto-oxidation of EGCG was determined by photocolorimetric analysis.

RESULTS

Activation of ERK1/2 was observed to be both time-and dose-dependent. Stimulation of cell signaling was dependent on MEK activity, but independent of EGFR activity. Unexpectedly, EGCG was depleted within one hour of incubation under traditional culture conditions. Auto-oxidation of EGCG generated a high level of hydrogen peroxide in the medium. Addition of catalase and SOD to the acidic medium inhibited the oxidation of EGCG. However, this particular condition also prevented the phosphorylation of ERK1/2. The generation of ROS by hydrogen peroxide may also induce ERK1/2 activation in Jurkat cells.

CONCLUSION

ERK1/2 phosphorylation was caused by auto-oxidation of EGCG. Traditional culture conditions were determined to be inappropriate for EGCG research.

Sensitization to docetaxel in prostate cancer cells by green tea and quercetin

Chemotherapy with docetaxel (Doc) is a standard treatment for metastatic and castration-resistant prostate cancer. However, chemoresistance and side effects of Doc limit its clinical success. We investigated whether natural products green tea (GT) and quercetin (Q), a flavonoid from apples and onions, will enhance the efficacy of Doc in androgen-independent (AI) prostate cancer cells. Two cell lines including LAPC-4-AI and PC-3 were treated in vitro with 40 μM of (-)-epigallocatechin gallate (EGCG), 5 μM of Q, 2 or 5 nM of Doc alone or in combination. The mixture of EGCG+Q+Doc increased the antiproliferative effect by threefold in LAPC-4-AI cells and eightfold in PC-3 cells compared to Doc alone. EGCG, Q and Doc in combination significantly enhanced cell cycle arrest at G2/M phase and increased apoptosis in both LAPC-4-AI and PC-3 cells compared to Doc alone. The mixture increased the inhibition of PI3K/Akt and the signal transducer and activator of transcription (Stat) 3 signaling pathways compared to Doc alone, and decreased the protein expression of multidrug resistance-related protein. In addition, the combination with EGCG and Q increased the inhibition of tumor cell invasion and colony formation in both LAPC-4-AI and PC-3 cells compared to Doc alone, and decreased the percentage of CD44(+)/CD24(-) stem-like LAPC-4-AI cells. In summary, GT and Q enhanced the therapeutic effect of Doc in castration-resistant prostate cancer cells through multiple mechanisms including the down-regulation of chemoresistance-related proteins. This study provides a novel therapeutic modality to enhance the efficacy of Doc in a nontoxic manner.

The anti-cancer activity of green tea, coffee and cocoa extracts on human cervical adenocarcinoma HeLa cells depends on both pro-oxidant and anti-proliferative activities of polyphenols

Thein vitroanti-cervical cancer potency of tested polyphenol extracts is exhibited in the following order: green tea > coffee > cocoa, with only green tea showing both pro-oxidative and anti-proliferative action.

Arctigenin in combination with quercetin synergistically enhances the antiproliferative effect in prostate cancer cells

SCOPE

We investigated whether a combination of two promising chemopreventive agents arctigenin (Arc) and quercetin (Q) increases the anticarcinogenic potency at lower concentrations than necessary when used individually in prostate cancer.

METHODS AND RESULTS

Androgen-dependent LAPC-4 and LNCaP prostate cancer cells were treated with low doses of Arc and Q alone or in combination for 48 h. The antiproliferative activity of Arc was 10- to 20-fold stronger than Q in both cell lines. Their combination synergistically enhanced the antiproliferative effect, with a stronger effect in androgen receptor (AR) wild-type LAPC-4 cells than in AR mutated LNCaP cells. Arc demonstrated a strong ability to inhibit AR protein expression in LAPC-4 cells. The combination treatment significantly inhibited both AR and PI3K/Akt pathways compared to control. A protein array analysis revealed that the mixture targets multiple pathways particularly in LAPC-4 cells including Stat3 pathway. The mixture significantly inhibited the expression of several oncogenic microRNAs including miR-21, miR-19b, and miR-148a compared to control. The mixture also enhanced the inhibition of cell migration in both cell lines compared to individual compounds tested.

CONCLUSION

The combination of Arc and Q that target similar pathways, at low physiological doses, provides a novel regimen with enhanced chemoprevention in prostate cancer.

Epigenetic effects of green tea polyphenols in cancer

Epigenetics describes heritable alterations of gene expression and chromatin organization without changes in DNA sequence. Both hypermethylation and hypomethylation of DNA can affect gene expression and the multistep process of carcinogenesis. Epigenetic changes are reversible and may be targeted by dietary interventions. Bioactive compounds from green tea (GT) such as (-)-epigallocatechin gallate have been shown to alter DNA methyltransferase activity in studies of esophageal, oral, skin, Tregs, lung, breast and prostate cancer cells, which may contribute to the chemopreventive effect of GT. Three out of four mouse model studies have confirmed the inhibitory effect of (-)-epigallocatechin gallate on DNA methylation. A human study demonstrated that decreased methylation of CDX2 and BMP-2 in gastric carcinoma was associated with higher GT consumption. It is the goal of this review to summarize our current knowledge of the potential of GT to alter epigenetic processes, which may be useful in chemoprevention.

Cell Cycle Control by Natural Phenols in Cisplatin-Resistant Cell Lines

Fifteen plant polyphenols, including flavonoids, cinnamic acids, coumarins and capsaicin, were investigated for their capacity to suppress cell growth and regulate the cell cycle of in vitro human ovarian carcinoma (2008 cell line) and cervix squamous carcinoma cells (A431), and their cisplatin (CDDP)-resistant subclones (C13 and A431Pt, respectively). Evaluation of the cytotoxic effects of the polyphenols (0.01–100 μM) indicated that especially rhein and quercetin were almost equiactive in wild type and CDDP-resistant cells, indicating lack of cross-resistance with cisplatin. Capsaicin was more potent in CDDP-resistant subclones than in wild type cells. The order of their potencies is flavonoids > anthraquinones > vanilloids > coumarins > phenols, cinnamic acids. The natural phenols which were most cytotoxic (rhein, quercetin and capsaicin) were able to cause the arrest of the cancer cell cycle, suggesting that specific cell cycle regulatory proteins are possibly involved in their intracellular mechanism of action. In particular, the natural compounds were revealed to be more active in CDDP-resistant cells than in wild types, especially inducing apoptotic death.

Increased chemopreventive effect by combining arctigenin, green tea polyphenol and curcumin in prostate and breast cancer cells

The low bioavailability of most flavonoids limits their application as anti-carcinogenic agents in humans. A novel approach of treatment with a mixture of bioactive compounds that share molecular anti-carcinogenic targets may enhance the effect on these targets at low concentrations of individual compound, thereby overcoming the limitations of reduced bioavailability. We therefore investigated whether a combination of three natural products arctigenin (Arc), a novel anti-inflammatory lignan from the seeds of Arctium lappa, green tea polyphenol (-)-epigallocatechin gallate (EGCG) and curcumin (Cur) increases the chemopreventive potency of individual compounds. LNCaP prostate cancer and MCF-7 breast cancer cells were treated with 2-4 mg/L (about 5-10μM) Cur, 1μM Arc and 40μM EGCG alone or in combination for 48h. In both cell lines treatment with the mixture of Cur, Arc and EGCG synergistically increased the antiproliferative effect. In LNCaP cells both Arc and EGCG increased the pro-apoptotic effect of Cur. Whereas in MCF-7 cells Arc increased the cell apoptosis of Cur while EGCG enhanced cell cycle arrest of Cur at G0/G1 phase. The strongest effects on cell cycle arrest and apoptosis were achieved by combining all three compounds in both cell lines. The combination treatment significantly increased the ratio of Bax to Bcl-2 proteins, decreased the activation of NFκB, PI3K/Akt and Stat3 pathways and cell migration compared to individual treatment. These results warrant in vivo studies to confirm the efficacy of this novel regimen by combining Arc and EGCG with Cur to enhance chemoprevention in both prostate and breast cancer.

Chemoprevention of oral cancer: Green tea experience

Oral cancer has a well characterized progression from premalignant oral epithelial changes to invasive cancer, making oral squamous cell carcinoma an optimal disease for chemoprevention interventions prior to malignant transformation. The primary goal of chemoprevention here is to reverse, suppress, or inhibit the progression of premalignant lesions to cancer. Due to the extended duration of oral pathogenesis, its chemoprevention using natural products has been found promising due to their decreased dose and limited toxicity profiles. This review discusses with an emphasis on the clinical trials using green tea extract (GTE) in chemoprevention of oral premalignant lesions along with use of GTE as a chemopreventive agent in various other cancers as well. It is worthwhile to include green tea extract in an oral screening program for evaluating the premalignant lesions comparing the results between the treated and untreated group. Given the wide acceptance of green tea, its benefits may help in effective chemoprevention oral cancer.

Anti-proliferative and pro-apoptotic activity of whole extract and isolated indicaxanthin from Opuntia ficus-indica associated with re-activation of the onco-suppressor p16(INK4a) gene in human colorectal carcinoma (Caco-2) cells

Phytochemicals may exert chemo-preventive effects on cells of the gastro-intestinal tract by modulating epigenome-regulated gene expression. The effect of the aqueous extract from the edible fruit of Opuntia ficus-indica (OFI extract), and of its betalain pigment indicaxanthin (Ind), on proliferation of human colon cancer Caco-2 cells has been investigated. Whole extract and Ind caused a dose-dependent apoptosis of proliferating cells at nutritionally relevant amounts, with IC50 400±25 mg fresh pulp equivalents/mL, and 115±15 μM (n=9), respectively, without toxicity for post-confluent differentiated cells. Ind accounted for ∼80% of the effect of the whole extract. Ind did not cause oxidative stress in proliferating Caco-2 cells. Epigenomic activity of Ind was evident as de-methylation of the tumor suppressor p16(INK4a) gene promoter, reactivation of the silenced mRNA expression and accumulation of p16(INK4a), a major controller of cell cycle. As a consequence, decrease of hyper-phosphorylated, in favor of the hypo-phosphorylated retinoblastoma was observed, with unaltered level of the cycline-dependent kinase CDK4. Cell cycle showed arrest in the G2/M-phase. Dietary cactus pear fruit and Ind may have chemo-preventive potential in intestinal cells.

Production of Hydrogen Peroxide by Polyphenols and Polyphenol-rich Beverages underQuasi-physiological Conditions

To investigate the ability of the production of H(2)O(2) by polyphenols, we incubated various phenolic compounds and natural polyphenols under a quasi-physiological pH and temperature (pH 7.4, 37 degrees C), and then measured the formation of H(2)O(2) by the ferrous ion oxidation-xylenol orange assay. Pyrocatechol, hydroquinone, pyrogallol, 1,2,4-benzenetriol, and polyphenols such as catechins yielded a significant amount of H(2)O(2). We also examined the effects of a metal chelator, pH, and O(2) on the H(2)O(2)-generating property, and the generation of H(2)O(2) by the polyphenol-rich beverages, green tea, black tea, and coffee, was determined. The features of the H(2)O(2)-generating property of green tea, black tea, and coffee were in good agreement with that of phenolic compounds, suggesting that polyphenols are responsible for the generation of H(2)O(2) in beverages. From the results, the possible significances of the H(2)O(2)-generating property of polyphenols for biological systems are discussed.