Detection and chemical identification of natural bio-antimutagens. A case of the green tea factor

Phase I/II clinical trial of efficacy and safety of EGCG oxygen nebulization inhalation in the treatment of COVID-19 pneumonia patients with cancer

BACKGROUND

The antiviral drug Nirmatrelvir was found to be a key drug in controlling the progression of pneumonia during the infectious phase of COVID-19. However, there are very few options for effective treatment for cancer patients who have viral pneumonia. Glucocorticoids is one of the effective means to control pneumonia, but there are many adverse events. EGCG is a natural low toxic compound with anti-inflammatory function. Thus, this study was designed to investigate the safety and efficacy of epigallocatechin-3-gallate (EGCG) aerosol to control COVID-19 pneumonia in cancer populations.

METHODS

The study was designed as a prospective, single-arm, open-label phase I/II trial at Shandong Cancer Hospital and Institute, between January 5, 2023 to March 31,2023 with viral pneumonia on radiographic signs after confirmed novel coronavirus infection. These patients were treated with EGCG nebulization 10 ml three times daily for at least seven days. EGCG concentrations were increased from 1760-8817umol/L to 4 levels with dose escalation following a standard Phase I design of 3-6 patients per level. Any grade adverse event caused by EGCG was considered a dose-limiting toxicity (DLT). The maximum tolerated dose (MTD) is defined as the highest dose with less than one-third of patients experiencing dose limiting toxicity (DLT) due to EGCG. The primary end points were the toxicity of EGCG and CT findings, and the former was graded by Common Terminology Criteria for Adverse Events (CTCAE) v. 5.0. The secondary end point was the laboratory parameters before and after treatment.

RESULT

A total of 60 patients with high risk factors for severe COVID-19 pneumonia (factors such as old age, smoking and combined complications)were included in this phase I-II study. The 54 patients in the final analysis were pathologically confirmed to have tumor burden and completed the whole course of treatment. A patient with bucking at a level of 1760 umol/L and no acute toxicity associated with EGCG has been reported at the second or third dose gradients. At dose escalation to 8817umol/L, Grade 1 adverse events of nausea and stomach discomfort occurred in two patients, which resolved spontaneously within 1 hour. After one week of treatment, CT showed that the incidence of non-progression of pneumonia was 82% (32/39), and the improvement rate of pneumonia was 56.4% (22/39). There was no significant difference in inflammation-related laboratory parameters (white blood cell count, lymphocyte count, IL-6, ferritin, C-reactive protein and lactate dehydrogenase) before and after treatment.

CONCLUSION

Aerosol inhalation of EGCG is well tolerated, and preliminary investigation in cancer population suggests that EGCG may be effective in COVID-19-induced pneumonia, which can promote the improvement of patients with moderate pneumonia or prevent them from developing into severe pneumonia.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05758571. Date of registration: 8 February 2023.

Efficacy of Epigallocatechin-3-Gallate in Preventing Dermatitis in Patients With Breast Cancer Receiving Postoperative Radiotherapy: A Double-Blind, Placebo-Controlled, Phase 2 Randomized Clinical Trial

Importance

Safe and effective prophylactic therapies for radiation-induced dermatitis (RID) remain an unmet need.

Objective

To determine if epigallocatechin-3-gallate (EGCG) solution reduces the incidence of RID in patients undergoing radiotherapy after breast cancer surgery.

Design, Setting, and Participants

This phase 2 double-blind, placebo-controlled randomized clinical trial enrolled 180 patients with breast cancer receiving postoperative radiotherapy at Shandong Cancer Hospital and Institute in Shandong, China, between November 2014 and June 2019. Data analysis was performed from September 2019 to January 2020.

Interventions

Participants were randomly assigned (2:1) to receive either EGCG solution (660 μmol/L) or placebo (0.9% NaCl saline) sprayed to the whole radiation field from day 1 of the radiation until 2 weeks after radiation completion.

Main Outcomes and Measures

The primary end point was incidence of grade 2 or worse RID, defined by the Radiation Therapy Oncology Group scale. The secondary end points included RID index (RIDI), symptom index, changes in the skin temperature measured by infrared thermal images, and safety.

Results

A total of 180 eligible patients were enrolled, of whom 165 (EGCG, n = 111; placebo, n = 54) were evaluable for efficacy (median [range] age, 46 [26-67] years). The occurrence of grade 2 or worse RID was significantly lower (50.5%; 95% CI, 41.2%-59.8%) in the EGCG group than in the placebo group (72.2%; 95% CI, 60.3%-84.1%) (P = .008). The mean RIDI in the EGCG group was significantly lower than that in the placebo group. Furthermore, symptom indexes were significantly lower in patients receiving EGCG. Four patients (3.6%) had adverse events related to the EGCG treatment, including grade 1 pricking skin sensation (3 [2.7%]) and pruritus (1 [0.9%]).

Conclusions and Relevance

In this randomized clinical trial, prophylactic use of EGCG solution significantly reduced the incidence and severity of RID in patients receiving adjuvant radiotherapy for breast cancer. It has the potential to become a new choice of skin care for patients receiving radiotherapy.

Trial Registration

ClinicalTrials.gov Identifier: NCT02580279.

Anti-inflammatory Effects of GTE in Eye Diseases

Ocular inflammation is a common complication of various eye diseases with wide consequences from irritations to potentially sight-threatening complications. Green tea is a popular beverage throughout the world. One of the proven health benefits of consuming green tea extract (GTE) is anti-inflammation. Catechins are the biologically active constituents of GTE. In in vitro and in vivo studies, GTE and catechins present inhibition of inflammatory responses in the development of ocular inflammation including infectious, non-infectious or autoimmune, and oxidative-induced complications. Research on the ocular inflammation in animal models has made significant progress in the past decades and several key disease mechanisms have been identified. Here we review the experimental investigations on the effects of GTE and catechins on various ocular inflammation related diseases including glaucoma, age-related macular degeneration, uveitis and ocular surface inflammation. We also review the pharmacokinetics of GTE constituents and safety of green tea consumption. We discuss the insights and perspectives of these experimental results, which would be useful for future development of novel therapeutics in human.

Plant Polyphenols: Natural and Potent UV-Protective Agents for the Prevention and Treatment of Skin Disorders

Nowadays, destructive and immunosuppressive effects from long-term exposure to UV radiation have been fully investigated and documented in the literature. UV radiation is known as the main cause of skin aging and carcinogenesis. Hence, skin protection against anti-oxidative and immunosuppressive processes is highly in demand. Now, plant polyphenols have been found as a versatile and natural tool for the prevention and treatment of various skin diseases. The presence of a large number of hydroxyl groups in the cyclic structure of polyphenols has induced valuable biological activities. Among them, their UV protective activity has attracted lots of attention due to promising efficacy and simple instruction to use.

Modulation of mutagenicity in Salmonella typhimurium and antioxidant properties and antiproliferative effects of fractions from Cassia fistula L. on human cervical HeLa and breast MCF-7 cancer cells

The present study investigated the antimutagenic, antioxidant, and antiproliferative properties of extracts of Cassia fistula prepared by sequentially fractionation of 80% methanolic (CaLM extract) extract of C. fistula leaves, namely CaLH (hexane), CaLC (chloroform), CaLE (ethyl acetate), CaLB (n-butanol), and CaLA (aqueous) fractions. The antimutagenicity of the fractions was tested against mutagens viz. S9-independent, namely 4-nitro-o-phenylenediamine (TA98) and sodium azide (TA100) and S9-dependent, 2-AF (2-aminofluorene). Among the tested fractions, CaLE fraction showed a potent efficacy with an inhibition percentage of 85.57% (TA98) and 89.93% (TA100) against the mutagenicity induced by 2-aminofluorene. The CaLE fraction could significantly scavenge free radicals in various assays, namely DPPH, lipid peroxidation inhibition, and superoxide anion radical scavenging assays with an IC₅₀ of 12.80, 144, and 257.3 μg/ml respectively. The antiproliferative potential of the effective CaLE fraction was assessed using MTT assay against HeLa and MCF-7 cancer cells with GI₅₀ value of 243.4 and 324.6 μg/ml respectively. The fraction exhibited remarkable apoptosis-inducing effects through the externalization of phosphatidylserine in HeLa cells as analyzed by annexin V-FITC/PI double staining assay. The HPLC analysis of CaLE revealed the presence of catechin, epiafzelechin, and chlorogenic acid which are responsible for its antimutagenic and antiproliferative efficacy. Graphical abstract.

Natural heat shock protein 90 inhibitors in cancer and inflammation

Heat shock protein (HSP)90 is the most abundant HSPs, which are chaperone molecules whose major roles are cell protection and maintenance by means of aiding the folding, the stabilization and the remodeling of a wide range of proteins. A few hundreds of proteins depend on HSP90 chaperone activity, including kinases and transcriptional factors that play essential roles in cancer and inflammation, so that HSP90-targeted therapies have been considered as a potential strategy for the treatment of cancer and inflammatory-associated diseases. HSP90 inhibition by natural, semi-synthetic and synthetic compounds have yield promising results in pre-clinical studies and clinical trials for different types of cancers and inflammation. Natural products are a huge source of biologically active compounds widely used in drug development due to the great diversity of their metabolites which are capable to modulate several protein functions. HSP90 inhibitors have been isolated from bacteria, fungi and vegetal species. These natural compounds have a noteworthy ability to modulate HSP90 activity as well as serve as scaffolds for the development of novel synthetic or semi-synthetic inhibitors. Over a hundred clinical trials have evaluated the effect of HSP90 inhibitors as adjuvant treatment against different types of tumors and, currently, new studies are being developed to gain sight on novel promising and more effective approaches for cancer treatment. In this review, we present the naturally occurring HSP90 inhibitors and analogues, discussing their anti-cancer and anti-inflammatory effects.

A Comprehensive Insight on the Health Benefits and Phytoconstituents of Camellia sinensis and Recent Approaches for Its Quality Control

Tea, Camellia sinensis, which belongs to the family Theaceae, is a shrub or evergreen tree up to 16 m in height. Green tea is very popular because of its marked health benefits comprising its anticancer, anti-oxidant, and antimicrobial activities, as well as its effectiveness in reducing body weight. Additionally, it was recognized by Chinese people as an effective traditional drink required for the prophylaxis against many health ailments. This is due to the complex chemical composition of green tea, which comprises different classes of chemical compounds, such as polyphenols, alkaloids, proteins, minerals, vitamins, amino acids, and others. The beneficial health effects of green tea ultimately led to its great consumption and increase its liability to be adulterated by either low-quality or non-green tea products with concomitant decrease in activity. Thus, in this review, green tea was selected to highlight its health benefits and phytoconstituents, as well as recent approaches for its quality-control monitoring that guarantee its incorporation in many pharmaceutical industries. More research is needed to find out other more biological activities, active constituents, and other simple and cheap techniques for its quality assurance that ascertain the prevention of its adulteration.

Structure, function and antagonism of semen amyloids

Amyloid fibrils are linear polypeptide aggregates with a cross-β structure. These fibrils are best known for their association with neurodegenerative diseases, such as Alzheimer's or Parkinson's, but they may also be used by living organisms as functional units, e.g. in the synthesis of melanin or in the formation of bacterial biofilms. About a decade ago, in a search for semen factors that modulate infection by HIV-1 (a sexually transmitted virus and the causative agent of the acquired immune deficiency syndrome (AIDS)), it was demonstrated that semen harbors amyloid fibrils capable of markedly increasing HIV infection rates. This discovery not only created novel opportunities to prevent sexual HIV-1 transmission but also stimulated research to unravel the natural role of these factors. We discuss here the identification of these intriguing structures, their molecular properties, and their effects on both sexually transmitted diseases and reproductive health. Moreover, we review strategies to antagonize semen amyloid to prevent sexual transmission of viruses.

Application of microencapsulation for the safe delivery of green tea polyphenols in food systems: Review and recent advances

Green tea has been associated with the prevention and reduction of a wide range of severe health conditions such as cancer, immune, and cardiovascular diseases. The health benefits associated with green tea consumption have been predominantly attributed to green tea polyphenols. The functional properties of green tea polyphenols are mainly anti-oxidative, antimutagenic, anticarcinogenic, anti-microbial, etc. These excellent properties have recently gained considerable attention in the food industry. However, their application is limited by their sensitivity to factors like temperature, light, pH, oxygen, etc. More, studies have reported the occurrence of unpleasant taste and color transfer during food processing. Lastly, the production of functional food requires to maintain the stability, bioactivity, and bioavailability of the active compounds. To tackle these obstacles, technological approaches like microencapsulation have been developed and applied for the formulation of green tea-enriched food products. The present review discusses the novelty in microencapsulation techniques for the safe delivery of green tea polyphenols in food matrices. After a literature on the green tea polyphenols composition, and their health attributes, the encapsulation methods and the coating materials are presented. The application of green tea encapsulates in food matrices as well as their effect on food functional and sensory properties are also discussed.

Head-to-Head Comparison of Anti-Inflammatory Performance of Known Natural Products In Vitro

Inflammation is an important therapeutic target. Due to their potency, steroidal drugs dominate the current treatment of inflammatory disorders. However, steroidal drugs can also exert a broad range of side effects and appear not always effective. This calls for the development of alternative drugs with a different mechanism of action, which are likely to be found in the field of natural products (NPs). For many NPs strong anti-inflammatory effects have been described, but usually investigating a single compound in a single assay. In this study, eight promising NPs were selected and tested against the strong anti-inflammatory drug prednisolone. For this head-to-head comparison, in vitro assays were used which represent different pathways of the inflammatory response: TNF-α and IL-6 expression by macrophages, IL-8 expression by colon epithelial cells, ROS production in polymorphonuclear leukocytes and platelet activation in whole blood. Performance profiles were established which allowed us to identify curcumin, berberine chloride and epigallocatechin gallate as potential alternatives for prednisolone or other glucocorticoids in inflammation.

Assessment of antimutagenic action of Celtis glabrata Steven ex Planch. (Cannabaceae) extracts against base pair exchange and frame shift mutations on Salmonella typhimurium TA98 and TA100 strains by Ames test

CONTEXT

Celtis glabrata is used in Turkey for the treatment of various health disorders.

OBJECTIVE

The acetone, chloroform, ethanol, and methanol extracts of C. glabrata leaf, fruit, and seed were investigated to evaluate their antimutagenic activities.

MATERIAL AND METHODS

The antimutagenicity of these extracts was determined by Ames test against mutagens (4-nitro-O-phenylenediamine, 2-aminofluorene (2-AF), and sodium azide (SA)). The extracts were used at concentrations between 5 and 0.005 mg/plate.

RESULTS

The ethanol extracts of leaves exhibited strong antimutagenicity (70%) against 2-AF with S9 at 5 mg/plate on TA98. But methanol (61%, 53%) and acetone (53%, 52%) also revealed strong inhibition rates at concentrations of ≥ 0.5 mg/plate. Among the extracts, the highest activity (96%) was obtained from acetone extract against SA without S9, followed by chloroform extract (91%) at a dose of 5 mg/plate on TA100 with S9. Ethanol (without S9) and chloroform (with S9) extracts showed strong antimutagenicity at all doses. Exception of chloroform and acetone (without S9), all fruit extracts (with/without S9) manifested strong antimutagenicity at doses of ≥ 0.5 mg/plate on TA98 strain. Ethanol extracts revealed 68% inhibition against 2-AF on TA98. Acetone and ethanol extracts manifested 84% and 82% inhibition against SA on TA100, respectively. All the extracts of seeds revealed strong inhibition against 2-AF at ≥ 0.5 mg/plate doses on TA98, but acetone extract showed excellent antimutagenicity (94%). Moreover, the chloroform (74, 73, 63, 54%), acetone (74, 72, 70, 65%) and methanol (74, 67, 63, 61%) extracts of seeds revealed strong antimutagenic activity on TA100 against SA with S9.

DISCUSSION AND CONCLUSION

This plant may be natural source of antimutagenic agents.

Green tea beverages enriched with catechins with a galloyl moiety reduce body fat in moderately obese adults: a randomized double-blind placebo-controlled trial

We investigated the effects of ingesting a green tea beverage enriched with catechins with a galloyl moiety during a meal on body fat reduction in moderately obese adults.

Discovery and resupply of pharmacologically active plant-derived natural products: A review

Medicinal plants have historically proven their value as a source of molecules with therapeutic potential, and nowadays still represent an important pool for the identification of novel drug leads. In the past decades, pharmaceutical industry focused mainly on libraries of synthetic compounds as drug discovery source. They are comparably easy to produce and resupply, and demonstrate good compatibility with established high throughput screening (HTS) platforms. However, at the same time there has been a declining trend in the number of new drugs reaching the market, raising renewed scientific interest in drug discovery from natural sources, despite of its known challenges. In this survey, a brief outline of historical development is provided together with a comprehensive overview of used approaches and recent developments relevant to plant-derived natural product drug discovery. Associated challenges and major strengths of natural product-based drug discovery are critically discussed. A snapshot of the advanced plant-derived natural products that are currently in actively recruiting clinical trials is also presented. Importantly, the transition of a natural compound from a "screening hit" through a "drug lead" to a "marketed drug" is associated with increasingly challenging demands for compound amount, which often cannot be met by re-isolation from the respective plant sources. In this regard, existing alternatives for resupply are also discussed, including different biotechnology approaches and total organic synthesis. While the intrinsic complexity of natural product-based drug discovery necessitates highly integrated interdisciplinary approaches, the reviewed scientific developments, recent technological advances, and research trends clearly indicate that natural products will be among the most important sources of new drugs also in the future.

Green tea in dermatology--myths and facts

Green tea consumption has a long tradition in Asian countries--especially China. The epidemiologically and experimentally observed anticarcinogenic and antiinflammatory effects of green tea have led to the implementation of green tea extracts in multiple therapeutic applications - both in dermatological and cosmeceutical preparations. The most abundant evidence exists for the anticarcinogenic and chemopreventive effect of green tea or its major constituent epigallocatechin-3-gallate. Almost equally evident is the effect in infectious diseases such as cutaneous viral infections. For external genital warts, a topical ointment with green tea extracts was licensed in the USA in 2010, and recently also in Europe. Experimental evidence pinpointing the block of central signal transduction factors in inflammatory mechanisms has led to the evaluation of catechins in inflammatory disorders such as atopic dermatitis. The belief of green tea as a "wonder weapon" against diseases dates back thousands of years. According to a Chinese legend, ancient Emperor Shen Nung noted a delightful aroma after some leaves of a nearby tree had fallen into boiling water. He immediately proclaimed the new "drink" as "heaven-sent", starting the belief - persisting until today - of green tea as a medication from nature against many different diseases. This review summarizes biological effects and clinical implications of green tea.

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.

Antifibrotic properties of epigallocatechin-3-gallate in endometriosis

STUDY QUESTION

Is epigallocatechin-3-gallate (EGCG) treatment effective in the treatment of fibrosis in endometriosis?

SUMMARY ANSWER

EGCG appears to have antifibrotic properties in endometriosis.

WHAT IS KNOWN ALREADY

Histologically, endometriosis is characterized by dense fibrous tissue surrounding the endometrial glands and stroma. However, only a few studies to date have evaluated candidate new therapies for endometriosis-associated fibrosis.

STUDY DESIGN, SIZE, DURATION

For this laboratory study, samples from 55 patients (45 with and 10 without endometriosis) of reproductive age with normal menstrual cycles were analyzed. A total of 40 nude mice received single injection proliferative endometrial fragments from a total of 10 samples.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The in vitro effects of EGCG and N-acetyl-l-cysteine on fibrotic markers (alpha-smooth muscle actin, type I collagen, connective tissue growth factor and fibronectin) with and without transforming growth factor (TGF)-β1 stimulation, as well as on cell proliferation, migration and invasion and collagen gel contraction of endometrial and endometriotic stromal cells were evaluated by real-time PCR, immunocytochemistry, cell proliferation assays, in vitro migration and invasion assays and/or collagen gel contraction assays. The in vitro effects of EGCG on mitogen-activated protein kinase (MAPK) and Smad signaling pathways in endometrial and endometriotic stromal cells were evaluated by western blotting. Additionally, the effects of EGCG treatment on endometriotic implants were evaluated in a xenograft model of endometriosis in immunodeficient nude mice.

MAIN RESULTS AND THE ROLE OF CHANCE

Treatment with EGCG significantly inhibited cell proliferation, migration and invasion of endometrial and endometriotic stromal cells from patients with endometriosis. In addition, EGCG treatment significantly decreased the TGF-β1-dependent increase in the mRNA expression of fibrotic markers in both endometriotic and endometrial stromal cells. Both endometriotic and endometrial stromal cell-mediated contraction of collagen gels were significantly attenuated at 8, 12 and 24 h after treatment with EGCG. Epigallocatechin-3-gallate also significantly inhibited TGF-β1-stimulated activation of MAPK and Smad signaling pathways in endometrial and endometriotic stromal cells. Animal experiments showed that EGCG prevented the progression of fibrosis in endometriosis.

LIMITATIONS, REASONS FOR CAUTION

The attractiveness of epigallocatechin-3-gallate as a drug candidate has been diminished by its relatively low bioavailability. However, numerous alterations to the EGCG molecule have been patented, either to improve the integrity of the native compound or to generate a more stable yet similarly efficacious molecule. Therefore, EGCG and its derivatives, analogs and prodrugs could potentially be developed into agents for the future treatment and/or prevention of endometriosis.

WIDER IMPLICATIONS OF THE FINDINGS

Epigallocatechin-3-gallate is a potential drug candidate for the treatment and/or prevention of endometriosis.

STUDY FUNDING/COMPETING INTERESTS

This study was supported in part by Karl Storz Endoscopy & GmbH (Tuttlingen, Germany). No competing interests are declared.

Epigallocatechin gallate decreases the micellar solubility of cholesterol via specific interaction with phosphatidylcholine

The mechanisms underlying the effect of epigallocatechin gallate (EGCG) on the micellar solubility of cholesterol were examined. EGCG eliminated both cholesterol and phosphatidylcholine (PC) from bile salt micelles in a dose-dependent manner in vitro. When the bile salt micelles contained a phospholipid other than PC, neither cholesterol nor the phospholipid was eliminated following the addition of EGCG. When vesicles comprised of various phospholipids were prepared and, EGCG was added to the vesicles, EGCG effectively and exclusively eliminated only PC. An intermolecular nuclear Overhauser effect (NOE) was observed between PC and EGCG in bile salt micelles with EGCG added, but not between cholesterol and EGCG, by using a NOE-correlated spectroscopy nuclear magnetic resonance method. The results of binding analyses using surface plasmon resonance (SPR) showed that EGCG did not bind to cholesterol. These observations strongly suggest that EGCG decreases the micellar solubility of cholesterol via specific interaction with PC.

Green tea polyphenols stimulate mitochondrial biogenesis and improve renal function after chronic cyclosporin a treatment in rats

Our previous studies showed that an extract from Camellia sinenesis (green tea), which contains several polyphenols, attenuates nephrotoxicity caused by cyclosporine A (CsA). Since polyphenols are stimulators of mitochondrial biogenesis (MB), this study investigated whether stimulation of MB plays a role in green tea polyphenol protection against CsA renal toxicity. Rats were fed a powdered diet containing green tea polyphenolic extract (0.1%) starting 3 days prior to CsA treatment (25 mg/kg, i.g. daily for 3 weeks). CsA alone decreased renal nuclear DNA-encoded oxidative phosphorylation (OXPHOS) protein ATP synthase-β (AS-β) by 42%, mitochondrial DNA (mtDNA)-encoded OXPHOS protein NADH dehydrogenase-3 (ND3) by 87% and their associated mRNAs. Mitochondrial DNA copy number was also decreased by 78% by CsA. Immunohistochemical analysis showed decreased cytochrome c oxidase subunit IV (COX-IV), an OXPHOS protein, in tubular cells. Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α, the master regulator of MB, and mitochondrial transcription factor-A (Tfam), the transcription factor that regulates mtDNA replication and transcription, were 42% and 90% lower, respectively, in the kidneys of CsA-treated than in untreated rats. These results indicate suppression of MB by chronic CsA treatment. Green tea polyphenols alone and following CsA increased AS-β, ND3, COX-IV, mtDNA copy number, PGC-1α mRNA and protein, decreased acetylated PGC-1α, and increased Tfam mRNA and protein. In association with suppressed MB, CsA increased serum creatinine, caused loss of brush border and dilatation of proximal tubules, tubular atrophy, vacuolization, apoptosis, calcification, and increased neutrophil gelatinase-associated lipocalin expression, leukocyte infiltration, and renal fibrosis. Green tea polyphenols markedly attenuated CsA-induced renal injury and improved renal function. Together, these results demonstrate that green tea polyphenols attenuate CsA-induced kidney injury, at least in part, through the stimulation of MB.

Enhancement or Suppression of ACE Inhibitory Activity by a Mixture of Tea and Foods for Specified Health Uses (FOSHU) That Are Marketed as "Support for Normal Blood Pressure"

The ACE inhibitory activities of mixtures of FOSHUs (Healthya, Goma-Mugicha, Lapis Support and Ameal) were examined in order to identify any antihypertensive interactions. Among combinations of Healthya with other samples that contain active peptides, only that with Ameal was found to have no inhibitory activity. Enhanced activity was observed in 2 other mixtures. The activity of a mixture of tea polyphenols and the whey component extracted from an Ameal solution was significantly decreased, thus demonstrating that whey protein lowered the ACE inhibitory activity of Healthya. Although oral administration of tea polyphenols alone significantly decreased SBP in SHR at 2 and 4 hr, combined administration with Ameal failed to decrease SBP at the same time points. In conclusion, the simultaneous intake of tea and FOSHUs that contain active peptides might affect daily self-antihypertensive management via enhancement or suppression of ACE inhibitory activity.

Green tea, phytic acid, and inositol in combination reduced the incidence of azoxymethane-induced colon tumors in Fisher 344 male rats

Experimental as well as epidemiologic studies in human populations provide evidence that consumption of phytochemicals reduces the incidence of degenerative diseases. Green tea (GT) catechins are known for their antioxidative potential. Phytic acid (PA) also acts as a natural antioxidant and may have numerous health benefits. This experiment was designed to investigate the inhibitory effects of combinations of 1% and 2% GT, PA, and inositol (I) in reducing the incidence of azoxymethane-induced colon tumors in Fisher 344 male rats. After an acclimatization period of 1 week, nine groups of rats (15 rats per group) were initially assigned to consume AIN 93 G diet and later AIN 93 M diet after 20 weeks of age. Treatments were given in drinking water. All rats received azoxymethane injections (16 mg/kg of body weight) subcutaneously at 7 and 8 weeks of age. Rats were killed at 45 weeks of age by CO(2) euthanasia. Tumor incidence (93.76%) and the number of tumors per tumor-bearing rat ratio (2.25) were significantly (P<.05) higher in the control group compared with treatment groups. Glutathione S-transferase activity was significantly (P<.05) higher in rats fed combinations of 2% GT+PA+I and GT+PA (33.25 ± 1.23 and 29.83 ± 1.10 μmol/mL, respectively) compared with other groups. These findings suggest that the synergistic effect of the 2% level of GT, PA, and I may reduce the incidence of colon tumors and therefore have potential as a chemopreventive agent.

Effects of Xylopia aethiopica (Annonaceae) fruit methanol extract on gamma-radiation-induced oxidative stress in brain of adult male Wistar rats

Xylopia aethiopica (XA) (Annonaceae) possesses great nutritional and medicinal values. This study was designed to investigate the effects of XA fruit methanol extract on oxidative stress in brain of rats exposed to whole body gamma-radiation (5 Gy). Vitamin C (VC) served as standard antioxidant. Forty-four rats were divided into 4 groups of 11 rats each. One group served as control, two different groups were treated with XA and VC (250 mg/kg), 6 weeks before and 8 weeks after irradiation, and fourth group was only irradiated. Rats were sacrificed 1 and 8 weeks after irradiation. The antioxidant status, viz. Lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST) and glutathione (GSH) were estimated. Results indicate a significant increase (p < 0.05) in levels of brain LPO after irradiation. LPO increased by 90% and 151%, after 1 and 8 weeks of irradiation, respectively. Irradiation caused significant (p < 0.05) decreases in levels of GSH and GST by 61% and 43% after 1 week and, 75% and 73%, respectively, after 8 weeks of exposure. CAT and SOD levels were decreased by 62% and 68%, respectively, after 8 weeks of irradiation. Treatment with XA and VC ameliorated the radiation-induced decreases in antioxidant status of the animals. These suggest that XA could have beneficial effect by inhibiting oxidative damage in brain of exposed rats.

Black-tea polyphenols decrease micellar solubility of cholesterol in vitro and intestinal absorption of cholesterol in rats

Administration of black-tea polyphenols (BTP) simultaneously reduced lymphatic recovery of both (3)H-cholesterol and (14)C-trioleoylglycerol in rats that were cannulated in the thoracic duct. BTP decreased the in vitro micellar solubility of cholesterol in a dose-dependent manner. When purified theaflavins, which are components of BTP, were used, theaflavin-monogallates (TFMGs), theaflavin-3-gallate (TF3G), and theaflavin-3'-gallate (TF3'G) were effective in eliminating cholesterol from bile salt micelles in vitro. Theaflavin (TF) and theaflavin-3,3'-digallate (TFDG) had no effect on the micellar solubility of cholesterol. The concentration of bile acid in the micelles was not influenced by the addition of any BTPs or theaflavins. These results suggest that the reduction of micellar cholesterol by BTP could be important to reducing cholesterol absorption.

Reduction of ciclosporin and tacrolimus nephrotoxicity by plant polyphenols

The immunosuppressants ciclosporin (cyclosporin A, CsA) and tacrolimus can cause severe nephrotoxicity. Since CsA increases free radical formation, this study investigated whether an extract from Camellia sinensis, which contains several polyphenolic free radical scavengers, could prevent nephrotoxicity caused by CsA and tacrolimus. Rats were fed powdered diet containing polyphenolic extract (0-0.1%) starting 3 days before CsA or tacrolimus. Free radicals were trapped with α-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) and measured using an electron spin resonance spectrometer. Both CsA and tacrolimus decreased glomerular filtration rates (GFR) and caused tubular atrophy, vacuolization and calcification and arteriolar hyalinosis, effects that were blunted by treatment with dietary polyphenols. Moreover, CsA and tacrolimus increased POBN/radical adducts in urine nearly 3.5 fold. Hydroxyl radicals attack dimethyl sulfoxide (DMSO) to produce a methyl radical fragment. Administration of CsA or tacrolimus with 12C-DMSO produced a 6-line spectrum, while CsA or tacrolimus given with 13C-DMSO produced a 12-line ESR spectrum, confirming formation of hydroxyl radicals. 4-Hydroxynonenal (4-HNE), a product of lipid peroxidation, accumulated in proximal and distal tubules after CsA or tacrolimus treatment. ESR changes and 4-HNE formation were largely blocked by polyphenols. Taken together, these results demonstrate that both CsA and tacrolimus stimulate free radical production in the kidney, most likely in tubular cells, and that polyphenols minimize nephrotoxicity by scavenging free radicals.

Black-tea polyphenols suppress postprandial hypertriacylglycerolemia by suppressing lymphatic transport of dietary fat in rats

Administration of black-tea polyphenols (BTP) at 100 and 200 mg/kg of body weight in rats suppressed postprandial hypertriacylglycerolemia in a dose-dependent manner. Administration of BTP also suppressed lymphatic recovery of (14)C-trioleoylglycerol in rats that were cannulated in the thoracic duct. BTP dose-dependently inhibited the activity of pancreatic lipase in vitro with an IC50 of 0.254 mg/mL. When purified theaflavins, which are components of BTP, were used, theaflavins with galloyl moieties, but not those without galloyl moiety, inhibited the activity of pancreatic lipase. Theaflavin-3,3'-digallate (TFDG) was more effective in inhibiting the activity of pancreatic lipase than epigallocatechin gallate (EGCG), epicatechin gallate (ECG), and a mixture of EGCG and ECG. BTP and TFDG had a similar effect in inhibiting the activity of pancreatic lipase when the total polyphenol amount was adjusted to the same. BTP had no effect on micellar solubility of hydrolysis products of triacylglycerol. These results suggest that BTP suppressed postprandial hypertriacylglycerolemia by reducing triacylglycerol absorption via the inhibition of pancreatic lipase activity.

Thermal effects on the stability and antioxidant activity of an acid polysaccharide conjugate derived from green tea

A technique of high-performance gel permeation chromatography (HPGPC)-evaporative light-scattering detection and circular dichroism (CD) was developed for the measurement of thermal effects on the homogeneity and conformation of polymeric carbohydrate conjugates and was applied to an acid polysaccharide conjugate (GTa) isolated from the composite enzyme extract of green tea. Incubations in water at 40 and 70 degrees C for 1.0, 2.5, and 5.0 h have no effects on GTa. In contrast, when incubated in water for 1.0, 2.5, and 5.0 h at 98 degrees C, a single symmetrical peak corresponding to GTa in HPGPC was split into two adjacent peaks representing two different components formed, and CD spectra revealed an additional positive Cotton effect at 216 nm. To contribute toward our understanding of thermal effects of this polymeric carbohydrate conjugate on antioxidant activity, GTa and related heat-treated samples (GTa-HTI, GTa-HTII, and GTa-HTIII), the latter being obtained from 1.0, 2.5, and 5.0 h incubations at 98 degrees C, respectively, were subjected to the self-oxidation of 1,2,3-phentriol assay and found to have respective scavenging activities in a concentration-dependent manner. In comparison with GTa, the scavenging potency of heat-treated samples was similar at the dosage range of 50-300 microg/mL but became stronger with continually increasing concentration. Moreover, the present study also provides further insights into the optimal preparation of tea polysaccharide conjugates.

In vitro toxicological properties of thymoquinone

Nigella sativa has been traditionally used for the treatment of inflammations, liver disorders, and arthritis. Experimentally, it has been demonstrated that N. sativa extracts and the main constituent of their volatile oil, thymoquinone, possess antioxidant, anti-inflammatory and hepato-protective properties. To further evaluate the toxicological properties in a metabolically competent cellular system, thymoquinone was applied to primary rat hepatocyte cultures, and both cyto- and genotoxic effects were tested. Mitotic indices and the rates of apoptoses and necroses were determined as endpoints of cytotoxicity, while chromosomal aberrations and micronucleated cells served as endpoints of genotoxicity. In this approach thymoquinone demonstrated cyto- and genotoxic effects in a concentration dependent manner: it induced significant anti-proliferative effects at 20 microM and acute cytotoxicity at higher concentrations. Thymoquinone significantly increased the rates of necrotic cells at concentrations between 2.5 and 20 microM. Furthermore, it induced significant genotoxicity at concentrations > or =1.25 microM. These observations support the previous finding that thymoquinone causes glutathione depletion and liver damage, but contradict the reports indicating antioxidant and anti-clastogenic effects. Thymoquinone might be metabolised to reactive species and increase oxidative stress, which contributes to the depletion of antioxidant enzymes and damage to DNA in hepatocytes treated with high thymoquinone concentrations.

A population-based, case-control study of green tea consumption and leukemia risk in southwestern Taiwan

OBJECTIVE

This study investigated the association between green tea consumption and leukemia.

METHODS

A total of 252 cases (90.3% response) and 637 controls (53.4% response) were enrolled. Controls were matched for cases on age and gender. Information was collected on participants' living habits, including tea consumption. Green tea was used as a standard to estimate the total amount of individual catechin consumption. We stratified individual consumption of catechins into four levels. Conditional logistic regression models were fit to subjects aged 0-15 and 16-29 years to evaluate separate associations between leukemia and catechin consumption.

RESULTS

A significant inverse association between green tea consumption and leukemia risk was found in individuals aged 16-29 years, whereas no significant association was found in the younger age groups. For the older group with higher amounts of tea consumption (>550 units of catechins), the adjusted odds ratio (OR) compared with the group without tea consumption was 0.47 [95% confidence interval (CI) = 0.23-0.97]. After we adjusted for smoking status and medical irradiation exposure, the overall OR for all participants was 0.49 (95% CI = 0.27-0.91), indicating an inverse relation between large amounts of catechins and leukemia.

CONCLUSION

Drinking sufficient amounts of tea, especially green tea, which contains more catechins than oolong tea and black tea, may reduce the risk of leukemia.

Green tea polyphenol epigallocatechin-3-gallate suppresses collagen production and proliferation in keloid fibroblasts via inhibition of the STAT3-signaling pathway

Keloids are benign skin tumors characterized by collagen accumulation and hyperproliferation of fibroblasts. To find an effective therapy for keloids, we explored the pharmacological potential of (-)-epigallocatechin-3-gallate (EGCG), a widely investigated tumor-preventive agent. When applied to normal and keloid fibroblasts (KFs) in vitro, proliferation and migration of KFs were more strongly suppressed by EGCG than normal fibroblast proliferation and migration (IC(50): 54.4 microM (keloid fibroblast (KF)) versus 63.0 microM (NF)). The level of Smad2/3, signal transducer and activator of transcription-3 (STAT3), and p38 phosphorylation is more enhanced in KFs, and EGCG inhibited phosphorylation of phosphatidylinositol-3-kinase (PI3K), extracellular signal-regulated protein kinase 1/2 (ERK1/2), and STAT3 (Tyr705 and Ser727). To evaluate the contribution of these pathways to keloid pathology, we treated KFs with specific inhibitors for PI3K, ERK1/2, or STAT3. Although a PI3K inhibitor significantly suppressed proliferation, PI3K and MEK/ERK inhibitors had a minor effect on migration and collagen production. However, a JAK2/STAT3 inhibitor and a STAT3 siRNA strongly suppressed proliferation, migration, and collagen production by KFs. We also found that treatment with EGCG suppressed growth and collagen production in the in vivo keloid model. This study demonstrates that EGCG suppresses the pathological characteristics of keloids through inhibition of the STAT3-signaling pathway. We propose that EGCG has potential in the treatment and prevention of keloids.

The antimutagenic activity of the major flavonoids of rooibos (Aspalathus linearis): some dose-response effects on mutagen activation-flavonoid interactions

The antimutagenic properties of the most prevalent flavonoids in rooibos (Aspalathus linearis) were compared in the Salmonella typhimurium mutagenicity assay using tester strains TA98 and TA100 with, respectively, 2-acetamido-fluorene (2-AAF) and aflatoxin B(1) (AFB(1)) as mutagens in the presence of metabolic activation. The flavonoids included the dihydrochalcones aspalathin and nothofagin and their flavone analogues, orientin and isoorientin, and vitexin and isovitexin, respectively, as well as luteolin, chrysoeriol, (+)-catechin, quercetin, isoquercitrin, hyperoside and rutin. Flavonoid-mutagen interactions ranged from antimutagenic, comutagenic and promutagenic to mutagenic, while dose-response effects were mutagen-specific and ranged from typical to atypical including biphasic and threshold effects. Aspalathin and nothofagin and their structural flavonoid analogues displayed moderate antimutagenic properties while luteolin and to some extent, chrysoeriol, showed activities comparable to those of the green tea flavonoid (-) epigallocatechin gallate (EGCG). Apart from their mutagenic and promutagenic properties, quercetin and isoquercitrin exhibited concentration-dependent comutagenic and/or antimutagenic effects against 2-AAF- and AFB(1)-induced mutagenesis. Different structural parameters known to affect the antimutagenic properties of flavonoids include their hydrophilic or lipophilic nature due to the extent of hydroxylation and O-methylation, glycosylation on the A and B rings, the C4-keto group and the C2-C3 double bond. The C ring does not appear to be a prerequisite when comparing for the antimutagenic activity of the dihydrochalcones when compared of the dihydrochalcones with the structural flavone analogues.