Protective effects of green tea polyphenol against reactive oxygen species-induced oxidative stress in cultured rat calvarial osteoblast

Dietary Calcium Intake and Osteoporosis Risk in Arab Adults

Osteoporosis is a major public health concern in Saudi Arabia's aging population. There is particularly limited information on how diet affects bone loss in this ethnic group. The purpose of this study was to examine the association between dietary calcium (Ca) intake and osteoporosis risk in Saudi adults. A total of 1950 patients (416 males and 1534 females) with known risk factors for osteoporosis participated in this cross-sectional study. A short questionnaire (CaQ) was used to assess dietary Ca intakes in patients attending tertiary hospitals in Riyadh City. The prevalence of osteoporosis was 21.3% and was more common in females (93.5%). Patients with osteoporosis were older (p < 0.001) and had lower BMI (p < 0.001). Results showed that the overall mean Ca intake was only 445.1 mg/day (recommended dietary intake of 1300 mg/day). Tea intake (OR = 0.8 95%CI: 0.7-1.0; p = 0.02) and consumption of fish and eggs (OR = 0.9 95%CI: 0.8-1.0; p = 0.01) were significantly associated with a lower risk of osteoporosis. Furthermore, consumption of biscuits, cake and bread slices were significantly associated with higher incidence of osteoporosis (OR = 1.3 95%CI: 1.0-1.5; p = 0.02). In conclusion, extremely low dietary Ca intake was observed among Saudi adults already at risk of osteoporosis. A balanced diet including high amount of Ca, vitamin D and omega-3 fatty acids accompanied by limiting consumption of foods high in saturated fats and glycemic index may be helpful in reducing osteoporosis risk in the Saudi adult population.

Association of Coffee and Tea Intake with Bone Mineral Density and Hip Fracture: A Meta-Analysis

Background and Objectives: Osteoporosis is characterized by low bone mass and high bone fragility. Findings regarding the association of coffee and tea intake with osteoporosis have been inconsistent. We conducted this meta-analysis to investigate whether coffee and tea intake is associated with low bone mineral density (BMD) and high hip fracture risk. Materials and Methods: PubMed, MEDLINE, and Embase were searched for relevant studies published before 2022. Studies on the effects of coffee/tea intake on hip fracture/BMD were included in our meta-analysis, whereas those focusing on specific disease groups and those with no relevant coffee/tea intake data were excluded. We assessed mean difference (MD; for BMD) and pooled hazard ratio (HR; for hip fracture) values with 95% confidence interval (CI) values. The cohort was divided into high- and low-intake groups considering the thresholds of 1 and 2 cups/day for tea and coffee, respectively. Results: Our meta-analysis included 20 studies comprising 508,312 individuals. The pooled MD was 0.020 for coffee (95% CI, -0.003 to 0.044) and 0.039 for tea (95% CI, -0.012 to 0.09), whereas the pooled HR was 1.008 for coffee (95% CI, 0.760 to 1.337) and 0.93 for tea (95% CI, 0.84 to 1.03). Conclusions: Our meta-analysis results suggest that daily coffee or tea consumption is not associated with BMD or hip fracture risk.

Oxidative stress: A common pathological state in a high-risk population for osteoporosis

Osteoporosis is becoming a major concern in the field of public health. The process of bone loss is insidious and does not directly induce obvious symptoms. Complications indicate an irreversible decrease in bone mass. The high-risk populations of osteoporosis, including postmenopausal women, elderly men, diabetic patients and obese individuals need regular bone mineral density testing and appropriate preventive treatment. However, the primary changes in these populations are different, increasing the difficulty of effective treatment of osteoporosis. Determining the core pathogenesis of osteoporosis helps improve the efficiency and efficacy of treatment among these populations. Oxidative stress is a common pathological state secondary to estrogen deficiency, aging, hyperglycemia and hyperlipemia. In this review, we divided oxidative stress into the direct effect of reactive oxygen species (ROS) and the reduction of antioxidant enzyme activity to discuss their roles in the development of osteoporosis. ROS initiated mitochondrial apoptotic signaling and suppressed osteogenic marker expression to weaken osteogenesis. MAPK and NF-κB signaling pathways mediated the positive effect of ROS on osteoclast differentiation. Antioxidant enzymes not only eliminate the negative effects of ROS, but also directly participate in the regulation of bone metabolism. Additionally, we also described the roles of proinflammatory factors and HIF-1α under the pathophysiological changes of inflammation and hypoxia, which provided a supplement of oxidative stress-induced osteoporosis. In conclusion, our review showed that oxidative stress was a common pathological state in a high-risk population for osteoporosis. Targeted oxidative stress treatment would greatly optimize the therapeutic schedule of various osteoporosis treatments.

Antioxidant and Anti-inflammatory Extracts From Sea Cucumbers and Tunicates Induce a Pro-osteogenic Effect in Zebrafish Larvae

Bone metabolic disorders such as osteoporosis are characterized by the loss of mineral from the bone tissue leading to its structural weakening and increased susceptibility to fractures. A growing body of evidence suggests that inflammation and oxidative stress play an important role in the pathophysiological processes involved in the rise of these conditions. As the currently available therapeutic strategies are often characterized by toxic effects associated with their long-term use, natural antioxidants and anti-inflammatory compounds such as polyphenols promise to be a valuable alternative for the prevention and treatment of these disorders. In this scope, the marine environment is becoming an important source of bioactive compounds with potential pharmacological applications. Here, we explored the bioactive potential of three species of holothurians (Echinodermata) and four species of tunicates (Chordata) as sources of antioxidant and anti-inflammatory compounds with a particular focus on polyphenolic substances. Hydroethanolic and aqueous extracts were obtained from animals' biomass and screened for their content of polyphenols and their antioxidant and anti-inflammatory properties. Hydroethanolic fractions of three species of tunicates displayed high polyphenolic content associated with strong antioxidant potential and anti-inflammatory activity. Extracts were thereafter tested for their capacity to promote bone formation and mineralization by applying an assay that uses the developing operculum of zebrafish (Danio rerio) to assess the osteogenic activity of compounds. The same three hydroethanolic fractions from tunicates were characterized by a strong in vivo osteogenic activity, which positively correlated with their anti-inflammatory potential as measured by COX-2 inhibition. This study highlights the therapeutic potential of polyphenol-rich hydroethanolic extracts obtained from three species of tunicates as a substrate for the development of novel drugs for the treatment of bone disorders correlated to oxidative stress and inflammatory processes.

Recent Advancements in Plant-Derived Nanomaterials Research for Biomedical Applications

Engineering, physics, chemistry, and biology are all involved in nanotechnology, which comprises a wide variety of multidisciplinary scientific field devices. The holistic utilization of metallic nanoparticles in the disciplines of bio-engineering and bio-medicine has attracted a great deal of attention. Medical nanotechnology research can offer immense health benefits for humans. While the advantages of developing nanomaterials have been well documented, it is precisely apparent that there are still some major issues that remain unattended to those need to be resolved immediately so as to ensure that they do not adversely affect living organisms in any manner. The existence of nanoparticles gives them particular value in biology and materials science, as an emerging scientific field, with multiple applications in science and technology, especially with numerous frontiers in the development of new materials. Presented here is a review of recent noteworthy developments regarding plant-derived nanomaterials and their use in the development of medicine and biomedical applications around the world.

Polyphenols-loaded electrospun nanofibers in bone tissue engineering and regeneration

Bone is a complex structure with unique cellular and molecular process in its formation. Bone tissue regeneration is a well-organized and routine process at the cellular and molecular level in humans through the activation of biochemical pathways and protein expression. Though many forms of biomaterials have been applied for bone tissue regeneration, electrospun nanofibrous scaffolds have attracted more attention among researchers with their physicochemical properties such as tensile strength, porosity, and biocompatibility. When drugs, antibiotics, or functional nanoparticles are taken as additives to the nanofiber, its efficacy towards the application gets increased. Polyphenol is a versatile green/phytochemical small molecule playing a vital role in several biomedical applications, including bone tissue regeneration. When polyphenols are incorporated as additives to the nanofibrous scaffold, their combined properties enhance cell attachment, proliferation, and differentiation in bone tissue defect. The present review describes bone biology encompassing the composition and function of bone tissue cells and exemplifies the series of biological processes associated with bone tissue regeneration. We have highlighted the molecular mechanism of bioactive polyphenols involved in bone tissue regeneration and specified the advantage of electrospun nanofiber as a wound healing scaffold. As the polyphenols contribute to wound healing with their antioxidant and antimicrobial properties, we have compiled a list of polyphenols studied, thus far, for bone tissue regeneration along with their in vitro and in vivo experimental biological results and salient observations. Finally, we have elaborated on the importance of polyphenol-loaded electrospun nanofiber in bone tissue regeneration and discussed the possible challenges and future directions in this field.

Modifiable lifestyle factors associated with fragility hip fracture: a systematic review and meta-analysis

INTRODUCTION

Among the various hip fracture predictors explored to date, modifiable risk factors warrant special consideration, since they present promising targets for preventative measures. This systematic review and meta-analysis aims to assess various modifiable risk factors.

MATERIAL AND METHODS

We searched four online databases in September 2017. We included studies that reported on modifiable lifestyle risk factors for sustaining fragility hip fractures. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS). The inclusion criteria consisted of (1) adult patients with osteoporotic hip fracture, (2) original study, (3) availability of full text articles in English, and (4) report of a modifiable lifestyle risk factor.

RESULTS

Thirty-five studies, containing 1,508,366 subjects in total, were included in this study. The modifiable risk factors that were significantly associated with an increased risk of hip fracture were the following: weight < 58 kg (128 lbs) (pooled OR 4.01, 95% CI 1.62-9.90), underweight body mass index (BMI) (< 18.5) (pooled OR 2.83, 95% CI 1.82-4.39), consumption of ≥ 3 cups of coffee daily (pooled OR 2.27, 95% CI 1.04-4.97), inactivity (pooled OR 2.14, 95% CI 1.21-3.77), weight loss (pooled OR 1.88, 95% CI 1.32-2.68), consumption of ≥ 27 g (approx. > 2 standard drinks) alcohol per day (pooled OR 1.54, 95% CI 1.12-2.13), and being a current smoker (pooled OR 1.50, 95% CI 1.22-1.85). Conversely, two factors were significantly associated with a decreased risk of hip fracture: obese BMI (> 30) (pooled OR 0.58, 95% CI 0.34-0.99) and habitual tea drinking (pooled OR 0.72, 95% CI 0.66-0.80).

CONCLUSION

Modifiable factors may be utilized clinically to provide more effective lifestyle interventions for at risk populations. We found that low weight and underweight BMI carried the highest risk, followed by high coffee consumption, inactivity, weight loss, and high daily alcohol consumption.

Antagonistic Effects of CAPE (a Component of Propolis) on the Cytotoxicity and Genotoxicity of Irinotecan and SN38 in Human Gastrointestinal Cancer Cells In Vitro

The incidence of gastrointestinal cancers is increasing every year. Irinotecan (CPT-11), a drug used in the treatment of colorectal cancer and gastric cancer, is metabolized by carboxylesterases to an active metabolite, SN-38, which is more cytotoxic. CAPE (caffeic acid phenethyl ester) is an active component of propolis, which has a high antibacterial, antiviral, and antineoplastic potential. This study analyses the impact of CAPE on the cytotoxic (MTT assay), genotoxic (comet assay) and proapoptotic (caspase-3/7 activity) potential of irinotecan and its metabolite SN-38 in cultures of gastrointestinal neoplastic cells (HCT116, HT29, AGS). Cytotoxicity and genotoxicity activities of these compounds were carried out in comparison with human peripheral blood lymphocytes (PBLs) in vitro. The antioxidant potential of CAPE was investigated in relation H₂O₂-induced oxidative stress in the both neoplastic cells and PBLs. CAPE expressed cytotoxic, genotoxic, and pro-apoptotic activity against AGS, HCT116, and HT29 tumor cells. CAPE, in the presence of different concentrations of irinotecan or SN38, decreased the cytotoxicity, genotoxicity, and pro-apoptotic activity in these cell lines, but it has no such action on normal human peripheral blood lymphocytes.

Polyphenol uses in biomaterials engineering

Polyphenols are micronutrients obtained from diet that have been suggested to play an important role in health. The health benefits of polyphenols and their protective effects in food systems as antioxidant compounds are well known and have been extensively investigated. However, their functional roles as a "processing cofactor" in tissue engineering applications are less widely known. This review focuses on the functionality of polyphenols and their application in biomaterials. Polyphenols have been used to stabilize collagen and to improve its resistance to degradation in biological systems. Therefore, they have been proposed to improve the performance of biomedical devices used in cardiovascular systems by improving the mechanical properties of grafted heart valves, enhancing microcirculation through the relaxation of the arterial walls and improving the capillary blood flow and pressure resistance. Polyphenols have been found to stimulate bone formation, mineralization, as well as the proliferation, differentiation, and the survival of osteoblasts. These effects are brought about by the stimulatory effect of polyphenols on osteoblast cells and their protective effect against oxidative stress and inflammatory cytokines. In addition, polyphenols inhibit the differentiation of the osteoclast cells. Collectively, these actions lead to promote bone formation and to reduce bone resorption, respectively. Moreover, polyphenols can increase the cross-linking of dentine and hence its mechanical stability. Overall, polyphenols provide interesting properties that will stimulate further research in the bioengineering field.

Urinary 8-hydroxydeoxyguanosine is a better biomarker of aging in non-smokers

Objective: The aim of this study is finding an optimal and convenient aging marker.

Method: The information of participants’ occupation, family background, life style, physical condition, etc. was obtained by a self-administered questionnaire. Spot urine and saliva samples were collected during the early morning after fasting overnight. 8-hydroxydeoxygunaosine (8-OHdG), 8-iso-prostaglandin F2[Formula: see text] (8-isoPGF2[Formula: see text]), advanced oxidation protein products (AOPPs), malondialdehyde (MDA), and dehydroepian drosterone sulfate (DHEA-S) were measured by ELISA.

Results: Around 112 non-smokers (males/females [Formula: see text] 61/51; mean age [Formula: see text] 44.9 years) were eligible and analyzed in this study. The mean urinary 8-OHdG level was [Formula: see text] (ng/mmol, creatinine) and mean 8-isoPGF2[Formula: see text] level was [Formula: see text] (pg/mmoL, creatinine). In saliva, the mean level of AOPPs, MDA, and DHEA-S was [Formula: see text] ([Formula: see text]mol/L), [Formula: see text] ([Formula: see text]mol/L) and [Formula: see text] (ng/mL), respectively. After analysis in multiple regression model, urinary 8-OHdG was influenced by age and tea consumption ([Formula: see text]); urinary 8-isoPGF2[Formula: see text] level was correlated with gender ([Formula: see text]); salivary DHEA-S was related to gender ([Formula: see text]) and marital status ([Formula: see text]); AOPPs and MDA in saliva presented no relationships with those factors.

Conclusion: Among healthy non-smokers, urinary 8-OHdG is the best aging biomarker comparing to other markers.

Association between tea consumption and osteoporosis: A meta-analysis

BACKGROUND

Previous reports have suggested a potential association of tea consumption with the risk of osteoporosis. As such association is controversial, we conducted a meta-analysis to assess the relationship between tea consumption and osteoporosis.

METHODS AND FINDINGS

We systematically searched PubMed, EMBASE and WanFang databases until March 30, 2016, using the keywords "tea and osteoporosis," without limits of language. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were derived by using random-effects models throughout the analyses. We conducted the analysis of the statistical heterogeneity using Cochrane I. The funnel plot was used to speculate the publication bias, while the subgroup analysis and multiround elimination method were employed.

RESULTS

Our study was based on 17 journal articles, including 2 prospective cohort studies, 4 case-control studies, and 11 cross-sectional studies. In the present study, the total OR of osteoporosis for the highest versus the lowest categories of tea consumption was 0.62 (95% CI, 0.46-0.83), with significant heterogeneity among studies (I = 94%, P < .01). There was, however, no publication bias of the meta-analysis about tea consumption and osteoporosis. Subgroup analysis showed that tea consumption could reduce the risk of osteoporosis in all examined subgroups.

CONCLUSION

In the present study, it can be concluded from the results that tea consumption can reduce the risk of osteoporosis.

Tea Consumption and Cognitive Impairment: A Cross-Sectional Study among Chinese Elderly

BACKGROUND

Laboratorial and epidemiological researches suggested that tea exhibited potential neuroprotective effect which may prevent cognitive impairment, but there were few data among the elderly aged 60 years and above in China.

OBJECTIVE

The objective was to explore the relationship between characteristics of tea consumption and cognitive impairment.

DESIGN

We analyzed the baseline data from Zhejiang Major Public Health Surveillance Program (ZPHS) which was conducted in 2014. Totally 9,375 residents aged 60 years and above were recruited in this study. Face-to-face interview based on a self-developed questionnaire was performed for each participant. Detailed tea consumption habits were included in the questionnaire. Cognitive impairment screening was performed by using Mini-Mental State Examination (MMSE). Education-specific cut-off points for Chinese were applied to determine the status of cognitive impairment. Logistic regression analysis was used to calculate odds ratios (ORs) of cognitive impairment associated with tea consumption.

RESULTS

The means (SD) of MMSE scores for the subjects who did not consume tea and consumed <2 cups/d, 2-4 cups/d, ≥4 cups/d were 23.3 (SD = 5.61), 23.8 (SD = 5.60), 24.5 (SD = 5.63) and 25.0 (SD = 5.08), respectively. An inverse correlation was found between tea consumption (of all types) and prevalence of cognitive impairment. Volume of tea consumption was significantly associated with cognitive impairment: compared with non-consumption participants, those who consumed < 2 cups/d, 2-4 cups/d, and ≥4 cups/d were observed ORs of 0.77 (95% CI: 0.56, 1.07), 0.62 (95% CI: 0.47, 0.81), and 0.49 (95% CI: 0.36, 0.66), respectively. Compared with non-consumption, black tea presented a positive correlation with cognitive function after controlling for potential confounders (OR = 0.52, 95% CI: 0.28, 0.95), while green tea showed no significant difference (OR = 1.04, 95% CI: 0.72, 1.51). Participants who consumed weak tea, moderate tea or strong tea more often were observed a better cognitive status when compared with those who did not have tea, with an OR of 0.51 (95% CI: 0.28, 0.92), 0.32 (95% CI: 0.19, 0.56) and 0.42 (95% CI: 0.22, 0.78) after adjusting for the potential confounders. But there was no statistically significant difference between any two of these ORs.

CONCLUSION

Black tea consumption was association with better cognitive performance among the elderly aged 60 years and above in China, while green tea presented no correlation. The positive association of cognitive status with tea consumption was not limited to particular type of concentration.

Coffee consumption and risk of fractures: a systematic review and dose-response meta-analysis

PURPOSE

The data on the association between coffee consumption and the risk of fractures are inconclusive. We performed a comprehensive literature review and meta-analysis to better quantify this association.

METHODS

We identified all potentially relevant articles by searching MEDLINE, EMBASE, Cochrane Library, Web of Science, SCOPUS, and CINAHL (until February 2013). The keywords "coffee," "caffeine," "drink," and "beverage" were used as the exposure factors, and the keyword "fracture" was used as the outcome factor. We determined the overall relative risk (RR) and confidence interval (CI) for the highest and lowest levels of coffee consumption. A dose-response analysis was performed to assess the risk of fractures based on the level of coffee consumption.

RESULTS

We included 253,514 participants with 12,939 fracture cases from 9 cohort and 6 case-control studies. The estimated RR of fractures at the highest level of coffee consumption was 1.14 (95% CI: 1.05-1.24; I(2)=0.0%) in women and 0.76 (95% CI: 0.62-0.94; I(2)=7.3%) in men. In the dose-response analysis, the pooled RRs of fractures in women who consumed 2 and 8 cups of coffee per day were 1.02 (95% CI: 1.01-1.04) and 1.54 (95% CI: 1.19-1.99), respectively.

CONCLUSIONS

Our meta-analysis suggests that daily consumption of coffee is associated with an increased risk of fractures in women and a contrasting decreased risk in men. However, future well-designed studies should be performed to confirm these findings.

Green Tea Extract (GTE) improves differentiation in human osteoblasts during oxidative stress

Background

Oxidative stress is involved in the pathogenesis of bone diseases such as osteoporosis, which has a high coincidence with fractures in elderly. Several studies showed positive effects of herbal bioactive substances on oxidative stress. This study analyses the effect of green tea extract (GTE) Sunphenon 90LB on primary human osteoblasts differentiation and viability during H₂O₂-induced oxidative stress. Moreover, it was analyzed, whether GTE acts during the HO-1 signaling pathway.

Methods

Human osteoblasts were isolated from femoral heads of patients undergoing total hip replacement. Beneficial effects of GTE on osteoblasts were examined in a dose- and time-dependent manner. Furthermore, GTE was given before, simultaneous with and after induction of oxidative stress with 1 mM H₂O₂ to simulate prophylactic, acute and therapeutic use, respectively. Cell damage was measured by LDH leakage and cell viability by MTT assay. Flow cytometry was applied to measure formation of Reactive Oxygen Species by using 2`7`-dichlorofluorescein-diacetate. The formation of Extracellular Matrix after differentiation with GTE supplementation during oxidative stress was visualized with von Kossa and Alizarin Red staining. Last one was additionally photometrically quantified. To assess the effects of H₂O₂ and GTE on the osteogenic genes, RT-PCR was performed. To evaluate the intramolecular influence of GTE after the stimulation the protein levels of HO-1 were analyzed.

Results

Stimulation of primary human osteoblasts with low doses of GTE during oxidative stress over 21 days improved mineralization. Furthermore, GTE supplementation in combination with H₂O₂ leads to a higher gene expression of osteocalcin and collagen1α1 during osteoblasts differentiation. Both are important for bone quality. Pre-incubation, co-incubation and post-incubation of osteoblasts with high doses of GTE protect the osteoblasts against acute oxidative stress as shown by increased cell viability, decreased LDH leakage, and reduced production of intracellular free radicals. Functional analysis revealed an increased HO-1 protein synthesis after stimulation with GTE.

Conclusions

Incubation of human primary osteoblasts with GTE significantly reduces oxidative stress and improves cell viability. GTE also has a beneficial effect on ECM production which might improve the bone quality. Our findings suggest that dietary supplementation of GTE might reduce inflammatory events in bone-associated diseases such as osteoporosis.

Role of oxidative and nitrosative stress in autogenous bone grafts to the mandible using guided bone regeneration and a deproteinized bovine bone material

The aim of this study was to evaluate the role of oxidative and nitrosative stress in autogenous bone grafts to the mandible based on immunohistochemical analysis.

MATERIAL AND METHODS

Using a well-established sheep model autogenous bone grafts were harvested form the iliac bone. A combination of a Collagen Membrane (CM) and Deproteinized Bovine Bone Material (DBBM) was used to cover the bone graft (Experiment 2). This modification was compared with simple onlay bone grafts (Experiment 1). Immunohistochemically, the expression of specific stable degradation products of oxidative and nitrosative stress was compared between the two experimental groups.

RESULTS

Specific markers for oxidative and nitrosative stress showed statistically significant differences in expression in the different experimental groups. The influence of oxidative and nitrosative stress on osteoblasts (OB), osteoclasts (OC), and osteocytes (OCy) was analysed. Experiment 2 showed increased expression of markers in OB and decreased expression in OC.

CONCLUSIONS

Taking the result of this study and reports from the literature into consideration grafts in Experiment 2 showed less resorption and atrophy, higher activity of OB and inhibition of OC, and less expression of Reactive Oxygen and Nitrogen Species (RONS) as markers of oxidative stress within the graft. These data illustrate the improved remodelling processes in grafts using CM and DBBM.

Targeting oxidative stress response by green tea polyphenols: clinical implications

Green tea polyphenols, the most interesting constituent of green tea leaves, have been shown to have both pro-oxidant and antioxidant properties. Both pro-oxidant and antioxidant properties are expected to contribute to modulation of oxidative stress response under ideal optimal dosage regimens. Exposure to a low concentration of a pro-oxidant prior to exposure to oxidative stress induces the expression of genes that code for proteins that induce adaptation in a subsequent oxidative stress. On the other hand, exposure to an antioxidant concurrently with exposure to the oxidative stress affords protection through free radical scavenging or through other indirect antioxidant mechanisms. In any case, the optimal conditions that afford protection from oxidative stress should be defined for any substance with redox properties. Green tea polyphenols, being naturally occurring substances, seem to be an ideal option for the modulation of oxidative stress response. This paper reviews available data on the pro-oxidant and antioxidant properties of green tea polyphenols focusing on their potential on the modulation of oxidative stress response.

Bone mineral density, polyphenols and caffeine: a reassessment

Several studies have shown beneficial associations between tea consumption and bone mineral density (BMD) and fracture risk. Current investigations into potential mechanisms of benefit are focused upon the F and polyphenol components of tea. However, previous studies have pointed towards caffeine consumption as a potential risk factor for low BMD and high fracture risk. Tea, therefore, represents an interesting paradox as a mildly caffeinated beverage that may enhance bone health. Fruit and vegetable intake has also been associated with BMD, and it is now apparent that several fruit and vegetable components, including polyphenols, may contribute positively to bone health. Evidence surrounding the function(s) of polyphenol-rich foods in bone health is examined, along with more recent studies challenging the relevance of caffeine consumption to in vivo Ca balance. Plant foods rich in polyphenols such as tea, fruit and vegetables, as significant factors in a healthy diet and lifestyle, may have positive roles in bone health, and the negative role of caffeine may have been overestimated. The present review covers evidence of dietary mediation in positive and negative aspects of bone health, in particular the roles of tea, fruit and vegetables, and of caffeine, flavonoids and polyphenols as components of these foods. Since the deleterious effects of caffeine appear to have been overstated, especially in respect of the positive effects of flavonoids, it is concluded that a reassessment of the role of caffeinated beverages may be necessary.

Protection against oxidative DNA damage and stress in human prostate by glutathione S-transferase P1

The pi-class glutathione S-transferase (GSTP1) actively protect cells from carcinogens and electrophilic compounds. Loss of GSTP1 expression via promoter hypermethylation is the most common epigenetic alteration observed in human prostate cancer. Silencing of GSTP1 can increase generation of reactive oxygen species (ROS) and DNA damage in cells. In this study we investigated whether loss of GSTP1 contributes to increased DNA damage that may predispose men to a higher risk of prostate cancer. We found significantly elevated (103%; P < 0.0001) levels of 8-oxo-2'-deoxogunosine (8-OHdG), an oxidative DNA damage marker, in adenocarcinomas, compared to benign counterparts, which positively correlated (r = 0.2) with loss of GSTP1 activity (34%; P < 0.0001). Silencing of GSTP1 using siRNA approach in normal human prostate epithelial RWPE1 cells caused increased intracellular production of ROS and higher susceptibility of cells to H2 O2 -mediated oxidative stress. Additionally, human prostate carcinoma LNCaP cells, which contain a silenced GSTP1 gene, were genetically modified to constitutively express high levels of GSTP1. Induction of GSTP1 activity lowered endogenous ROS levels in LNCaP-pLPCX-GSTP1 cells, and when exposed to H2 O2 , these cells exhibited significantly reduced production of ROS and 8-OHdG levels, compared to vector control LNCaP-pLPCX cells. Furthermore, exposure of LNCaP cells to green tea polyphenols caused reexpression of GSTP1, which protected the cells from H2 O2 -mediated DNA damage through decreased ROS production compared to nonexposed cells. These results suggest that loss of GSTP1 expression in human prostate cells, a process that increases their susceptibility to oxidative stress-induced DNA damage, may be an important target for primary prevention of prostate cancer.

Green tea extract (epigallocatechin-3-gallate) reduces efficacy of radiotherapy on prostate cancer cells

OBJECTIVES

To assess the influence of epigallocatechin-3-gallate (EGCG) on the efficacy of ionizing radiation on prostate cancer cells because of the increased use of dietary interventions, especially by patients with prostate cancer. Radiotherapy is used to treat localized prostate cancer. Some people consume green tea (EGCG) as a chemopreventive agent against prostate cancer. Green tea can act as an antioxidant and induce superoxide dismutase enzymes, which could scavenge the free oxygen radicals generated by radiotherapy.

METHODS

Prostate cancer cell line DU145 cells were treated with EGCG or radiotherapy, or both. Cell death was assessed using trypan blue cell counting, and apoptosis was confirmed by assessing poly (adenosine phosphate ribose) polymerase cleavage. The antioxidant potential was assessed using Western immunoblotting for manganese superoxide dismutase and copper zinc superoxide dismutase enzymes. Radiotherapy was delivered using a linear accelerator. Cell cycle analysis was performed using flow cytometry.

RESULTS

Radiotherapy at 3.5 Gy induced a 5.9-fold increase in apoptosis of DU145 cells. Subapoptotic doses of EGCG (1.5-7.5 μM) significantly reduced ionizing radiation-induced apoptosis (P < .001), with the inhibitory effect of EGCG on ionizing radiation being most effective when added 30 minutes before radiotherapy (P < .001). In addition, when radiotherapy and EGCG were used together, an approximate 1.5-fold increase in manganese superoxide dismutase levels was seen compared with the control and a 2-fold increase compared with radiotherapy alone.

CONCLUSIONS

Radiotherapy is effective in inducing apoptosis in DU145 cells, but its effect was significantly reduced in the presence of EGCG, and this was associated with an increase in the induction of manganese superoxide dismutase.

Role of galloylation and polymerization in cytoprotective effects of polyphenolic fractions against hydrogen peroxide insult

Byproducts and wastes generated by agricultural, food, and forestry industries contain large amounts of polyphenols, which can be potentially used as sources of natural or semisynthetic antioxidants. This study examined and compared the protection against peroxidative damage induced in erythrocytes and 3T3 cell line of polyphenolic fractions from white grape pomace, pine bark, and witch hazel bark. The work pays special attention to the different degrees of polymerization and galloylation of the extracts to contribute to the understanding of their mechanisms of action. Fractions demonstrated different protections against erythrocyte lipid peroxidation, hemolysis, and 3T3 cytotoxicity caused by H(2)O(2). Galloylation is claimed to be related to antioxidant protective capacity, and it is also responsible for the pro-oxidant effect observed at high doses. The results show that not only the percentage of galloylation but also the degree of polymerization are important modulators of their antioxidant capacity. In this sense, it is crucial that novel polyphenolic fractions were prepared attending a value of 3 for the mean degree of polymerization and did not exceed a 30% of galloylation to reach the highest antioxidant capacity with the lowest cytotoxic effects. For this reason, the grape extracts appear to be the best strategy to fight against hydrogen peroxide cell damage.

Neuroprotective properties of Spanish red wine and its isolated polyphenols on astrocytes

The neuroprotective effect of Merlot red wine and its isolated polyphenols was evaluated in an oxidative stress model induced by Fenton reaction and hydrogen peroxide in the human astrocytoma U373 MG cell line. Compared with cells treated only with oxidative stress inductors, the pre-incubation with Merlot red wine for 24h caused a significant increase in cell viability for all concentrations assayed. The most abundant polyphenols found in Merlot red wine were the flavonoids catechin (37.8mg/l), epicatechin (52.3mg/l), quercetin (5.89mg/l) and procyanidins (15.2mg/l), the hydroxybenzoic acid gallic acid (16.7mg/l), and the phenolic alcohol tyrosol (31.4mg/l). The potential protective role of these polyphenols when isolated was then assessed in treated Fenton reaction U373 MG cells. Polyphenols decreased reactive oxygen species generation and increased the activity and the protein expression of the antioxidant enzymes catalase, superoxide dismutase, glutathione reductase and glutathione peroxidase. Of the polyphenols, quercetin and procyanidins showed the highest neuroprotective effect.

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

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

Preferential inhibition by antidiarrheic 2-methoxy-4-methylphenol of Ca(2+) influx across acquired N-methyl-D-aspartate receptor channels composed of NR1/NR2B subunit assembly

In our previous studies, particular phenolic ingredients, such as 2-methoxy-4-methylphenol (2M4MP), of the antidiarrheic drug wood creosote significantly prevented cell death by both hydrogen peroxide and glutamate in cultured rat hippocampal neurons. In this study, we further evaluated the pharmacological properties of 2M4MP on Ca(2+) influx across native and acquired N-methyl-D-aspartate (NMDA) receptor (NMDAR) channels. The addition of 2M4MP significantly prevented the loss of cellular viability and the increase in intracellular free Ca(2+) levels as determined by Fluo-3 in cultured rat hippocampal neurons briefly exposed to NMDA. Brief exposure to NMDA also led to a marked increase in mitochondrial free Ca(2+) levels determined by Rhod-2, in addition to intracellular free Ca(2+) levels, in HEK293 cells expressing either NR1/NR2A or NR1/NR2B subunit channels. The further addition of the general NMDAR channel blocker dizocilpine similarly inhibited the increase of intracellular Ca(2+) levels by NMDA in both types of acquired NMDAR channels, whereas the NR2B subunit selective antagonist ifenprodil drastically inhibited the increase by NMDA in HEK293 cells expressing NR1/NR2B, but not NR1/NR2A, subunits. Similarly, 2M4MP significantly and selectively inhibited the NMDA-induced influx of Ca(2+) across acquired NR1/NR2B channels in a concentration-dependent manner. Moreover, prior daily oral administration of 2M4MP significantly reduced the infarct volume in the ipsilateral cerebral hemisphere in rats with middle cerebral artery occlusion 1 day after reperfusion. These results suggest that 2M4MP may protect neurons from excitotoxicity through preferential inhibition of Ca(2+) influx across NMDAR channels composed of NR1/NR2B subunits.

Effects of epigallocatechin gallate on osteogenic capability of human mesenchymal stem cells after suspension in phosphate-buffered saline

Administration of culture-expanded mesenchymal stem cells (MSCs) has been sought for regeneration of various damaged tissues/organs in clinical situations. Liquid suspensions of MSCs have either been directly injected into organs or generally infused. In this study, we focused on the viability and differentiation of MSCs after suspension in phosphate-buffered saline. When the MSCs were treated with epigallocatechin gallate, which is purified from green tea catechin, the MSCs showed high viability as well as osteogenic differentiation capability even while suspended in phosphate-buffered saline for 4 days at 4 degrees C. In contrast, nontreated MSCs showed low viability and showed hardly any differentiation. The rate of proliferation of the treated MSCs was much higher than that of the nontreated MSCs. These results indicate the usefulness of epigallocatechin gallate treatment for fabrication of ready-to-use cellular products of MSC suspension.

Beneficial Effects of Freezing Rate Determined by Indirect Thermophysical Calculation on Cell Viability in Cryopreserved Tissues

Many types of mammalian cells, such as sperm, blood, embryos, etc., have been successfully cryopreserved for the last few decades, while no optimal method for the cryopreservation of mammalian tissues or organs has been established, showing a poor survival after thawing with a low recovery of function. In this study, the freezing rate was determined by indirect thermodynamic calculation, and its potential effect on the cryoprotection of human saphenous veins and tissue-engineered bones was investigated. The vein segments were frozen according to the calculated freezing rate, using rate-controlled freezing devices, with a freezing solution composed of 10% dimethylsulphoxide and 20% fetal bovine serum in RPMI 1640 media. The efficacy of indirect calculation was assessed by the cell viability measured using fluorescence double-staining methods. The results indicated that the freezing rate determined by indirect calculation significantly (P < 0.05) maintained the post-thaw cellular viability of the blood vessel, particularly in terms of the endothelial cells. However, it exerted relatively less protective effect on the osteoblastic cell-cultured scaffolds. These results suggest that freezing-induced injuries may occur in tissues, and the freezing rate determined by indirect thermophysical calculation can be used for the optimization of tissue cryopreservation by minimizing the injuries.

Biobased epicatechin conjugates protect erythrocytes and nontumoral cell lines from H2O2-induced oxidative stress

This paper reports the study of the protective action of epicatechin and epicatechin derivatives, obtained by depolymerizing polymeric flavanols in the presence of cysteine or cysteamine, on red blood cells (RBC) and nontumoral cell lines challenged by exogenous H(2)O(2). The epicatechin derivatives showed more effective antioxidant properties than epicatechin. Among them, 4β-(2-aminoethylthio)epicatechin 3-O-gallate showed the highest antioxidant activity against three markers of oxidative stress: hemolysis, lipid peroxidation, and cytotoxicity. Furthermore, as this compound lacks the pyrogallol group on the condensed flavanic structure, it might be safer than other potent gallocatechin-type polyphenols. These findings indicate that these epicatechin derivatives, which are byproducts of the agro-food industry show potential for application in the food and drug industries.

[Inhibitory effects of "Goishi-tea" as a post-fermented-tea on dietary-induced hypercholesteremia and atherosclerosis in rabbits]

Since lipid oxidation is involved in the deterioration of hypercholesterolemia-related atherosclerosis, ingestion of drinks and foods with antioxidant actions is useful for preventing lipid oxidation. Goishi-tea is a post-fermented-tea manufactured by a unique method in Japan, and may be useful for preventing various disorders. However, there is no scientific evidence. In this study, we compared the radical scavenging activity of goishi-tea with that of other teas, and administered this tea to a rabbit model of hypercholesteremia to evaluate its usefulness in the inhibition of hypercholesteremia and atherosclerosis. The radical scavenging activity of goishi-tea was similar to that of green-tea, and was higher than that of other types of fermented-teas. On the other hand, some difference of components was found between goishi-tea and green-tea. In cholesterol-fed rabbits, low-density lipoprotein (LDL)-cholesterol level in the goishi-tea-group was lower than that in the green-tea-group. Plasma lipidperoxide value was also lower in the goishi-tea-group than in the green-tea and tap-water-groups. On aortic endothelial staining, fat area in the goishi-tea-group was lower than that in the tap-water-group. Furthermore, fat accumulation in the aortic intima in the goishi-tea-group was very low. Goishi-tea has higher antioxidant activities than the other fermented-teas tested, which were generally low, and decreased serum lipid levels, suggesting that goishitea is a very peculiar fermented-tea with usefulness in the prevention of hypercholesterolemia and atherosclerosis.

Protection of rabbit kidney from ischemia/reperfusion injury by green tea polyphenol pretreatment

Reactive oxygen species (ROS) have been implicated in the pathogenesis of renal injury after ischemia/reperfusion (I/R). Recently, green tea polyphenols (GTP) have been found to protect the myocardium and liver against II/R injury. Less attention, however, has been paid to the protective effects of GTP with respect to the kidneys. This study was designed to determine whether GTP could protect renal cells from ischemic injury. The rabbits were divided into three groups of equal size: control (sham-operated), I/R + vehicle (normal saline) and I/R + GTP groups. Each group consisted of six rabbits. Animals underwent 30, 60, 90 and 120 min of ischemia, followed by 24 h of reperfusion, respectively. GTP (200 microg/kg) or the vehicle was administered 45 min prior to commencement of I/R. The results demonstrated that GTP administration resulted in a significant (P < 0.05) reduction of renal damage after 90 min of ischemia, as indicated by the decreased levels of creatinine and urea nitrogen in serum. These results were confirmed by histological examinations, which showed that GTP pretreatment inhibited necrosis and sloughing of the proximal tubules induced by I/R. Examinations also showed decreased necrotic areas in the medulla and decreased glomerular collapse in the I/R-injured rabbits. Moreover, the infiltration of CD8+ T cells was considerably decreased in GTP-treated kidneys. The results of this study suggest that GTP can reduce renal injury by preventing the oxidative stress dependent on I/R and may be used in renal transplantation as an antioxidant.

Oxidative stress as a component of chromium-induced cytotoxicity in rat calvarial osteoblasts

It has been documented that medical prosthetic alloys release metal ions into surrounding tissues and cause cytotoxicity, but the mechanisms remain undefined. In that regard the cellular oxidative stress may be a common pathway in cellular responses to metal ions. The objective of this study was to approach the hypothesis that oxidative stress mediates chromium-induced cytotoxicity in rat calvarial osteoblasts. Osteoblasts were exposed to different concentrations of Cr6+ or Cr3+ (5-20 microM) in the presence or absence of the antioxidant N-acetyl-cysteine (NAC; 1-5 mM). Cellular viability, differentiation, and intracellular ultrastructural alterations were evaluated by MTT assay, alkaline phosphatase (ALP) activity assay, and transmission electron microscopy. Cellular oxidative stress was evaluated by intracellular reactive oxygen species (ROS) production. ROS production was monitored by the oxidation-sensitive fluorescent probe 2'7'-dichlorofluorescin diacetate (DCFH-DA). A time- and concentration- dependent increased cytotoxicity, time-dependent increased intracellular ROS production were indicated on exposure to Cr6+. Pretreatment of osteoblasts with 1-5 mM NAC afforded dose-dependent cytoprotective effects against Cr6+-induced cytotoxicity in osteoblasts. NAC decreased the level of intracellular ROS induced by Cr6+, too. While Cr3+ and NAC did not have any significant effects on osteoblasts (5-20 microM). These results suggest that oxidative stress is involved in Cr6+-induced cytotoxicity in osteoblasts, and NAC can provide protection for osteoblasts against Cr6+-induced oxidative stress. Cr3+ (5-20 microM) have no significant cytotoxicity in osteoblasts based on the results of this study.

Walnut extract (Juglans regia L.) and its component ellagic acid exhibit anti-inflammatory activity in human aorta endothelial cells and osteoblastic activity in the cell line KS483

Epidemiological studies suggest that the incidence of CVD and postmenopausal osteoporosis is low in the Mediterranean area, where herbs and nuts, among others, play an important role in nutrition. In the present study, we sought a role of walnuts (Juglans regia L.) in endothelial and bone-cell function. As the endothelial cell expression of adhesion molecules has been recognised as an early step in inflammation and atherogenesis, we examined the effect of walnut methanolic extract and ellagic acid, one of its major polyphenolic components (as shown by HPLC analysis), on the expression of vascular cell adhesion molecule (VCAM)-1 and intracellular adhesion molecule (ICAM)-1 in human aortic endothelial cells. After incubating the cells with TNF-α (1 ng/ml) in the absence and in the presence of walnut extract (10–200 μg/ml) or ellagic acid (10− 7–10− 5m), the VCAM-1 and ICAM-1 expression was quantified by cell-ELISA. We further evaluated the effect of walnut extract (10–50 μg/ml), in comparison with ellagic acid (10− 9–10− 6m), on nodule formation in the osteoblastic cell line KS483.Walnut extract and ellagic acid decreased significantly the TNF-α-induced endothelial expression of both VCAM-1 and ICAM-1 (P < 0·01; P < 0·001). Both walnut extract (at 10–25 μg/ml) and ellagic acid (at 10− 9–10− 8m) induced nodule formation in KS483 osteoblasts. The present results suggest that the walnut extract has a high anti-atherogenic potential and a remarkable osteoblastic activity, an effect mediated, at least in part, by its major component ellagic acid. Such findings implicate the beneficial effect of a walnut-enriched diet on cardioprotection and bone loss.

Cytoprotective properties of phenolic antidiarrheic ingredients in cultured astrocytes and neurons of rat brains

We have previously shown that particular phenolic antidiarrheic ingredients, including 2-methoxy-4-methylphenol (2M4MP) and 2-methoxy-4-ethyphenol (2M4EP), but not 2-methoxyphenol (2MP), significantly inhibit cellular maturation and differentiation of the bone-resorbing osteoclasts with concomitant protection of the bone-forming osteoblasts against oxidative stress by hydrogen peroxide (H(2)O(2)). In the present study, we evaluated the pharmacological actions of these three major phenolic antidiarrheic ingredients on the cellular viability in cultured astrocytes and neurons of the rat brain in vitro. Both 2M4MP and 2M4EP induced more efficient prevention of cell death induced by the brief exposure to 0.1 mM H(2)O(2) for 2 h than 2MP upon simultaneous exposure in cultured rat cortical astrocytes. Similarly, both 2M4MP and 2M4EP were more effective than 2MP in significantly protecting the cytotoxicity by brief exposure to 0.1 mM H(2)O(2) for 6 h in cultured rat hippocampal neurons, with concomitant suppression of the generation of intracellular reactive oxygen species in neurons exposed to H(2)O(2). Moreover, the three ingredients not only significantly prevented cell death in hippocampal neurons exposed to 0.1 mM glutamate for 1 h when determined 48 h after the brief exposure, but also inhibited the generation of intracellular reactive oxygen species and the elevation of intracellular Ca(2+) ions in neurons exposed to glutamate. These results suggest that particular phenolic antidiarrheic ingredients may prevent cell death through a mechanism related to diminution of the neurotoxicity of glutamate in neurons, in addition to eliciting cytoprotection against oxidative stress in astrocytes and neurons, in the rat brain.

Moderate alcohol consumption and increased bone mineral density: potential ethanol and non-ethanol mechanisms

Mounting epidemiological evidence indicates an association between the moderate ingestion of alcoholic beverages and higher bone mineral density (v. abstainers). More limited findings provide some evidence for translation of this association into reduced fracture risk, but further studies are required. Here, these data are reviewed and caveats in their assimilation, comparison and interpretation as well as in the use and application of bone health indices are discussed. Whilst it is concluded that evidence is now strong for the moderate alcohol-bone health association, at least in relation to bone mineral density, mechanisms are less clear. Both ethanol and non-ethanol components have been implicated as factors that positively affect bone health in the light of moderate consumption of alcoholic beverages, and four particular areas are discussed. First, recent findings suggest that moderate ethanol consumption acutely inhibits bone resorption, in a non-parathyroid hormone- and non-calcitonin-dependent fashion, which can only partly be attributed to an energy effect. Second, critical review of the literature does not support a role for moderate ethanol consumption affecting oestrogen status and leading to a knock-on effect on bone. Third, Si is present at high levels in certain alcoholic beverages, especially beer, and may have a measurable role in promoting bone formation. Fourth, a large body of work indicates that phytochemicals (e.g. polyphenols) from alcoholic beverages could influence bone health, but human data are lacking. With further work it is hoped to be able to model epidemiological observations and provide a clear pathway between the magnitude of association and the relative contribution of these mechanisms for the major classes of alcoholic beverage.

Oral administration of phenolic antidiarrheic ingredients prevents ovariectomy-induced bone loss

In the present study, we have attempted to evaluate the pharmacological actions of three major phenolic antidiarrheic ingredients, including 2-methoxyphenol (2MP), 2-methoxy-4-methylphenol (2M4MP) and 2-methoxy-4-ethyphenol (2M4EP), on the functionality and integrity of bone by in vitro and in vivo experimental techniques. Intermittent oral administration of 2M4MP and 2M4EP, but not 2MP, significantly prevented reductions of bone mineral density in total femur, distal femur and tibia, in addition to alterations of several osteoclastic parameters on histomorphometric analysis, when determined 28 days after ovariectomy in mice. All three phenolic ingredients examined significantly inhibited the developmental increase in the number of multinucleated cells positive to tartrate-resistant acid phosphatase staining in cultured mouse osteoclasts differentiated from bone marrow precursors in the presence of both macrophage-colony stimulating factor and receptor activator of nuclear factor-kappaB ligand, which occurred in a concentration-dependent manner at a concentration range of 1 microM-1mM without inducing cell death. Moreover, both 2M4MP and 2M4EP at 1mM not only prevented the cell death induced by 0.5mM H2O2 in cultured rat calvarial osteoblasts, but also suppressed the generation of intracellular reactive oxygen species in osteoblasts exposed to H2O2, with a radical scavenging action as revealed by electron spin resonance analysis. These results suggest that particular phenolic antidiarrheic ingredients may prevent ovariectomy-induced bone loss through a mechanism related to the inhibition of osteoclastogenesis in association with an anti-oxidative property in osteoblasts.

Antifungal susceptibility of epigallocatechin 3-O-gallate (EGCg) on clinical isolates of pathogenic yeasts

This is the first report to investigate the antifungal susceptibility of 21 clinical isolates of seven Candida species to epigallocatechin 3-O-gallate (EGCg) and to compare with six antifungal agents, amphotericin B (AMPH), fluconazole (FLCZ), flucytosin (5FC), itraconazole (ITCZ), micafungin (MCFG), and miconazole (MCZ), using a method following the National Committee for Clinical Laboratory Standards (NCCLS) M27-A guidelines. Among the tested species, Candida glabrata exhibited the highest susceptibility to EGCg (MIC50, 0.5-1 microg/ml and MIC90, 1-2 microg/ml) compared favorably with FLCZ, although they were slightly less susceptible than to AMPH, 5FC, MCFG, ITCZ, and MCZ. Candida guilliemondii and Candida parapsilosis (MIC50, 1-4 microg/ml and MIC90, 2-16 microg/ml) were also susceptible to EGCg, although they appear to be slightly less susceptible to EGCg than C. glabrata and the other antifungal agents tested. Moreover, the susceptibility of Candida krusei strains (MIC50, 2 microg/ml and MIC90, 4-8 microg/ml) to EGCg was approximately 2- to 8-fold higher than those of 5FC and FLCZ. Our data indicate that EGCg can inhibit clinically pathogenic Candida species, although the concentrations of EGCg for antifungal susceptibility were slightly higher than those of tested antifungal agents on the whole. Based on these results, we suggest that EGCg may be effectively used as a possible agent or adjuvant for antifungal therapy in Candidiasis.

Inhibitory effects of epigallocatechin-3-O-gallate on serum-stimulated rat aortic smooth muscle cells via nuclear factor-kappaB down-modulation

The abnormal growth of vascular smooth muscle cells (VSMCs) plays an important role in vascular diseases, including atherosclerosis and restenosis after angioplasty. Although (-)-epigallocatechin-3-O-gallate (EGCG) has antiproliferative effects on various cells, relatively a little is known about precise mechanisms of the inhibitory effects of EGCG on SMCs. In this study, the inhibitory effects of EGCG on attachment, proliferation, migration, and cell cycle of rat aortic SMCs (RASMCs) with serum stimulation were investigated. Also, the involvement of nuclear factor-kappaB (NF-kappaB) during these inhibitions by EGCG was examined. EGCG treatment resulted in significant (p<0.05) inhibition in attachment and proliferation of RASMCs induced by serum. While non-treated RASMCs migrated into denuded area in response to serum and showed essentially complete closure after 36 h, EGCG-treated cells covered only 31% of the area even after 48 h of incubation. Furthermore, EGCG treatment resulted in an appreciable cell cycle arrest at both G0/G1- and G2/M-phases. The immunoblot analysis revealed that the constitutive expression of NF-kappaB/p65 nuclear protein in RASMCs was lowered by EGCG in both the cytosol and the nucleus in a dose-dependent manner. These results suggest that the EGCG-caused inhibitory effects on RASMCs may be mediated through NF-kappaB down-modulation.

Protection of osteoblastic cells from freeze/thaw cycle-induced oxidative stress by green tea polyphenol

Green tea polyphenol (GTP) together with dimethylsulphoxide (DMSO) were added to a freezing solution of osteoblastic cells (rat calvarial osteoblasts and human osteosarcoma cells) exposed to repeated freeze/thaw cycles (FTC) to induce oxidative stress. When cells were subjected to 3 FTCs, freezing medium containing 10% (v/v) DMSO and 500 mug GTP ml(-1) significantly (p<0.05) suppressed cell detachment and growth inhibition by over 63% and protected cell morphology. Furthermore, the alkaline phosphatase activity of osteoblastic cells was appreciably maintained after 2 and 3 FTCs in this mixture. Polyphenols may thus be of use as a cell cryopreservant and be advantageous in such fields as cell transplantation and tissue engineering.

Survival rates of patients with malignant melanoma of the skin

This paper reports on cases of malignant melanoma of the skin diagnosed in Finland between 1963 and 1968. Sufficient data for estimating the survival was obtained in 691 cases. The ten-year relative survival rate for the entire series was 41% for males and 53% for females. This sex difference remained constant throughout the various divisions of the material. The ten-year relative survival rate of males with tumour in stage I was 52% and that of females 59%. The highest survival rate of stage I tumour in males was for the tumours of the lower extremities (77%) and in females for those in the head and neck (79%). The relative survival of patients with tumour of the trunk in stage I was lowest in both sexes (males 49%, females 45%). The ten-year relative survival rate of patients with a local recurrence was 33% in males and 27% in females. The relative ten-year survival rates of patients with superficial melanoma were 130% in males and 92% in females.

Protection of Human Fibroblasts from Reactive Oxygen Species by Green Tea Polyphenolic Compounds

The potential protective roles played by green tea compounds (GTPCs) against reactive oxygen species-induced oxidative stress in cultured fetal human dermal fibroblasts (fHDFs) were investigated according to cell viability measurement methods, such as fluorescence double staining followed by flow cytometry (FCM), MTT assay and crystal violet uptake. Oxidative stress was induced in the fHDFs, either by adding 50 mM H2O2 or by the action of 40 U/L xanthine oxidase (XO) in the presence of xanthine (250 µM). FCM analysis was the most suitable to show that both treatments produced a significant (p < 0.05) reduction in the fHDF viability, attributed to its high sensitivity. On the microscopic observations, the cell death with necrotic morphology was appreciably induced by both treatments. These oxidative stress-induced damages were significantly (p < 0.05) prevented by pre-incubating the fHDFs with 200 µg/ml GTPC for 1 h. These results suggest that GTPC can act as a biological antioxidant in a cell culture experimental model and prevent oxidative stress-induced cytotoxicity in cells.

Prevention of reactive oxygen species-induced oxidative stress in human microvascular endothelial cells by green tea polyphenol

The potential protective roles played by green tea polyphenol (GTP) against the injurious effects of reactive oxygen species in human microvascular endothelial cells (HUMVECs) were investigated. Oxidative stress was induced in cultured HUMVECs, either by adding 10 mM H2O2 or by the action of 10 U/l xanthine oxidase (XO) in the presence of xanthine (250 microM). Both treatments produced a significant reduction (to 68% and 71%, respectively) in HUMVEC viability, as assessed by fluorescence double staining method followed by flow cytometric analysis. On the microscopic observations, the morphological changes and necrotic detachment were appreciably induced by both treatments. The H2O2-induced alterations were completely prevented by pre-incubating the ECs with 10 microg/ml GTP for 1 h. When the oxidative stress was induced by XO, the cell viability and morphology were also significantly maintained at the same GTP concentration. These results demonstrate that GTP can act as a biological antioxidant in a cell culture experimental model and prevent oxidative stress-induced cytotoxicity in ECs.