Mitigating effects of antioxidant properties of black berry juice on sodium fluoride induced hepatotoxicity and oxidative stress in rats

Fluorosis is a serious public health problem in many parts of the world. As in the case of many chronic degenerative diseases, increased production of reactive oxygen species has been considered to play an important role, even in the pathogenesis of chronic fluoride toxicity. Black berry is closely linked to its protective properties against free radical attack. Therefore, the aim of this study was to demonstrate the role of black berry juice (BBJ) in decreasing the hepatotoxicity and oxidative stress of sodium fluoride (NaF). Results showed that NaF caused elevation in liver TBARS and nitric oxide (NO), and reduction in superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC) and glutathione (GSH). Plasma transaminases (AST and ALT), creatine kinase (CK), lactate dehydrogenase (LDH), total lipids (TL), cholesterol, triglycerides (TG), and low density lipoprotein–cholesterol (LDL–c) were increased, while high density lipoprotein–cholesterol (HDL–c) was decreased. On the other hand, BBJ reduced NaF-induced TBARS, NO, TL, cholesterol, TG, LDL–c, AST, ALT, CK and LD. Moreover, it ameliorated NaF-induced decrease in SOD, CAT, GSH, TAC and HDL–c. Therefore, the present results revealed that BBJ has a protective effect against NaF-induced hepatotoxicity by antagonizing the free radicals generation and enhancement of the antioxidant defence mechanisms.     

Effect of commercially available green and black tea beverages on drug-metabolizing enzymes and oxidative stress in Wistar rats

The effect of commercially available green tea (GT) and black tea (BT) drinks on drugmetabolizing enzymes (DME) and oxidative stress in rats was investigated. Male Wistar rats were fed a laboratory chow diet and GT or BT drink for 5 weeks. Control rats received de-ionized water instead of the tea drinks. Rats received the GT and BT drinks treatment for 5 weeks showed a significant increase in hepatic microsomal cytochrome P450 (CYP) 1A1 and CYP1A2, and a significant decrease in CYP2C, CYP2E1 and CYP3A enzyme activities. Results of immunoblot analyses of enzyme protein contents showed the same trend with enzyme activity. Significant increase in UDP-glucuronosyltransferase activity and reduced glutathione content in liver and lungs were observed in rats treated with both tea drinks. A lower lipid peroxide level in lungs was observed in rats treated with GT drink. Electrophoretic mobility shift assay revealed that both tea drinks decreased pregnane X receptor binding to DNA and increased nuclear factor-erythroid 2 p45-related factor 2 binding to DNA. These results suggest that feeding of both tea drinks to rats modulated DME activities and reduced oxidative stress in liver and lungs. GT drink is more effective on reducing oxidative stress than BT drink.     

Antioxidant properties of novel benzimidazole retinoids

Our approach was to examine the antioxidant activity of novel retinoid derivatives containing the benzimidazole moiety. Their in vitro effects on rat liver microasomal, NADPH-dependent lipid peroxidation levels and superoxide anion formation were determined. Lipid peroxidation in rat liver microsomes was reduced by some of the compounds in a dose-dependent manner.     

Gastroprotective activity of Camellia sinensis black tea brew in rats

This study examined the gastroprotective potential of a black tea brew (BTB) of Camellia sinensis Linn. O. Kuntze (Theaceae) using Sri Lankan high grown Dust grade No: 1 tea in a rat ethanol-induced gastric lesion model. Three oral doses of BTB (84, 167, or 501?mg/mL) were used in evaluation of the gastroprotective activity. The results showed a strong dose dependent and significant (p?<?0.05) gastroprotective activity (in terms of number, length, and area of hemorrhagic lesions). The gastroprotective activity of BTB was superior to that of the reference drug cimetidine. The high dose of BTB (only dose tested) also offered gastroprotection in rat indomethacin- and serotonin-induced gastric lesion models. Intraperitoneal treatment of BTB and oral treatment of BTB following decaffeination suppressed its gastroprotective potential. However, indomethacin pretreatment did not reduce the gastroprotective potential of BTB in the ethanol-induced gastric lesion model. BTB also increased the gastric mucus content (by Alcian blue test), thickness of the gastric mucus layer (by histopathology), pH of the gastric contents, and possibly the gastric mucosal blood flow, and reduced the gastric acid output of the stomach. BTB also had antihistamine (by wheal test) and antioxidant activity (by the DPPH method) and impaired the gastric transit (by charcoal plug test). It is concluded that BTB of C. sinensis possesses strong oral gastroprotective action, which is mediated via multiple mechanisms. The results also justify the claim made by Sri Lankan traditional practitioners that BTB of C. sinensis has gastroprotective action.     

Fluoride levels in various black tea,herbal and fruit infusions consumed in Turkey

The fluoride contents were determined by ion-selective electrode in 26 black tea samples originally produced in Turkey, Sri Lanka, India and Kenya, and in 14 herbal and seven fruit infusions originated from Turkey. Fluoride content in black tea infusions ranged from 0.57 to 3.72 mg/L after 5 min of brewing. Higher fluoride levels were found in black teas originated from Turkey when compared with teas originated from Sri Lanka. Moreover higher fluoride levels were determined in black tea bags compared with granular and stick-shaped black teas. However, herbal and fruit infusions were characterized by low values of fluoride (0.02–0.04 mg/L) after 5 min of brewing and increasing brewing time to 10 min caused only slight increases in some infusions. As a result, consuming tea infusions prepared from some black tea available in Turkish market, especially black tea bags, in large quantities may lead to exposion to a high amount of fluoride which may cause dental fluorosis. Although fruit and herbal infusions are safer to consume their fluoride contents are too low for caries prevention. In countries such as Turkey where tea is traditionally consumed, the fluoride concentration and daily safety precautions should be indicated on tea products.     

红茶浸出物抑制人舌鳞状细胞癌细胞增殖活力的实验研究

目的本文研究红茶浸出物抑制体外培养人舌鳞状细胞癌Tca8113细胞增殖效应及其对细胞内硫氧还蛋白还原酶(TrxRs)活力的影响。方法 MTT法检测红茶浸出物及不同程度EGCG氧化产物体外抑制癌细胞增殖效应,金抑制法测定细胞内TrxRs活力水平。结果结果表明,本研究制备的EGCG各种氧化产物在浓度100μmol时均具有与其单体相当的抑癌活性;红茶浸出物抑制增殖表现剂量和时间效应,IC50剂量为250μg/ml。经红茶浸出物处理的细胞内TrxRs活力显著降低(P<0.01)。结论红茶浸出物抑制人舌鳞状细胞癌Tca8113细胞体外增殖,其机制涉及打击细胞内TrxRs活力。     

Effect of Kombucha,a fermented black tea in attenuating oxidative stress mediated tissue damage in alloxan induced diabetic rats

Diabetic complications associated with increased oxidative stress can be suppressed by antioxidants. In the present study we investigated the antidiabetic and antioxidant effects of Kombucha (KT), a fermented black tea, in comparison to that of unfermented black tea (BT), in ALX-induced diabetic rats. ALX exposure lowered the body weight and plasma insulin by about 28.12% and 61.34% respectively and elevated blood glucose level and glycated Hb by about 3.79 and 3.73 folds respectively. The oxidative stress related parameters like lipid peroxidation end products (increased by 3.38, 1.7, 1.65, 1.94 folds respectively), protein carbonyl content (increased by 2.5, 2.35, 1.8, 3.26 folds respectively), glutathione content (decreased by 59.8%, 47.27%, 53.69%, 74.03% respectively), antioxidant enzyme activities were also altered in the pancreatic, hepatic, renal and cardiac tissues of diabetic animals. Results showed significant antidiabetic potential of the fermented beverage (150 mg lyophilized extract/kg bw for 14 days) as it effectively restored ALX-induced pathophysiological changes. Moreover, it could ameliorate DNA fragmentation and caspase-3 activation in the pancreatic tissue of diabetic rats. Although unfermented black tea is effective in the above pathophysiology, KT was found to be more efficient. This might be due to the formation of some antioxidant molecules during fermentation period.     

Glucose-lowering effect of powder formulation of African black tea extract in KK-Ay/TaJcl diabetic mouse

We observed the suppressive effect of a powder formulation of African black tea extract prepared from the leaves of Camellia sinensis on type 2 non-insulin dependent diabetic mice, KK-A(y)/TaJcl. Black tea extract significantly showed suppressive effect of the elevation of blood glucose on oral glucose tolerance test of 8 week-old KK-A(y)/TaJcl mice (P < 0.05). Long-term treatment with black tea extract showed significant suppression of post-prandial blood glucose and obesity (P < 0.05). The weight of the intestine of mice treated with black tea extract was significantly reduced (P < 0.05). From these results, African black tea used in this study showed a suppressive effect on the elevation of blood glucose during food intake and the body weight.     

The effect of manganese chloride on gentamicin-induced nephrotoxicity in rats

The aim of this study was to investigate the effects of manganese chloride on gentamicin-induced nephrotoxicity in rats. Thirty-six adult Wistar Albino rats were divided into six equal groups. They were injected with gentamicin sulfate (100 mg kg⁻¹per day i.p.) and manganese chloride (2 or 20 mg kg⁻¹ per day i.p.) and gentamicin together with manganese chloride for 6 days. The animals were killed 24 h after the last injection. Nephrotoxicity was biochemically and histopathologically evaluated. The concentrations of creatinine, urea, sodium and potassium in plasma, malondialdehyde (MDA) and reduced glutathione (GSH) levels, glutathione peroxidase (GSH-Px) and catalase (CAT) activities in kidney tissue were determined. Administration of gentamicin to rats induced a marked renal failure, characterized with a significant increase in plasma creatinine and urea concentrations. A significant increase in kidney MDA and a decrease in GSH concentrations were observed in gentamicin-treated rats. No change was observed in the activities of GSH-Px and CAT in rats treated with gentamicin alone. Administration of the low dose of manganese (Mn²⁺) produced amelioration in biochemical indices of nephrotoxicity in plasma and kidney tissue when compared to gentamicin group. The histological signs of renal proximal tubules followed a similar pattern. The high dose of Mn²⁺ (20 mg kg⁻¹) caused an opposite effect on nephrotoxicity induced by gentamicin, causing exacerbation in the tubular necrosis. The results suggest that low dose of Mn²⁺ may have an antioxidant effect in kidneys of gentamicin administrated rats, but its high doses had no beneficial effect.     

Regular black tea habit could reduce tobacco associated ROS generation and DNA damage in oral mucosa of normal population

Tobacco and tea habit are very common in world wide. In the present study, an attempt was made to evaluate the effect of regular drinking of black tea on reactive oxygen species (ROS) generation and DNA damage in buccal cells of normal subjects with or without tobacco habit. Expression of ROS associated proteins IκB, NF-κB as well as DNA repair associated proteins p53, MLH1 were also analyzed. Exfoliated buccal cells were collected from 308 healthy individuals and classified according to age, tobacco and tea habits. In all age groups, comparatively high ROS level and significantly high DNA damage frequency were seen in individuals with tobacco habit than the subjects without tea and tobacco habits. Tea habit effectively lowered ROS level and restrict DNA damage in tobacco users irrespective of ages. The DNA damage seen in the subjects was not associated with apoptosis. Moreover, tea habit effectively lowered the expression of IκB, NF-κB, p53 and MLH1 in tobacco users in all age groups. It seems that regular black tea habit could have anti-genotoxic effect as revealed by reduced tobacco associated ROS generation and DNA damage in buccal cells.     

SOD诱生剂对慢性氟中毒骨损伤的保护作用

用含氟饮水给ＳＤ大鼠染氟,同时服用ＳＯＤ诱生剂－－绞股蓝复方制剂,通过组织氟、尿氟、血清ＳＯＤ的测定以及骨组织的光镜观察及体视学分析,探讨氟中毒所致骨组织的损伤是否与脂质过氧化损伤有关,并观察绞股蓝复方制剂对氟中毒所致骨损伤有否保护作用。染氟４月后,示经处理的染氟大鼠血清ＳＯＤ显著降低,尿氟、骨氟明显升高;６月后,染氟对照大鼠出现骨髓腔狭窄,骨小梁面积浓度增大等骨质硬化表现,部分动物有骨赘形成。股     

Protective role of selenium against renal toxicity induced by cadmium in rats

Cadmium is an environmental toxic metal implicated in human diseases. The mechanism of its toxicity is not fully understood. Therefore, the role of cadmium in renal toxicity, and the protective role of selenium against this toxicity were investigated. Forty-five male rats were used through out the study and divided into three groups of 15. The first group received saline solution daily for 10 days. The second group, received cadmium chloride (CdCl₂) (2 mg/kg body weight) intraperitoneally daily for a period of 10 days. The third group, received sodium selenite (1 mg/kg body weight, twice a day) and CdCl₂ (once a day) for a period of 10 days. The results showed that cadmium treatment increased renal lipid peroxidation (measured as malondialdehyde, MDA) which was associated with a significant decrease in the antioxidant systems such as reduced glutathione levels and the activities of glutathione peroxidase (GPx) and thioredoxin reductase (TrxR). On the other hand, pretreatment of rats with selenium and cadmium led to a significant decrease in MDA concentration, and increased levels of GSH and the activities of GPx and TrxR when compared with those of cadmium-treated group. The total levels of phospholipid, triglyceride, and cholesterolester classes were decreased, while free fatty acids levels were markedly increased after cadmium treatment. In addition, the total levels of both mono- and poly-unsaturated fatty acids of different lipid classes were significantly decreased, while the total saturated fatty acids was significantly increased by cadmium treatment. Pretreatment of rats with selenium, was found to protect kidney tissues of rats against the biochemical changes resulting from cadmium administration. These results suggest that cadmium causes renal toxicity by inducing lipid peroxidation, decreasing antioxidant systems, and also by altering lipid metabolism. In addition, selenium treatment could protect the kidney tissues against the toxicity of cadmium since it reduced MDA levels and increased the activities of antioxidant enzymes in these tissues. These results could be important for the further understanding of the complex mechanisms of cadmium toxicity in kidney tissues and in the development of better treatments for people and/or animals exposed to the heavy metal.     

Antioxidant properties of the triphenylethylene antiestrogen drug toremifene

The aim of the present study was to investigate antioxidativity of the triphenylethylene antiestrogen toremifene. Toremifene and its structural analogues were studied for their ability to inhibit chain reactions of lipid peroxidation and to act as scavengers of free radicals in vitro, and the effects of toremifene were compared to those of the estrogens, tamoxifen and known antioxidants. Moreover, the in vivo antioxidativity of toremifene was tested in a long-term experiment with rats. The ability of toremifene to prevent lipid peroxidation was assayed in two different test systems. In the first assay (initiated with ascorbate/ADP-FeCl₃, detection by the formation of TBA-reactive material) toremifene was found to act as an efficient membrane antioxidant with an IC50-value (18 μM) comparable to that of tamoxifen (26 μM) and α-tocopherol (43 μM). Toremifene derivatives 4-hydroxytoremifene (IC50 = 8 μM) and Fc 1159 (IC50 = 31 μM), as well as diethylstilbestrol (IC50 = 17 μM) were also active while estradiol showed only weak antioxidativity (IC50 = 300 μM) in this test system. In the other assay (peroxidation initiated with t-butylhydroperoxide, detection by luminol-enhanced chemiluminescence) toremifene prevented lipid peroxidation only at high concentrations (IC50 = 450 μM) but the metabolite 4-hydroxytoremifene (IC50 = 0.18 μM), estradiol (IC50 = 4.6 μM) and diethylstilbestrol (IC50 = 1.7 μM) showed potent antioxidant activity. The potency of 4-hydroxytoremifene even exeeded that of α-tocopherol (IC50 = 2.0 μM) and butylated hydroxyanisole (IC50 = 1.1 μM). Toremifene was found to have some superoxide anion but no peroxyl radical scavenging activity. Interestingly, diethylstilbestrol turned out to be a potent scavenger of peroxyl radicals. Treatment of female Sprague-Dawley rats with toremifene (12 or 48 mg/kg) was found to decrease serum levels of lipid peroxides. This was seen at various time points (2 days, 5 weeks, 6 and 12 months) during long-term administration of toremifene to rats, and results obtained with two different methods (diene conjugation, TBA-reactive material) gave similar results. The present study thus showed that (i) like steroidal estrogens and tamoxifen toremifene is a potent membrane antioxidant in vitro, (ii) the antioxidant action of toremifene is not due to scavenging of free radicals and, importantly, (iii) toremifene acts antioxidatively also in living organisms in vivo. Received: 10 February 1997 / Accepted: 27 May 1997     

Effect of nonylphenol on male reproduction: analysis of rat epididymal biochemical markers and antioxidant defense enzymes

The mechanism by which nonylphenol (NP) interferes with male reproduction is not fully elucidated. Therefore, the present study was conducted to evaluate the effect of NP on male reproductive organ's weight, sperm characteristics, and to elucidate the nature and mechanism of action of NP on the epididymis. Adult male Wistar rats were gavaged with NP, dissolved in corn oil, at 0, 100, 200 or 300 mg/kg/day for 30 consecutive days. Control rats were gavaged with vehicle (corn oil) alone. Body weight did not show any significant change while, absolute testes and epididymides weights were significantly decreased. Sperm count in cauda and caput/corpus epididymides, and sperm motility was significantly decreased. Daily sperm production was significantly decreased in a dose-related manner. Sperm transit time in cauda epididymis was significantly decreased by 300 mg/kg, while in the caput/corpus epididymis it was significantly decreased by 200 and 300 mg/kg of NP. Plasma LDH was significantly increased while; plasma testosterone was significantly decreased in a dose-related pattern. In the epididymal sperm, NP decreased acrosome integrity, Δψm and 5′-nucleotidase activity. Hydrogen peroxide (H₂O₂) production and LPO were significantly increased in a dose-related pattern. The activities of SOD, CAT and GPx were significantly decreased in the epididymal sperm. In conclusion, this study revealed that NP treatment impairs spermatogenesis and has a cytotoxic effect on epididymal sperm. It disrupts the prooxidant and antioxidant balance. This leads oxidative stress in epididymal sperms of rat. Moreover, the reduction in sperm transit time may affect sperm quality and fertility potential.     

Antioxidant potential of tea reduces arsenite induced oxidative stress in Swiss albino mice

Environmental arsenic (As) is a potent human carcinogen and groundwater As contamination is a major health concern in West Bengal, India. Oxidative stress has been one of the prime factors in As-induced carcinogenicity. Generation of reactive oxygen species (ROS), beyond the body’s endogenous antioxidant balance cause a severe imbalance of the cellular antioxidant defence mechanism. Tea, a popular beverage has excellent chemopreventive and antioxidant properties. In this study it was investigated whether these flavonoids could ameliorate the arsenite (As III) induced oxidative stress in Swiss albino mice. Bio-monitoring with comet assay elicited that the increase in genotoxicity caused by As III was counteracted by both black tea and green tea. Elevated levels of lipid peroxides and protein carbonyl by As III were effectively reduced with green as well as black tea. They also exhibited protective action against the As III induced depletion of antioxidants like catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST) and glutathione (GSH) in mice liver tissue. Thus the tea polyphenols by virtue of their antioxidant potential may be used as an effective agent to reduce the As III induced oxidative stress in Swiss albino mice.     

Evaluation of trace metal and polychlorinated biphenyl levels in tea brands of different origin commercialized in Italy

The objectives of this study were to investigate the trace element (Hg, Cd, Pb, Cu, Zn, Ni, Fe, Cr and Se) and polychlorinated biphenyl (PCBs) content of several commercially available brands of green and black tea marketed in Italy. The concentrations these chemicals were found to be variable and largely dependent upon the type and brand of analysed tea. The most abundant element among the essential elements was Fe, followed by Zn, Cu, Se, Ni and Cr, whereas Pb was the predominant among the tested nonessential elements followed by Hg and Cd. Assessment based on several available guidelines showed that element content were low, except for Hg and Ni. The PCBs concentrations were generally low, with a homologue profile dominated by low-chlorinated congeners, namely three- and tetra-PCBs accounting for more than 60% of the total residue. Apart from trace elements, this is the first study documenting in detail the concentrations and congener distribution of PCBs in tea samples of different origin.     

Effects of acute ethanol intoxication,chronic ethanol intoxication,and ethanol withdrawal on magnesium and calcium metabolism in the rat

Effects of ethanol intoxication and withdrawal on magnesium and calcium metabolism were studied in rats. During acute ethanol intoxication, plasma [Mg²⁺] was increased and plasma [Ca²⁺] decreased. During chronic intoxication, plasma [Mg²⁺] was normalized whereas plasma [Ca²⁺] was persistently subnormal. Ethanol withdrawal was followed by a decrease in plasma [Mg²⁺] and a normalization of plasma [Ca²⁺]. These various changes are probably related to changes in systemic pH and to the biochemical effects of ethanol and ethanol withdrawal on intermediary metabolism. Cerebrospinal fluid [Mg²⁺] was unchanged during intoxication and withdrawal and it was concluded that no etiological role can presently be ascribed to the magnesium ion as far as cerebral signs of ethanol intoxication and withdrawal in the rat are concerned. No consistent changes in erythrocyte [Mg²⁺] were encountered during ethanol intoxication and withdrawal in rats.     

Enhancement of pavlovian conditioned suppression by mild ethanol intoxication

Rats were trained to bar-press for food and then received aversive Pavlovian conditioning following low doses of ethanol (0–1600 mg/kg in different groups). They were tested for Pavlovian conditioned suppression of barpressing 48 h, 7 days, and 14 days later following no additional differential treatments. The results showed that very low doses of ethanol (approximately 200 mg/kg) during training enhanced later conditioned suppression, whereas more moderate doses (800–1600 mg/kg) disrupted Pavlovian conditioning. These results parallel earlier observations that very low ethanol doses enhance Pavlovian conditioned eyeblink and heart rate responses in rabbits, and suggest that facilitation of Pavlovian conditioning may be a general effect of mild ethanol intoxication.     

Chromium(VI) induces oxidative stress in the mouse brain

Potassium dichromate was given to female Swiss mice (25 mg/kg per day) orally in water for 1–3 days. Brain homogenates were prepared to evaluate the occurrence of oxidative stress in this organ through the measurement of the antioxidant defense levels, and the extent of lipid peroxidation. In addition, mitochondrial fractions were isolated from brain homogenates to determine the production of reactive oxygen species in this subcellular fraction. The administration of potassium dichromate for 3 days caused increases of 72 and 74% in superoxide dismutase and catalase activities, respectively, in the homogenates. The treatment with this metal for 3 days increased brain homogenate chemiluminescence and thiobarbituric acid-reactive substances by 34 and 29%, respectively. The brain contents of the non-enzymatic antioxidants -tocopherol and sulfhydryl groups decreased by 35 and 32%, respectively. Ascorbic acid levels were not modified by the administration of potassium dichromate. Finally, there was a significant increment in the mitochondrial production of oxidants in the brain of treated mice as compared with controls. These results suggest that chromium(VI) produces an increased formation of reactive oxygen species and brain lipid peroxidation. The increase in the antioxidant enzyme activities reflects an adaptive response against oxidative stress, while the reduction in the levels of non-enzymatic antioxidants might be due to their reaction with reactive oxygen species generated during the metabolism of chromium(VI).