Anti-tumor promoting activity of Asteracantha longifolia against experimental hepatocarcinogenesis in rats.

Vegetables, natural products of plant origin and numerous non-nutritive dietary constituents have been shown to play a salutary role in cancer chemoprevention. The present study aims to evaluate the chemopreventive efficacy of the methanol fraction of Asteracantha longifolia seed extract against development of 2-acetylaminofluorene (2-AAF)-selected gamma-glutamyl transpeptidase (gamma-GT)-positive foci following diethylnitrosamine (DEN) initiation. Treatment of rats with doses 200 and 400 mg/kg body weight of methanol extract of A. longifolia seeds on alternate days, subsequent to carcinogen treatment, for 6 weeks significantly reduced the incidence and size distribution of gamma-GT-positive foci and tumor formation. Administration of A. longifolia seeds significantly (P<0.001) ameliorated the activities of antioxidant enzymes, glutathione peroxidase (GPx) and catalase (CAT), in a dose-dependent manner. Prophylactic administration of seed extract simultaneous to 2-AAF in the diet, at same doses, significantly suppressed 2-AAF and partial hepatectomy (PH)-induced ornithine decarboxylase (ODC) activity and [(3)H]thymidine incorporation into hepatic DNA, in a dose-dependent manner. Assimilation of the quantitative foci data together with the findings of the modulation of tumor promoting markers give ample evidence to the anti-tumor promoting potential of A. longifolia seeds against chemically-induced hepatocarcinogenesis in Wistar rats.     

Grape seed and skin extracts inhibit platelet function and release of reactive oxygen intermediates

Red wine and purple grape juice contain polymeric flavonoids with antioxidant properties believed to be protective against cardiovascular events but the alcohol and sugar content of these beverages has curtailed their medicinal use. Acute cardiac events are also associated with enhanced inflammation and thrombosis. In this study, the extracts from grape skins or seeds were examined for their anti-inflammatory properties and effect on platelet release of reactive oxygen intermediates. Incubation of platelets with seed or skin extract led to a decrease in platelet aggregation from 68.8+/-19.8% to 45+/-3.6% for seeds and to 27+/-7.2% for skin, respectively (P<0.05). Platelet incubation with grape skin or seed extracts led to a marked decrease in superoxide release from 73+/-6.2 to 2+/-3.4 for grape seeds and to 0.33+/-0.57 for grape skin (chemilum. units; P<0.05) as well as a significant increase in radical-scavenging activity, decrease in reactive oxygen species release by confocal microscopy, and enhanced platelet NO was measured using an NO-sensitive microelectrode. These effects were dose dependent for both grape extracts. Coincubation with seeds and skins led to additive inhibition of platelet aggregation, enhanced NO release, and prevented superoxide production. Incubation with seed or skin extracts led to an immediate attenuation of release of the inflammatory mediator, soluble CD40 ligand. Thus, the extracts from purple grape skins and seeds inhibit platelet function and platelet-dependent inflammatory responses at pharmacologically relevant concentrations. These findings suggest potentially beneficial platelet-dependent antithrombotic and anti-inflammatory properties of purple grape-derived flavonoids.     

Chemomodulatory action of Foeniculum vulgare (Fennel) on skin and forestomach papillomagenesis, enzymes associated with xenobiotic metabolism and antioxidant status in murine model system

The chemopreventive effect of different doses of test diet of Foeniculum vulgare Mill (Fennel) seeds was examined on DMBA-induced skin and B(a)P-induced forestomach papillomagenesis in Swiss albino mice. To the best of our knowledge, this is the first report of Fennel seeds exhibiting a significant reduction in the skin and the forestomach tumor incidence and tumor multiplicity as compared to the control group. Further, biochemical assays showed a significant increase in the content/activities of phase I enzymes especially in the case of 6% test diet. A concomitant increase in the activities of the phase II enzymes were observed with all the doses of test diet under study. A significant enhancement in the activities of antioxidant enzymes were observed especially at 4% and 6% test diets of Fennel. Glyoxalase I activity and the content of reduced glutathione were significantly elevated. Expectedly, the levels of peroxidative damage along with lactate dehydrogenase activity, exhibited a significant reduction at all three doses of test diets. These findings were indicative of chemopreventive potential of Fennel against carcinogenesis.     

Influence of asimadoline, a new kappa-opioid receptor agonist, on tubular water absorption and vasopressin secretion in man

AIMS: The purpose of the study was to investigate the effects of asimadoline, a new kappa-opioid agonist, on renal function and on hormones related to body fluid balance as well as its tolerability in healthy subjects. METHODS: In a placebo-controlled, randomised, double-blind crossover design we studied the effects of single oral doses of 1, 5, and 10 mg of asimadoline, in 24 healthy volunteers. Two hour control urine collections were followed by 2 h postdose urine collections and subsequently 2.5% saline was given i.v. at a rate of 0.3 ml min(-1) kg(-1) during another 2 h urine collection. Blood was obtained hourly. Arginine-vasopressin (AVP), atrial natriuretic peptide (alpha-hANP), endothelin (ET-1) and cAMP were determined by r.i.a. or ELISA. RESULTS: GC-MS measurements revealed Cmax values of asimadoline in plasma ranging from 18 ng ml(-1) at the 1 mg dose, 91 ng ml(-1) at the 5 mg dose, to 214 ng ml(-1) at the 10 mg dose after an average of 1.1-1.4 h. Without effects on blood pressure, heart rate, GFR or urine electrolyte excretion, urine volume increased after 1-2 h after administration of 5 and 10 mg asimadoline from 3.3+/-1.3 to 5.6+/-1.4 (P<0.05) and from 3.2 +/-1.6 to 5.5+/-2.2 ml min(-1) (P<0.01), respectively. CH2O rose from 0.2+/-1.5 to 2.0+/-1.6 (P<0.05) and from 0.6+/-1.6 to 3.0+/-1.6 ml min(-1) (P<0.01). Urinary excretion of AVP was suppressed only with the 10 mg dose from 46+/-23 to 25+/-15 fmol min(-1) (P<0.05) without and from 410+/-206 to 181+/-125 fmol min(-1) (P<0.05) with stimulation by 2.5% saline. Plasma AVP was suppressed only by the 10 mg dose of asimadoline in six of eight subjects during the 2.5% saline infusion. Changes in the alpha-hANP or ET-1 systems were not affected by asimadoline. CONCLUSIONS: Asimadoline is diuretic in man after single doses of 5 or 10 mg probably through a direct effect at the renal tubular level. Suppression of AVP secretion was observed only at the highest dose level of 10 mg of asimadoline.     

Restoration on tissue antioxidants by fenugreek seeds (Trigonella Foenum Graecum) in alloxan-diabetic rats

The influence of fenugreek seed powder supplementation in the diet on lipid peroxidation and antioxidant status was studied in normal and alloxan-diabetic rats. The protective effect of the aqueous extract of the seeds on the activity of calcium-dependent adenosinetriphosphatase (Ca2+ ATPase) in liver homogenate in the presence of Fe2+/ascorbate in vitro was also investigated. Normal and diabetic rats were provided with a diet supplemented with fenugreek seed powder for 30 days at a dosage of 2 g/kg body weight. The diabetic rats exhibited enhanced lipid peroxidation and increased susceptibility to oxidative stress associated with depletion of antioxidants in liver, kidney and pancreas. However, treatment with fenugreek seed powder normalised the alterations. In normal rats supplementation resulted in increased antioxidant status with reduction in peroxidation. Ca2+ ATPase activity in liver was protected by the aqueous extract to nearly 80% of the initial activity. The findings suggest that the soluble portion of the seeds could be responsible for the antioxidant property.     

Garlic-induced alteration in rat liver and kidney morphology and associated changes in endogenous antioxidant status.

The effects of chronic garlic intake on various endogenous antioxidant enzymes and lipid peroxidation on two major organs, the liver (L) and kidneys (K), were investigated. Wistar albino rats were fed with fresh garlic homogenate daily by gavage in three different doses (250, 500 and 1000 mg/kg/day) for 30 days. After this period, rats were sacrificed and liver and kidneys were harvested for biochemical estimation. In comparison to saline-treated rats, the 250 mg/kg/day dose significantly (P<0.02) reduced thiobarbituric acid reactive substances (TBARS) (L: 187.48+/-9.23 vs 150.66+/-11.45; K: 177.38 15.88 vs 120.66+/-9.39 nmol/g wet. weight) and glutathione peroxidase (GPx) (L: 0.2438+/-0.05 vs 0.0046+/-0.0005; K: 0.1459+/-0.034 vs 0.0055+/-0.0003 U/mg protein). There was no change in catalase and reduced glutathione (GSH) but superoxide dismutase (SOD) increased significantly (P<0.01) (L: 5.49+/-0.76 vs 18.38+/-2.26; K: 11.47+/-1.48 vs 21.22+/-3.19 U/mg protein). Both 500 and 1000 mg/kg/day doses significantly (P<0.05) reduced endogenous antioxidants (catalase and SOD) without altering TBARS. A 1000 mg/kg/day dose of garlic caused marked histopathological and ultrastructural changes in both liver and kidneys. The results suggest that garlic in low doses has the potential to enhance the endogenous antioxidant status, although at higher doses a reversal of these effects is observed. The present study also highlights the potential ability of a high dose of garlic to induce morphological changes in the liver and kidneys, indicating the need to identify a safe dose range for garlic.     

Hepatoprotection of tea seed oil (Camellia oleifera Abel.) against CCl4-induced oxidative damage in rats.

The oil of tea seed (Camellia oleifera Abel.) is used extensively in China for cooking. This study was designed to evaluate the effects of tea seed oil on CCl(4)-induced acute hepatotoxicity in rats. Male SD rats (200+/-10 g) were pre-treated with tea seed oil (50, 100, and 150 g/kg diet) for six weeks before treatment with a single dose of CCl(4) (50% CCl(4), 2 mL/kg of bw, intraperitoneally), the rats were sacrificed 24h later, and blood samples were collected for assaying serum biochemical parameters. The livers were excised for evaluating peroxidation products and antioxidant substances, as well as the activities of antioxidant enzymes. Pathological histology was also performed. The results showed that a tea seed oil diet significantly (p<0.05) lowered the serum levels of hepatic enzyme markers (alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase), inhibited fatty degeneration, reduced the content of the peroxidation product malondialdehyde, and elevated the content of GSH. Pre-treatment of animals with tea seed oil (150 g/kg diet) could increase the activities of glutathione peroxidase, glutathione reductase and glutathione S transferase in liver when compared with CCl(4)-treated group (p<0.05). Therefore, the results of this study show that a tea seed oil diet can be proposed to protect the liver against CCl(4)-induced oxidative damage in rats, and the hepatoprotective effect might be correlated with its antioxidant and free radical scavenger effects.     

Phytoextract of Indian mustard seeds acts by suppressing the generation of ROS against acetaminophen-induced hepatotoxicity in HepG2 cells

Abstract

Context: Indian mustard [Brassica juncea (L.) Czern. & Coss. (Brassicaceae)] is reported to possess diverse pharmacological properties. However, limited information is available concerning its hepatoprotective activity and mechanism of action.

Objective: To study the protective mechanism of mustard seed extract against acetaminophen (APAP) toxicity in a hepatocellular carcinoma (HepG2) cell line.

Materials and methods: Hepatotoxicity models were established using APAP (2.5–22.5?mM) based on the cytotoxicity profile. An antioxidant-rich fraction from mustard seeds was extracted and evaluated for its hepatoprotective potential. The mechanism of action was elucidated using various in vitro antioxidant assays, the detection of intracellular generation of reactive oxygen species (ROS), and cell cycle analysis. The phytoconstituents isolated via HPLC-DAD were also evaluated for hepatoprotective activity.

Results: Hydromethanolic seed extract exhibited hepatoprotective activity in post- and pre-treatment models of 20?mM APAP toxicity and restored the elevated levels of liver indices to normal values (p?<?0.05). Post-treatment suppressed the generation of ROS by 58.37% and pre-treatment effectively prevented the generation of ROS by 90.5%. The mechanism of ROS suppression was further supported by antioxidant activity (IC₅₀) data from DPPH (103.37?±?4.2?µg AAE/mg), FRAP (83.26?±?1.1?µg AAE/mg), ORAC (1115?µM GAE/ml), ABTS (83.05?µg GAE/ml), and superoxide (345.22?±?5.15?µg AAE/mg) scavenging assays and by the restoration of cell cycle alterations. HPLC-DAD analysis revealed the presence quercetin, vitamin E, and catechin, which exhibited hepatoprotective activity.

Discussion and conclusions: A phytoextract of mustard seeds acts by suppressing the generation of ROS in response to APAP toxicity.     

Antioxidant activities and lipid lowering effects of isoflavone in male rabbits.

Dietary flavonoids appear to play a role in the prevention of a number of chronic diseases such as cancer and cardiovascular disease and the soy isoflavones have been the focus of particular. Consumption of soy isoflavones may reduce the risk of cardiovascular disease both through reduction in serum lipids and by the antioxidant properties. We have therefore investigate the effects of either 2.5 or 5 mg/kg B.W. doses of isoflavones on the levels of free radicals, lipids and lipoproteins in male New Zealand White rabbits. Animals were orally given 2.5 or 5 mg/kg B.W. doses of isoflavones. The tested doses were given to rabbits every other day for 13 weeks. Treatment with isoflavones caused significant (P<0.05) decrease in the concentrations of free radicals in plasma by 33% and 35%, liver by 18% and 27%, brain by 12% and 33%, testes by 40% and 21%, and kidney by 38% and 20% for 2.5 or 5 mg/kg B.W. doses, respectively, as compared to the control. On the other hand, the activity of glutathione S-transferase (GST) did not change in treated animals as compared to control. Also, results showed that isoflavones caused a significant decrease (P<0.05) in the levels of plasma total lipids (TL) by 16% and 19%, total cholesterol by 20% and 20%, triglyceride (TG) by 18% and 23%, low density lipoprotein (LDL) by 19%, 22%, very low density lipoprotein (VLDL) by 18% and 23%, and LDL:HDL ratio by 36% and 39% for 2.5 or 5 mg/kg B.W. doses, respectively, as compared to the control. While the level of high density lipoprotein (HDL) increased by 29% and 32%. The present results showed that the 5 mg/kg dose of isoflavone seemed to be related to a better plasma lipid and lipoprotein profiles and antioxidant activity.     

Caffeine-herbal ephedra combination increases resting energy expenditure, heart rate and blood pressure

1. The purpose of the present study was to determine whether the consumption of an acute dose of caffeine and Ma Huang increases resting energy expenditure (REE), heart rate (HR) and blood pressure (BP) over a 3 h period. 2. A randomized, double-blind cross-over study was performed evaluating the acute effects of caffeine (150 mg)/herbal ephedra (Ma Huang; 20 mg ephedra alkaloids) versus a placebo. A total of eight healthy subjects (four males and four females) with a mean (+/-SD) age of 23.4+/-0.8 years (mean ages for males and females: 25.3+/-0.7 and 22.0+/-0.7 years, respectively) and 22.5+/-3.1% body fat (15.7+/-1.2 and 27.6+/-3.5% body fat for males and females, respectively) were recruited to the study. Participants were moderate caffeine users (approximately 150-300 mg/day). 3. Subjects reported to the laboratory following a 12 h fast and 48 h of a caffeine-free diet. Resting energy expenditure was measured prior to supplementation and for 15 min every 30 min for 3 h following supplementation. Heart rate and BP were obtained every 15 min. Blood samples were obtained every 30 min following the measurement of REE and analysed for caffeine, ephedrine, free fatty acids and glucose. 4. By 3 h, HR was 22.7+/-5.5% higher (P<0.05) than baseline for the caffeine/ephedra trial compared with 8.9+/-2.2% higher for the placebo group. At 3 h, systolic BP was 9.1+/-2.2% higher (P<0.05) than baseline for the caffeine/ephedra trial compared with only 1.9+/-2.9% different from baseline for the placebo trial. There was no effect of the caffeine/ephedra combination on diastolic BP. Resting energy expenditure during the last 30 min was 4.5+/-2.5% higher in the placebo trial and 10.7+/-2.5% higher (P<0.05) in the caffeine/ephedra trial; REE was 8.5 +/- 2.0% higher (P<0.05) in the caffeine/ephedra trial compared with the placebo trial. Free fatty acids increased over time in the placebo and caffeine/ephedra trials (from 0.5+/-0.05 to 0.63+/-0.05 mEq/L and from 0.48+/-0.06L to 0.8+/-0.05 mEq/L, respectively). 5. Caffeine and herbal ephedra, at doses of 150 mg and 20 mg (ephedrine), respectively, result in a significant elevation in REE, HR and BP. Although significant, the increase in energy expenditure is negligible in terms of weight loss.     

Antioxidant biofactor, a processed grain food, inhibits iron nitrilotriacetate-induced renal tumorigenesis, hyperproliferative response, and oxidative damage

We have evaluated the effect of dietary antioxidant, antioxidant biofactor (a processed grain food), on iron nitrilotriacetate-induced renal tumorigenesis, hyperproliferative response, and oxidative damage. In tumorigenesis studies, iron nitrilotriacetate alone treatment resulted in a development of 75% renal cell tumor incidence, whereas, in the group of animals fed with antioxidant biofactor diet and treated with iron nitrilotriacetate, only 43% of renal cell tumor incidence was observed. In oxidative damage studies, the decrease in the level of renal glutathione and antioxidant enzymes induced by iron nitrilotriacetate was significantly reversed by antioxidant biofactor diet pretreatment in a dose-dependent manner (18-71% recovery, P < 0.05). Antioxidant biofactor diet pretreatment also resulted in a dose-dependent inhibition (35-49% inhibition, P < 0.05) of iron nitrilotriacetate-induced lipid peroxidation as measured by thiobarbituric acid reactive substances formation in renal tissues. Similarly, in hyperproliferation studies, antioxidant biofactor diet pretreatment showed a strong inhibition of iron nitrilotriacetate-induced renal ornithine decarboxylase activity (18-54% inhibition, P < 0.05). In addition, antioxidant biofactor fed diet pretreatment also protected the kidney tissues against observed histopathological alterations. From this data, it can be concluded that antioxidant biofactor diet can abrogate the toxic and tumor promoting effects of iron nitrilotriacetate and can serve as a potent chemopreventive agent to suppress oxidant-induced tissue injury and tumorigenesis.     

Safety evaluation studies on argemone oil through dietary exposure for 90days in rats.

Epidemic dropsy is a disease caused by the consumption of mustard oil contaminated with argemone oil (AO). During 1998 dropsy in New Delhi, which is so far the largest with more than 3000 victims and over 60 deaths, it was enquired at various scientific and regulatory meetings about the maximum tolerated dose of AO. Hence, the present study was aimed to investigate the safety levels of AO in rats. Animals were given AO in diet at a dose of 0.001%, 0.01%, 0.1%, 0.5% and 1% daily for 90 days and the two control groups received the standard diet with and without 1% mustard oil. A decrease in body weight gain (28-31%) was observed in 0.5% and 1% AO groups; while significant increases in relative lungs and liver weight was noticed in respective doses of 0.01% and 0.1% AO groups as well as in higher dosage animals. Reduction in RBC count and hemoglobin content (p<0.05) was noticed in 0.01% and 0.1% AO exposed animals. This effect was more pronounced in higher AO doses. Serum marker enzymes including alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) were found to be significantly elevated in 0.01-1% AO groups. Further, a decrease in albumin/globulin ratio (42-78%) was observed in the serum of 0.01% to higher AO dose groups. The levels of serum triglycerides and VLDL cholesterol were found to be enhanced (p<0.05) in AO treated (0.01-1.0%) animals. Histopathological changes in lung were observed at 0.01% dose of AO while liver, kidney and heart produced changes at 0.1% AO and above doses. None of the parameters were found to be affected in 0.001% AO treated animals. These results suggest that the no observed adverse effect level (NOAEL) dose of AO is 0.001% in rats and considering a factor of 100 for humans for highly toxic compound, the safe limit of 0.00001% (100 ppb or 100 ng AO/g oil) AO can be implicated which shall contain only 0.55% of sanguinarine equivalent to 0.6 ng sanguinarine per gram oil. However, the minimum detectable limit of AO is 5 ppm (equivalent to 5 microg sanguinarine per gram oil) with the present existing HPLC method, thereby suggesting that mustard oil should be absolutely free from AO contamination.     

Flax seed oil and flax seed meal reduce the formation of aberrant crypt foci (ACF) in azoxymethane-induced colon cancer in Fisher 344 male rats.

Flax seed oil and flax seed meal are good sources of omega-3 fatty acids. The objective of this study was to explicate the effects of feeding flax seed oil and flax seed meal on AOM-induced aberrant crypt foci (ACF) in Fisher 344 male rats. Following an acclimatization period, rats were divided into six groups and fed AIN 93G diet Control (C), C+7 and 14% soybean oil (SBO), C+7 and 14% flax seed oil (FSO) and C+10 and 20% flax seed meal (FSM). All rats received 16 mg/kg body weight of AOM at 7 and 8 weeks of age. The rats were euthanized with CO2 at 17 weeks of age. FSM and FSO reduced the incidence of ACF which are putative precursor lesions in the development of colon cancer in the distal colon by 88% and 77%, in the proximal colon by 86% and 87% with a total reduction of 87.5% and 84%, respectively. Glutathione-S-transferase (GST) activities were significantly (P<0.05) higher in rats fed C+7 and 14% FSO and C+10 and 20% FSM, as compared to rats fed C+SBO diets. Results of this study showed that FSO and FSM reduced the incidence of AOM-induced ACF formation and may therefore be effective chemopreventive agents.     

Dose-response efficacy of caraway (Carum carvi L.) on tissue lipid peroxidation and antioxidant profile in rat colon carcinogenesis

Colon cancer is a leading cause of cancer death and its prevention is of great interest throughout the world. This study was conducted to examine the efficacy of different doses of dietary caraway (Carum carvi L.) on tissue lipid peroxidation (LPO) and antioxidant profile in rat colon carcinogenesis. Wistar male rats were divided into 6 groups and were fed a modified pellet diet for the whole of 30 weeks. To induce colon cancer, rats were given a weekly subcutaneous injection of 1,2-dimethylhydrazine (DMH) at a dose of 20 mg kg(-1) (based on body weight) for the first 15 weeks. Caraway was supplemented every day orally at doses of 30, 60 and 90 mg kg(-1) for different groups of rats for the total period of 30 weeks. All rats were sacrificed at the end of 30 weeks, the colons were examined visually for masses and were subsequently evaluated histologically. The results showed diminished levels of intestinal, colonic and caecal LPO products, such as conjugated dienes (CD), lipid hydroperoxides (LOOH) and thiobarbituric acid reactive substances (TBARS) and also the antioxidants superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and glutathione reductase (GR) in DMH treated rats, which were significantly reversed (P<0.05) on caraway supplementation. Moreover, enhanced activity of intestinal, colonic and caecal glutathione peroxidase (GPx), glutathione S-transferase (GST) and colonic ascorbic acid and alpha-tocopherol levels were observed in carcinogen-treated rats, which were significantly (P<0.05) reduced on caraway supplementation. Thus, our study showed that caraway supplementation at a dose of 60 mg kg(-1) had a modulatory role on tissue LPO, antioxidant profile and prevented DMH-induced histopathological lesions in colon cancer rats.     

Phenolic compounds and squalene in olive oils: the concentration and antioxidant potential of total phenols, simple phenols, secoiridoids, lignansand squalene.

The aim of this study was to evaluate the phenolic antioxidant and squalene content in a range of olive and seed oils. A mean of 290 +/- 38 (SEM) mg squalene/100 g was detected. However, while there was a weak significant difference between extra virgin (424 +/- 21 mg/kg) and refined virgin (340 +/- 31 mg/100 g; P<0.05) olive oils, highly significant differences were evident between extra virgin olive oils (P<0.0001) refined virgin olive oils (P<0.0001) and seed oils (24 +/- 5 mg/100 g). While seed oils were devoid, on average, the olive oils contained 196 +/- 19 mg/kg total phenolics as judged by HPLC analysis, but the value for extra virgin (232 +/- 15 mg/kg) was significantly higher than that of refined virgin olive oil (62 +/- 12 mg/kg; P<0.0001). Appreciable quantities of simple phenols (hydroxytyrosol and tyrosol) were detected in olive oils, with significant differences between extravirgin (41.87 +/- 6.17) and refined virgin olive oils (4.72 +/- 215; P<0.01). The major linked phenols were secoiridoids and lignans. Although extra virgin contained higher concentrations of secoiridoids (27.72 +/- 6.84) than refined olive oils (9.30 +/- 3.81) this difference was not significant. On the other hand, the concentration of lignans was significantly higher (P<0.001) in extra virgin (41.53 +/- 3.93) compared to refined virgin olive oils (7.29 +/- 2.56). All classes of phenolics were shown to be potent antioxidants. In future epidemiologic studies, both the nature and source of olive oil consumed should be differentiated in ascertaining cancer risk.     

Dietary supplementation of curcumin enhances antioxidant and phase II metabolizing enzymes in ddY male mice: possible role in protection against chemical carcinogenesis and toxicity

Dietary antioxidants protect laboratory animals against the induction of tumours by a variety of chemical carcinogens. Among possible mechanism of protection against chemical carcinogenesis could be mediated via-antioxidant-dependent induction of detoxifying enzymes. Curcumin, a yellow pigment from Curcuma longa, is a major component of turmeric and is commonly used as a spice and food colouring material and exhibits antiinflammatory antitumour, and antioxidant properties. In this study we therefore investigated the effect of dietary supplementation of curcumin on the activities of antioxidant and phase II-metabolizing enzymes involved in detoxification, and production of reactive oxygen species were quantified in ddY male mice. Dietary supplementation of curcumin (2%, w/v) to male ddY mice for 30 days significantly increased the activities of glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase and catalase to 189%, 179%, 189%, and 181% in liver and 143%, 134%, 167% and 115% in kidney respectively as compared with corresponding normal diet fed control (P<0.05-0.001). Parallel to these changes, curcumin feeding to mice also resulted in a considerable enhancement in the activity of phase II-metabolizing enzymes viz. glutathione S-transferase and quinone reductase to 1.7 and 1.8 times in liver and 1.1 and 1.3 times in kidney respectively as compared with corresponding normal diet fed control (P<0.05-0.01). In general, the increase in activities of antioxidant and phase II-metabolizing enzymes was more pronounced in liver as compared to kidney. The induction of such detoxifying enzymes by curcumin suggest the potential value of this compound as protective agent against chemical carcinogenesis and other forms of electrophilic toxicity. The significance of these results can be implicated in relation to cancer chemopreventive effects of curcumin against the induction of tumours in various target organs.     

Postischemic administration of CGX-1051, a peptide from cone snail venom, reduces infarct size in both rat and dog models of myocardial ischemia and reperfusion

CGX-1051 is a synthetic version of a peptide originally isolated from the venom of cone snails. In the present studies, we tested the potential cardioprotective effect of CGX-1051 in a rat and dog model of myocardial ischemia/reperfusion. CGX-1051 was administered 5 minutes before reperfusion as intravenous bolus doses of 30, 100, and 300 microg/kg. Infarct size (IS) is reported as IS/area at risk (AAR). In the rat, the vehicle control group had an IS/AAR of 59.8+/-2.1%. Postischemic administration of CGX-1051 at doses of 30, 100, and 300 microg/kg resulted in an IS/AAR of 52.6+/-4.2%, 34.6+/-5.6% (P<0.05), and 40.8+/-5.2% (P<0.05), respectively. In the dog, the vehicle control group had an IS/AAR of 18.8+/-1.7%. Postischemic administration of CGX-1051 at doses of 30, 100, and 300 microg/kg resulted in an IS/AAR of 16.9+/-2.5%, 8.4+/-2.9% (P<0.05) and 9.9+/-2.4% (P<0.05), respectively. These results demonstrate that administration of CGX-1051 at a clinically relevant time point results in a dose-dependent reduction in IS in both rats and dogs.     

Low dose anandamide affects food intake, cognitive function, neurotransmitter and corticosterone levels in diet-restricted mice

This investigation reports the possible role of the endocannabinoid anandamide on modulating the behavioral and neurochemical consequences of semi-starvation. We studied the effect of very low dose anandamide (0.001 mg/kg) administration on food intake, cognitive function and catecholaminergic and serotonergic pathways in two murine brain areas concerned with appetite (hypothalamus) and learning (hippocampus), and the peripheral corticosterone response to the stress of 40% diet restriction. Anandamide-treated mice consumed 44% more food (P<0.05) during 1 week of 2.5-h feeding each day. In the hypothalamus, there were significantly increased concentrations of norepinephrine (P<0.01), dopamine (P<0.05) and 5-hydroxytryptamine (5-HT) (P<0.001). In the hippocampus, anandamide increased significantly norepinephrine and dopamine, but decreased 5-HT (all at P<0.001). Diet restriction was accompanied in both areas by a significant decrease in all neurotransmitter concentrations that were partially restored by anandamide for dopamine and 5-HT, but not for norepinephrine. In animals on diet restriction, anandamide significantly improved impaired maze performance. Norepinephrine turnover and plasma corticosterone levels were also raised significantly by anandamide. The fact that low dose anandamide improved food intake, cognitive function and reversed some of the neurotransmitter changes caused by diet restriction, might have implications for the treatment of cachexia associated with acquired immunodeficiency syndrome (AIDS) and cancer, for mood changes sometimes associated with dieting, and in the extreme case, of patients with anorexia.     

Delayed protection against ventricular arrhythmias by monophosphoryl lipid-A in a canine model of ischaemia and reperfusion.

Bacterial endotoxin reduces the severity of ventricular arrhythmias which occur when a coronary artery is occluded several hours later. We have now examined in anaesthetised dogs the effects on ischaemia and reperfusion-induced arrhythmias, of a non-toxic derivative component of the endotoxin molecule of the lipid-A (monophosphoryl lipid-A). This was given intravenously, in doses of 10 and 100 microg kg(-1), 24 h prior to coronary artery occlusion. Arrhythmia severity was markedly reduced by monophosphoryl lipid-A. During ischaemia, ventricular premature beats were reduced from 315+/-84 in the vehicle controls to 89+/-60 (with the lower dose of monophosphoryl lipid-A) and 53+/-23 (P<0.05) with the higher dose. The incidence of ventricular tachycardia was reduced from 75% to 25% (P<0.05) and 31% (P<0.05), and the number of episodes of ventricular tachycardia from 13.4+/-4.9 per dog to 1.1+/-1.1 (P<0.05) and 1. 2+/-0.9 (P<0.05) after doses of 10 and 100 microg kg(-1), respectively. The incidence of ventricular fibrillation during occlusion and reperfusion in the control group was 96% (15/16), i.e., only 6% (1/16) dogs survived the combined ischaemia-reperfusion insult. Monophosphoryl lipid-A (100 microg kg(-1)) significantly reduced the incidence of occlusion-induced ventricular fibrillation (from 50% to 7%; P<0.05), and increased survival following reperfusion to 54% (P<0.05). Monophosphoryl lipid-A also significantly reduced ischaemia severity as assessed from ST-segment elevation recorded from epicardial electrodes as well as the degree of inhomogeneity of electrical activation within the ischaemia area. There were no haemodynamic differences prior to coronary occlusion between vehicle controls and monophosphoryl lipid-A-treated dogs. These results demonstrate that monophosphoryl lipid-A reduces arrhythmia severity 24 h after administration. Although the precise mechanisms are still unclear, there is some evidence that nitric oxide and prostanoids (most likely prostacyclin) may be involved because the dual inhibition of nitric oxide synthase and cyclooxygenase enzymes by administration of aminoguanidine and meclofenamate abolished the marked antiarrhythmic protection resulted from monophosphoryl lipid-A treatment 24 h previously.     

Myrica nagi attenuates cumene hydroperoxide-induced cutaneous oxidative stress and toxicity in Swiss albino mice

In recent years, considerable efforts have been made to identify new chemopreventive agents which could be useful for man. Myrica nagi, a subtropical shrub, has been shown to possess significant activity against hepatotoxicity and other pharmacological and physiological disorders. We have shown a chemopreventive effect of Myrica nagi on cumene hydroperoxide-induced cutaneous oxidative stress and toxicity in mice. Cumene hydroperoxide treatment at a dose level of 30 mg/animal/0.2 ml acetone enhances susceptibility of cutaneous microsomal membrane for iron-ascorbate-induced lipid peroxidation and induction of xanthine oxidase activity which are accompanied by decrease in the activities of cutaneous antioxidant enzymes such as catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase and depletion in the level of cutaneous glutathione. Parallel to these changes a sharp decrease in the activities of phase II metabolizing enzymes such as glutathione S-transferase and quinone reductase has been observed. Application of Myrica nagi at doses of 2.0 mg and 4.0 mg/kg body weight in acetone prior to that of cumene hydroperoxide (30 mg/animal/0.2 ml acetone) treatment resulted in significant inhibition of cumene hydroperoxide-induced cutaneous oxidative stress and toxicity in a dose-dependent manner. Enhanced susceptibility of cutaneous microsomal membrane for lipid peroxidation induced by iron ascorbate and xanthine oxidase activities were significantly reduced (P<0.05). In addition the depleted level of glutathione, the inhibited activities of antioxidants, and phase II metabolizing enzymes were recovered to a significant level (P<0.05). The protective effect of Myrica nagi was dose-dependent. In summary our data suggest that Myrica nagi is an effective chemopreventive agent in skin and capable of ameliorating cumene hydroperoxide-induced cutaneous oxidative stress and toxicity.