The Effect of an Aqueous Extract of Teucrium polium on Glutathione Homeostasis In Vitro: A Possible Mechanism of Its Hepatoprotectant Action.

Background. Teucrium polium is used in Arab traditional medicine to treat liver diseases. Glutathione is an important intracellular antioxidant, and intrahepatic glutathione levels are depleted in liver diseases. Hypothesis and Aim. This investigation tested the hypothesis that aqueous extracts of T. polium maintains intracellular glutathione levels by augmenting glutathione peroxidase and glutathione reductase activity in cultured hepatocytes. Methods. The effects of increasing concentrations (0.01-1 mg/mL) of aqueous extract of T. polium were assessed in cultured HepG2 cells following 24 hours incubation on (1) cellular integrity using (a) the Trypan blue exclusion assay, (b) the [di-methylthiazol-2yl]-2,5-diphenyl-tetrazoliumbromide (MTT) assay, and (c) the lactate dehydrogenase (LDH) assay; (2) glutathione redox state; and (3) glutathione peroxidase and glutathione reductase activities using a repeated measures experimental design. Results. At concentrations of 0.375 mg/mL and 0.5 mg/mL, the extract increased the intracellular levels of total and reduced glutathione and had no effect on the intracellular amounts of oxidized glutathione. The extract had no effect on glutathione peroxidase and glutathione reductase activities. Conclusion. These data indicate that the mechanism of the hepatoprotective action of aqueous extracts of T. polium may be, in part, due to augmenting intracellular glutathione levels.

The evolutionary theories of aging revisited--a mini-review.

This short review portrays the evolutionary theories of aging in the light of the existing discoveries from genomic and molecular genetic studies on aging and longevity. At the outset, an historical background for the development of the evolutionary theories of aging is presented through the works of August Weismann (programmed death and the germ plasm theories) including his exceptional theoretical postulation, later experimentally validated by the existence of cell division limits. Afterwards, the theory of mutation accumulation of Peter Medawar and the theory modification by Charlesworth (late-life mortality plateau) are presented as well as the antagonistic pleiotropy hypothesis of George Williams, and the disposable soma theory of Kirkwood and Holliday. These theories are discussed in the light of the different research studies, which include studies on insulin signaling and longevity, the possibility that nuclear factor kappa B may be a major mediator of aging, studies of anti-aging Sirtuins and studies on heat shock proteins and longevity and on gene sets as biomarkers of aging. Finally, the proposals for future research in biogerontology, such as studies on the control of protein synthesis, validation of biomarkers of aging, understanding the biochemistry of longevity and research in the field of gerontologic pathology are presented. Likewise, further attention is suggested regarding the work on telomere shortening, stem cells and studies on understanding the biochemical and molecular basis for longevity in centenarians.

Exercise and immobilization in aging animals: the involvement of oxidative stress and NF-kappaB activation.

In the early 1980s, the concept of threshold of age in exercise and aging was proposed. In several studies it was shown that subjecting young animals to short periods of moderate to intense exercise improved the biochemical and morphological status of their skeletal muscles. This was not the case for old animals subjected to the same exercise regimens. Thus, by measuring several muscle energy-providing enzymes as well as antioxidant enzymes it was demonstrated that their levels and activities increased in young animals postexercise, while in old animals reduced activity of these enzymes was found on completion of the training. However, old animals that started training in young and middle age were still capable of improving their muscle condition as a result of exercise, as long as the onset of training was below a specific age threshold. In the following years, it was shown that intense physical exercise in young humans and animals is accompanied by elevation of oxidative stress parameters in muscles and other organs. Specifically, strenuous training of animals led to increased protein oxidation as measured by protein carbonyl accumulation in muscles, which could be attenuated by the administration of vitamin E. Nuclear factor kappaB (NF-kappaB) is a redox-sensitive transcription factor responsive to closely related reactive oxygen species (ROS) and reactive nitrogen species (RNS) redox cascades. Its involvement in exercise and immobilization has been demonstrated in several studies, indicating that these conditions may lead to inflammatory responses and to oxidative damage to tissues. Indeed, recent studies have revealed that NF-kappaB is involved in inflammatory responses that may result in muscle protein degradation. Additional studies have also demonstrated that the pattern and type of the NF-kappaB activation pathway vary between muscles of young and old animals subjected to limb immobilization for several weeks. This indicates that NF-kappaB may play a crucial role in the regulation of both inflammatory processes and protein turnover and degradation in muscles of old animals. Thus, the modulation of NF-kappaB activity in muscles of old animals by specific inhibitors may provide a means to retard muscle damage and protein degradation under conditions of immobilization.

Risk factors for methicillin-resistant Staphylococcus aureus colonization in a geriatric rehabilitation hospital.

BACKGROUND: Knowledge of the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonization, and the frequency of transmission is vital for the implementation of MRSA infection control measures in hospitals. We assessed risk factors for and rates of colonization of MRSA upon admission to a geriatric rehabilitation hospital, and studied the contribution of the colonization on hospital mortality. METHODS: This was a prospective study conducted over a 6-month period. All patients were screened at admission, using nasal and throat swabs. Whenever necessary, blood, sputum, urine, or wound cultures were obtained. Data collected on admission included age, sex, functional status, reasons for admission to the rehabilitation unit, previous hospitalizations, known carriage or infection with MRSA in previous hospitalizations, underlying diseases, prescribed antibiotics in previous hospitalization, serum albumin, creatinine clearance, and patient management data. Risk factors for MRSA carriage on admission were estimated by using multivariate analysis. RESULTS: Of the 337 patients admitted during the study period, 24 (7.1%) had a MRSA isolate, and 87.4% of these were detected through screening specimens only. Of the 24 positive admissions with MRSA, 23 (95.8%) were newly identified MRSA carriers. In the multivariate analysis, the following variables were highly associated with MRSA carriage: presence of tracheotomy (p =.0001), hospitalization for deconditioning (p =.007), renal failure (p =.039), and quinolone use prior to hospitalization (p =.037). The morbidity associated with MRSA was very low, and length of stay was not influenced by carriage. CONCLUSION: The prevalence of MRSA carriage on admission to geriatric rehabilitation hospitals is high. Screening on admission is probably useful, as it detects almost all MRSA carriers. However, given the low morbidity associated with MRSA observed in this study, eradication of the MRSA carrier state is questionable. Further studies are needed to determine the usefulness and cost/benefit ratio of screening.

Aqueous extracts of Teucrium polium possess remarkable antioxidant activity in vitro.

Teucrium polium L. (Lamiaceae) (RDC 1117) is a medicinal plant whose species have been used for over 2000 years in traditional medicine due to its diuretic, diaphoretic, tonic, antipyretic, antispasmodic and cholagogic properties. The therapeutic benefit of medicinal plants is often attributed to their antioxidant properties. We previously reported that an aqueous extract of the leaves and stems of this plant could inhibit iron-induced lipid peroxidation in rat liver homogenate at concentrations that were not toxic to cultured hepatic cells. Others have reported that organic extracts of the aerial components of this plant could inhibit oxidative processes. Against this background, we felt further investigation on the antioxidant action of the extract of T. polium prepared according to traditional Arab medicine was warranted. Accordingly, we assessed (i) its ability to inhibit (a) oxidation of beta-carotene, (b) 2,2'-azobis(2-amidinopropan) dihydrochloride (AAPH)-induced plasma oxidation and (c) iron-induced lipid peroxidation in rat liver homogenates; (ii) to scavenge the superoxide (O2*-) radical and the hydroxyl radical (OH(*)); (iii) its effects on the enzyme xanthine oxidase activity; (iv) its capacity to bind iron; and (v) its effect on cell glutathione (GSH) homeostasis in cultured Hep G2 cells. We found that the extract (i) inhibited (a) oxidation of beta-carotene, (b) AAPH-induced plasma oxidation (c) Fe(2+)-induced lipid peroxidation in rat liver homogenates (IC(50) = 7 +/- 2 mug ml(-1)); (ii) scavenged O2*-(IC(50) = 12 +/- 3 mug ml(-1)) and OH(*) (IC(50) = 66 +/- 20 mug ml(-1)); (iii) binds iron (IC(50) = 79 +/- 17 mug ml(-1)); and (iv) tended to increase intracellular GSH levels resulting in a decrease in the GSSG/GSH ratio. These results demonstrate that the extract prepared from the T. polium possesses antioxidant activity in vitro. Further investigations are needed to verify whether this antioxidant effect occurs in vivo.

Fertilization-induced changes in growth parameters and antioxidant activity of medicinal plants used in traditional Arab medicine.

In response to increased popularity and greater demand for medicinal plants, a number of conservation groups are recommending that wild medicinal plants be brought into cultivation systems. We collected four medicinal herbs Cichorium pumilum, Eryngium creticum, Pistacia palaestina and Teucrium polium used in traditional Arab medicine for greenhouse cultivation to assess the effects of different fertilization regimes on their growth and antioxidant activity. Wild seedlings were collected and fertilized with either 100% Hoagland solution, 50% Hoagland solution, 20% Hoagland solution or irrigated with tap water. Plant height was measured and the number of green leaves and branches counted weekly. Thereafter, the aboveground parts of plants were harvested for preparing a water-soluble powder extracts of which antioxidant activity was measured by their ability to suppress the oxidation of beta-carotene. Of the fertilization regimes, we found either 20 or 50% Hoagland solution produced the most consistent response of the plant growth parameters. All powders prepared from the four wild growing plants inhibited oxidation of beta-carotene. Increasing the amount of fertilizer caused a significant concentration-dependent increase in antioxidant activity of the cultivated T. polium compared with the wild type. In contrast, increasing the amount of fertilizer caused a significant concentration-dependent reduction in the antioxidant activity of powders prepared from the cultivated E. creticum when compared with wild plants. Our results showed that cultivation success should not rely solely on parameters of growth but should incorporate assessment related to indices of therapeutic potential.

Ursodeoxycholic acid and superoxide anion.

AIM: To investigate the ability of ursodeoxycholic acid (UDCA) to scavenge superoxide anion (O(2)(-)). METHODS: We assessed the ability of UDCA to scavenge (O(2)(-)) generated by xanthine-xanthine oxidase (X-XO) in a cell-free system and its effect on the rate of O(2)(-)-induced ascorbic acid (AA) oxidation in hepatic post-mitochondrial supernatants. RESULTS: UDCA at a concentration as high as 1 mmol/L did not impair the ability of the X-XO system to generate O(2)(-), but could scavenge O(2)(-) at concentrations of 0.5 and 1 mmol/L, and decrease the rate of AA oxidation at a concentration of 100 micromol/L. CONCLUSION: UDCA can scavenge O(2)(-), an action that may be beneficial to patients with primary biliary cirrhosis.

The effects of aqueous extracts prepared from the leaves of Pistacia lentiscus in experimental liver disease.

In a previous study, we identified Pistacia lentiscus was worthy for further laboratory evaluation because an aqueous extract of the plant suppressed iron-induced lipid peroxidation in rat liver homogenates without affecting mitochondrial respiration in cultured HepG2 and PC12 cells. The present study was undertaken to evaluate the efficacy of an aqueous extract prepared from the dried leaves of Pistacia lentiscus in a rat model of hepatic injury caused by the hepatotoxin, thioacetamide. We assessed the impact of daily dosing on biochemical and morphological indices and the extent of oxidative stress in the livers of healthy and thioacetamide-treated rats. In healthy rats, long-term administration of the extract induced hepatic fibrosis and an inflammatory response, mild cholestasis and depletion of reduced glutathione associated with an increase in its oxidized form. In thioacetamide-treated rats, long-term administration of extract aggravated the inflammatory and fibrotic and glutathione depleting responses without affecting the extent of lipid peroxidation. Although our previous in vitro study established that extracts prepared from the leaves of Pistacia lentiscus had antioxidant activity, this in vivo study establishes these extracts also contains hepatotoxins whose identity may be quite different from those compounds with antioxidant properties. The results of this study suggest complementing in vitro experiments with those involving animals are essential steps in establishing the safety of medicinal plants. Furthermore, these data confirm that complete reliance on data obtained using in vitro methodologies may lead to erroneous conclusions pertaining to the safety of phytopharmaceuticals.

Effect of interferon, ribavirin and ursodeoxycholic acid in patients with hepatitis C infection.

BACKGROUND/AIMS: Combination therapy of interferon-alpha (IFNalpha) and the oral nucleoside analog, ribavirin is the standard treatment for individuals suffering from hepatitis C virus (HCV) infection. Several studies have shown combination therapy of IFN and antioxidants is therapeutically beneficial in these patients. Ursodeoxycholic acid (UDCA) is a hydrophilic bile acid possessing antioxidant properties. This study evaluated the clinical outcome and extent of oxidative stress in a group of non-responding and disease-relapsed HCV patients treated with IFNalpha, ribavirin and UDCA (triple therapy) for 6 months. METHODOLOGY: Twenty patients with chronic HCV disease were treated with triple therapy for six months. During this period, they were monitored for the presence of HCV RNA, standard serum parameters of liver function and the plasma levels of lipid peroxides (LP) and glutathione (GSH) as indices of oxidative stress. The patients were reassessed six months after completion of treatment. RESULTS: During the 6-month treatment period, the health status of the patients improved reflected by falls in the serum activities of alanine and aspartate aminotransferases and gamma-glutamyl transpeptidase and an initial lowering of viral (HCV RNA) load. Six months after cessation of treatment, the patients showed biochemical and virological evidence of disease relapse. The elevated plasma LP levels normalized during the treatment period and remained within normal levels 6 months after completion of treatment. Plasma GSH levels fluctuated within the normal range over the 12-month observation period. CONCLUSIONS: Treatment of individuals with chronic HCV hepatitis with triple therapy comprising IFNalpha, ribavirin and UDCA improves the health status, as well as lowering the extent of oxidative stress in these individuals. This treatment regimen also resulted in a sustained lowering of plasma lipid peroxide levels in the face of laboratory evidence of disease relapse. This preliminary study is unable to provide an apt explanation for the persistence of normal plasma LP levels in the face of evidence of disease relapse 6 months after completion of treatment. However, we believe these preliminary findings are sufficiently intriguing to warrant further study. Such investigations should include more patients with assessment of the extent of hepatic fibrosis during and after completion of treatment to determine whether this treatment can modify the natural progress of the disease.

Antioxidant activity of Crataegus aronia aqueous extract used in traditional Arab medicine in Israel.

BACKGROUND: The medicinal use of extracts prepared from plant parts of the genus Crataegus dates back to ancient times. Furthermore, it has been proposed that its antioxidant constituents account for its beneficial therapeutic effects. A decoction of leaves and unripe fruits from Crataegus aronia syn. azarolus (L) (Rosaceae), the indigenous Israeli hawthorn, is used to treat cardiovascular diseases, cancer, diabetes and sexual weakness in Arab traditional medicine. PURPOSE: Because laboratory data on the bioactivity of extracts prepared from the indigenous Israeli hawthorn is lacking, we evaluated the antioxidant and cytotoxic potentials of an extract prepared from leaves and unripe fruits in a variety of cell and cell-free in vitro assays. METHODS: The antioxidant assays measured: (a) its ability to inhibit (i) oxidation of beta-carotene, (ii) 2,2'-azobis(2-amidino-propan) dihydrochloride (AAPH)-induced plasma oxidation and (iii) iron-induced lipid peroxidation in rat liver homogenates; (b) its ability to scavenge the superoxide (O2-) radical; (c) its effects on the enzyme xanthine oxidase (XO) activity; (d) its effect on the redox state of glutathione (GSH) in cultured Hep G2 cells. In addition, we also evaluated the effects of the extract on cell membrane integrity and mitochondrial respiration in cultured Hep G2 cells. RESULTS AND CONCLUSIONS: Water-soluble extracts inhibited (1) oxidation of beta-carotene, (2) AAPH-induced plasma oxidation and (3) Fe(2+)-induced lipid peroxidation in rat liver homogenates. In addition, the extract (4) is an efficient scavenger of the O2- (5) increases intracellular GSH levels and (6) is not cytotoxic. Accordingly, we propose that the therapeutic benefit of Crataegus aronia can be, at least in part, attributed to its effective inhibition of oxidative processes, efficient scavenging of O2- and possible increasing GSH biosynthesis.

Antioxidant activity and cytotoxicity of eight plants used in traditional Arab medicine in Israel.

Ethnopharmacological surveys conducted among herbal practitioners of traditional Arab medicine in Israel and the Palestinian area have revealed a large number of indigenous plant species are used as sources of their herbal therapies. Some of these herbal therapies are used to treat liver disease, jaundice or diabetes, conditions in which oxidative stress is prominent. No laboratory data on the bioactivity of herbal medicines in these settings exist in traditional Arab medicine. We hypothesized that the beneficial effect of these plants might be due to their antioxidant properties. Accordingly, we selected eight plants used to treat these two conditions and assessed their antioxidant potential by measuring their ability to suppress the extent of iron-induced lipid peroxidation in rat liver homogenates and their potential toxicity by evaluating their effects on mitochondrial respiration and cell membrane integrity in cultured PC12 and HepG2 cells. We found that all the extracts can suppress iron-induced lipid peroxidation and are not toxic. Of these extracts, those prepared from Teucrium polium and Pistacia lentiscus were the most effective in suppressing iron-induced lipid peroxidation. Further investigations are now needed to establish the exact mechanism of action and identify the active bio-ingredient(s) of each extract in order to explain their therapeutic efficacy.

Cholemic transgenic mice: a novel animal model to investigate the effects of bile acids.

INTRODUCTION: Laboratory investigations into cholestatic liver disease and the effects of cholemia on organ function are long-standing subjects of scientific enquiry. A widely-used strategy to investigate these topics relies on animal-based research using experimental animal models. Targeted inactivation of the spgp gene, the gene responsible for expressing the bile salt export pump (BSEP) in the hepatocyte canalicular membrane impairs the canalicular secretion of bile salts resulting in systemic cholemia. The results of in vitro experiments have established bile acids as pro-oxidants and the collection of unambiguous in vivo data on the pro-oxidant activity of bile acids in the existing models of cholemia cannot be done. Therefore, we decided to use these genetically modified mice to determine whether this model of cholemia has evidence of extrahepatic or systemic oxidative stress, one of the features of cholestatic liver disease. METHODS: The extent of lipid peroxidation in livers, kidneys, hearts and brains harvested from cholemic homozygous (spgp -/-) mice using the thiobarbituric acid reactive substances (TBARS) assay. The data were compared to equivalent data collected from heterozygous (spgp +/-) and control mice. RESULTS: We found (1) substantial increases in malondialdehyde (MDA) levels in the brains and hearts; (2) a moderate increase in MDA levels in the kidneys; and (3) no change in MDA levels in the livers of the homozygous cholemic mice compared to the control and heterozygous mice. DISCUSSION: The transgenic mouse model of cholemia has an intact enterohepatic circulation and is uncomplicated by the adverse consequences of hepatotoxins or biliary surgery. Hepatocellular injury, as well as plasma and tissue accumulation of bilirubin and other liver-derived compounds are also negligible. Although this preliminary study could not establish a causal relationship between cholemia and oxidative stress, we believe this model is worthy of further investigation to study the impact of short-term and long-term cholemia on diverse physiological and biochemical functions such as trying to establish a causal role for bile acids in the development of oxidative stress in cholestatic liver disease.