Variations in the chemical profile and biological activities of licorice (Glycyrrhiza glabra L.), as influenced by harvest times

This study investigates the variations in the chemical profile, free radical scavenging, antioxidant and gastroprotective activities of licorice extracts (LE) from plants harvested during the months of February to November. Correlations between biological properties and the chemical composition of LE were also investigated. The results showed that the total contents of phenols, flavonoids and tannins in LE varied at different harvest times. Liquiritin and glycyrrhizin, the major components of LE, varied in the range of 28.65–62.80 and 41.84–114.33 mg g^?1, respectively. The relative proportion of glycyrrhizin derivative (3), glabridin (4), glabrene (5) and liquiritigenin derivative (6), varied in the range of 0.88–11.38 %, 1.86–10.03 %, 1.80–18.40 % and 5.53–16.31 %, respectively. These fluctuations correlated positively with changes in the antioxidant and free radical scavenging activities of licorice. In general, the samples from May and November showed the most favorable free radical scavenging and antioxidant effects, whereas the best gastroprotective effect was in May. Liquiritin and glycyrrhizin, the major constituents in the February and May LE, appeared to contribute to the superoxide radical scavenging and gastroprotective effects. Glabridin and glabrene, the compounds with the highest relative proportion in the November LE, accounted for the antioxidant and DPPH scavenging activities of licorice. It is concluded that the chemical profile of licorice quantitatively varied at different harvest times and these fluctuations determined changes in its bioactivities. These data could pave the way to optimize harvesting protocols for licorice in relation with its health-promoting properties.     

响应面设计法优化单葡萄糖醛酸基甘草次酸（GAMG）发酵转化培养基

以甘草酸（dycyfrhizin,GL）为底物,利用产紫青霉（Penicillium purpurogenum Li-3）液态发酵转化单葡萄糖醛酸甘草次酸（GAMG）,采用响应面设计法对初始发酵培养基进行优化。用部分因子分析法研究原始发酵培养基各成分对响应值的显著程度,发现甘草酸（GL）、NaNO3和K2HPO4的质量浓度对发酵产生GAMG的影响显著（P〈0．01）。用中心组合设计确立甘草酸、NaNO3和K2HPO4的适宜质量浓度分别为2．8、3．0和0．8g／L。在优化条件下进行发酵时,GAMG的转化率从75．49％提高到89．11％,比优化前提高了13．62％。     

Effects of natural antioxidant Ginkgo biloba extract (EGB 761) on myocardial ischemia-reperfusion injury

Recently, it was reported that Ginkgo biloba extract (EGb 761), which is known to have antioxidant properties, also has antiarrhythmic effects on cardiac reperfusion-induced arrhythmias. In the present study, effects of EGb 761 on cardiac ischemia-reperfusion injury were investigated from the point of view of recovery of mechanical function as well as the endogenous antioxidant status of ascorbate. Isolated rat hearts were perfused using the Langendorff technique, and 40 min of global ischemia were followed by 20 min of reperfusion. EGb 761 improved cardiac mechanical recovery and suppressed the leakage of lactate dehydrogenase (LDH) during reperfusion. Furthermore, EGb 761 diminished the decrease of myocardial ascorbate content after 40 min of ischemia and 20 min of reperfusion. Interestingly, EGb 761 also suppressed the increase of dehydroascorbate. These results indicate that EGb 761 protects against cardiac ischemia-reperfusion injury and suggest that the protective effects of EGb 761 depend on its antioxidant properties.     

The constituents of licorice (Glycyrrhiza uralensis) differentially suppress nitric oxide production in interleukin-1β-treated hepatocytes

Licorice (Glycyrrhizae radix) is the roots and stolons of Glycyrrhiza uralensis Fischer or Glycyrrhiza glabra Linnaeus in the Japanese Pharmacopoeia. Glycyrrhizae radix has been widely used as a sweetener and a traditional medicine. A Glycyrrhizae radix extract contains many constituents and has antispasmodic, antitussive, anti-ulcer, and anti-inflammatory effects. However, reports comparing the anti-inflammatory effects of these constituents are very few. Here, we purified several constituents from the roots and stolons of G. uralensis and examined and compared their anti-inflammatory effects by monitoring the levels of the inflammatory mediator, nitric oxide (NO), in interleukin (IL)-1β-treated rat hepatocytes. From the G. uralensis extract, we purified the main constituent glycyrrhizin and the constituents that are characteristic of G. uralensis (chalcones and flavanones). These constituents suppressed NO production in IL-1β-treated rat hepatocytes, and isoliquiritigenin showed the greatest suppression activity. Isoliquiritigenin, isoliquiritin, and liquiritigenin significantly decreased both protein and mRNA for the inducible nitric oxide synthase. These constituents reduced the levels of mRNAs encoding tumor necrosis factor α and IL-6. In contrast, although glycyrrhizin is abundant, it showed a 100-fold lower potency in NO suppression. Therefore, both glycyrrhizin and the minor constituents (isoliquiritigenin, isoliquiritin, and liquiritigenin) may be responsible for the anti-inflammatory effects of G. uralensis. It is also implied that these constituents may have a therapeutic potential for inflammatory hepatic disorders.     

Glycyrrhizin and glycyrrhetinic acid directly modulate rat cardiac performance

Root extract of liquorice is traditionally used to treat several diseases. Liquorice-derived constituents present several biological actions. In particular, glycyrrhizin and its aglycone, glycyrrhetinic acid, exhibit well-known cardiovascular properties. The aim of this research was to explore the direct cardiac activity of glycyrrhizin and glycyrrhetinic acid.The effects of synthetic glycyrrhizin and glycyrrhetinic acid were evaluated on the isolated and Langendorff perfused rat heart. The intracellular signaling involved in the effects of the two substances was analyzed on isolated and perfused heart and by Western blotting on cardiac extracts. Under basal conditions, both glycyrrhizin and glycyrrhetinic acid influenced cardiac contractility and relaxation. Glycyrrhizin induced significant positive inotropic and lusitropic effects starting from very low concentrations, while both inotropism and lusitropism were negatively affected by glycyrrhetinic acid. Both substances significantly increased heart rate. Analysis of the signal transduction mechanisms suggested that glycyrrhizin acts through the endothelin receptor type A/phospholipase C axis while glycyrrhetinic acid acts through endothelin receptor type B/Akt/nitric oxide synthase/nitric oxide axis.To our knowledge, these data reveal, for the first time, that both glycyrrhizin and glycyrrhetinic acid directly affect cardiac performance. Additional information on the physiological significance of these substances and their cardiac molecular targets may provide indication on their biomedical application.     

Oral administration of (-)catechin protects against ischemia-reperfusion-induced neuronal death in the gerbil

The effect of ad libitum oral-administration of (-)catechin solution on ischemia-reperfusion-induced cell death of hippocampal CA1 in the gerbil was histologically examined. When (-)catechin solution instead of drinking water was orally administered ad libitum for 2 weeks, dose-dependent protection against neuronal death following by transient ischemia and reperfusion was observed. To evaluate the involvement of reduction of reactive-oxygen-species (ROIs) by the antioxidant activity of (-)catechin in this protection, the superoxide scavenging activity of the brain in catechin-treated gerbils was measured by ESR and spin-trapping using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The superoxide scavenging activities of the brains obtained from catechin-treated gerbils were significantly higher than those of catechin-untreated animals. From these results, it was suggested that orally administered (-)catechin was absorbed, passed through the blood-brain barrier and that delayed neuronal death of hippocampal CA1 after ischemia-reperfusion was prevented due to its antioxidant activities.     

Effect of vitamin E on the response to ischemia-reperfusion of Langendorff heart preparations from hyperthyroid rats

Hyperthyroidism has been reported to decrease heart antioxidant capacity and increase its susceptibility to in vitro oxidative stress. This may affect the heart response to ischemia-reperfusion, a condition that increases free radical production. We compared the functional recovery from in vitro ischemia-reperfusion (Langendorff) of hearts from euthyroid (E), hyperthyroid (H, ten daily intraperitoneal injections of T3, 10 microg/100g body weight), vitamin E-treated (VE, ten daily intramuscular injections, 20 mg/100g body weight) and hyperthyroid vitamin E-treated (HVE) rats. We also determined lipid peroxidation, tissue antioxidant capacity and the tissue capability to face an oxidative stress in vitro. A significant tachycardia was displayed during reperfusion following 20 min ischemia by the hyperthyroid hearts, together with a low recovery of left ventricular developed pressure (LVDP) and left ventricular dP/dt(max). When H hearts were paced at 300 beats/min, the functional recovery (LVDP and dP/dt(max)) was close to 100% and significantly higher than in E paced hearts. At the end of the ischemia-reperfusion protocol, myocardium antioxidant capacity was significantly lower, whereas lipid peroxidation and the susceptibility to in vitro oxidative stress were higher in the T3 treated (H) than in euthyroid rats. The in vitro tachycardic response, the reduction in the antioxidant capacity and the increase in lipid peroxidation were prevented by treatment of hyperthyroid rats with vitamin E (HVE). These results suggest that the tachycardic response to reperfusion following chronic T3 pretreatment was associated with the reduced capability of the heart to face oxidative stresses in hyperthyroidism.     

Elevated semicarbazide-sensitive amine oxidase (SSAO) activity in lung with ischemia-reperfusion injury: protective effect of ischemic preconditioning plus SSAO inhibition

Ischemic preconditioning (IP) has been shown to protect the lung against ischemia-reperfusion (I/R) injury. Although the production of reactive oxygen species (ROS) has been postulated to play a crucial role in I/R injury, the sources of these radicals in I/R and the mechanisms of protection in IP remain unknown. Since it was postulated that deamination of endogenous and exogenous amines by semicarbazide-sensitive amine oxidase (SSAO) in tissue damage leads to the overproduction of hydrogen peroxide (H2O2), we investigated the possible contribution of tissue SSAO to excess ROS generation and lipid peroxidation during I/R and IP of the lung. Male Wistar rats were randomized into 6 groups: control lungs were subjected to 30 min of perfusion in absence and presence of SSAO inhibitor, whereas the lungs of the I/R group were subjected to 2 h of cold ischemia following the 30 min of perfusion in absence and presence of SSAO inhibitor. IP was performed by two cycles of 5 min ischemia followed by 5 min of reperfusion prior to 2 h of hypothermic ischemia in absence and presence of SSAO inhibitor. Lipid peroxidation, reduced (GSH) and oxidized (GSSG) glutathione levels, antioxidant enzyme activities, SSAO activity, and H2O2 release were determined in tissue samples of the study groups. Lipid peroxidation, glutathione disulfide (GSSG) content, SSAO activity and H2O2 release were increased in the I/R group, whereas GSH content, GSH/GSSG ratio and antioxidant enzyme activities were decreased. SSAO activity, H2O2 release, GSSG content and lipid peroxidation were markedly decreased in the IP group, whereas GSH content, GSH/GSSG ratio and antioxidant enzyme activities were significantly increased. SSAO activity was found to be positively correlated with H2O2 production in all study groups. Increased lipid peroxidation, SSAO activity, GSSG and H2O2 contents as well as decreased GSH and antioxidant enzyme levels in I/R returned to their basal levels when IP and SSAO inhibition were applied together. The present study suggests that application of IP and SSAO inhibition together may be more effective than IP alone against I/R injury in the lung.     

Extract from Clerodendron colebrookianum Walp protects rat heart against oxidative stress induced by ischemic-reperfusion injury (IRI)

Reactive oxygen species (ROS) have pathogenic effects on ischemic-reperfusion injury of heart. Hence, it is important to identify natural antioxidative agents to mitigate such effects. Recently, it has been reported that Clerodendron colebrookianum (CC) leaf extract has antioxidant and hypolipidemic effects in experimental animals. The aim of this study was to examine whether acute treatment with CC extract offers protection against ischemic-reperfusion injury (IRI) and IRI-induced changes in endogenous antioxidant enzyme activities of rat heart. Isolated rat hearts were perfused using the Langendorff's technique, and 20 min of global ischemia was followed by 40 min of reperfusion. Lipid peroxidation after the ischemic-reperfusion episode was significantly reduced in the CC extract-treated heart compared to the control group and suppressed the leakage of lactate dehydrogenase (LDH) during reperfusion. Moreover, CC extract diminished the depletion of myocardial antioxidant enzymes (SOD, Catalase, GSH and GPx) after ischemia-reperfusion. Furthermore, IRI-induced cellular damage was significantly less in CC extract treated myocytes. These results indicate that CC leaf extract protects against oxidative stress and cellular injury associated with ischemic-reperfusion injury of rat heart and suggests that the protective effects of CC extract depend on its antioxidant properties.     

GC-MS-employed phytochemical characterization,synergistic antioxidant,and cytotoxic potential of Triphala methanol extract at non-equivalent ratios of its constituents

Triphala is a famous triherbal drug, comprising three herb fruits, including Terminalia chebula (Haritaki), Terminalia bellirica (Bibhitaki), and Phyllanthus emblica (Amalaki). It is enriched with vitamin C, polyphenols, flavonoids, sterols, saponins, etc., and is well-documented for its potent antioxidant, anticancer, chemoprotective, antimicrobial, and anti-inflammatory effects. This research was conducted to evaluate the synergistic antioxidative and cytotoxic potential of mixtures of the individual constituents of Triphala at their nonequivalent ratios along with the chemical characterization of individual constituents of Triphala to identify and quantify individual compounds. The antioxidative potential was measured using total antioxidant capacity (TAC), DPPH free radical scavenging assay, and total phenolic content (TPC) tests. The cytotoxic potential was assessed on brain cancer cells (N4X4) using MTT assay, and phytochemical characterization was performed by GS-MS analysis. Nonequivalent ratios of Triphala constituents exhibited significantly higher synergistic antioxidant and cytotoxic potential than the equivalent ratios of them. Moreover, the nonequivalent ratio where the quantity of Amalaki was doubled than the other two constituents showed the highest synergistic antioxidant and cytotoxic effect. GC-MS analysis of individual constituents of Triphala identified and quantified the presence of a wide array of compounds, and fatty acid, fatty acid ester, triterpene, and aminoglycoside remained the predominant class of compounds. Thus, it can be inferred that the observed bioactivities can be attributed to the phytocompounds characterized and extracts at the nonequivalent ratio of Triphala constituents where Amalaki is doubled can be more effective in treating oxidative degenerative diseases and glioblastoma.     

The influence of N-[imino(1-piperidinyl)methyl]guanidine and N-[imino(4-morpholinyl)methyl]guanidine on citrate content,activities of aconitase and citrate synthase in rats exposed to cerebral ischemia-reperfusion

The effect of guanidine derivatives on citrate content and activity of aconitate hydratase and citrate synthase have been investigated in rats with cerebral ischemia-reperfusion. Administration of N-[imino(1-piperidinyl)methyl]guanidine and N-[imino(4-morpholinyl)methyl]guanidine resulted in changes of specific activities of aconitase and citrate synthase towards control values. Under these conditions the citrate level considerably decreased versus rats with untreated ishemia-reperfusion. Administration of these biguanidines compounds also decreased the degree of DNA fragmentation, which was markedly increased in rats with ischemia-reperfusion. The dose-dependent effects of guanidine derivatives suggest that they exhibit not only antioxidant but also prooxidant effects.     

Dual inhibitory effect of Glycyrrhiza glabra (GutGard™) on COX and LOX products

Glycyrrhiza glabra and its phytoconstituents have been known to possess widespread pharmacological properties as an anti-inflammatory, anti-viral, antitumour and hepatoprotective drug. In this study, we examined the inhibitory potential of extract of G. glabra (GutGard™) root and its phytoconstituents (glabridin, glycyrrhizin, and isoliquiritigenin) on both cyclooxygenase (COX) and lipoxygenase (LOX) products in order to understand the mechanism of its anti-inflammatory action. Inhibitory effect of GutGard™ and its phytoconstituents on lipopolysaccharide (LPS) induced prostaglandin E₂ (PGE₂), calcimycin (A23187) induced thromboxane (TXB₂), and leukotriene (LTB₄) release was studied using murine macrophages (J774A.1) and human neutrophil (HL-60) cells. Results revealed that, G. glabra and glabridin significantly inhibited PGE₂, TXB₂ (COX) and LTB₄ (LOX), while, isoliquiritigenin exerted inhibitory effect only against COX products but failed to suppress LOX product. However, glycyrrhizin at the tested concentrations failed to exhibit inhibitory effect on both COX and LOX products. Here, we report for the first time that G. glabra (almost devoid of glycyrrhizin) exhibits anti-inflammatory property likely through the inhibition of PGE₂, TXB₂ and LTB₄ in mammalian cell assay system, which could be influenced in part by glabridin and isoliquiritigenin.     

Ischemia-reperfusion alters gene expression of Na+-K+ ATPase isoforms in rat heart

The present study investigated whether oxidative stress plays a role in ischemia-reperfusion-induced changes in cardiac gene expression of Na(+)-K(+) ATPase isoforms. The levels of mRNA for Na(+)-K(+) ATPase isoforms were assessed in the isolated rat heart subjected to global ischemia (30 min) followed by reperfusion (60 min) in the presence or absence of superoxide dismutase (5 x 10(4)U/L) plus catalase (7.5 x 10(4)U/L), an antioxidant mixture. The levels of mRNA for the alpha(2), alpha(3), and beta(1) isoforms of Na(+)-K(+) ATPase were significantly reduced in the ischemia-reperfusion hearts, unlike the alpha(1) isoform. Pretreatment with superoxide dismutase+catalase preserved the ischemia-reperfusion-induced changes in alpha(2), alpha(3), and beta(1) isoform mRNA levels of the Na(+)-K(+) ATPase, whereas the alpha(1) mRNA levels were unaffected. In order to test if oxidative stress produced effects similar to those seen with ischemia-reperfusion, hearts were perfused with an oxidant, H(2)O(2) (300 microM), or a free radical generator, xanthine (2mM) plus xanthine oxidase (0.03 U/ml) for 20 min. Perfusion of hearts with H(2)O(2) or xanthine/xanthine oxidase depressed the alpha(2), alpha(3), and beta(1) isoform mRNA levels of the Na(+)-K(+) ATPase, but had lesser effects on alpha(1) mRNA levels. These results indicate that Na(+)-K(+) ATPase isoform gene expression is altered differentially in the ischemia-reperfusion hearts and that antioxidant treatment appears to attenuate these changes. It is suggested that alterations in Na(+)-K(+) ATPase isoform gene expression by ischemia-reperfusion may be mediated by oxidative stress.     

Exploiting the anti-inflammatory properties of olive (Olea europaea) in the sustainable production of functional food and neutraceuticals

Olive oil is an important lipid source of the Mediterranean diet which has been associated with lower incidence of cardiovascular diseases whereas olive pomace (OP), a natural by-product of olive oil production, has been found to contain micro constituents with antioxidant, antithrombotic and antiatherogenic activities. The evaluation of OP in order to produce sustainable functional food and neutraceuticals has been the subject of research over the last years. All recent data, focusing on the anti-inflammatory properties of olive oil derived from olive (Olea europaea) and OP along with the potential production of sustainable functional food and neutraceuticals, are presented in this review.     

Protective activity of (-)-epicatechin 3-O-gallate against peroxynitrite-mediated renal damage

The protective effect of ( -)-epicatechin 3- O -gallate (ECg) against peroxynitrite (ONOO -)-mediated damage was examined using an animal model and a cell culture system. In rats subjected to lipopolysaccharide (LPS) administration plus ischemia-reperfusion, the plasma 3-nitrotyrosine level, an indicator of ONOO - production in vivo , was elevated, whereas it declined significantly and dose-dependently after the oral administration of ECg at doses of 10 and 20 μmoles/kg body weight/day for 20 days prior to the process. Moreover, oral administration of ECg significantly enhanced the activities of the antioxidant enzymes, superoxide dismutase, catalase and glutathione peroxidase, and the antioxidant glutathione, showing enhancement of the biological defense system against the damage induced by ONOO -. In addition, the significant increase in the renal mitochondrial thiobarbituric acid-reactive substance level of LPS and ischemic-reperfused control rats was attenuated in rats given ECg. Furthermore, the elevations in the plasma urea nitrogen and creatinine (Cr) levels and the urinary methylguanidine/Cr ratio induced by the procedure were attenuated markedly after oral administration of ECg, implying amelioration of renal impairment. The addition of ECg (25 or 125 μM) prior to 3-morpholinosydnonimine (SIN-1, 800 μM) exposure reduced ONOO - formation and increased the viability of cultured renal epithelial (LLC-PK 1 ) cells in a dose-dependent manner. In particular, ECg inhibited ONOO --mediated apoptotic cell death, which was confirmed by decreases in the DNA fragmentation rate and the presence of apoptotic morphological changes, i.e. small nuclei and nuclear fragmentation. Furthermore, adding ECg before SIN-1 treatment regulated the cell cycle by enhancing G 2 /M phase arrest. This study provides evidence that ECg has protective activity against the renal damage induced by excessive ONOO - in cellular and in vivo systems.     

Cyclooxygenase 1-dependent production of F2-isoprostane and changes in redox status during warm renal ischemia-reperfusion

The detrimental role of oxidative stress has been widely described in tissue damage caused by ischemia-reperfusion. A nonenzymatic, reactive oxygen species-related pathway has been suggested to produce 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)), an epimer of prostaglandin F(2alpha) (PGF(2alpha)), which has been proposed as an indicator of oxidative stress. Using an in vivo ischemia-reperfusion model in rat kidneys, we investigated intrarenal accumulation of 8-iso-PGF(2alpha) and PGF(2alpha). Both prostanoids accumulated in the ischemic kidney and disappeared upon reperfusion. In addition, a nonselective (acetylsalicylic acid) or selective cyclooxygenase (COX) 1 inhibitor (SC-560) completely abrogated the 8-iso-PGF(2alpha) and PGF(2alpha) formation in kidneys subjected to ischemia. COX2 inhibition had no effect on the production of these prostanoids. Therefore the two metabolites of arachidonic acid seemed to be produced via an enzymatic COX1-dependent pathway. Neither COX overexpression nor COX activation was detected. We also investigated renal glutathione, which is considered to be the major thiol-disulfide redox buffer of the tissue. Total and oxidized glutathione was decreased during the ischemic period, whereas no further decrease was seen for up to 60 min of reperfusion. These data demonstrate that a dramatic decrease in antioxidant defense was initiated during warm renal ischemia, whereas the 8-iso-PGF(2alpha) was related only to arachidonate conversion by COX1.     

Coffee constituents as modulators of Nrf2 nuclear translocation and ARE (EpRE)-dependent gene expression

Oxidative cellular stress initiates Nrf2 translocation into the nucleus, thus inducing antioxidant response element (ARE)-mediated expression of Phase II enzymes involved in detoxification and antioxidant defence. We investigated whether coffee extracts (CEs) of different proveniences and selected constituents have an impact on the Nrf2/ARE pathway in human colon carcinoma cells (HT29). Assessed as increased nuclear Nrf2 protein, Nrf2 nuclear translocation was modulated by different CEs as observed by Western blot analysis. In addition to the known Nrf2 activator 5-O-caffeoylquinic acid (CGA), pyridinium derivatives like the N-methylpyridinium ion (NMP) were identified as potent activators of Nrf2 nuclear translocation and ARE-dependent gene expression of selected antioxidative Phase II enzymes in HT29. Thereby, the substitution pattern at the pyridinium core structure determined the impact on Nrf2-signalling. In contrast, trigonelline was found to interfere with Nrf2 activation, effectively suppressing the NMP-mediated induction of Nrf2/ARE-dependent gene expression. In conclusion, several coffee constituents, partly already present in the raw material as well as those generated during the roasting process, contribute to the Nrf2-translocating properties of consumer-relevant coffee. A fine tuning in the degradation/formation of activating and deactivating constituents of the Nrf2/ARE pathway during the roasting process appears to be critical for the chemopreventive properties of the final coffee product.     

Separation and isolation methods for analysis of the active principles of Sho-saiko-to (SST) oriental medicine

Sho-saiko-to (SST) was introduced into Japan as an oriental classical medicine from China approximately 1500 years ago, and it is currently the most representative Kampo medicine (traditional Japanese medicine). SST is manufactured in Japan as an ethical drug on a modern industrial scale in which the quality of ingredients is standardized with Good Manufacturing Practices (GMP) regulation. SST is widely used for the treatment of chronic hepatitis. Experimental and clinical studies including multi-center, placebo-controlled, double-blind studies have demonstrated the various pharmacological effects of SST. SST is prepared from the hot water extraction of seven raw materials, therefore many kinds of constituents are included. Three-dimensional (3D) HPLC analysis is useful for obtaining many kinds of constituents, especially low molecular ultraviolet (UV) quenching compounds, contained in SST as well as its fractions. Fingerprint pattern provided by 3D HPLC analysis makes possible to identify the overall-viewing of SST. Databases of UV spectra of the components of medicinal herbs obtained by reversed-phase (RP) HPLC using a photodiode array (PDA) and fingerprint patterns of crude drugs made by 3D HPLC analysis facilitate the identification, analysis and quality of herbal drugs. Studies using both PDA HPLC and an amino acid analysis with a fluorometric detector have found that SST contains fifteen major low molecular compounds (i.e. baicalin, wogonin-7-O-glucuronide, liquiritin, their three aglycons, liquiritin apioside, glycyrrhizin, saikosaponin b1, saikosaponin b2, ginsenoside Rg1, ginsenoside Rb1, (6)-gingerol, (6)-shogaol and arginine). These compounds have various pharmacological actions, and are assumed to be responsible, at least partly, for the pharmacological effects of SST. Although there have only been a few investigations on high molecular compounds with pharmacological actions contained in SST, several kinds of polysaccharides have been isolated from constituent herbs of SST. This review paper summarizes analytical methods of separation, isolation and identification of compounds with biological activities from SST, which is a mixture drug of medicinal herbs. Accordingly, this paper would not focus on methods of separation, isolation and analysis of particular compounds from each constituent herb of SST.     

Mitochondrial ABC transporters function: the role of ABCB10 (ABC-me) as a novel player in cellular handling of reactive oxygen species

Mitochondria are one of the major sources of reactive oxygen species (ROS) in the cell. When exceeding the capacity of antioxidant mechanisms, ROS production may lead to different pathologies, such as ischemia-reperfusion injury, neurodegeneration, anemia and ageing. As a consequence of the endosymbiotic origin of mitochondria, eukaryotic cells have developed different transport mechanisms that coordinate mitochondrial function with other cellular compartments. Four mitochondrial ATP-binding cassette (ABC) transporters have been described to date in mammals: ABCB6, ABCB8, ABCB7 and ABCB10. ABCB10 is located in the inner mitochondrial membrane forming homodimers, with the ATP binding domain facing the mitochondrial matrix. ABCB10 expression is highly induced during erythroid differentiation and its overexpression increases hemoglobin synthesis in erythroid cells. However, ABCB10 is also expressed in nonerythroid tissues, suggesting a role not directly related to hemoglobin synthesis. Recent evidence points toward ABCB10 as an important player in the protection from oxidative stress in mammals. In this regard, ABCB10 is required for normal erythropoiesis and cardiac recovery after ischemia-reperfusion, processes intimately related to mitochondrial ROS generation. Here, we review the current knowledge on mitochondrial ABC transporters and ABCB10 and discuss the potential mechanisms by which ABCB10 and its transport activity may regulate oxidative stress. We discuss ABCB10 as a potential therapeutic target for diseases in which increased mitochondrial ROS production and oxidative stress play a major role.     

Licorice compounds glycyrrhizin and 18beta-glycyrrhetinic acid are potent modulators of bile acid-induced cytotoxicity in rat hepatocytes

The accumulation of hydrophobic bile acids results in cholestatic liver injury by increasing oxidative stress, mitochondrial dysfunction, and activation of cell signaling pathways. Licorice root and its constituents have been utilized as antihepatotoxic agents. The purpose of this study was to evaluate the potential modulation by a primary component of licorice root, glycyrrhizin (GL), and its metabolite, 18beta-glycyrrhetinic acid (GA), in a hepatocyte model of cholestatic liver injury. Preincubation of fresh rat hepatocyte suspensions with GL or GA reduced glycochenodeoxycholic acid (GCDC)-dependent reactive oxygen species generation, with GA more potent than GL. Interestingly, GL and GA had opposing effects toward GCDC-induced cytotoxicity; GA prevented both necrosis and apoptosis, whereas GL enhanced apoptosis. GCDC promoted activation of caspase 10, caspase 3, and PARP; all were inhibited by GA but not GL. Induction of apoptosis by GCDC was also associated with activation of JNK, which was prevented by GA. Activation of caspase 9 and dissipation of mitochondrial membrane potential were prevented by GA but not GL. In liver mitochondrial studies, GL and GA were both potent inhibitors of the mitochondrial permeability transition, reactive oxygen species generation, and cytochrome c release at submicromolar concentrations. Results from this study suggest that GL exhibits pro-apoptotic properties, whereas GA is a potent inhibitor of bile acid-induced apoptosis and necrosis in a manner consistent with its antioxidative effect.