Malate transporters play a critical role in aluminum (Al) tolerance responses for some plant species, such as Arabidopsis (Arabidopsis thaliana). Here, we further characterize AtALMT1, an Arabidopsis aluminum-activated malate transporter, to clarify its specific role in malate release and Al stress responses. Malate excretion from the roots of accession Columbia was sharply induced by Al, which is concomitant with the induction of AtALMT1 gene expression. The malate release was specific for Al among rhizotoxic stressors, namely cadmium, copper, erbium, lanthanum, sodium, and low pH, which accounts for the specific sensitivity of a null mutant to Al stress. Al-specific malate excretion can be explained by a combined regulation of AtALMT1 expression and activation of AtALMT1 protein, which is specific for Al. Although low pH treatment slightly induced gene expression, other treatments did not. In addition, malate excretion in Al-activated seedlings was rapidly stopped by removing Al from the solution. Other rhizotoxic stressors were not effective in maintaining malate release. Protein kinase and phosphatase inhibitor studies indicated that reversible phosphorylation was important for the transcriptional and posttranslational regulation of AtALMT1. AtALMT1 promoter-β-glucuronidase fusion lines revealed that AtALMT1 has restricted expression within the root, such that unnecessary carbon loss is likely minimized. Lastly, a natural nonsense mutation allele of AtALMT1 was identified from the Al-hypersensitive natural accession Warschau-1.

Epidemiological studies suggest that the consumption of flavonoid-rich diets decreases the risk of cardiovascular diseases. However, the target sites of flavonoids underlying the protective mechanism in vivo are not known. Quercetin represents antioxidative/anti-inflammatory flavonoids widely distributed in the human diet. In this study, we raised a novel monoclonal antibody 14A2 targeting the quercetin-3-glucuronide (Q3GA), a major antioxidative quercetin metabolite in human plasma, and found that the activated macrophage might be a potential target of dietary flavonoids in the aorta. Immunohistochemical studies with monoclonal antibody 14A2 demonstrated that the positive staining specifically accumulates in human atherosclerotic lesions, but not in the normal aorta, and that the intense staining was primarily associated with the macrophage-derived foam cells. In vitro experiments with murine macrophage cell lines showed that the Q3GA was significantly taken up and deconjugated into the much more active aglycone, a part of which was further converted to the methylated form, in the activated macrophages. In addition, the mRNA expression of the class A scavenger receptor and CD36, which play an important role for the formation of foam cells, was suppressed by the treatment of Q3GA. These results suggest that injured/inflamed arteries with activated macrophages are the potential targets of the metabolites of dietary quercetin. Our data provide a new insight into the bioavailability of dietary flavonoids and the mechanism for the prevention of cardiovascular diseases.Flavonoids are widely distributed in plant foods and beverages and therefore are regularly ingested with the human diet. In 1936, Rusznyak and Szent-Gyoygi (1) found citrus flavonoids reduced capillary fragility and permeability in blood vessels. Thereafter, a large number of biological activities of flavonoids have been described which overall are believed to be beneficial for good health. Quercetin (3,3Ј,4Ј,5,7-pentahydroxyflavone) is a prime example of such a flavonoid and is bound to sugars in foods, mainly as ␤-glycosides. The quercetin glycosides occur in broccoli, apples, and especially in onions, with an abundance as high as 0.25-0.5 g/kg (2). The average daily intake of the flavonoids subclasses in The Netherlands is 23 mg (calculated as aglycones) of which quercetin supplies 16 mg (3). Epidemiological evidence links diets rich in quercetin with decreased incidence of cardiovascular and neoplastic diseases (4 -9). Because oxidative stress has been implicated in the pathogenesis of these diseases, the bioavailability of quercetin and other flavonoids has been investigated in relation to their antioxidant activities in vivo. The antioxidant potential of quercetin is related to the number and position of the free hydroxyl groups in the molecule (10); therefore, the regioselectivity of conjugation of the hydroxyl groups can be expected to modulate the biological activity of quercetin. Upon ingestion with the diet, quercetin glycosides are rapidly ...

In recent years, depression has become recognized as a major public health problem. It is estimated that in the US approximately 20% of the population has some depressive symptoms, and around 2-5% are thought to suffer from severe forms of depression.1) Understanding how to prevent and treat depression is therefore an urgent subject. Although the mechanism provoking depression has not been clearly elucidated, the main trigger is known to be exposure to chronic stress.2,3) Many types of antidepressant drugs such as tricyclic antidepressants, and selective serotonin reuptake inhibitors (SSRI), as well as antidepressant herbal medicines like St. John's wort are used to treat depression. However, most of the synthetic drugs are not without side effects. 4)Furthermore disturbance of the drug metabolizing enzyme systems were revealed with St. John's wort, 5) and thus, the search for a new antidepressant herb without side effects is deemed important.The Ginkgo biloba tree has been used as a traditional Chinese herbal medicine for thousands of years.6) Several research groups have shown that extracts from the green leaves of the G. biloba tree (EGB) have diverse effects on improvement of mood and cognitive performance, protection of memory deficits and central nervous system (CNS) disorders, and alleviation of the symptoms of mild to moderate Alzheimer-type dementia.7-12) Until now, no antidepressant effect of EGB has yet been revealed. EGB is thought to possess anti-stress properties, 13) and is safe to use without distinct side effects. 8,14) EGB might be a useful option for the prevention and treatment for stress-induced disorders such as depression. In the present study, we evaluated the antidepressant effect of EGB using two behavioral models for screening antidepressants, the forced swimming test (FST) in rats and tail suspension test (TST) in mice. MATERIALS AND METHODS ChemicalsThe EGB used in the present study was Ginkgolon-24 from Tokiwa Phytochemical Co., Ltd. (Chiba, Japan), which was 75% ethanol extracts from the leaves of Japanese G. biloba tree. This product contains 25.5% of flavonoid glycosides, including more than 8.2% quercetin glycosides, more than 6.4% kaempferol glycosides, 1.6% methylmyricetin glycosides and 1.3% isorhamnetin glycosides, and 6.5% of terpenoids in the form of 2.98% bilobalide, 1.59% ginkgolide A, 1.16% ginkgolide B, and 0.75% ginkgolide C. The antidepressant drug imipramine (hydrochloride form) was purchased from Sigma-Aldrich Co. (St. Louis, MO, U.S.A.).Animals Male CD rats (240-260 g; Charles River Japan, Inc., Yokohama, Japan) and male C57BL/6J mice (22-26 g; SLC, Inc., Hamamatsu, Japan) were used in the FST and TST, respectively. All animals were housed in a controlled room (temperature, 25Ϯ1°C; humidity, 45-50%; light-dark cycle, 12 h each) with free access to laboratory chow (MF; Oriental Yeast Co., Ltd., Tokyo, Japan) and tap water. Rodents were divided randomly into control and experimental groups. This study was performed according to the guidelines for the care and use of...

The bioavailability of polyphenols in human and rodents has been discussed regarding their biological activity. We found different metabolite profiles of quercetin in rat plasma between two administration procedures. A single intragastric administration (50 mg/kg) resulted in the appearance of a variety of metabolites in the plasma, whereas only a major fraction was detected by free access (1% quercetin). The methylated/non-methylated metabolites ratio was much higher in the free access group. Mass spectrometric analyses showed that the fraction from free access contained highly conjugated quercetin metabolites such as sulfo-glucuronides of quercetin and methylquercetin. The metabolite profile of human plasma after an intake of onion was similar to that with intragastric administration in rats. In vitro oxidation of human low-density lipoprotein showed that methylation of the catechol moiety of quercetin significantly attenuated the antioxidative activity. These results might provide information about the bioavailability of quercetin when conducting animal experiments.

Bovine colostrum is a rich source of tissue repair and growth factors, and inhibits gastrointestinal injury induced by the side effects of nonsteroidal antiinflammatory drugs (NSAID), such as indomethacin. Nonsteroidal antiinflammatory drugs are drugs with analgesic and antipyretic effects, but in higher doses they have inflammatory effects. The pathogenesis of small intestinal damage caused by NSAID is unclear. The present study was performed to investigate the antiinflammatory effects of skimmed, sterilized, and concentrated bovine late colostrum on intestinal injury induced by side effects of NSAID, and then to identify the active ingredient in the colostrum for intestinal tissue. In Japan, the sale of bovine colostrum within 5 d after parturition is prohibited by law. Therefore, we focused on bovine late colostrum obtained from healthy lactating cows 6 to 7 d after parturition. Proliferation of small intestine epithelial cells was stimulated in mice fed the colostrum for 1 wk. With regard to indomethacin-induced enteropathy, both prefeeding and postfeeding with colostrum facilitated growth of the intestinal villi, indicating preventive and healing effects. Furthermore, to identify the active ingredient in the colostrum responsible for this effect, the casein and whey fractions were prepared from the colostrum and fed to normal mice. Only the colostrum casein fraction stimulated intestinal villus elongation, whereas the whey fraction and mature milk casein showed no such effect. Taken together, these observations indicate that the skimmed, sterilized, and concentrated bovine late colostrum, especially the casein fraction, could be used to treat the injurious effects of NSAID in the intestine and could be effective for treatment of other ulcerative conditions in the bowel, suggesting that the colostrum has therapeutic potential for intestinal inflammation.

We developed and validated a RIA for measuring serum activin A. The least detectable value of this assay was 0

The frequency of HLA-B5 (66%, n = 38) in Japanese patients with Takayasu's disease was significantly higher than in controls (32%, n = 160). The level of significance was x2 = 13.53, P less than 0.0005 and corrected P less than 0.009.

The effect of OP-41483, a stable prostacyclin (PGI2) analog, on ischemic acute renal failure (ARF) was investigated in dogs. Administration of OP-41483 for three days after ischemia significantly increased renal cortical blood flow (RCBF) when compared with dogs treated with the saline vehicle. In the OP-41483-treated group, serum creatinine levels remained relatively low during postoperative days 1-3 and mean survival time was prolonged. Injection of a silicone rubber vascular casting compound (Microfil) revealed increased numbers of visible renal cortical glomeruli and microvessels compared to the saline vehicle group. Histologic sections showed only very limited tubular necrosis, whereas sections of kidneys treated with saline showed extensive tubular necrosis. In conclusion, this stable prostacyclin analog provided a significant degree of protection for the kidneys from ischemic injury and may be useful in a clinical setting.