A review of plants used in the treatment of liver disease: part two.
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Botanical medicines have been used traditionally by herbalists and indigenous healers worldwide for the prevention and treatment of liver disease. Clinical research in this century has confirmed the efficacy of several plants in the treatment of liver disease, while basic scientific research has uncovered the mechanisms by which some plants provide their therapeutic effects. This article is Part Two in a review of botanicals used in the treatment of liver disease. Curcuma longa (turmeric), Camellia sinensis (green tea), and Glycyrrhiza glabra (licorice) are reviewed in this installment. Silybum marianum (milk thistle) and Picrorhiza kurroa (kutkin) were reviewed in Part One. (+info)
Induction of isoflavonoid and retrochalcone branches of the flavonoid pathway in cultured Glycyrrhiza echinata cells treated with yeast extract.
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Yeast extract-treated suspension cultures of a new cell line, AK-1, of Glycyrrhiza echinata were induced to produce an isoflavonoid phytoalexin (medicarpin) and metabolites of retrochalcone/flavone pathway (echinatin, licodione, and 7,4'-dihydroxyflavone). From these cells, putative full-length cDNAs encoding cytochrome P450s, (2S)-flavanone 2-hydroxylase and isoflavone 2'-hydroxylase, were cloned. (+info)
Cloning and functional expression of a cytochrome P450 cDNA encoding 2-hydroxyisoflavanone synthase involved in biosynthesis of the isoflavonoid skeleton in licorice.
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Isoflavonoids are distributed predominantly in leguminous plants and play critical roles in plant physiology. A cytochrome P450 (P450), 2-hydroxyisoflavanone synthase, is the key enzyme in their biosynthesis. In cultured licorice (Glycyrrhiza echinata L., Fabaceae) cells, the production of both an isoflavonoid-derived phytoalexin (medicarpin) and a retrochalcone (echinatin) is rapidly induced upon elicitation. In this study, we obtained a full-length P450 cDNA, CYP Ge-8 (CYP93C2), from the cDNA library of elicited G. echinata cells. When the flavanones liquiritigenin and naringenin were incubated with the recombinant yeast microsome expressing CYP93C2, major products emerged and were readily converted to the isoflavones daidzein and genistein by acid treatment. The chemical structures of the products from liquiritigenin (2-hydroxyisoflavanone and isoflavone) were confirmed by mass spectrometry. CYP93C2 was thus shown to encode 2-hydroxyisoflavanone synthase, which catalyzes the hydroxylation associated with 1,2-aryl migration of flavanones. Northern-blot analysis revealed that transcripts of CYP93C2, in addition to those of other P450s involved in phenylpropanoid/flavonoid pathways, transiently accumulate upon elicitation. (+info)
Free radicals in licorice-flavored sweets can Be detected noninvasively using low frequency electron paramagnetic resonance after oral administration to mice.
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The observation of the fate of free radicals coming from food after oral administration could be important in evaluating their reactivity in vivo. The aim of this study was to demonstrate that it is feasible to detect directly in vivo free radicals coming from food with the use of low frequency electron paramagnetic resonance (EPR) spectroscopy. Because polyphenols are easily oxidized into stable radicals, we assumed that these radicals could be detected in food. We chose licorice, which contains several types of polyphenols. The presence of free radicals was demonstrated in licorice-flavored sweets. Using low frequency EPR spectroscopy, we detected these free radicals directly and noninvasively after oral administration to mice. These radicals were rather stable in the guts of the mice. This study is the first report demonstrating noninvasively the presence of free radicals in vivo coming from food. (+info)
Turkish pepper (extra hot).
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A 38 year old female office worker was admitted with a newly discovered blood pressure of 250/110 mm Hg. Evaluation for secondary forms of hypertension was negative and treatment was begun. Sodium excretion was markedly reduced, plasma aldosterone was normal, and plasma renin activity was low. Therefore, presence of an aldosterone-like activity was suspected. Eventually, the patient confessed to abusing "Turkish Pepper", a brand of Scandinavian liquorice candies and "Fisherman's Friend", another brand of liquorice candies, concurrently. After eliminating liquorice from her diet, the hypertension disappeared thus allowing her antihypertensive treatment to be stopped. (+info)
Tyrosinase inhibitory activity of Bangladeshi indigenous medicinal plants.
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The tyrosinase-inhibitory activity of 15 kinds of Bangladeshi medicinal plants was evaluated. Methanol extracts were prepared for screening tests, and other kinds of extracts were also studied for those with high activity. Swertia chirata, Piper nigrum, Glycyrrhiza glabra, Piper longam and Ocimum americanum were screened as highly inhibiting samples. Methanol was found to be the most efficient solvent for extracting the active compounds. The 50% tyrosinase-inhibitory concentration of the Glycyrrhiza glabra methanol extract was 21.2 microg/ml. (+info)
Aldosterone receptor antagonism normalizes vascular function in liquorice-induced hypertension.
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The enzyme 11beta-hydroxysteroid dehydrogenase (11beta-HSD2) provides mineralocorticoid receptor specificity for aldosterone by metabolizing glucocorticoids to their receptor-inactive 11-dehydro derivatives. The present study investigated the effects of the aldosterone receptor antagonists spironolactone and eplerenone on endothelial function in liquorice-induced hypertension. Glycyrrhizic acid (GA), a recognized inhibitor of 11beta-HSD2, was supplemented to the drinking water (3 g/L) of Wistar-Kyoto rats over a period of 21 days. From days 8 to 21, spironolactone (5.8+/-0.6 mg. kg(-1). d(-1)), eplerenone (182+/-13 mg. kg(-1). d(-1)), or placebo was added to the chow (n=7 animals per group). Endothelium-dependent or -independent vascular function was assessed as the relaxation of preconstricted aortic rings to acetylcholine or sodium nitroprusside, respectively. In addition, aortic endothelial nitric oxide synthase (eNOS) protein content, nitrate tissue levels, and endothelin-1 (ET-1) protein levels were determined. GA increased systolic blood pressure from 142+/-8 to 185+/-9 mm Hg (P<0.01). In the GA group, endothelium-dependent relaxation was impaired compared with that in controls (73+/-6% versus 99+/-5%), whereas endothelium-independent relaxation remained unchanged. In the aortas of 11beta-HSD2-deficient rats, eNOS protein content and nitrate tissue levels decreased (1114+/-128 versus 518+/-77 microgram/g protein, P<0.05). In contrast, aortic ET-1 protein levels were enhanced by GA (308+/-38 versus 497+/-47 pg/mg tissue, P<0.05). Both spironolactone and eplerenone normalized blood pressure in animals on GA (142+/-9 and 143+/-9 mm Hg, respectively, versus 189+/-8 mm Hg in the placebo group; P<0.01), restored endothelium-dependent relaxation (96+/-3% and 97+/-3%, respectively, P<0.01 versus placebo), blunted the decrease in vascular eNOS protein content and nitrate tissue levels, and normalized vascular ET-1 levels. This is the first study to demonstrate that aldosterone receptor antagonism normalizes blood pressure, prevents upregulation of vascular ET-1, restores NO-mediated endothelial dysfunction, and thus, may advance as a novel and specific therapeutic approach in 11beta-HSD2-deficient hypertension. (+info)
Birth outcome in relation to licorice consumption during pregnancy.
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A role for glucocorticoids is suspected in the etiology of low birth weight. The authors tested whether maternal consumption of glycyrrhizin (an inhibitor of cortisol metabolism) in licorice affects birth weight in humans. A sample of 1,049 Finnish women and their healthy singleton infants was studied in 1998. Glycyrrhizin intake was calculated from detailed questionnaires on licorice consumption. Glycyrrhizin exposure was grouped into three levels: low (<250 mg/week; n = 751), moderate (250-499 mg/week; n = 145), and heavy (> or =500 mg/week; n = 110). Birth weight and gestational age (from ultrasound measurements) were obtained from hospital records. Babies with heavy exposure to glycyrrhizin were not significantly lighter at birth, but they were significantly more likely to be born earlier: The odds ratio for being born before 38 weeks' gestation was 2.5 (95% confidence interval: 1.1, 5.5; p = 0.03). Although the effect of heavy glycyrrhizin intake on mean duration of gestation was small (2.52 days) when expressed as an effect on the mean, this shift to the left of the distribution of duration of gestation was sufficient to double the risk of being born before 38 weeks. The association remained in multivariate analyses. In conclusion, heavy glycyrrhizin exposure during pregnancy did not significantly affect birth weight or maternal blood pressure, but it was significantly associated with lower gestational age. (+info)