Planta medica
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The involvement of ginsenosides in the signal cascade that stimulates cellular growth was investigated. It was found that ginsenosides Rh1 and Rh2 extracted from the root of Panax ginseng inhibited cellular proliferation in NIH 3T3 fibroblasts. ⋯ We also observed that the phosphorylation of myristoylated alanine-rich C kinase substrate, one of the major substrates of protein kinase C in cells, was inhibited by the ginsenosides. Data suggest that the ginsenoside Rh1 or Rh2 exerts antiproliferative effects by inhibiting phospholipase C, which produces second messengers necessary for the activation of protein kinase C.
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Ginseng saponin metabolites produced by human intestinal bacteria and the urinary and blood compounds after oral administration of Ginseng extract and its saponins in human and specific pathogen-free rats were examined in order to elucidate their metabolites absorbed from the intestines. The main metabolites of ginsenosides Rb1, Rb2, Rc, Re, and Rg1 after anaerobic incubation with fecal flora were identified as 20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol (I) 20-O-[alpha-L-arabinopyranosyl (1-->6)-beta-D-glucopyranosyl]-20(S)-protopanaxadiol (II), 20-O-[alpha-L- arabinofuranosyl(1-->6)-beta-D-glucopyranosyl]-20(S)-protopanaxadiol+ ++ (III), and 20(S)-protopanaxatriol (IV), though the metabolic rate and mode were affected by fermentation media. Furthermore, metabolites I-IV and 20(S)-protopanaxadiol (XII) were detected in blood (0.3-5.1 micrograms/ml) and in urine (2.2-96 micrograms/ day) after the oral administration of Ginseng extract (150 mg/ kg/day) to human and of total saponin (1 g/kg/day) to rats.
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Culture conditions have been standardized for initiation of callus cultures of Himalayan yew (Taxus wallichiana) using young stem and needle explants from mature trees. Cultures were established on a modified Murashige and Skoog's medium supplemented with various levels of auxins (2.4-D, NAA) and cytokinin (kinetin). ⋯ Supplementation of ascorbic acid (30 mg/l) amongst various anti-phenolic agents tested significantly reduced browning of initiated callus. Two taxanes (2-deacetoxytaxinine 1 and 2'-deacetoxyaustrospicatine) known to occur in stem bark, have also been isolated from undifferentiated tissue of T. wallichiana in equal or higher yields, for the first time.
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A genuine glycoside, named ginsenoside Rh4, was isolated from Korean red ginseng (Panax ginseng C. A. ⋯ The stereochemistry of a double bond at C-20(22) of ginsenoside Rh4 was characterized as (E) from a NOESY experiment in the 1H-NMR of the aglycone. Cytotoxic activities of ginsenoside Rh4 and its aglycone against cancer cell lines were evaluated by use of the SRB method.
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Isolation of a human intestinal bacterium capable of transforming barbaloin to aloe-emodin anthrone.
A strictly anaerobic bacterium, Eubacterium sp. BAR, was isolated from human feces as one of the intestinal bacteria capable of metabolizing barbaloin. The bacterium grew in PYF broth containing barbaloin and converted barbaloin to aloe-emodin anthrone. On the other hand, the bacterium had little metabolic activity in GAM broth.