Novel synthesis of flavonoids of Scutellaria baicalensis Georgi.

School of Pharmacy, National Defense Medical Center, Taiwan.
CHEMICAL & PHARMACEUTICAL BULLETIN (Impact Factor: 1.38). 04/2003; 51(3):339-40. DOI: 10.1248/cpb.51.339
Source: PubMed

ABSTRACT A concise and efficient total synthesis of the flavonoids baicalein, oroxylin A and wogonin was described. Intramolecular oxidative cyclization followed by demethylation of chalcone 1, readily prepared from trimethoxyphenol, afforded, depending upon the controlled conditions, baicalein or oroxylin A in excellent yields. Demethylation of 1 yielded 3, which, by oxidation with I(2)/dimethyl sulfoxide (DMSO), was readily converted to oroxylin A and wogonin after column chromatography.

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    ABSTRACT: The objective of the current research work was to evaluate the neuroprotective effect of the ethanol extract of Scutellaria baicalensis (S.B.) on the excitotoxic neuronal cell death in primary rat cortical cell cultures. The inhibitory effects of the extract were qualitatively and quantitatively estimated by phase-contrast microscopy and lactate dehydrogenase (LDH) assays. The extract exhibited a potent and dose-dependent inhibition of the glutamate-induced excitotoxicity in the culture media. Further, using radioligand binding assays, it was observed that the inhibitory effect of the extract was more potent and selective for the N-methyl-D-aspartate (NMDA) receptor-mediated toxicity. The S.B. ethanol extract competed with [(3)H] MDL 105,519 for the specific binding to the NMDA receptor glycine site with 50% inhibition occurring at 35.1 μ g/mL. Further, NMDA receptor inactivation by the S.B. ethanol extract was concluded from the decreasing binding capability of [(3)H]MK-801 in the presence of the extract. Thus, S.B. extract exhibited neuroprotection against excitotoxic cell death, and this neuroprotection was mediated through the inhibition of NMDA receptor function by interacting with the glycine binding site of the NMDA receptor. Phytochemical analysis of the bioactive extract revealed the presence of six phytochemical constituents including baicalein, baicalin, wogonin, wogonoside, scutellarin, and Oroxylin A.
    05/2014; 2014:459549. DOI:10.1155/2014/459549
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    ABSTRACT: A series of chalcones, a flavone and one flavanone were synthesized and elucidated structurally by IR and 1 H NMR spectroscopies. The synthetic compounds were then screened for acetylcholinesterase inhibitory activity using thin layer chromatography (TLC) and microplate assays. In the TLC assay, only 2′-hydroxy-4-methoxychalcone and 2′-hydroxy-4′-O-prenyl-2,6-dichlorochalcone were found to show moderate and weak activity respectively against acetylcholinesterase (AchE) at 0.1 mM concentration compared to the control galanthamine. 4′-Hydroxy-2,6-dichlorochalcone, 2′-hydroxy-4-nitrochalcone, 2′-hydroxy-4-(dimethyl)aminochalcone and 2′-hydroxy-4-methoxychalcone showed moderate AchE inhibitory activity with percentage inhibition of 54.24, 46.14 and 49.32 % respectively in the microplate assay.
    Jurnal Pengurusan 06/2014; 691(69:1):97-102.
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    Journal of the Korean Chemical Society 01/2009; 53(3). DOI:10.5012/jkcs.2009.53.3.382


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