76
X. Hu et al.
Arch. Pharm. Chem. Life Sci. 2011, 2, 71–77
purchased from Sanchang Chemical Co. (ShangHai, China). a-
Glucosidase and 4-nitrophenyl-b-D-glucopyranoside (PNPG) were
purchased from Sigma Chemical Co. All commercially available
reagents and solvents were used without further purification.
Kinetic Assay of a-Glucosidase Inhibition
Various concentrations of PNPG (0.1 to 1.2 mM) as the substrate,
10 mL of a-glucosidase, and 10 mM potassium phosphate buffer
(pH 7.0) were added to a test tube in a total volume assay mixture
of 1000 mL. The initial rate of the reaction mixture was deter-
mined by the increase of absorbance at 400 nm per min (DOD400
min). The Michaelis constant (Ki) and the maximal velocity (Vmax
of the a-glucosidase activity were determined by the Lineweaver–
Burk plot.
/
)
Synthesis
To the mixture of appropriate phenol (50 mmol) and polyhy-
droxybenzoic acid (55.6 mmol), anhydrous zinc chloride (27.2 g),
and phosphorus oxychloride (25 mL) were added. The reaction
mixture was refluxed for 2.5 h in the water bath of 708C with
stirring. Then the mixture was added to appropriate ice and
cooled to 48C for 24 h. The precipitate solid was filtered, washed
with 3% sodium bicarbonate twice, and purified by recrystalli-
zation from boiling water to afford compounds 1–18 (Fig. 1). The
synthetic route of compounds 1–18 is given in Scheme 1.
NMR spectra were recorded on a Varian INOVA 300 MB NMR
spectrometer in DMSO-d6 and tetramethylsilane was used as an
internal standard. IR spectra were obtained on a Bruker
EQUINOX55 Fourier transformation infrared spectrometer.
This work was supported by the Undergraduate Research Programmes of
Sun Yat-sen University, China (2009-73).
The authors have declared no conflict of interest.
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