ABSTRACT
@#In this study, a novel phthalic acid ester (1) and a known iridoid glycoside (2) were isolated from the root bark of Anthocleista vogelii. The structures of the novel compound and iridoid glycoside were elucidated on the basis of their chemical and spectral data (UV, FT-IR, EI-MS, 1D and 2D NMR) and found to be phthalic acid ester, 4-ethyl-6-propyl-4,5,6,7-tetrahydro- 3H-2,8-benzodioxacycloundecine-1,9-dione (1) and sweroside (2). The compounds were evaluated for their in vitro inhibitory activities against pancreatic lipase, α-amylase and α- glucosidase, and in vivo laxative activity in rats. The metabolite phthalic acid ester (1) exhibited moderate inhibitory activity against pancreatic lipase (IC50 = 24.43 ± 0.096 μg/mL) and relatively good activity against α-glucosidase (IC50 = 10.28 ± 0.015 μg/mL). Sweroside (2) displayed weak activity against α-glucosidase (IC50 = 40.28 ± 0.063 μg/mL) but significantly (p<0.05) increased the feacal output of the treated animals compared to the normal and sodium picosulfate controls.
ABSTRACT
A sensitive and selective high-performance liquid chromatographic method was developed for the determination of itraconazole and its active metabolite, hydroxyitraconazole, in human plasma. Prior to analysis, both compounds together with the internal standard were extracted from alkalinized plasma samples using a 3:2 (v/v) mixture of 2,2,4-trimethylpentane and dichloromethane. The mobile phase comprised 0.02 M potassium dihydrogen phosphate-acetonitrile (1:1, v/v) adjusted to pH 3.0. Analysis was run at flow-rate of 0.9 ml/min with excitation and emission wavelengths set at 260 and 365 nm, respectively. Itraconazole was found to adsorb on glass or plastic tubes, but could be circumvented by prior treating the tubes using 10% dichlorodimethylsilane in toluene. Moreover, rinsing the injector port with acetonitrile helped to overcome any carry-over effect. This problem was not encountered with hydroxyitraconazole. The method was sensitive with limit of quantification of 3 ng/ml for itraconazole and 6 ng/ml for hydroxyitraconazole. The calibration curve was linear over a concentration range of 2.8-720 ng/ml for itraconazole and 5.6-720 ng/ml for the hydroxy metabolite. Mean recovery value of the extraction procedure for both compounds was about 85%, while the within-day and between-day coefficient of variation and percent error values of the assay method were all less than 15%. Hence, the method is suitable for use in pharmacokinetic and bioavailability studies of itraconazole.
