salicylates and ethyl-acetate

In vitro α-glucosidase inhibitory activity of Ginkgo biloba leaves was investigated. The inhibitory activity of methanol extracts from yellow and green leaves was 13.8 and 40.1 μg mL(-1), respectively. Each methanol extract was separated into its respective fraction by solvent-solvent extraction with n-hexane, chloroform, ethyl acetate and n-butanol. The n-hexane fractions (in both methanol extracts from green and yellow leaves) exhibited high α-glucosidase inhibitory activity with IC50 values of 13.6 and 13.4 μg mL(-1), respectively. Further fractionation of the n-hexane fractions by silica gel column chromatography gave the most active fraction which was identified as ginkgolic acid (C13:0) and a mixture (C13:0, C15:0, C15: 1, C17:1 and C17:2). Ginkgolic acid (C13:0) exhibited the highest α-glucosidase inhibitory activity. This is the first study to successfully isolate ginkgolic acids as α-glucosidase inhibitors.

Topics: 1-Butanol; Acetates; Chemical Fractionation; Chloroform; Gas Chromatography-Mass Spectrometry; Ginkgo biloba; Glycoside Hydrolase Inhibitors; Hexanes; Methanol; Molecular Structure; Phytotherapy; Plant Extracts; Plant Leaves; Plants, Medicinal; Salicylates; Solvents

Soybean [Glycine max (L.) Merr.] is a rich source of isoflavones that are often affected by biotic and abiotic factors. The objectives of this study were to evaluate the effect of various concentrations of three natural elicitors applied at different soybean growth stages on isoflavone content and to compare the efficiency of several solvent systems in isoflavone extraction and quantification. The isoflavones extracted from R96-3444 soybean using eight solvent systems were separated, identified, and quantified by a high-performance liquid chromatography (HPLC) procedure. The soybean plants were sprayed with salicylic acid, methyl salicylate, or ethyl acetate at 0, 10(-6), 10(-3), and 10(-1) M at R1 (blooming) or R4 (full pods) growth stage. Results showed that 10(-3) M ethyl acetate sprayed at the R1 stage significantly increased total isoflavone content and the levels of some individual isoflavones in soybean seeds. With all the elicitors that were tested, concentration was a more important factor than application time with respect to isoflavone content with lower concentrations being more effective on most isoflavones. A 53% acetonitrile solvent system was the best solvent system for extracting total isoflavone, malonyl glucosides, genistein, glycitin, genistin, acetyl-daidzin, and acetyl-genistin. The results of this study will be useful for increasing the isoflavone content in desirable soybean varieties and improving isoflavone concentration during extraction.

Topics: Acetates; Chromatography, High Pressure Liquid; Glycine max; Isoflavones; Salicylates; Salicylic Acid; Seeds

DanShen is a Chinese medicine that is used to treat cardiovascular disorders. DanShen is moderately to strongly protein bound, mainly to albumin. Because impaired protein binding of albumin-bound drugs in uremia has been reported, we studied protein binding of DanShen by measuring the digoxin-like immunoreactive component of this Chinese medicine. We observed a significantly higher percentage of free fraction of DanShen in uremic sera in vitro. Impaired protein binding of DanShen was also observed in sera from patients with liver disease, who had elevated concentrations of bilirubin. Treating uremic sera with activated charcoal significantly improved the protein binding of DanShen, indicating that uremic compounds are responsible for the impaired protein binding of DanShen. On the other hand, when various amounts of bilirubin were added to aliquots of the normal pool supplemented with DanShen, we observed only a modest displacement of DanShen from the protein-binding sites by bilirubin, indicating that hypoalbuminemia may play a major role in impaired protein binding of DanShen in sera with elevated bilirubin concentrations. We conclude that protein binding of DanShen is lower in uremic sera and in sera with elevated bilirubin concentrations.

Topics: Acetates; Benzenesulfonates; Bilirubin; Blood Proteins; Charcoal; Creatine; Digoxin; Drugs, Chinese Herbal; Fluorescence Polarization Immunoassay; Humans; Hyperbilirubinemia; Phenanthrolines; Protein Binding; Salicylates; Salvia miltiorrhiza; Serum Albumin; Uremia

Interference by salicylic acid was noted in a high pressure liquid chromatographic assay of theophylline in serum. The acid eluted very close to theophylline in a mobile phase consisting of 0.01 M acetate buffer, pH 4.0, containing 28% methanol on a C-18 reverse-phase column. The two peaks could be resolved by switching to a mobile phase containing 18% methanol, 1.6% acetonitrile, and 1.6% acetic acid in water. However, in this mobile phase traces of the extracting solvent, ethyl acetate, caused a sharpening of the theophylline peak leading to spuriously high results. The problem was overcome by using chloroform to extract the theophylline from serum.

Topics: Acetates; Chromatography, High Pressure Liquid; Humans; Salicylates; Salicylic Acid; Theophylline