Somyote Sutthivaiyakit

Cytotoxic and antimycobacterial prenylated flavonoids from the roots of Eriosema chinense.

Eight new prenylated flavonoids, khonklonginols A-H (1-8), together with six known compounds including five flavonoids, lupinifolinol (9), dehydrolupinifolinol (10), flemichin D (11), eriosemaone A (12), and lupinifolin (13), and one lignan, yangambin (14), have been isolated from hexane and dichloromethane extracts of the roots of Eriosema chinense. The structures of 1-8 were elucidated by spectroscopic methods. The compounds were evaluated for cytotoxic activity against the small-cell lung (NCI-H187) and oral epidermal carcinoma (KB) human cell lines as well as for antimycobacterial activity against Mycobacterium tuberculosis H37Ra.

New Reagent for Trace Determination of Protein-Bound Metabolites of Nitrofurans in Shrimp Using Liquid Chromatography with Diode Array Detector

The synthesis of derivatives of metabolites from furazolidone, furaltadone, nitrofurazone, and nitrofurantoin using a new derivatizing reagent, 2-naphthaldehyde (NTA), is described. The reaction product was used in liquid chromatography with diode array detector (LC-DAD) for determination of protein-bound metabolites of nitrofurans in shrimp followed by two steps of liquid-liquid extraction. Derivatives of nitrofuran metabolites are well separated from NTA remaining in the extract upon separation on a ChromSpher 5 Pesticide (250 x 4.6 mm, 5 microm) column at 40 degrees C with acetonitrile/5 mM ammonium acetate adjusted to pH 7.5 gradient as the mobile phase and DAD detection at 308 nm except for naphthyl derivative of 1-aminohydantoin at 310 nm. The high absorptivity of these derivatives makes simultaneous screening of these metabolites in shrimp at 1 microg/kg possible for the first time using LC-DAD. The method was validated using blank shrimp fortified with all four metabolites at 1, 1.5, and 2 microg/kg. Recoveries were >86% with relative standard deviations of <14% for all four metabolites. Comparison between LC-DAD and APCI-MS/MS shows very good agreement for shrimp samples.

Diterpenes, Sesquiterpenes, and a Sesquiterpene−Coumarin Conjugate from Jatropha integerrima

Five new compounds, 2alpha-hydroxyjatropholone (1), 2beta-hydroxyjatropholone (2), 1,5-dioxo-2,3-dihydroxyrhamnofola-4(10),6,11(18),15-tetraene (3), 2-keto-5-hydroxyguai-3,11-diene (4), and a sesquiterpene-coumarin conjugate, jatrophadioxan (5), and nine known compounds have been isolated from the roots of Jatropha integerrima. The structures were established from spectroscopic data, and the relative configuration of 1 was confirmed by X-ray crystallography. Six diterpenes were evaluated for their antiplasmodial, antituberculosis, and cytotoxic activities.

A novel 8,9-seco-rhamnofolane and a new rhamnofolane endoperoxide from Jatropha integerrima roots

Abstract Integerrimene, a possible biogenetic precusor of the rhamnofolane diterpenes and a new rhamnofolane endoperoxide 2-epicaniojane together with caniojane and 1,11-bisepicaniojane were isolated from J. integerrima roots. Their structures were elucidated by spectroscopic methods. The X-ray structure of 2-epicaniojane is also presented.

Constituents and bioactivity of the tubers of Euphorbia sessiliflora

The diterpene ent-12-hydroxy-12[R]-abieta-8(14),13(15)-dien-16,12-olide was isolated from the tubers of Euphorbia sessiliflora Roxb., together with four known ent-abietadienolides, four known cycloartane triterpenes and ellagic acid-beta-D-glucopyranoside. Two of these metabolates displayed moderate antibacterial activities.

Antiplasmodial sesquiterpene alkaloids from the roots of Maytenus mekongensis.

Eight new sesquiterpene alkaloids (1-8) and four known sesquiterpene alkaloids (9-12) have been isolated from the roots of Maytenus mekongensis. Structures were determined using extensive spectroscopic methods. The relative configuration of 7-epi-mekongensine (2) was established by single-crystal X-ray crystallographic analysis. The alkaloids were evaluated for antiplasmodial activity against Plasmodium falciparum, K1 strain, and for cytotoxicity using a panel of cell lines.

Labdane and pimarane diterpenes from Croton joufra.

From the chloroform extract of the leaves of Croton joufra, the diterpenes 2alpha,3alpha-dihydroxy-labda-8(17),12(13),14(15)-triene and 3beta-hydroxy-19-O-acetyl-pimara-8(9),15-dien-7-one, were isolated. Their structures were established by spectroscopic methods. One of the compounds showed weak lethality in the brine shrimp assay.

Determination of Nitrofurans in Chicken Feed by High-Performance Liquid Chromatography–Tandem Mass Spectrometry

Liquid chromatography with tandem mass spectrometry was used for the determination of nitrofurantoin, nitrofurazone, furazolidone, and furaltadone in chicken feed. The nitrofurans were extracted with phosphate buffer (pH 7) and sodium chloride. Proteins and lipids were removed with acetonitrile and hexane before purification with ethyl acetate, dilution in 1:1 acetonitrile-5 millimolar ammonium acetate at pH 7.3, and filtration prior to analysis. The limits of detection were 1.69, 1.74, 2.01, and 1.45 microgram per kilogram for nitrofurantoin, nitrofurazone, furazolidone, and furaltadone, respectively. The mean recoveries were between 84.6 and 110.6 percent. The method was employed to determine nitrofurans in chicken feed.

Anti-inflammatory 12,20-Epoxypregnane and 11,12- seco -Pregnane Glycosides from the Stems of Hoya kerrii

Five 12,20-epoxypregnane glycosides (1-3, 5, and 6) and two 11,12-seco-pregnane glycosides (4 and 7) with spirodilactone motifs, as well as spirodilactone cleavage products 8 and 9, were isolated from the stems of Hoya kerrii. The relative configurations of the three related skeletons were supported by ROESY experiments and X-ray crystallographic analyses. The isolates were evaluated for their anti-inflammatory activity based on the inhibition of NO production in RAW264.7 cells, and some showed IC50 values ranging from 12.6 to 96.5 μM. The most potent compound, 9a, was also examined for its anti-inflammatory mechanism against mRNA expression and was found to down-regulate mRNA expression of iNOS and COX-2 in a dose-dependent manner.

Degradation products of profenofos as identified by high-field FTICR mass spectrometry: Isotopic fine structure approach

ABSTRACT This study was performed to identify the degradation products of profenofos “a phenyl organothiophosphate insecticide” in raw water (RW) collected from the entry point of Metropolitan Water Works Authority “Bangkaen, Thailand” and ultrapure water (UPW) with and without TiO2 under simulated sunlight irradiation. Degradation of profenofos was followed with ultrahigh performance liquid chromatography (UHPLC) and follows pseudo first-order kinetic. Accordingly, high-field FTICR mass spectrometry coupled to an electrospray ionization source was used to reveal the degradation routes of profenofos and the isotopic fine structures (IFS) elucidations to approve the chemical structures of its degradation products. More degradation products were detected in UPW as compared to RW. Consequently, two main degradation pathways namely (i) interactive replacements of bromine and hydrogen by hydroxyl functional groups and (ii) rupture of PO, PS, CBr and CCl bonds were observed. None interactive replacement of chlorine by hydroxyl functional group was detected. Accordingly, mechanistical pathways of the main degradation products were established.