Cytotoxic 20,22-Dihydrodigitoxigenin Glycosides and Other Constituents of Vallaris glabra Stems.

Ten cardiac glycosides (1-10) including six 20,22-dihydrodigitoxigenin and four gitoxigenin glycosides were isolated from the stems of Vallaris glabra together with six known triterpenoid cinnamates. Spectroscopic data of these previously undescribed compounds are reported. All isolates were evaluated for their growth inhibitory activities against three cancer cell lines, and compound 2 was the most active against KB cells with an IC50 value of 0.03 ± 0.001 µM. Also, compounds 1, 3, 5, and 6 and the triterpenoid cinnamates 11-13 showed inhibitory activity (IC50 < 10 µM) for one or more of the cell lines used.

Magnetic molecularly imprinted polymer prepared by microwave heating for confirmatory determination of chloramphenicol in chicken feed using high-performance liquid chromatography-tandem mass spectrometry.

A magnetic molecularly imprinted polymer (MMIP) for chloramphenicol was prepared using a surface-imprinted and microwave-heating-induced polymerization method. The surfaces of the magnetic particles were first double-bond functionalized with 3-(trimethoxysilyl)propyl methacrylate (γ-MPS), followed by the copolymerization of 4-vinyl pyridine (4-VP) and trimethylolpropane trimethacrylate (TRIM) in the presence of chloramphenicol as a template and 1,1-azobis(cyclohexane-carbonitrile) (ABCN) as an initiator in a mixture of dimethyl sulfoxide and water with microwave heating at 80°C. The magnetic polymer possesses supraparamagnetic properties and was used to concentrate and cleanup chicken feed extract, followed by chromatographic separation using a Lichrospher®100 RP C8 column and detection with two multi-reaction monitoring transitions at m/z 321→ 152 and m/z 321→ 257. The mean recoveries obtained at two spiking levels were in the range of 94.6-100% The relative intra- and inter-day standard deviations were in the range of 1.4-2.6% and 5.1-5.7%, respectively. The detection limit of the method was 0.12 µg kg-1. This confirmatory method was successfully applied to determine chloramphenicol in chicken feed samples.

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.

Cytotoxic Cardiac Glycoside Constituents of Vallaris glabra Leaves.

Thirteen cardenolide glycosides (1-13) were isolated from the CH2Cl2 and MeOH extracts of Vallaris glabra leaves. The structures of the new compounds (2-13) were identified by spectroscopic methods, with the absolute configurations of the sugar moieties determined by acid hydrolysis. All compounds were evaluated for their cytotoxic activity against human cervix adenocarcinoma, lung carcinoma, and colorectal adenocarcinoma cell lines. The two most potent compounds [2'-O-acetylacoschimperoside P (1) and oleandrigenin-3-O-α-l-2'-O-acetylvallaropyranoside (2)] exhibited IC50 values in the range of 0.03-0.07 µM.

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

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.

Furostanol glycosides, stilbenoids and nucleosides from the roots of Smilax perfoliata, and evaluation of their cytotoxic and anticholinesterase activities.

Three undescribed compounds including two furosteroid glycosides (perfoloside and 22-O-methylperfoloside) and one stilbenedimer (perfolostilbene) together with 21 known compounds were isolated from the roots of Smilax perfoliata. The structural elucidation was established by extensive uses of HRMS, 1D and 2D spectroscopic techniques. The assignment of the stereocenters in perfolostilbene was based on NOESY data and ECD calculation. Among the isolates, two compounds showed marginal cytotoxic activity against KB and Hela cell lines while seven stilbenoids showed strong to weak antiacetylcholinesterase and antibutyrylcholinesterase activities with IC50 ranging between 2-197 µM.

Neolignans from Myristica fragrans seeds, revision of their absolute configurations, reduction products and biological activities.

Chromatographic purification of the CH2Cl2 extract of Myristica fragrans seeds provided 19 known compounds, four dihydrofuran neolignans, licarines A, B and maceneolignans A, B were among the isolates. Prior to hydrogenation, in order to obtain their di- and tetrahydrogenated products, the absolute configuration of these compounds was thoroughly investigated based on their optical rotations and ECD spectra. This report provides evidences concerning the disagreement between the use of an aromatic quadrant rule and time-dependent density function theory calculation for the prediction of the absolute configurations at C-7 and C-8 in these dihydrobenzofuran neolignans. The absolute configurations of licarines A, B and maceneolignans A, B were subsequently redefined. The antimicrobial and cytotoxic activities of the isolates and reduction products of licarines A, B and maceneolignans A, B were also investigated.

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.

Citrusosides A-D and furanocoumarins with cholinesterase inhibitory activity from the fruit peels of Citrus hystrix.

Four new compounds, citrusosides A-D (1-4), and 15 known compounds were isolated from the hexanes and CH(2)Cl(2) extracts of the peels of Citrus hystrix fruits. Compound 1 is a 1-O-isopropyl-6-O-ß-D-glucopyranosyl ester of 5'',9''-dimethyl-2'',8''-decadienoic acid. Compounds 2-4 possess a 1-O-isopropyl-ß-D-glucopyranosyl and a dihydroxyprenylfuranocoumarin moiety conjugated to the 3-hydroxy-3-methylglutaric acid as diesters. Several furanocoumarins were evaluated for their cholinesterase inhibitory activity. (R)-(+)-6'-Hydroxy-7'-methoxybergamottin, (R)-(+)-6',7'-dihydroxybergamottin, and (+)-isoimparatorin showed IC(50) values of 11.2 ± 0.1, 15.4 ± 0.3, and 23 ± 0.2 µM, respectively. Bioassay results indicated that the presence of a dioxygenated geranyl chain in the test compounds is crucial for the inhibitory activity.

Cytotoxic cardenolides from the leaves of Calotropis gigantea.

Two 15beta-hydroxycardenolides (1,2) and a 16alpha-hydroxycalactinic acid methyl ester (3) along with eleven known compounds including 16alpha-hydroxycalotropagenin, coroglaucigenin, 16alpha-hydroxycalotropin, calactinic acid, calotoxin, 6'-O-(E-4-hydroxycinnamoyl)desglucouzarin, 12beta-hydroxycoroglaucigenin, frugoside, calotropagenin, 9,12,13-trihydroxyoctadeca-10(E),15(Z)-dienoic acid and R-(-)-mevalonolactone were isolated from the polar fraction of the CH(2)Cl(2) extract, and n-BuOH extract of the leaves of this plant. The isolated compounds were evaluated for their inhibitory activities against a panel of cell lines.

Siphonagarofurans A-J: Poly-O-acylated ß-dihydroagarofuran sesquiterpenoids from the fruits of Siphonodon celastrineus.

Ten poly-O-acylated ß-dihydroagarofuran sesquiterpenoids, siphonagarofurans A-J, were obtained from the fruits of Siphonodon celastrineus using chromatographic techniques. Their structures were elucidated by extensive use of 2-D NMR spectroscopic methods. The absolute configurations of siphonagarofurans A-J were assigned following analysis of calculated and experimental ECD spectra. The absolute configuration of siphonagarofuran A was also confirmed by X-ray crystallographic analysis. Selected compounds were evaluated for their cytotoxic activity against KB, Vero and Hela cell lines with siphonagarofuran J identified as the most active compound, with IC50 values ranging from 14 to 27 µM.

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.

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.

Prenylfuranocoumarin-HMGA-flavonol glucoside conjugates and other constituents of the fruit peels of Citrus hystrix and their anticholinesterase activity.

Sixteen compounds including dihydroxy prenylfuranocoumarins/3-hydroxy-3-methylglutaric acid conjugates and dihydroxy prenylfuranocoumarins/3-hydroxy-3-methylglutaric acid/1-O-flavonyl-ß-d-glucopyranoside conjugates, together with other dihydroxyprenylfuranocoumarins conjugates, were isolated from the ethyl acetate extract of the fruit peels of Citrus hystrix. Some of the isolates were evaluated for their cholinesterase inhibitory activity, but only one compound possessing a 3-O-ß-d-glucopyranosyl-3,5,7,4'-tetrahydroxy-6,8,3'-trimethoxyflavonol nucleus in the prenylfuranocoumarin-HMGA conjugate showed strong activity.

Photo-catalysis of bromacil under simulated solar light using Au/TiO2: evaluation of main degradation products and toxicity implications.

Bromacil (5-bromo-3-sec-butyl-6-methyluracil) is a substituted uracil herbicide used worldwide. It is not readily biodegradable and has the potential to contaminate different types of water bodies with possible impact on diverse non-target species. In this work, degradation of bromacil in aqueous Au/TiO2 suspension under simulated sunlight allowed fourteen degradation products to be identified. The photodegradation of bromacil followed (pseudo) first order kinetics in the presence of 0.2 g L(-1) of Au/TiO2 with a half-life of 25.66 ± 1.60 min and a rate constant of 0.0271 ± 0.0023 min(-1). Transformation routes of the photo-catalytic degradation of bromacil were then proposed. Complementary toxicity assessment of the treated bromacil solution revealed a marked decrease in toxicity, thereby confirming that by-products formed would be less harmful from an environmental point of view. Photo-catalytic degradation of bromacil thus appears to hold promise as a cost-effective treatment technology to diminish the presence of this herbicide in aquatic systems.

Eriosema chinense: a rich source of antimicrobial and antioxidant flavonoids.

Six prenylated flavonoids, (2R,3S)-3,5,4'-trihydroxy-6″-6″dimethylpyrano(2″,3″:7,6)-8-(3″', 3″'-dimethylallyl)flavanone, (2R,3S)-3,5,2'-trihydroxy-4'-methoxy-6″,6″-dimethylpyrano(2″,3″:7,6)-8-(3″',3″'-dimethylallyl)flavanone, (2R,3R)-3,5,2',4'-tetrahydroxy-6″,6″-dimethylpyrano(2″,3″:7,6)-8-(3″',3″'-dimethylallyl)flavanone, 3,5,2',4'-tetrahydroxy-6″,6″-dimethylpyrano(2″,3″:7,6)-8-(3″',3″'-dimethylallyl)flavone, (2R,3R,2″'R)-3,5,2″'-trihydroxy-4'-methoxy-6″,6″-dimethylpyrano(2″,3″:7,6)-8-(3″'-methylbut-3″'-enyl)flavanone, (2R,3R)-3,5-dihydroxy-4'-methoxy-6″,6″-dimethylpyrano(2″,3″:7,6)-8-(2″',3″'-epoxy-3″'-methyl butyl)flavanone, an isoflavone, 6,7-dimethoxy-5,2',4'-trihydroxyisoflavone, and octaeicosanyl-trans-p-coumarate together with 12 known compounds, were isolated from roots of Eriosema chinense. This structural elucidation was determined by spectroscopic methods. Several isolates and derivatives were evaluated for their antimicrobial and antioxidant activities. Results obtained provide additional evidence showing that the presence of both the free phenolic OH and the lipophilic prenyl groups are crucial for potent antimicrobial activity against yeast, gram positive and gram negative bacteria, whereas the presence of free phenolic OH group is required for strong radical scavenging property.

Reactions of phenylurea compounds with aqueous chlorine: Implications for herbicide transformation during drinking water disinfection.

Phenylurea herbicides have been known to contaminate surface waters serving as potable supplies. To access the potential for transformation of these compounds during drinking water treatment, reactions of phenylurea compounds with aqueous chlorine at different pHs were investigated. The effect of substitution at the amino-N on the rate of transformation depends upon pH. Under acidic conditions, all of the phenylurea studied except 3,4-dichloro-3'-N-methylphenylurea (3,4-DCMPU) exhibited third-order kinetics, second order with respect to chlorine and first order with respect to phenylurea, while the reactions of 3,4-DCMPU were first order with respect to both chlorine and the organic compound. Under neutral and alkaline conditions, all compounds exhibited second-order kinetics that was first order with respect to chlorine and the organic compound. Apparent second-order rate constants at 25°C and pH 7 were 0.76 ± 0.16, 0.52 ± 0.11, 0.39 ± 0.02, 0.27 ± 0.04 and 0.23 ± 0.05 M(-1)s(-1) for phenylurea, 3, 4-dichlorophenylurea, 3, 4-DCMPU, metoxuron and monuron, respectively. Studies of the chlorination products, monitored by LC/MS/MS, under different pH values indicated the reaction to take place at both N atoms and also at ortho- and para- positions of the phenylurea aromatic group. The main chlorinating species were found to be different in different pH ranges. Under conditions typically encountered in drinking water treatment systems, transformation of these compounds by chlorine will be incomplete.

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.

Acetylenic fatty acids, triglyceride and triterpenes from the leaves of Hymenodictyon excelsum.

Two new acetylenic fatty acids (1, 2), a new triglyceride (3), along with eleven known compounds including 3-oxo-11alpha,12alpha-epoxyurs-13beta,28-olide (4) previously reported as a synthetic compound, have been isolated from the leaves of Hymenodictyon excelsum. The structural identification was established from spectroscopic data.

Antimalarial and antituberculous poly-O-acylated jatrophane diterpenoids from Pedilanthus tithymaloides.

Six new poly-O-acylated jatrophane diterpenes (1- 6) have been isolated along with five known compounds from the white latex of Pedilanthus tithymaloides. The structural identification was accomplished on the basis of 2D NMR and MS investigations. Some of these highly oxygenated jatrophane diterpenes possess a rare O-acetyl enol moiety. Compounds 1 and 3- 5 showed antiplasmodial activity with IC(50) values of 3.4-4.4 microg/mL and antimycobacterial activity against Mycobacterium tuberculosis with minimum inhibition concentration (MIC) values ranging from 12.5 to 100 microg/mL.