Portion Of Extract Research Articles

Brominated polyunsaturated lipids with protein tyrosine phosphatase-1B inhibitory activity from Chinese marine sponge Xestospongia testudinaria

A new brominated polyunsaturated lipid, methyl (E,E)-14,14-dibromo-4,6,13-tetradecatrienoate (1), along with three known related analogues (2–4), were isolated from the Et2O-soluble portion of the acetone extract of Chinese marine sponge Xestospongia testudinaria treated with diazomethane. The structure of the new compound was elucidated by detailed spectroscopic analysis and by comparison with literature data. Compound 3 exhibited significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of type II diabetes and obesity, with an IC50 value of 5.30 ± 0.61 μM, when compared to the positive control oleanolic acid (IC50 = 2.39 ± 0.26 μM).

Chemical constituents of Osmanthus fragrans

By Silica gel, Sephadex LH-20 and other materials for isolation and purification and by physicochemical methods and spectral analysis for structural identification, 32 compounds were isolated and identified from ethyl acetate portion of alcohol extract of the Osmanthus fragrans. Their structures were identified as boschniakinic acid (1), ursolaldehyde (2), augustic acid (3), arjunolic acid (4), 5-hydroxymethyl-2-furancarboxaldehyde (5), isoscutellarein (6), 6, 7-dihydroxycoumarin (7), 2α-hydroxy-oleanolic acid (8), quercetin-3-0-β-D-glu-copyranoside (9), D-allito (10), 5, 4'-dihydroxy-7- methoxyflavone-3-0-β-D-glucopyranoside (11), 5,7-dihydroxychromone (12), lupeol (13), naringenin (14), acetyloleanolic acid (15), chlorogenic acid (16), kaempferol-3-0-β- D-glucopyranoside (17), oleanolic acid (18), kaempferol-3-0-β-D-galactopyanoside (19), 3', 7-dihydroxy-4'-methoxyisoflavon (20), ergosta-4,6,8 (14), 22-tetraen-3-one (21), p-hydroxycinnamic acid (22), syringaresinol (23), 3,4-dihydroxyacetophenonel (24), β-sitosterol (25), ethyl p-hydroxyphenylacetate (26), benzoic acid (27), caffeic acid (28), coelonin (29), p-hydorxy-phenylacetic acid (30), p-hydroxyacetophenone (31), and methyl-p-hydroxphenylacetate (32). Except for compounds 2, 4, 5, 8-11, 13, 15, 18, 20, 25, and 27, the rest were isolated from the Osmanthus fragrans for the first time.

Determination of Caffeine Content and Antioxidant Activity of Coffee

Attempt has been made to look into caffeine contents and antioxidant activity of coffee grown at Wembera, Goncha, Zegie, and Burie localities of North-West Ethiopia. The caffeine content of the extracts in % w/w has been found to be 1.53 ± 0.003 for Wembera coffee, 1.41 ± 0.040 for Goncha coffee, 1.29 ± 0.033 for Zegie coffee and 0.97 ± 0.049 for Burie coffee. The antioxidant activities of the coffee extracts were measured by using ferric reducing power assay and Rancimat assay. Ferric reducing power assay was used to measure the total antioxidant power of water soluble components of coffee and is expressed as ascorbic acid equivalent antioxidant capacity in milligram per gram of the dried coffee samples. The ferric reducing power values of the extracts were 9.532 ± 0.201, 9.159 ± 0.441, 8.955 ± 0.180, 6.751 ± 0.284 for Wembera, Burie, Goncha and Zegie coffees, respectively. The Rancimat assay was also used to measure antioxidant activity of lipid soluble portions of coffee extracts using sunflower oil as the oxidizable substrate. It was found that all the coffee extracts improved the oxidative stability of sunflower oil. The protection factors were 1.36 ± 0.027, 1.31 ± 0.027, 1.26 ± 0.069 and 1.17 ± 0.015 for Wembera, Burie, Goncha and Zegie coffees respectively. Based on these results, it is suggested that Wembera coffee has the higher caffeine content and antioxidant activities than Burie, Goncha and Zegie coffee varieties.

A hybrid DNA extraction method for the qualitative and quantitative assessment of bacterial communities from poultry production samples.

The efficacy of DNA extraction protocols can be highly dependent upon both the type of sample being investigated and the types of downstream analyses performed. Considering that the use of new bacterial community analysis techniques (e.g., microbiomics, metagenomics) is becoming more prevalent in the agricultural and environmental sciences and many environmental samples within these disciplines can be physiochemically and microbiologically unique (e.g., fecal and litter/bedding samples from the poultry production spectrum), appropriate and effective DNA extraction methods need to be carefully chosen. Therefore, a novel semi-automated hybrid DNA extraction method was developed specifically for use with environmental poultry production samples. This method is a combination of the two major types of DNA extraction: mechanical and enzymatic. A two-step intense mechanical homogenization step (using bead-beating specifically formulated for environmental samples) was added to the beginning of the "gold standard" enzymatic DNA extraction method for fecal samples to enhance the removal of bacteria and DNA from the sample matrix and improve the recovery of Gram-positive bacterial community members. Once the enzymatic extraction portion of the hybrid method was initiated, the remaining purification process was automated using a robotic workstation to increase sample throughput and decrease sample processing error. In comparison to the strict mechanical and enzymatic DNA extraction methods, this novel hybrid method provided the best overall combined performance when considering quantitative (using 16S rRNA qPCR) and qualitative (using microbiomics) estimates of the total bacterial communities when processing poultry feces and litter samples.

Sulfated steroid – amino acid conjugate from the Irish marine sponge Polymastia boletiformis

Polymastia boletiformis, a brightly coloured orange-yellow fistulose sponge is widespread on the coasts of Britain and Ireland. Previous studies on this genus have yielded a number of interesting polyenes [1] and steroids. [2]. In the course of our on-going investigations within the frame of Beaufort Marine Biosdiscovery Research Programme directed to the biological screening and isolation of bioactive metabolites from Irish marine organisms [3], we have evaluated the antifungal activity of a number of Irish marine sponges against the plant pathogen Cladosporium cucumerinum. The crude extract of P. boletiformis, collected from the west coast of Ireland, showed activity against C. cucumerinum at 1 mg/mL. Antifungal activity-guided fractionation of the aqueous methanol-soluble portion of the crude extract by RP18 Flash CC, Sephadex LH-20 gel chromatography and RP18 HPLC led to the isolation of a new, minor sulfated steroid – amino acid conjugate (1). The structure of the new natural product was elucidated on the basis of extensive spectral data analysis, including 1D and 2D NMR experiments (COSY, NOESY, HSQC, HMBC) and HRMS. The assessment of antifungal activity of this metabolite and the identification of the absolute stereochemistry of the chiral centers on the side chain of the molecule is currently underway.

Biological Parameters for Evaluating the Toxic Potency of Petroleum Ether Extract of Wattakaka volubilis in Wistar Female Rats.

Objectives:The present study investigated the toxic properties of petroleum ether extract of Wattakaka (W.) volubilis in Wistar female rats.Methods:An in vitro brine shrimp lethality bioassay was studied in A. Salina nauplii, and the lethality concentrations were assessed for petroleum ether extract of W. volubilis. A water soluble portion of the test extract was used in different concentrations from 100-1000 μg/mL of 1 mg/mL stock solution. A 24-hours incubation with a 1-mL aliquot in 50 mL of aerated sea water was considered to calculate the percentage rate of dead nauplii with test extract administration against a potassium-dichromate positive control. The acute and the sub-acute toxicities of petroleum ether extract of W. volubilis were evaluated orally by using gavage in female Wistar rats. Food and water intake, body weight, general behavioral changes and mortality of animals were noted. Toxicity or death was evaluated following the administration of petroleum ether extract for 28 consecutive days in the female rats. Serum biochemical parameters, such as alanine aminotransferase (ALT), alkaline phosphatase (ALP), bilirubin, total cholesterol, triglyceride, total protein, glucose, urea, creatinine, sodium, potassium and α-amylase levels, were measured in the toxicity evaluations. Pathological changes in isolated organs, such as the liver, kidneys, and pancreas, were also examined using hematoxylin and eosin dye fixation after the end of the test extract’s administration.Results:The results of the brine-shrimp assay indicate that the evaluated concentrations of petroleum ether extract of W. volubilis were found to be non-toxic. In the acute and the sub-acute toxicity evaluations, no significant differences were observed between the control animals and the animals treated with extract of W. volubilis. No abnormal histological changes were observed in any of the animal groups treated with petroleum ether extract of W. volubilis.Conclusion:These results suggest that petroleum ether extract of W. volubilis has a non-toxic effect in Wistar female rats.

Chemical Constituents of Rhododendron lepidotum from Nepal Himalayas

Rhododendron lepidotum (family Ericaceae) is a highly variable, low and compact to upright, lean shrub, up to 2 m tall. The flowers are of open type, having a white, yellow, pink, or purple color. The leaves are elliptic with a dark green upper surface and a lower surface with large brownish scales. The distribution of R. lepidotum is from Kashmir to southeastern Tibet at an altitude ranging from 2400 to 4900 m. The genus Rhododendron has a long history of use as folk medicine in various countries. Rhododendron adamsii Rehder is used as a stimulant and tonic [1, 2]. Dried leaves of R. dauricum are used as an expectorant and in the treatment of acute and chronic bronchitis [3, 4]. The leaves and twigs of R. dauricum display significant anti-HIV activity [5]. The leaf and flower powder of R. lepidotum have been used as a snuff in the treatment of headache [6], etc. Coumarin glycosides such as rhodonin and rhodonetin [7], 7-O--D-glucopyranosyl-8-methoxybenzopyranone and 7-hydroxy-8-O--glycosylbenzopyranone [8], coumarins named daphnin, daphnetin, daphnetin glucoside, rhodonetin, rhodonin, and umbelliferone [9], 2,4,6-trihydroxacetophenone3,5-di-C--D-glucoside, lupeol, ursolic acid, avicularin, quercetin, myricetin, hyperoside, myricetin-3-O--Dxyloside, (+)-taxifolin-3-O--L-arabinopyranoside, (+)-taxifolin-3-O--D-glucopyranoside, lyoniside, confluentin, 2-(4-hydroxyphenyl)-ethyltriacontanoate, 2,6-dimethoxy-4-hydroxyphenyl-1-O--D-glucopyranoside, (–)-2-hydroxy-5-(2-hydroxyethyl)phenyl-O--D glucopyranoside, (–)-isolariciresinol, and isofraxoside [10] have been isolated from R. lepidotum. The leaves and twigs of Rhododendron lepidotum were collected from Godha Tabala Village of Langtang National Park (3800 m) of Nepal during November 2008. Four new compounds have been characterized from its biologically active crude methanol extract. Previously, the activity of the crude extract was determined by antimicrobial, IC50, brine shrimp, and antiproliferative (HeLa cell) tests [11]. The water-insoluble portion of the methanol extract was subjected to column chromatography to afford four triterpenoids (1–4). Compound 1 was obtained as a white solid on crystallization from acetone. The IR spectrum showed an ester carbonyl, and three methyl protons appeared in the 1H NMR spectrum, which was further supported by a peak at m/z 408 (M – CH3CO2H) in addition to the [M]+ 468 corresponding to the molecular formula C32H52O2 for 1. The 1H NMR spectrum showed the presence of a terminal alkene besides a vinylic methyl. The 13C NMR and DEPT confirmed CHEMICAL CONSTITUENTS OF Rhododendron lepidotum FROM NEPAL HIMALAYAS

Analysis of Selected Carbonyl Compounds in Tobacco Samples by Using Pentafluorobenzylhydroxylamine Derivatization and Gas Chromatography-Mass Spectrometry

SUMMARY A simple, accurate, and reliable method for routine analysis of trace carbonyl compounds, including formaldehyde, acetaldehyde, acetone, propionaldehyde, methyl-ethyl ketone (MEK), butyraldehyde, and crotonaldehyde, in processed tobacco products was developed. One gram of tobacco sample was spiked with a mixture of isotopelabeled carbonyls as internal standards and extracted with water. A portion of aqueous extract was derivatizated with o-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine hydrochloride (PFBHA). The PFBHA derivatives of carbonyls were extracted with hexane and analysed by gas chromatography- mass spectrometry (GC-MS). The accuracy and precision of the method were evaluated with spiked Kentucky Reference Cigarette 3R4F and CORESTA smokeless reference products CRP1, CRP2, CRP3, and CRP4. For the investigated carbonyl compounds, excellent recoveries (95-107%) and precisions (5-10%) were achieved with different spiked tobacco products, with the exception of acrolein, which was found unstable in all tested tobacco products. The linear range of the developed method was from 0.07 to 36 μg/g with limits of quantification ranged from 0.10 to 0.15 μg/g. Using this method, formaldehyde (0.31-6.24 μg/g) and acetaldehyde (0.84-17.7 μg/g) were detected in all tested reference tobacco products. Acetone (0.55-2.12 μg/g) was found in 3R4F, CRP1, CRP2, and CRP3. Detectable levels of propionaldehyde were only found in CRP1 and CRP3. The levels of MEK, butyraldehyde, and crotonaldehyde in all tested reference products were below the method quantification limits. It was found that the effects of storage conditions (storage time, container, and temperature) on yields of carbonyls detected in reference tobacco product samples (3R4F, CRP2, CRP3) were dependent on compound and sample matrix: the concentrations of formaldehyde in all tested reference products gradually increased as the storage time increased, while the concentrations of acetone in 3R4F samples dramatically decreased as the storage time increased. [Beitr. Tabakforsch. Int. 26 (2014) 86-97]

In vitro evaluation of potential bitterness-masking terpenoids from the Canada goldenrod (Solidago canadensis).

In a screening of extracts of selected plants native to Ohio against the human bitterness receptor hTAS2R31, a chloroform-soluble extract of the aerial parts of Solidago canadensis (Canada goldenrod) was determined to have hTAS2R31 antagonistic activity and, thus, was fractionated for isolation of potential bitterness-masking agents. One new labdane diterpenoid, solidagol (1), and six known terpenoids, including two labdane diterpenoids (2 and 3), three clerodane diterpenoids (6β-angeloyloxykolavenic acid, 6β-tigloyloxykolavenic acid, and crotonic acid), and a triterpenoid (longispinogenin), were isolated. Among these compounds, 3β-acetoxycopalic acid (2) was found to be the first member of the labdane diterpene class shown to have inhibitory activity against hTAS2R31 activation (IC50 8 μM). A homology model of hTAS2R31 was constructed, and the molecular docking of 2 to this model indicated that this diterpenoid binds well to the active site of hTAS2R31, whereas this was not the case for the closely structurally related compound 3 (sempervirenic acid). The content of 2 in the chloroform-soluble portion of the methanolic extract of S. canadensis was up to 2.24 g/100 g dry weight, as determined by HPLC.

Evaluation of fractions and isolated polysaccharides from Sasa veitchii for their preventive effects on influenza A virus infection

The fractions and polysaccharides from Sasa veitchii were evaluated for their preventive effects on influenza A virus (IFV-A) infection. In IFV-A infected mice, the high-molecular portion (SH) of hot-water extract from S. veitchii significantly reduced virus yields in lung and bronchoalveolar lavage fluid (BALF) and increased in IFV-A-specific secretory IgA in BALF and intestine samples, and neutralizing antibody titers in BALFs and sera. Separation of SH by combination with ion-exchange column and gel filtration yielded six purified polysaccharides. Among them, SH2A1B1 with molecular weight of 29.7 kDa was found to reduce virus yields in lung as well as BALF in IFV-A-infected mice. A significant increase in the production of neutralizing antibody was also observed in BALFs on day 15 post-infection. Furthermore, significant enhancement of nitrite oxide production in RAW 264.7 cells was observed. These results suggest that the fractions from S. veitchii and SH2A1B1 could provide useful materials for prevention of IFV-A infection.

DETERMINATION OF FLORFENICOL AMINE IN SWINE MUSCLE BY HYDROPHILIC INTERACTION LIQUID CHROMATOGRAPHY–TANDEM MASS SPECTROSCOPY

Nuflor (florfenicol) Premix for Swine is approved by the U.S. Food and Drug Administration (FDA) and the same regulatory agencies from many other countries for control of swine respiratory disease. A simple and fast LC-MS/MS method for the assay of florfenicol amine, the marker residue of florfenicol in swine muscle is described. A 24-hr strong acid hydrolysis of tissue residues converts florfenicol and its known metabolites into florfenicol amine and also fully releases florfenicol amine from florfenicol residues covalently bound to the swine muscle. The majority of fatty acids and lipids are removed via hexane extraction. Then, the pH of the extracted hydrolysate is adjusted to 11 and florfenicol amine is extracted by ethyl acetate. A portion of ethyl acetate extract is dried under nitrogen and reconstituted with 1 mL acetonitrile. Dispersive solid-phase extraction is used for cleanup in which 100 mg primary secondary amine sorbent is mixed with the extract. After the centrifugation, the supernatant is diluted 20-fold for a hydrophilic interaction LC-MS/MS analysis. No matrix effect is observed in the LC-MS/MS assay and the recovery is nearly 100%. In the comparison with the current US FDA Center for Veterinary Medicine regulatory surveillance method, the new method is simple, fast, and accurate. The validated method is used to investigate the depletion of florfenicol from the swine administrated with Nuflor (florfenicol) Premix.

Catalytic hydroconversion of extraction residue from Shengli lignite over Fe–S/ZSM-5

A highly dispersive Fe/ZSM-5 as the precursor of Fe–S/ZSM-5 was prepared by decomposing Fe(CO)5 onto ZSM-5 zeolite at 250°C. Shengli lignite (SL) was isolated to extractable portion (EP) and extraction residue (ER) by exhaustive extraction with isometric carbon disulfide/acetone mixed solvent (IMCDSAMS) under ultrasonic irradiation. The EP and ER were analyzed with a direct analysis in real time ionization source coupled to ion trap mass spectrometer. Both of them and SL were analyzed with a Fourier transform infrared spectrometer. The ER was subjected to non-catalytic hydroconversion (NCHC) and catalytic hydroconversion (CHC) over Fe–S/ZSM-5, which was formed by in situ reaction of Fe/ZSM-5 with sulfur added, in cyclohexane under pressurized hydrogen at 300°C. The reaction mixtures were sequentially extracted with petroleum ether, carbon disulfide, methanol, acetone, and IMCDSAMS to afford extracts 1–5 (E1–E5), which were analyzed with a gas chromatography/mass spectrometer (GC/MS). As model reactions, the CHCs of di(1-naphthyl)methane (DNM) and diphenylmethane (DPM) over Fe–S/ZSM-5 were also conducted in cyclohexane at 300°C. The results show that more than 50% of organic matter in the ER was converted to a soluble portion by the CHC, whereas the yield of soluble portion from the NCHC is only 10.52%. GC/MS-detectable species only appear in the E1, which mainly consists of alkanes, arenes, and arenols either from the NCHC or from the CHC. DNM was selectively hydrocracked to naphthalene and 1-methylnaphthalene over Fe–S/ZSM-5, while DPM hydrocracking did not proceed, indicating that Fe–S/ZSM-5 catalyzed the formation of radical hydrogen from molecular hydrogen and subsequent radical hydrogen transfer (RHT) to the ipso-position of naphthalene ring in DNM. Some CH2 and O in the ER could be connected to condensed aromatic rings (CARs). Analogously, RHT to the ipso-position of CARs in the ER resulted in the release of arenes and phenols from the ER.

Rapid chemical characterisation of stilbenes in the root bark of Norway spruce by off-line HPLC/DAD-NMR.

Stilbenes are plant secondary metabolites that have shown promising and varied biological activities. Stilbenes are presently actively studied for the exploitation of this primary raw material resource, involving the concept of biorefining. Methods for the rapid discovery of new and known stilbene structures from various plant sources are thus keenly sought. To establish a simple and rapid technique of off-line HPLC with a diode-array detector (DAD) and NMR for the unambiguous structural elucidation of stilbene structures in the root bark of Norway spruce [Picea abies (L.) Karst.]. The stilbene containing fraction was extracted from the plant bark with an ethanol:water mixture (95:5, v/v) preceded by defatting of hydrophobic compounds with n-hexane using the accelerated solvent extraction technique. A portion of the ethanol-water soluble extract was hydrolysed with β-glucosidase to prepare stilbene aglycones. The extracts were further purified and enriched using a polymeric adsorbent. Stilbene-enriched extracts were directly characterised by off-line HPLC/DAD-NMR in conjunction with HPLC/DAD and HPLC/DAD with electrospray ionisation MS(n). Trans-isorhapontin and trans-astringin were identified as the major, and trans-piceid as a minor, stilbene glucosides of the bark of roots of Picea abies. Not only stilbene glucosides but also the corresponding stilbene aglycones, such as trans-resveratrol, trans-piceatannol and trans-isorhapontigenin, were rapidly identified from the hydrolysed extract. The acquired heteronuclear single-quantum coherence and heteronuclear multiple bond correlation spectra were used to assign the complete carbon NMR chemical shifts of trans-isorhapontin and trans-astringin without the need of acquiring a (13)C-NMR spectrum. The off-line HPLC/DAD-NMR method is expedient for the unambiguous identication of structurally similar stilbenes in plant extracts.

English

Acanthospermum hispidum (Asteraceae), used ethnomedically in the treatment of inflammatory conditions and fever, was evaluated for antiprotozoal activities such as trypanocidal and antiplasmodial effects. This study was carried out to investigate the anti-trichomonal potential of the plant. The air-dried leaf was extracted successively with petroleum ether, chloroform, ethylacetate and methanol using the soxhlet extraction method. Bioactivity-guided fractionation of the most active extract was carried out using the vacuum liquid chromatographic technique for antitrichomonal activity using Trichomonas gallinae in vitro. The ethyl acetate extract (A3) was the most active extract with LC50-LC90 values of 0.58-1.06 and 0.58-1.05 mg/ml at 24 and 48 h, respectively. Subfraction C7 had the highest antitrichomonal activity with 0.25-0.66 and 0.25-0.54 mg/ml at 24 and 48 h, respectively comparable to the activity of metronidazole at 0.20-0.39 and 0.16-0.36 mg/ml at 24 and 48 h, respectively. A . hispidum possessed antitrichomonal activity which resided in the chloroform portion of the ethyl acetate extract of the plant. Keywords: Trichomonas gallinae , vacuum liquid chromatography, antiprotozoal African Journal of Biotechnology , Vol 13(11), 1303-1307

The first report on flavonoid isolation from Annona crassiflora Mart

Annona crassiflora, a native tree from Brazilian Cerrado, is reported to possess several ethnomedical uses. Here, we report the isolation and unambiguous characterisation of the flavonoids quercetin-3-O-β-D-glucopyranosil(1 → 6)-O-α-L-arabinoside (1), known as peltatoside, kaempferol-3-O-β-D-galactopyranoside (2), quercetin-3-O-β-D-galactopyranoside (3), quercetin-3-O-β-L-arabinopiranoside (4) and the ( − )-epicatechin (5) from the hydroalcoholic portion of the leaf ethanolic extract. Their structures were elucidated by using 1D and 2D NMR, ESI-MS, UV/Vis spectroscopy, optical rotation analysis and literature data comparison. The leaf ethanolic extract and its isolated compounds were evaluated by using antimicrobial, antioxidant and larvicidal assays, expressing antimicrobial and antioxidant activities. This is the first report on flavonoid isolation from A. crassiflora.

Libidibia ferrea mature seeds promote antinociceptive effect by peripheral and central pathway: possible involvement of opioid and cholinergic receptors.

Libidibia ferrea (LF) is a medicinal plant that holds many pharmacological properties. We evaluated the antinociceptive effect in the LF aqueous seed extract and Lipidic Portion of Libidibia ferrea (LPLF), partially elucidating their mechanisms. Histochemical tests and Gas chromatography of the LPLF were performed to characterize its fatty acids. Acetic acid-induced abdominal constriction, formalin-induced pain, and hot-plate test in mice were employed in the study. In all experiments, aqueous extract or LPLF was administered systemically at the doses of 1, 5, and 10 mg/kg. LF aqueous seed extract and LPLF demonstrated a dose-dependent antinociceptive effect in all tests indicating both peripheral anti-inflammatory and central analgesia properties. Also, the use of atropine (5 mg/kg), naloxone (5 mg/kg) in the abdominal writhing test was able to reverse the antinociceptive effect of the LPLF, indicating that at least one of LF lipids components is responsible for the dose related antinociceptive action in chemical and thermal models of nociception in mice. Together, the present results suggested that Libidibia ferrea induced antinociceptive activity is possibly related to its ability to inhibit opioid, cholinergic receptors, and cyclooxygenase-2 pathway, since its main component, linoleic acid, has been demonstrated to produce such effect in previous studies.

The surface reactivity of chalk (biogenic calcite) with hydrophilic and hydrophobic functional groups

The surface properties of calcium carbonate minerals play an important role in a number of industrial and biological processes. Properties such as wettability and adsorption control liquid–solid interface behaviour and thus have a strong influence on processes such as biomineralisation, remediation of aquifers and oil recovery. We investigated how two model molecules of different polarity, namely water and ethanol, interact with reservoir and outcrop chalk samples and we compared their behaviour with that of pure, inorganically precipitated calcite. Thermodynamic quantities, such as the work of wetting, surface energy and isosteric adsorption enthalpy, were determined from vapour adsorption isotherms. The chalks were studied fresh and after extraction of organic residues that were originally present in these samples. The work of wetting correlates with the amount of organic matter present in the chalk samples but we observed a fundamental difference between the adsorption properties of chalk and pure, inorganically precipitated calcite toward the less polar, ethanol molecule. Further analysis of the chemical composition of the organic matter extracted from the chalk samples was made by gas chromatography (GC–MS). Monitoring surface composition by X-ray photoelectron spectroscopy (XPS) before and after extraction of the organic material, and with atomic force microscopy (AFM), showed that nanometer sized clay crystals observed on the chalk particle surfaces could be an important part of the reason for the differences. Removal of the extractable portion of the hydrocarbons liberates adsorption sites that have different wetting properties than the rest of the chalk and these have an energy distribution that is similar to clays. Thus, the results exemplify the complexity of biogenic calcite adsorption behaviour and demonstrate that chalk wetting in drinking water aquifers as well as oil reservoirs is controlled partly by the nanoparticles of clay that have grown on the chalk surfaces and partly by adsorbed organic material.

A Bicyclic Diterpenoid with a New 15,16-Dinorlabdane Carbon Skeleton from Leonurus japonicus and Its Coagulant Bioactivity

A new 15,16-dinorlabdane diterpenoid 1 and a known labdane diterpenoid 2, together with three known ergosterols 3–5, were isolated from the EtOAc-soluble portion of the EtOH extract of Leonurus japonicus. Their structures were elucidated by physical and spectroscopic analysis. Compound 1 showed in vitro coagulant activity in the APTT, PT, TT, and FIB assays.

Stilbenoids from Vitis labrusca “Isabella” Stems

Studies on the chemical constituents of each part of the Vitis species, especially Vitis vinifera L., have been performed since this species has promising biological activities, including antioxidant [1,2] and anticancer activities [3,4]. Meanwhile, investigations on the chemical composition of Vitis labrusca, to which the American grape belongs, have never been reported. This paper reports for the first time the chemical components of Vitis labrusca “Isabella”. The stems of V. labrusca “Isabella” were collected from Kebun Percobaan Banjarsari, Probolinggo, East Java, Indonesia in April 2008. The dried-powdered stems (3.0 kg) were cold extracted using methanol at room temperature for 62 hours. The methanolic extract (342.14 g) was dissolved in methanol–water (9:1) and re-extracted successively with n-hexane (17.78 g) and ethyl acetate (145.36 g). The ethyl acetate extract was investigated. A portion of the ethyl acetate extract (135.36 g) was fractionated by vacuum liquid chromatography using Merck silica gel 60 (230–400 mesh) with a solvent gradient of n-hexane–ethyl acetate to give 10 major fractions. Fractions 4 and 5 were further purified using several chromatographic techniques, including column chromatography on a glass column using Merck silica gel 60 (70–230 mesh), medium- pressure chromatography using Supelco Versa Pack Silica Cartridge (40 × 75 mm), prep-TLC and centrifugal prep-TLC using Merck silica gel PF254, and also by Sephadex LH-20. TLC analysis was performed on Merck pre-coated silica gel F254 plates (2 mm thickness), and spots were visualized by UV light (254 and 365 nm) and spraying with vanillin sulfuric acid reagent followed by heating. Melting points were measured using a melting point apparatus equipped with a Leica Gallen III microscope and were uncorrected. Five compounds were isolated from the ethyl acetate extract. Based on the spectroscopic analysis and comparison with previously reported data, compounds 1–5 were identified as resveratrol (1) [5,6], e-viniferin (2) [7,8], pallidol (3) [9], ampelopsin A (4) [8,10], and α-viniferin (5) [11]. The 1H NMR (400 MHz) and 13C NMR (100 MHz) spectra were recorded on a Bruker Avance 400 spectrometer using acetone-d6 as the solvent. Residual solvent was used as an internal standard. The IR spectra were run on PerkinElmer FT-IR spectrometer recorded in KBr pellet. The UV spectra were taken on a Perkin–Elmer UV-Vis spectrophotometer. Mass and LC-MS spectra were obtained from Kent Mass Spectrometry Services, United Kingdom and Department of Metrology, SIRIM BHD, respectively.

Isolation of Gallic Acid and Estimation of Total Phenolic Content in Some Medicinal Plants and Their Antioxidant Activity

Gallic acid was isolated from ethylacetate soluble portion of the methanol extract of fruit pulp of Terminalia chebula and characterized by comparing the melting point, Rf values, UV and IR spectra with authentic gallic acid. Quantitative determination of phenolics from different extracts of medicinal herbs such as Adhatoda vasica Nees, Bergenia ciliata (Haw) Sternb, Phyllanthus emblica Linnaeus, Terminalia bellirica (Gaerth) Roxb, Terminalia chebula Retzius and Vitex negundo Linnaeus which are commonly used as home herbal remedies for the primary health care was carried out using Folin-Ciocalteu colorimetric method. Gallic acid was used as the standard for the estimation of phenolics. All the investigated plant extracts contained high amount of phenolics but the highest amount was detected in 70% acetone extract of B. ciliata (357.08 mg GAE/g sample) and the lowest amount was detected in 50% aqueous methanol extract of T. bellirica (108.69 mg GAE/g sample). The antioxidant activity of selected extracts was determined by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay. The extract having the highest phenolic content showed the lowest IC50 demonstrating the positive correlation between radical scavenging activity and total phenolic content. Nepal Journal of Science and Technology Vol. 14, No. 1 (2013) 95-102 DOI: http://dx.doi.org/10.3126/njst.v14i1.8928