Recursos de colección

Universidad Nacional de La Plata (74.783 recursos)

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vol. 30, no. 03

Mostrando recursos 1 - 20 de 36

  1. Determination of galangin in commercial extracts of Alpinia officinarum by RP-HPLC-DAD

    Verza, Simone G.; Pavei, Cabral; Borré, Gustavo Luis; Silva, Ana P. C.; González Ortega, George; Mayorga, Paulo
    Alpinia officinarum has been used by long time in the traditional medicine and several commercial extracts containing it are available on the market. In this paper a reversed phase high performance liquid chromatography-diode array detection (RP-HPLC-DAD) method for Alpinia officinarum preparations was proposed using galangin as a marker. The quantification was undertaken by a combination of RP-HPLC-DAD. The LC system employed a Gemini Phenomenex RP-18 column with phosphoric acid, tetrahydrofuran and acetonitrile as mobile phase and detection at 267 nm. The method validation was throughout satisfactory. The determination coefficient was r2 = 0.998 with LOD 0.48 µg mL-1 and LOQ...

  2. Apparent molar volumes of sodium naproxen in water at several concentrations and temperatures

    Holguín, Andrés R.; Delgado, Daniel R.; Ruidiaz, Miller A.; Vargas, Edgar F.; Martínez, Fleming
    Densities of aqueous solutions of sodium naproxen have been measured as functions of concentration (from 0.0250 to 0.5000 mol kg-1 ) and temperature (from 278.15 to 313.15 K). The apparent molar volumes, partial molar volumes at infinite dilution and partial molar expansibility were calculated. The dependence of these properties with temperature is also shown. The results are interpreted in terms of solute-solvent interactions.

  3. Determination of troxerutin in rabbit plasma by LC-ESI-MS and its application to a pharmacokinetic study

    Ma Jianshe; Zhang, Yuqing; Zhang, Meiling; Fan, Xiaofang; Shentu, Yangping; Wang, Xianqin; Wang, Zhibin; Wang, Zhiyi
    A sensitive and selective liquid chromatography/electrospray mass spectrometry (LC-ESIMS) method for determination of troxerutin in rabbit plasma was developed. After addition of paeoniflorin as internal standard (IS), protein precipitation by methanol: acetonitrile (3:1, v/v) was used as sample preparation. Chromatographic separation was achieved on an Allure (TM) PFP Propyl (2.1 mm × 100 mm, 5 μm) column with methanol-water as mobile phase with gradient elution. Electrospray ionization (ESI) source was applied and operated in positive ion mode; selected ion monitoring (SIM) mode was used to quantification using target fragment ions m/z 765 for troxerutin and m/z 503 for the IS....

  4. Alkaloid isomerization induced by spray drying of Uncaria tomentosa bark extracts

    Pavei, Cabral; Borré, Gustavo Luis; Kaiser, Samuel; González Ortega, George
    Cat's claw (Uncaria tomentosa (Willd) DC) is an alkaloid rich-liana from the Peruvian Amazon rainforest. Regarding several oxindole alkaloids from cat's claw bark, the isomerization induced by pH, temperature and solvent polarity is reported in the literature. Some industrial drying processes, such as spray drying, can provide therefore favorable conditions of heating and moisture for isomerization, and it is expected to have effects on the alkaloid composition during technological processing. In this work we focused on the effect of spray drying on the isomerization of alkaloids of dried extracts obtained from Uncaria tomentosa bark. High isomerization levels were observed in...

  5. In vitro photoprotective activity of plants extracts from Zona da Mata Mineira (Brazil)

    Polonini, Hudson C.; Caneschi, César A.; Brandão, Marcos A. F.; Raposo, Nádia N. B.
    Many plants have recently been considered as potential sunscreen resources because of their capacity to absorb the solar ultraviolet radiation. The objective of this work was to evaluate the sunscreen activity of ten Zona da Mata Mineira plants extracts by in vitro test using ultraviolet spectrophotometry. From the studied species, three (Lantana aff. fucata Lindl, Solidago microglossa DC and Stachytarpheta gesnerioides Cham.) showed sun protection factor (SPF) higher than 2, which is the minimum value required by the Brazilian legislation to label a product as containing a SPF. These results suggest that it can be possible to utilize these species...

  6. Laccase-based biosensor for determination of acetaminophen

    Cordeiro, Diogo D.; Gil, Éric S.
    The use of biosensors based on laccase is an interesting alternative for monitoring phenolic compounds in pharmaceutical and environmental analysis. The detection and determination of acetaminophen in pharmaceutical samples, using a biosensor with carbon paste modified with laccase is described. The method showed good linearity (r = 0.9954) and low detection and quantification limits (2.4 x 10-6 mol.L-1 and 7.9 x 10-6 mol.L-1, respectively). Furthermore, the proposed methodology using an enzyme electrode showed appropriated reproducibility and selectivity.

  7. Morphoanatomy and phytochemical screening of entire fruits of Momordica tuberosa Cogn. (Cucurbitaceae)

    Kumar, Pramod; Devala Rao, G.; Lakshmayya, B.; Ramachandra Setty, S.
    Momordica tuberosa (Cucurbitaceae) is traditionally used as abortifacient in India. Morphoanatomy, physicochemical and phytochemical nature of fruits and seeds of this plant were studied in order to contribute to complete the profile of these parts to aid in their identification and avoid confusion in taxanomic species. Macroscopic and microscopic characters were established using light microscopy, WHO recommendations and standard physicochemical and phytochemical procedures. Fruits presented the typical characters of Cucurbitaceae plants possessing ridges with 1 mm thickness and pericarp 550 µm thick. Phytochemical screening revealed the presence of flavonoids, steroids, triterpenes and alkaloids in various extracts. The findings from morphoanatomy,...

  8. Preliminary experimental diuretic activity of plants used by cuban population

    Pérez, Maykel; Boffill Cárdenas, María de los Ángeles; Morón, Francisco; Monteagudo, Emilio; Sueiro, Mario L.; Lorenzo Monteagudo, Geidy
    Diuretic activity of five medicinal plants (Cassia alata L., Zanthoxylum fagara L., Nectandra coriacea Sw, Costus pictus D. Don, and Persea americana Miller) used by Cuban population was assessed. Plants decoctions (30 %) were applied to Wistar male rats (400 mg/kg BW), based on total solids and completed with physiological saline solution up to a total constant administration volume of 40 ml/kg BW and administered to 7 experimental groups: 5 treated, a positive control (furosemide, 20 mg/kg) and a negative control (NaCl, 0,9 %). Animals were placed in metabolic cages, decoctions administered and urinary excretion quantified after ½, 1, 2,...

  9. Influence of ACE inhibitors on the ECG of acute renal hypertension induced rats

    Moinuddin, Ghulam; Inamdar, Mohammed N.; Kulkarni, Kala S.; Kulkarni, Chanda
    The present study was designed to assess the influence of ACE inhibitors on the electrocardiograph of acute renal hypertensive rats. Acute Renal Hypertension (ARH) was induced in healthy Wistar male rats by clamping/occluding the left renal artery for 4 h. The ECG of the control (normotensive), sham-Operated, hypertensive and ARH Induced rats, treated with ramipril (2.5 mg/kg b.w. p.o) and captopril (4 mg/kg b.w. p.o.) were recorded using the computerized ECG recording system (NIVIQURE). The RR intervals in hypertensive rats were increased significantly when compared to control group. Ramipril increased the RR interval significantly (P < 0.001). However, captopril did...

  10. Pharmacological explanation for medicinal use of St. John's wort in the hypo-motility disorder of gut

    Khan, Arif-ullah; Gilani, Anwarul-Hassan; Khan, Munasib; Subhan, Fazal
    St. John's wort (Hypericum perforatum) is widely used in traditional medical system as a laxative agent against gastrointestinal hypo-motility disorders, such as constipation. The present research was carried out to rationalize its therapeutic potential in constipation. St. John's wort aqueous extract (Sw.Aq), which tested positive for presence of flavonoids, saponins and tannins caused concentration-dependent (1.0-10 mg/mL) contractile effect in the isolated rabbit jejunum preparations. Pretreatment of tissues with atropine (0.1 µM) abolished the stimulatory effect of Sw.Aq, suggesting that the spasmogenic effect of St. John's wort is mediated possibly through muscarinic receptor activation. In the in-vivo studies, Sw.Aq exhibited laxative...

  11. Determination of gemcitabine in rabbit plasma by LC-ESI-MS using an Allure PFP propyl column

    Lin, Guanyang; Hu, Lufeng; Pan, Yibin; Wang, Xianqin
    A sensitive and selective liquid chromatography/electrospray mass spectrometry (LC-ESIMS) method for determination of gemcitabine in rabbit plasma was developed. Chromatographic separation was achieved on a Restek Allure (TM) PFP Propyl (2.1 mm × 100 mm, 5 µm) column with (85: 15, v/v) methanol-water as mobile phase. Electrospray ionization (ESI) source was applied and operated in positive ion mode; selected ion monitoring (SIM) mode was used to quantify gemcitabine using target fragment ions m/z 264. Calibration plots were linear over the range of 5-4000 ng/mL for gemcitabine in plasma. Lower limit of quantitation (LLOQ) for gemcitabine was 5 ng/mL. Mean recovery...

  12. Quantitative structure activity relationship studies of some 5-aryl thiazolidine-2, 4-diones as antidiabetic agents

    Sonawane, Lalit V.; Bari, Sanjaykumar B.
    Quantitative Structure Activity Relationship (QSAR) studies were carried out for a series of 16 compounds which acts as ligands for PPAR-γ receptor. TSAR software was used to identify the essential structural and physicochemical features for their PPAR-γ agonistic activity by performing multiple regression analysis. Significant correlation coefficients (q² = 0.9178) was obtained. The predicted values are in good agreement with the observed activity, suggesting that the model could be useful in the design of novel, more potent PPAR-γ agonist.

  13. A simple HPLC method for determination tobramycin in plasma and Iis application in the study of pharmacokinetics in rats

    Zhang, Zhenyuan; Peng, Jingdong
    A simple HPLC method was developed to study the pharmacokinetics of tobramycin in rat after intravenous administration. The plasma samples were deproteinized with acetonitrile after addition of the internal standard, netilmicin. The separation was achieved on a reversed-phase C18 column after derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) in borate buffer (0.2 M, pH 6.5) for 15 min at 25 ºC. The mobile phase was water-acetonitrile (6:94, v/v) at a flow rate of 1.0 mL/min. The fluorescence excitation and emission wavelengths were 265 and 315 nm, respectively. The method was linear over the range of 0.12-10.48 μg/mL for tobramycin in plasma. The...

  14. Gastroprotective effects of Bauhinia purpurea, Dolichos lablab and Vitex parviflora

    Tarin, Janel K.M.R.; Chichioco Hernández, Christine L.
    Peptic ulcer is a chronic and recurrent disease affecting millions of people worldwide. Ulcerations can be brought about by inadequate dietetic habits leading to diminished mucosal resistance, increased acid secretion, or infection by Helicobacter pylori. Methanolic extracts from the leaves of Bauhinia purpurea, Dolichos lablab and Vitex parviflora were evaluated for their efficacy as an antiulcer agent in ethanol and aspirin-induced models in mice. All three plant extracts significantly reduced the number of ulcerations in both models of ulcer. Alkaloids, flavonoids, terpenoids, phenolic compounds and saponins were also found in the extracts and their bioactivity could be attributed to the...

  15. Microbiological assay for apramycin soluble powder

    Lourenço, Felipe R.; Barbosa, Elisabete A.; Pinto, Terezinha J. A.
    The aim of this study was to validate an agar diffusion method through the parameters linearity, precision and accuracy, to quantify apramycin in soluble powder. The calibration curve of apramycin was constructed by plotting log of concentrations (µg ml-1) versus zone diameter (mm) and shows good linearity in the range of 1.0-4.0 µg ml-1. The precision of the assay was determined by assaying samples at the same day (repeatability - R.S.D. = 2.00%) and on different days (intermediate precision - R.S.D. = 5.06%) and indicate good precision. The accuracy expresses the agreement between the accepted value and the value found. The mean recovery...

  16. Antimicrobial and cytotoxic activity from Lasia spinosa and isolated lignan

    Alam, Fakrul; Haque, Mozammel; Sohrab, Hossain; Monsur, Mohammad A.; Hasan, Choudhury M.; Ahmed, Nuruddin
    Studies were carried out on the rhizome of Lasia spinosa (L.). The petroleum ether, ethyl acetate and the methanolic extract revealed moderate activities against Escherichia coli, Bacillus cereus, Staphylococcus aureus, Candida albicans, Aspergillus niger and Vibrio parahemolyticus test organisms. The crude extracts and purified compound, meridinol (1) were screened for antimicrobial activity against a wide range of gram-positive and gram-negative bacteria and fungi by the disc diffusion method. The cytotoxic potential of the extractives and meridinol was also determined by using brine shrimp lethality bioassay, where the extractives demonstrated significant cytotoxic activities. The petroleum ether, ethyl acetate, methanol extracts, one...

  17. Hepatoprotective activity of Cayratia trifolia (L.) domin against nitrobenzene induced hepatotoxicity

    Guru Kumar, Dugganaboyana; Sonumol, Vattachanakkal M.; Rathi, Muthaiyan A.; Thirumoorthi, Lakshmanan; Meenakshi, Periasamy; Gopalakrishnan, Velliyur K.
    The hepatoprotective activity of ethanolic extract of the whole plant of Cayratia trifolia (L.) Domin was evaluated against nitrobenzene (NB) (50 mg/Kg bw, orally) induced hepatic damage in rats. The extract at the dose of 200 mg/kg body weight were administered orally once every day for 7 successive days. The treatment restores the elevated levels of the liver marker enzymes such as alanine amino transferase, aspartate amino transferase, alkaline phosphatase in serum and lipid peroxidation in tissue homogenate. Whereas the antioxidant enzymes such as superoxide dismutase, catalase and glutathione peroxidase remains decreased in carcinogen induced group and after treatment the levels of antioxidant...

  18. Isolation and identification of compounds present in rhizomes of Paris axialis H. Li and study of their cytotoxic effects

    Huang, Xianxiao; Gao, Wenyuan; Man, Shuli; Gao, Ying; Huang, Luqi; Liu, Changxiao
    Ten compounds were isolated from the rhizomes of Paris axialis H. Li (PA). Based on spectral data, the isolated compounds were identified as Diosgenin (1), Paris saponin V (2), Paris saponin VI (3), Paris saponin I 4), Paris saponin H (5), Paris saponin II (6), Paris saponin VII (7), luteolin (8), luteoloside (9), isorhamnetin-3-O-α-L-rhamnopyranosyl (1→2)-β-D-glycopyranoside (10). Their cytotoxicity on LA795 cells was evaluated. Paris saponins and flavonoids have synergistic anti-tumor effect on LA795 cells.

  19. Effect of pH, vehicles and chemical enhancers on the skin permeation of loratadine

    Li, Zhen; Hao, Tangna; Ding, Pingtian; Mei, Lin; Gao, Dongyan; Liu, Kexin; Tian, Yan; Li, Lei; Tian, Ge
    The objective of this work was to investigate feasibility of transdermal delivery of loratadine. Effect of pH, vehicles and chemical enhancers on the skin permeation of loratadine was studied in vitro, using rat abdominal skin as a barrier. In the permeation studies, horizontal 2-chamber diffusion cells were used. The amount of loratadine transferred through the skin into the receptor solution, 30 % ethanolsaline solution (v/v), was determined at a predetermined time intervals for 8 h using a high performance chromatography (HPLC). The results showed that transdermal transport of loratadine was not significantly affected by pH. 30 % ethanol-saline solution in...

  20. Quantitative determination of amlodipine besylate in tablets by high performance liquid chromatography and UV spectrophotometry

    Leite, Helen D.; Santoro, Maria Ines Rocha Miritello; Porto, João M.A.; López García, Pedro; Almeida, Mariana M. de; Tavares, Vanessa F.; Kedor-Hackmann, Erika R.M.
    The purpose of this study was to develop and validate analytical methods for determination of amlodipine besylate in tablets. Simple, accurate and precise liquid chromatographic and spectrophotometric methods are proposed. For the chromatographic method, the conditions were: a LiChrospher®100 RP-18 Merck® (125 mm x 4.6 mm, 5 µm) column; methanol/water containing 1 % of trietylamine adjusted to pH 5.0 with phosphoric acid (35:65) as mobile phase; a flow rate of 1.0 mL/min and UV detector at 238 nm. Linearity was in the range of 50.0 - 350.0 µg/mL with a correlation coefficient (r) = 0.9999. For the spectrophotometric method, the...

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