Adsorption of chlorhexidine on synthetic hydroxyapatite and in vitro biological activity

The kinetic of chlorhexidine digluconate (CHXDG) uptake from aqueous solution by hydroxyapatite (HA) was investigated by ultraviolet (UV) analysis performed in HA powder (UV-solid) after the CHX adsorption. Adsorption isotherm of chlorhexidine (CHX) uptake was modeled by a combination of Languimir and Langmuir-Freundlich mechanisms. Strong molecule-molecule interactions and positive cooperativity predominated in the surface when CHX concentration was above 8.6 μg(CHX)/mg(HA). UV-solid spectra (shape, intensity and band position) of CHX bound to HA revealed that long-range molecular structures, such as aggregates or micelles, started to be formed at low CHX concentrations (1.52 μg(CHX)/mg(HA)) and predominated at high concentrations. Grazing-incidence X-ray diffraction (GIXRD) analysis from synchrotron radiation discarded the formation of crystalline structures on HA surface or precipitation of CHX crystalline salts, as suggested in previous works. The effect of the HA/CHX association on HA in vitro bioactivity, cytotoxicity and CHX antimicrobial activity was evaluated. It was shown that CHX did not inhibit the precipitation of a poorly crystalline apatite at HA/CHX surface after soaking in simulating body fluid (SBF). Cell viability studies after exposure to extracts of HA and HA/CHX showed that both biomaterials did not present significant in vitro toxicity. Moreover, HA/CHX inhibited Enterococcus faecalis growth for up to 6 days, revealing that binding to HA did not affect antimicrobial activity of CHX and reduced bacterial adhesion. These results suggested that HA/CHX association could result in a potential adjuvant antimicrobial system for clinical use.     

Role of surface activity in the biological actions of ranitidine and famotidine

The role of surface activity has been studied in the biological actions of ranitidine (RNT) and famotidine (FMT). The drugs have been shown to generate liquid membranes in series with a supporting membrane with the virtue of their amphiphilicity. Transport of histamine, acetylcholine, and ions (chloride, bicarbonate, potassium, sodium and calcium) have been studied in the presence of liquid membranes generated by surface-active RNT and FMT. The data on the modifications in the permeability of histamine, acetylcholine and ions indicate that the liquid membranes generated by RNT and FMT may play a significant role in their biological action.

The surface-active nature of the drugs has been discussed with relevance to their pharmacological effects.     

Photo-induced synthesis and in vitro biological activity of a Sansalvamide A analog

Photoinduced single electron transfer (SET) cyclization processes for synthesis of a Sansalvamide A analog containing double pharmacophores (cyclicpeptides and O-phthalimide moiety) is described to develop novel antitumor cyclopeptide drug. The resultant compound is active in drug-sensitive HeLa, HepG-2 and MCF-7 cell lines. Specifically, the title compound was found to inhibit MCF-7 cells with an IC₅₀ value of 15 μM (13.4 μg/mL), which may serve as a potential candidate for antitumor drug development.     

Photosensitized oxidation of cholesterol in biological systems: reaction pathways, cytotoxic effects and defense mechanisms.

Cholesterol resembles other unsaturated lipids in being susceptible to peroxidative degradation when exposed to a sensitizing agent, exciting light of suitable wavelength and molecular oxygen. Selected hydroperoxides of cholesterol can be used as relatively convenient and reliable indicators of primary photochemical mechanisms, allowing a distinction to be made between free radical-mediated and singlet oxygen-mediated reactions. When generated in cell membranes, hydroperoxides of cholesterol and other lipids can have deleterious effects on membrane structure and function. Such damage may be exacerbated if these photoproducts undergo one-electron reduction to oxyl radicals which in turn initiate chain peroxidation reactions. Cells can resist these effects by using a membrane-based glutathione peroxidase to catalyze the two-electron reduction and detoxification of lipid hydroperoxides. Recent advances in our understanding of cholesterol photo-oxidation from the standpoints of (a) mechanistic information, (b) cytotoxicity and (c) cytoprotection are discussed in this article.     

Simultaneous determination of phosphorus-32 and calcium-45 activity in biological samples

Using the technique of liquid scintillation,³²P and⁴⁵Ca activites were determined in biological samples such as bones, blood, milk and egg shells, white and yolk. Samples were mineralized in 70% HClO₄ and 30% H₂O₂ at 70 °C and measured after addition of the “Aquasol” scintillation liquid. A correction for quenching was made by the method of sample channels ratio. High detection efficiencies were obtained, above 80% for⁴⁵Ca and about 50% for³²P in a second measuring channel. Recoveries amounted to 0.95–1.06 for³²P and to 0.93–0.98 for⁴⁵Ca.     

Flow microcalorimetry in monitoring biological activity of aerobic and anaerobic wastewater-treatment processes

A flow microcalorimetric system which is compatible with the experimental conditions of industrial processes was used to monitor the biological activity of wastewater-treatment systems. Two industrial wastewater-treatment processes were investigated: an activated-sludge (aerobic) treatment of a textile factory effluent and a methane fermentation (anaerobic) treatment of effluents from a cheese factory. In both types of system, the heat flux resulting from metabolic reactions during bacterial degradation of organic substances in the effluent could be measured adequately. Depending on the measurements selected, the calorimetric data could be used to monitor the bacterial activity in the bioprocess, or the effluent degradability or toxicity, or the overall content of degradable substrates in the effluent (loading). The non-invasive measurement of heat flux enabled continuous or semi-continuous on-line monitoring of these biological processes. The response time of the flow calorimetric unit is of the order of minutes, thus yielding process data with minimal delay. These data enable rapid intervention to optimize process parameters (e.g., to control the inlet flow rate or dilution, divert or dilute toxic contaminants, etc.).     

Biological activity of detonation nanodiamond and prospects in its medical and biological applications

The present review summarizes and analyzes recent advances in the field of medical and biological applications of detonation nanodiamond and, on this basis, considers most promising ways of creation of anticancer and antimicrobial drugs, diagnostic agents, and nanocompositions for orthopedic surgery. In addition, progress in the surface chemistry of detonation nanodiamond is discussed and problems related to purposeful surface modification with a view to obtain detonation nanodiamond with desired properties ensuring their successful application in biology and medicine are considered.     

Comparison of the biological activity of phytochemical compositions in native and liposomal forms

The biological activities of phytochemical compositions in native and liposomal forms were compared, and membrane-stabilizing and antioxidant properties of phytocompositions, which have an anti-inflammatory and wound-healing action on the cell walls of protozoa, were studied.     

Correlation of bilayer membrane cation transport and biological activity in alkyl-substituted lariat ethers

Dialkyldiaza-18-crown-6 lariat ethers having twin n-octyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl, 1-oxodecyl and 1-oxododecyl side arms were prepared and studied. Cation transport in liposomes mediated by these compounds showed discontinuous activity that correlated with toxicity to the bacteria E. coli and B. Subtilis, and the yeast S. Cerevisiae. Transport, toxicity and membrane depolarization studies all suggest that side chain length affords very different interactions in a bilayer membrane compared with bulk phases. An explanation for activity in terms of carrier transport and restricted transverse relaxation is proposed.     

Chemometrical analysis of computed QSAR parameters and their use in biological activity prediction

This study gives a quantitative structure-activity relationship (QSAR) correlation of the 72 N-benzylsalicylamide derivatives properties with their antimycobacterial activity. The antimycobacterial activity was measured as the minimal inhibition concentration (MIC) determined for four strains of mycobacterium (M. avium, M. kansasii, M. kansasii clin.-clinically isolated form, and M. tuberculosis) after 14 days and after 21 days of cultivation. The objective was to identify the factors most closely defining biological activity of N-benzylsalicylamides, in order to enable QSAR prediction of new derivatives with high antimycobacterial activity. Optimal properties for the QSAR analysis were selected from several physicochemical properties, including lipophilicity parameter log P, molecular mass M, molar refraction MR, NMR chemical shifts, polarizability, etc. Many of the considered properties are different from those typically used in traditional QSAR. Selection of the most important properties was performed by one-way Analysis of Variance (ANOVA) and correlation analysis using the significance coefficients and the correlation coefficients, respectively. The chosen variables were further used in artificial neural networks (ANN) for predicting biological activity in the form of-log(MIC). Presented at the 1st International Conference “Applied Natural Sciences” on the occasion of the 10th anniversary of the University of Ss. Cyril and Methodius, Trnava, 7–9 November 2007.     

Alkaloid accumulation dynamics in Veratrum lobelianum growing in Georgia and biological activity of Jervine

The alkaloid accumulation dymanics in Veratrum lobelianum were investigated. Jervine was found from 0.02 to 0.11% in the subterranean part at all vegetation stages. The jervine content was greatest in subterranean plant organs, reaching a maximum (0.3%) during natural dying off of aerial organs. Jervine, a natural analog of serotonin, can be used as a specific fibroblast growth factor. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 57–59, January–February, 2006.     

天花粉蛋白溶液构象与稳定性及生物活性的关系

用圆二色性研究了天花粉蛋白在不同PH,不同温度和不同的时间条件下的溶液构象变化.阐明了天花粉蛋白溶液的外部环境,并研究了天花粉蛋白的溶液构象与抗生育活性的关系,结果表明随着溶液中a-helix含量的增加,抗生育活性也相应增加,当a-helix含量减少到15%以下,其抗生育活性也就丧失.     

Biotransformation of benzoylheteratisine in the animal organism and biological activity of its main metabolite

Abstact The metabolism of the alkaloid benzoylheteratisine in the animal organism has been studied and it has been shown that its main metabolic product is heteratisine. In experiments on various models of arrhythmia the antiarrhythmic activity of heteratisine proved to be lower than that of benzoylheteratisine.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 391–393, May–June, 1996. Original article submitted March 4, 1996.     

Synthesis and in vivo biological activity of large-ringed calixarenes against Mycobacterium tuberculosis

A series of large-ringed calix[6,7,8]arene analogues have been synthesised and their affect against Mycobacterium tuberculosis in vivo established. In general, when p-phenylcalixarenes and tert-butylcalixarenes were not functionalised at the lower rim, low biological activities were observed. However on going from partially to fully lower rim pegylated calixarenes the anti-mycobacterial properties improved. The addition of cyanopropoxy groups at the lower rim gave rise to low activities, whereas the addition of acetate moieties interestingly had pro-TB effects. Two upper rim sulfonated calixarenes showed promising properties. In the course of this work, a high yielding procedure to synthesise p-phenylcalix[7]arene was also established.     

冰片及其酯/酰胺类衍生物的合成和活性研究进展

冰片是重要的芳香开窍类中药,具有开窍醒神,清热止痛等功效,常被作为佐药与其他中药配伍使用。目前,冰片及其衍生物广泛用于医药、农药、化工及香料领域,市场前景好,研究和开发价值高。本文对天然冰片、合成冰片及其酯/酰胺类衍生物的主要合成方法和生物活性方面进行了系统总结,并对冰片酯类衍生物未来的研究方向进行了展望,以期为冰片及其酯/酰胺类衍生物的进一步的研究提供有益参考。     

Comparison of reversed-phase,anion-exchange,and hydrophilic interaction HPLC for the analysis of nucleotides involved in biological enzymatic pathways

Nucleotides and other phosphate-containing compounds are integral to enzymatic reactions such as those of the methylerythritol phosphate (MEP) pathway and glycolysis. Traditional chromatographic analysis of phosphates is often plagued by long run times and/or lack of MS compatibility. This study compares separation of five enzymatically-important nucleotides using ion-pair reversed phase (IP-RP), strong anion exchange (SAX), and hydrophilic interaction (HILIC) methods. These three methods were evaluated and compared based on separation parameters describing retention, resolution, efficiency, peak symmetry, selectivity, and inter- and intraday peak drift. Use of the FructoShell-N HILIC column led to separation of the five nucleotides isocratically with the shortest run time of all three methods tested. Additionally, the FructoShell HILIC method yielded a very low intraday variability and low peak asymmetry, issues that are often observed with HILIC separations on other stationary phases. To our knowledge, this column has not been applied to the separation of phosphates in biological samples and future work will focus on in vitro and in vivo analysis as well as broadening the applicability to other pathways. To this end, we have shown that the column will retain fructose bisphosphate, the substrate of the aldolase enzyme, under the same chromatographic conditions used for nucleotides.     

Isolation and identification of O- and N-linked glycoproteins in milk from different mammalian species and their roles in biological pathways which support infant growth

Milk serves as the sole nutrition for newborns, as well as a medium for the transfer of immunological components from the mother to the baby. This study reveals different glycoprotein profiles obtained from human, bovine, and caprine milk and their potential roles in supporting infant growth. Proteins from these three milk samples are separated and analyzed using two-dimensional gel electrophoresis (2-DE). Glycosylated proteins from all samples are enriched by affinity chromatography using lectins from the seeds of Artocarpus integer before analysis using LC/MS-QTOF. The glycoproteome profiling demonstrates that glycosylated proteins are higher in caprine milk compared to other samples. Analysis using LC/MS-QTOF identified 42 O-glycosylated and 56 N-glycosylated proteins, respectively. Among those identified, human milk has 17 glycoproteins, which are both O- and N-glycosylated, whereas caprine and bovine have 10 and 1, respectively. Only glycoproteins from human milk have shown positive matching to important human biological pathways, such as vesicle-mediated transport, immune system and hemostasis pathways. Human milk remains unique for human babies with the presence of antibodies in the form of immunoglobulins that are lacking in ruminant milk proteomes.