Cytomorphological Studies on Stem of Luffa echinata Roxb

Luffa echinata Roxb., commonly known as Bindal in Hindi is used for its hypoglycemic activity in the indigenous system of medicine. No pharmacognostical study on stem is reported in the literature till date; therefore, it was decided to study macroscopical and cytomorphological characters in detail to bring out salient diagnostic features. The stem pieces available in the market are 1.5–17 cm long and 5–8 mm in diameter, showing yellowish-brown to brownish-black surface with longitudinal furrows, fracture is fibrous, and taste is bitter. Mature stem shows single-layered epidermis, seven layers of collenchyma below five ridges but one to two layers of parenchyma in rest of the region beneath the epidermis, continuous wide wavy layer of pericycle composed of three to eight layers of fiber. There are five conjoint bi-collateral open vascular bundles one below each ridge and additional four medullary vascular bundles in the pith each facing furrows.

Polyelectrolyte-assisted formation of molecular nanoparticles exhibiting strongly enhanced fluorescence

A polyelectrolyte-assisted reprecipitation method is developed to fabricate nanoparticles of highly soluble molecules. The approach is demonstrated by using a zwitterionic diaminodicyanoquinodimethane molecule bearing remote ammonium functionalities with high solubility in water as well as organic solvents. Nanoparticles are prepared by injecting aqueous solutions of this compound containing an optimum concentration of sodium poly(styrenesulfonate) into methanol. The strong fluorescence exhibited by the compound in the aggregated state is reflected in the enhanced fluorescence of the polyelectrolyte complex in water. The nanoparticles formed in the colloidal state manifest even stronger fluorescence, which leads to an overall enhancement by about 90 times relative to aqueous solutions of the pure compound. The conditions for achieving the emission enhancement are optimized and a model for the molecular-level interactions and aggregation effects is developed through a range of spectroscopy, microscopy, and calorimetry investigations and control experiments.

Production of poly-3-hydroxyalkanoic acids by a moderately halophilic bacterium, Halomonas marina HMA 103 isolated from solar saltern of Orissa, India

Halomonas marina HMA 103 (MTCC 8968), the moderately halophilic bacterium isolated and characterized from the solar saltern of Orissa, India, grows optimally at 10% (w/v) NaCl in culture medium and is able to synthesize poly(3-hydroxybutyrate) [P(3HB)] during growth. This study is an attempt to optimize the cultural conditions for efficient production of P(3HB) by H. marina in batch cultivation. Growth of the organism under shake-flask culture using 2% (w/v) glucose resulted in P(3HB) accumulation accounting for more than 59% of cell dry weight after 50 h of incubation. The optimum P(3HB) production was attained with a combined supply of NH4Cl and yeast extract as N-source, 0.01% (w/v) phosphate, 1.5% (w/v) sulphate and 10% (w/v) NaCl. Qualitative and quantitative 1HNMR and FT-IR analysis of cells grown in alkanoic acids (C3-C6) as sole source of carbon and co-substrates revealed synthesis of PHA co-polymers composed of 3-hydroxybutyric acid and 3-hydroxyvaleric acid [P(3HB-co-3HV)]. In two-step cultivation, accumulation of the co-polymer was significantly improved (80% CDW) in glucose medium supplemented with valerate (0.1%, w/v) as co-substrate and the polymer contained 88.1 and 12.8 mol% 3HB and 3HV monomers, respectively.

Studies on intracellular degradation of polyhydroxyalkanoic acid–polyethylene glycol copolymer accumulated by Azotobacter chroococcum MAL-201

Azotobacter chroococcum MAL-201 accumulates poly(3-hydroxybutyric acid) [PHB] when grown in glucose containing nitrogen-free Stockdale medium. The same medium supplemented with valerate alone and valerate plus polyethylene glycol (PEG) leads to the accumulation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [PHBV] and PEG containing PHBV-PEG polymers, respectively. The intracellular degradation of these polymers as studied in carbon-free Stockdale medium showed a rapid degradation of PHB followed by PHBV, while it was least in case of PHBV-PEG. The rate of such degradation was 44.16, 26.4 and 17.0 mg h(-1)l(-1) for PHB, PHBV and PHBV-PEG, respectively. During the course of such of PHBV and PHBV-PEG degradation the 3HB mol% of polymers decreased significantly with increase of 3HV mol fraction, the EG mol% in PHBV-PEG, however, remained constant. After 50h of degradation the decrease in intrinsic viscosity and molecular mass of PHBV-PEG were 37.5 and 43.6%, respectively. These values appeared low compared to PHB and PHBV. Moreover, the increasing EG content of polymer retarded their extent of degradation. Presence of PEG, particularly of low molecular weight PEG was inhibitory to intracellular PHA depolymerise (i-PHA depolymerase) activity and the relative substrate specificity of the i-PHA depolymerase of MAL-201 appeared to be PHB > PHBV > PHBV-PEG.

Tuning the size and optical properties in molecular nano/microcrystals: manifestation of hierarchical interactions

Intermolecular interactions, such as hydrogen bonding, dipolar and van der Waals, occurring in molecular crystals cover a range of magnitudes. As the crystal evolves from a relatively softer state in the nanoscopic size regime to a harder one in the microcrystalline and bulk solid state, the impact of the hierarchy of intermolecular interactions can be expected to emerge in a progressive fashion. The strongest interactions alone would be manifested at small sizes; as the crystal grows, the effect of the weaker ones will be added on, with the bulk crystals exhibiting the cumulative impact of the different interactions. We demonstrate this phenomenon through investigations of the solution, colloid, and solid state of a novel zwitterionic molecule based on the diaminodicyanoquinodimethane framework. A reprecipitation-digestion protocol is developed for the fabrication of nano/microcrystals of varying sizes. Microscopic and spectroscopic characterizations reveal tuning of the size and optical properties of this material. The optical absorption of the colloidal particles evolves with size towards that of the bulk solid, the emission showing a steady enhancement of intensity. Crystallographic investigations coupled with semiempirical computations provide a viable model to describe the range of observations in terms of the gradual accumulation of hierarchical intermolecular interactions.

Incorporation of polyethylene glycol in polyhydroxyalkanoic acids accumulated by Azotobacter chroococcum MAL-201

Azotobacter chroococcum MAL-201 (MTCC 3853), a free-living nitrogen-fixing bacterium accumulates poly(3-hydroxybutyric acid) [PHB, 69% of cell dry weight (CDW)] when grown on glucose and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [PHBV with 19.2 mol% 3HV] when grown on glucose and valerate. Use of ethylene glycol (EG) and/or polyethylene glycols (PEGs) of low molecular weight as sole carbon source were detrimental to A. chroococcum growth and polymer yields. PEG-200, however, in the presence of glucose was incorporated into the polyhydroxyalkanoate (PHA) polymer. Addition of PEG-200 (150 mM) to culture medium during mid-log phase growth favored increased incorporation of EG units (12.48 mol%) into the PHB polymer. In two-step culture experiments, where valerate and PEG simultaneously were used in fresh medium, EG was incorporated most effectively in the absence of glucose, leading to the formation of a copolymer containing 18.05 mol% 3HV and 14.78 mol% EG. The physico-mechanical properties of PEG-containing copolymer (PHBV-PEG) were compared with those of the PHB homopolymer and the PHBV copolymer. The PHBV-PEG copolymer appeared to have less crystallinity and greater flexibility than the short-chain-length (SCL) PHA polymers.

Discovery of substituted isoxazolecarbaldehydes as potent spermicides, acrosin inhibitors and mild anti-fungal agents

BACKGROUND

The continued endeavour to design novel, non-detergent molecules that can be useful as topical, prophylactic contraceptives has led to the discovery of substituted isoxazolecarbaldehydes as a new class of compounds exhibiting both spermicidal and acrosin inhibitory activities simultaneously.

METHODS

Normal human semen samples were used to detect the spermicidal and acrosin inhibitory activities of the new compounds. Lactobacillus, HeLa and Candida cultures were used to determine the safety of compounds towards normal vaginal flora, their cytotoxicity and anti-fungal activity. Supravital staining and the hypo-osmotic swelling test (HOST) were used to detect the effect on sperm membrane integrity. Nonoxynol-9 (N-9) was used as a reference standard.

RESULTS

The 5- and 3-substituted isoxazolecarbaldehydes showed significant spermicidal [minimum effective concentration (MEC)=0.005-2.5%] and acrosin inhibitory (IC50=3.9-58 x 10(-4) mol/l) activities in several molecules along with weak fungicidal activity against Candida albicans. Lineweaver-Burk and Dixon plot analysis of a representative structure showed non-competitive inhibition of human acrosin enzyme, and the most potent acrosin inhibitors also considerably diminished the induction of the acrosome reaction by Ca2+ ionophore. Some compounds were found to be significantly safer than N-9 towards Lactobacillus acidophilus in vitro at their respective spermicidal MECs. In the cytotoxicity assay, the IC50 of these compounds towards the HeLa cell line was of the same order as N-9 (0.9-0.1 mmol/l); however, in contrast, the compounds exhibited only a moderate effect on sperm membrane integrity.

CONCLUSIONS

This study indicates that 5- and 3-substituted isoxazolecarbaldehydes are 'first generation' multifunctional, spermicidal molecules that hold promise for development as topical contraceptives with useful associated activities that can add considerably to their effectiveness, safety and prophylaxis.

Baylis–Hillman reaction assisted parallel synthesis of 3,5-disubstituted isoxazoles and their in vivo bioevaluation as antithrombotic agents

The solution-phase parallel synthesis involving reactions of Baylis-Hillman products of 3-substituted-5-isoxazolecarbaldehydes with nucleophiles and their in vivo antithrombotic evaluations are described along with the results of in vitro platelet aggregation inhibition assay of a few compounds. Results of the detailed evaluation of one of the compounds as an inhibitor of platelet aggregation are also presented.

Isoxazole-based derivatives from Baylis-Hillman chemistry: assessment of preliminary hypolipidemic activity

The synthesis of isoxazole-based derivatives utilizing Baylis-Hillman chemistry and results of their preliminary bioevaluation as hypolipidemic agents in triton model are described.

Effect of different strains of yeast on stereocontrolled reduction of 5-acetylisoxazolines

The stereocontrolled reduction of 3-aryl-5-acetylisoxazolines (1) to the corresponding alcohols (2 and 3) in the presence of four different yeast strains, recognized as Baker's yeast (commercial), Candida krusei (ATCC 14243), Pichia farinosa (NRRL Y110) and Sacchromyces sp. (soil isolate) have been attempted. The C. krusei was found to be diastereoselective for the (R)-1 while the Sacchromyces sp. led to complete reduction to yield the RS- and SS-alcohol in 1:1 ratio at 10 g/L scale.

Combinatorial synthesis and biological evaluation of isoxazole-based libraries as antithrombotic agents

The 3-substituted phenyl-5-isoxazolecarboxaldehydes have been identified as activated aldehydes for the generation of isoxazole-based combinatorial libraries on solid phase through automation. Three highly functionalized isoxazole-based libraries comprising of 32, 96 and 45 compounds each have been synthesized in parallel format using Baylis Hillman reaction, Michael addition, reductive amination and alkylation reactions. With an objective of lead generation all the three libraries were evaluated for their antithrombin activity in vivo.

Role of the finite element model in dental implants

Computer-aided design and finite element methods (FEM) have interested dental researchers because of its use in the computer simulation and design of dental implants, a process greatly facilitated by the development of new computer technology and more accurate modeling technologies. FEM allows for a better understanding of stresses along the surfaces of an implant and in surrounding bone. This will aid in the optimization of implant design and placement of the implant into the bone; it will also help when designing the final prostheses to minimize stresses. The purpose of this review is to elucidate the role of FEM and the impact of this technology in clinical dentistry in the new millennium.

Histone deacetylase and DNA methyltransferase in human prostate cancer

CpG island hypermethylation and chromatin remodeling play important roles in repression of various genes during malignant transformation. We hypothesized that histone deacetylases (HDACs) and DNA methyltransferases (DNMTase) are associated with prostate cancer and we examined the enzyme activity, gene, and protein expression of HDAC1 and DNMT1 in cell lines and tissues. We found that DNMTase and HDACs activities were two- to threefold higher in cell lines compared to benign prostatic hyperplasia (BPH-1) cell line. Treatment of cells with 5-aza-2'-deoxycytidine decreased the activity of HDAC and DNMTase. The mRNA expression of these genes in BPH-1 cells and BPH tissues was lower than that in prostate cancer cells and tissues. HDAC1 and DNMT1 protein expression was higher in prostate cancer compared to BPH. This is the first report to demonstrate that DNMT1 and HDAC1 levels are up-regulated in prostate cancer compared to BPH, suggesting their roles in inactivation of various genes, by DNA-methylation-induced chromatin-remodeling, in prostate cancer.

Antibacterial activity of luteoforol from Bridelia crenulata

The methanol extract of Bridelia crenulata stem bark (50-1.5625 mg/ml) and its isolated luteoforol (2-0.25 mg/ml) showed concentration-dependent inhibiting activity against all 10 tested bacteria.

Cleogynol, a novel dammarane triterpenoid from Cleome gynandra

Chemical examination of Cleome gynandra (whole plant excluding seeds) led to the isolation and identification of a novel (20S, 24S)-epoxy-19,25-dihydroxydammarane-3-one hemiketal (1). The structure of the new compound, designated cleogynol, was determined using spectral and chemical methods.