Evaluation of anti-diarrhoeal activity in seed extracts of Mangifera indica

Mangifera indica is commonly grown in many parts of the world. Its seeds have been used for anti-diarrhoeal activity in Indian traditional medicine. This study evaluates the potential anti-diarrhoeal activity of methanolic (MMI) and aqueous (AMI) extracts of seeds of M. indica in experimental diarrhoea, induced by castor oil and magnesium sulphate in mice. Both MMI and AMI were given orally in the dose of 250 mg/kg, showed significant anti-diarrhoeal activity comparable with that of the standard drug loperamide. However, only MMI significantly reduced intestinal transit in charcoal meal test as compared with atropine sulphate (5 mg/kg; im). The in vitro antimicrobial activity of MMI and AMI showed variable results. While, AMI significantly inhibited growth of Streptococcus aureus and Proteus vulgaris, both MMI and AMI did not show any significant effect on growth of E. coli and Klebsiella. The results illustrate that the extracts of M. indica have significant anti-diarrhoeal activity and part of the activity of MMI may be attributed to its effect on intestinal transit.

Solid-phase synthesis and bioevaluation of Lupeol-based libraries as antimalarial agents

The use of the triterpenoid lupeol as a scaffold for the synthesis of lupeol-based libraries is described. Lupeol was anchored to a solid support (Rink amide/Sieber Amide) through aliphatic dicarboxylic acid moieties, which also served as a site for introducing diversity. The resulting polymer linked 3beta-O (resin-alkanoyl)-lup-20(29)-ene 3 was used to generate key intermediates 3beta-O (resin-alkanoyl)-30-bromo-lup-20(29)-ene 4 and 3beta-O (resin-alkanoyl)-30-amino-lup-20(29)-ene 6 for the generation of libraries based on disubstituted lupeol derivatives. A 96-member library was screened for its in-vitro antimalarial activity against Plasmodium falciparum.

Combinatorial synthesis of unsymmetrical secondary amines. Application to arylethanolamines, arylpropanolamines and aryloxypropanolamines

Combinatorial libraries of unsymmetrical secondary amines: arylethanolamine, arylpropanolamines and aryloxypropanolamines [1], in particular have been synthesized by four different routes using styrenes, aldehydes, hydroxyaromatic acids and bromoaliphatic acids. The structurally diverse libraries were generated in parallel format using solid phase methodology. The compounds corresponding to prototype I-IV were obtained in high yields and purities.

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.

Identification of novel antifungal nonapeptides through the screening of combinatorial peptide libraries based on a hexapeptide motif

Four sets of mixture based nonapeptide libraries derived from an antifungal hexapeptide pharmacophore Arg-D-Trp-D-Phe-Ile-D-Phe-His-NH(2) (II) have been synthesized. The three C-terminal positions 7, 8 and 9 were subject to randomization using 19 genetically coded amino acids. They were then screened for their antifungal activity against Candida albicans and Cryptococcus neoformans in order to quantify inhibition at each step of the nonapeptide sublibrary deconvolution. The studies led to the identification of several novel nonapeptides with potent antifungal activity. Two of the nonapeptides exhibited approximately 17-fold increase in the activity in comparison to the lead hexapeptide motif His-D-Trp-D-Phe-Phe-D-Phe-Lys-NH(2) (I) against C. albicans.

Identification of enzyme inhibitors using combinatorial libraries

Potent enzyme inhibitors have long been recognized as powerful tools for assessing the physiological roles of enzymes and have led to the therapeutic drugs able to modulate their activities in vivo. However, to be valuable tools such inhibitors should be selective so that they do not interfere with other members of the particular enzyme family. Combinatorial chemistry has proven to be a novel approach for the identification of molecules with a desired selectivity profile from the libraries of several million compounds. In recent years it has been extensively used in conjunction with computational methods for the development of potent inhibitors of therapeutically interesting targets. This review describes the various structurally diverse enzyme inhibitors identified by screening combinatorial libraries of peptides and small organic molecules.

Relevance of biophysical concepts in the scintigraphic detection of gastrointestinal leaks

The application of some physical concepts is described to explain the inherent insensitivity of 99Tc(m)-red blood cell (RBC) and 99Tc(m)-human serum albumin (HSA) in the detection of gastrointestinal bleeding and protein-losing enteropathy (PLE), respectively. Inferences drawn from the laws of radioactive decay, partition physics, hydrodynamics and electrostatic forces have been used to suggest that the clearance pattern, size and charge of radiopharmaceuticals, and the viscosity of the medium, affect the sensitivity of these tests. As the outflow from gastrointestinal lesions is non-specific, other labelled macromolecules can be used instead of RBCs or HSA. Based on biophysical concepts, we suggest that chargeless macromolecules in the size range 5-50 nm are superior to the conventional agents used for this purpose.

Intellectual and motor functions in school children from severely iodine deficient region in Sikkim

High prevalence of endemic goitre (54%) and endemic cretinism (3.5%) exist in Sikkim. The level of intellectual functioning and motor performance were assessed in 90 school children in the age group of 10 to 12 years selected randomly from four severely iodine-deficient villages. Bender Visual Motor Gestalt Test, Binet-Kamat Test for mental ability and Raven's Coloured Progressive Matrices were the tests used. The results show an impairment in intellectual and other neuropsychological functions in a high percentage of the children. Visuomotor coordination was poor in 62 (69%). Binet-Kamat test results showed that 19 (21%) children were intellectually subnormal (IQ < 70). Majority of the children (> 80%) had significant impairment in language, meaningful memory, non-meaningful memory, conceptual thinking, numerical reasoning and motor skills. The children did better on non-verbal reasoning and social intelligence. Goitre was detected in 82 (91.1%). Urine samples for iodine estimations was collected from every second child examined. The mean urinary iodine concentration was 4.23 micrograms/dl (SD 2.16). Urinary iodine concentration was less than 2 micro gm/dl in 26.1% (11 children) and less than 5 micro gm/dl in 84.8% (39 children) indicating severe iodine deficiency. The test results show impairment of psychomotor development in children born and brought up in iodine-deficient environment.

Reproducibility of histology in leprosy lesions

The variability of three commonly used histological parameters in leprosy histology was examined within and between lesions on individual patients by taking two biopsies, either from opposing edges of the same lesion or from the edge of two separate lesions. There was little variation in granuloma fraction (GF), bacterial index (BI), or histological classification on the Ridley-Jopling scale between biopsies from opposing edges of the same lesion, but there was considerable variation in the GF between biopsies from the edge of different lesions. A lesser degree of variation was seen in the BI between different lesions, and there was little difference in histological classification between established lesions. Thus, it appears that local factors influence the size of the leprosy granuloma, but its histological composition and bacterial load are determined systemically.

Third-harmonic generation using an ultrahigh-spectral-brightness ArF source

Tunable coherent radiation in the vicinity of 64 nm has been produced by third-harmonic generation of the output of an ultrahigh-spectral-brightness ArF*source in various simple gaseous media. The following performance parameters of the ArF* system are used: pulse energy, ~300 mJ; pulse duration, ~7 nsec; spectral width, <260 MHz; beam divergence, ~5microradx15microrad; and repetition rate up to 10 Hz. Third-harmonic generation with peak powers up to 30 W has been observed in an apparatus that eliminates photoabsorption of the third harmonic in the differential pumping stages.