No abstract

No abstract

We introduce and discuss the stability of Jungck and Jungck-Mann iterative procedures for a pair of Jungck-Osilike-type maps on an arbitrary set with values in a metric or linear metric space

Two coincidence theorems in a metric space are proved for a multi-valued mapping that commutes with a single-valued mapping and satisfies a general multi-valued contraction type condition

A new triterpene saponin and known steroidal glucoside were isolated from the alcohol extract, and a new cycloartenol from n-hexane extract of seeds of Nigella sativa L. and were identified as 3-O-[beta-D-xylopyranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]-11-methoxy-16,23-dihydroxy-28-methylolean-12-enoate (1), stigma-5,22-dien-3-beta-D-glucopyranoside (2) and cycloart-23-methyl-7,20, 22-triene-3beta,25-diol (3), respectively. They were characterised on the basis of spectral analysis and comparison with literature data. The hexane and alcohol extract of the seeds showed antimicrobial activity. The antioxidant activity of hexane extract is also described.

Lipídeos inéditos foram isolados de matéria insaponificável extraída de sementes de Nigella sativa Linn, usando-se n-hexano. O dienoato e os dois monoésteres inéditos foram identificados por técnicas espectrométricas, incluindo IV, RMN de 1 H e 13 C, espectrometria de massas, e análise química. O dienoato (1) foi identificado como metilnonadeca-15, 17-dienoato e os dois monoésteres foram identificados como pentil hexadec-12-enoato (2) e pentil pentadec-11-enoato (3). Ácido linoleico, ácido oléico, b-sitosterol e stigmasterol foram identificados como parte das estruturas dos lipídeos. Todos os compostos mostraram atividade moderada contra Staphylococcus aureus e baixa atividade contra shigella spp e Klebsiella pneumoniae.Novel lipids were isolated from the unsaponifiable matter extracted from seeds of Nigella sativa Linn by using n-hexane. The new dienoate and two monoesters were the new lipids identified by spectral (IR, 1 H-and 13 C-NMR spectra, mass spectrum, elemental analysis) and chemical analysis. The dienoate (1) was identified as methylnonadeca-15,17-dienoate and two monoesters were identified as pentyl hexadec-12-enoate (2) and pentyl pentadec-11-enoate (3). Linoleic acid, oleic acid, b-sitosterol and stigmasterol were identified as part of the lipid structures. All compounds exhibited moderate activity against Staphylococcus aureus and poor activity against shigella spp, and Klebsiella pneumoniae.Keywords: Nigella sativa, seeds, Ranunculaceae, aliphatic esters IntroductionNigella sativa Linn., a plant belonging to the family Ranunculaceae, grows as a small herb and is cultivated throughout India and other tropical regions of the world. 1,2 It is commonly known as black cumin seed and kalaungi in Hindi in India. The seed contains alkaloids nigellidine, 3 nigellimine and nigellicine, 4,5 tannin, steroids a-spinasterol, 6 campesterol, cholesterol, stigmasta-7-en3b-ol, stigmasterol and b-sitosterol, flavonoids of trigillin quercetin-3-glucoside, saponin and nigellone. 7,.8 Recent pharmacological investigations of the seed extract revealed that a wide spectrum of biological activities including anti-inflammatory, antidiabetic, analgesic, antibacterial, antifungal, anti-helmintic, 9 bronchodilatory, 10 hypertensive and immunoprotecting activities. 11 The seeds are believed to have carminative, diuretic, lactogoge, stimulatory and diaphoretic properties and are used in the treatment of bronchial asthma and eczema. [12][13][14][15] The hexane and benzene extracts of its seeds were exhibited 67% and 40% post-coital anti-implantation activity at the dose level of 500 mg kg -1 per day, respectively. 16 The present study reports the isolation and structural elucidation of three new lipids (Figure 1) isolated from seeds of Nigella sativa Linn. Linoleic acid, oleic acid, b-sitosterol and stigmasterol were identified as part of the structures of the new lipids. Results and DiscussionThe novel natural compounds were identified mainly by their 1D ( 1 H and 13 C NMR), 2D ( 1 H-1 H COSY), DEPT and mass spectrometry analy...

Mycobacterium tuberculosis shikimate kinase (Mtb-SK) is a key enzyme involved in the biosynthesis of aromatic amino acids through the shikimate pathway. Since it is proven to be essential for the survival of the microbe and is absent from mammals, it is a promising target for anti-TB drug discovery. In this study, a combined approach of in silico similarity search and pharmacophore building using already reported inhibitors was used to screen a procured library of 20,000 compounds of the commercially available ChemBridge database. From the in silico screening, 15 hits were identified, and these hits were evaluated in vitro for Mtb-SK enzyme inhibition. Two compounds presented significant enzyme inhibition with IC50 values of 10.69 ± 0.9 and 46.22 ± 1.2 μM. The best hit was then evaluated for the in vitro mode of inhibition where it came out to be an uncompetitive and noncompetitive inhibitor with respect to shikimate (SKM) and ATP, respectively, suggesting its binding at an allosteric site. Potential binding sites of Mtb-SK were identified which confirmed the presence of an allosteric binding pocket apart from the ATP and SKM binding sites. The docking simulations were performed at this pocket in order to find the mode of binding of the best hit in the presence of substrates and the products of the enzymatic reaction. Molecular dynamics (MD) simulations elucidated the probability of inhibitor binding at the allosteric site in the presence of ADP and shikimate-3-phosphate (S-3-P), that is, after the formation of products of the reaction. The inhibitor binding may prevent the release of the product from Mtb-SK, thereby inhibiting its activity. The binding stability and the key residue interactions of the inhibitor to this product complex were also revealed by the MD simulations. Residues ARG43, ILE45, and PHE57 were identified as crucial that were involved in interactions with the best hit. This is the first report of an allosteric binding site of Mtb-SK, which could largely address the selectivity issue associated with kinase inhibitors.

No abstract