Preparation of methyl 10-oxo-15S-hydroxyprosta-5E,13Z-dienoate

The synthesis of methyl 10-oxo-15S-hydroxyprosta-5E,13Z-dienoate is described.     

Kinetics of polymerization of acrylonitrile initiated by acidic permanganate/thioacetamide redox system

The kinetics of vinyl polymerization of acrylonitrile (AN) initiated by an acidic permanganate/thioacetamide (TAm) redox system have been investigated in aqueous media at 30 ± 0.2°C in nitrogen, and the rate of polymerization measured. The effect of additives like organic solvents, neutral electrolytes, and complexing agents on the rate have been assessed. Based on the experimental results, a suitable reaction scheme involving initiation by organic free radicals generated by the interaction of Mn(IV) with protonated thioacetamide and termination by Mn(III) has been suggested. Various rate and energy parameters have been evaluated.     

Extraction and TLC Desitometric Determination of Triterpenoid Acids (Arjungenin, Arjunolic Acid) from Terminalia arjuna Stem Bark Without Interference of Tannins

The stem bark of Terminalia arjuna Linn. (fam: Combretaceae), commonly known as Arjuna in Indian systems of medicine, is a reputed drug used for various cardiac disorders. T. arjuna stem bark is reported to contain different groups of chemical constituents including phenolics, tannins, saponins and triterpenoid acids. From our earlier experience with tannin containing herbal drugs, we are aware that tannins interfere in the extraction of certain compounds and hence in their quantification. In the present experiment, we report a sample preparation method to overcome the interference of the tannins by adsorbing them with carboxy methyl cellulose, which facilitates the efficient extraction of the triterpenoid acids. Further we established TLC densitometric methods for the quantification of two of the triterpenoid acids of T. arjuna stem bark viz., arjungenin and arjunolic acid using HPTLC. The methods were validated in terms of accuracy, precision and repeatability. The calibration curve showed linearity in the range of 160–480 ng spot^?1 and 160–560 ng spot^?1 for arjungenin and arjunolic acid respectively. The percentage of arjungenin and arjunolic acid were found to be 0.324% w/w and 0.524% w/w in the stem bark by this modified method of extraction, which was many times higher than when compared to that using the extraction method without CMC (0.018% and 0.049% respectively). The study reiterates the importance of sample preparation in the quantification of non polar phytochemicals from herbal raw materials, such that the compounds of interest are extracted efficiently, overcoming the interference of other compounds like tannins in the matrix of plant material.     

Development and validation of a thin-layer chromatography-densitometric method for the quantitation of alliin from garlic (Allium sativum) and its formulations

A selective, precise, and accurate high-performance thin-layer chromatographic (HPTLC) method has been proposed for the analysis of garlic and its formulations for their alliin content. The method involves densitometric evaluation of alliin after resolving it by HPTLC on silica gel plates with n-butanol-acetic acid-water (6 + 2 + 2, v/v) as the mobile phase. For densitometric evaluation, peak areas were recorded at 540 nm after derivatizing the resolved bands with ninhydrin reagent. The relation between the concentration of alliin and corresponding peak areas was found to be linear within the range of 250 to 1500 ng/spot. The method was validated for precision (interday and intraday), repeatability, and accuracy. Mean recovery was 98.36%. The method was applied for the quantitation of alliin in bulbs of Allium sativum Linn. (garlic) and its formulations. The proposed TLC method was found to be precise, specific, sensitive, and accurate and can be used for routine quality control of garlic and its formulations.     

Effect of hydrolysis on the yield of hederagenin and High-performance thin-layer chromatography densitometric quantification of hederagenin in fruit pericarp of Sapindus spp

Fruit pericarp of Sapindus species are reported to contain glycosides with hederagenin as an aglycone. To free the aglycone from the glycosides, they need to be hydrolyzed, and the commonly used method is hydrolysis with either hydrochloric or sulfuric acid. In the present work, we studied the effect of hydrolysis on the yield of hederagenin from the fruit pericarp of 3 species of Sapindus, viz., S. mukorossi, S. laurifolius, and S. emarginatus. A high-performance thin-layer chromatography densitometric method for the quantification of hederagenin was developed and validated. It involved automated application of samples as bands onto silica gel 60F254 plates, development with toluene-ethyl acetate-formic acid (7 + 3 + 5, v/v/v) mobile phase, detection with anisaldehyde-sulfuric acid reagent, and scanning at 595 nm. The yield of hederagenin ranged from 0.035 to 1.29% (w/w) with different methods of hydrolysis. Hydrolysis with 3.5 M aqueous sulfuric acid under reflux for 6 h gave the maximum yield of hederagenin in all 3 species, with the highest amount in S. emarginatus (1.29%, w/w).     

High-performance thin-layer chromatography densitometric method for simultaneous quantitation of phyllanthin, hypophyllanthin, gallic acid, and ellagic acid in Phyllanthus amarus

Whole plant of Phyllanthus amarus Linn. is a reputed drug of the Indian systems of medicine that is used as hepatoprotective agent. A simple high-performance thin-layer chromatography (HPTLC) densitometric method has been developed for the simultaneous quantitation of phyllanthin, hypophyllanthin, gallic acid, and ellagic acid in the whole plant of P. amarus. They were found at levels of 0.37, 1.16, 0.36, and 0.17% (w/w), respectively. The method was validated for precision, repeatability, and accuracy. Instrumental precision was found to be 0.54, 0.93, 0.08, and 0.78% (coefficient of variation, CV); repeatability of the method was 1.01, 0.79, 0.98, and 1.06% (CV) for phyllanthin, hypophyllanthin, gallic acid, and ellagic acid, respectively. Accuracy of the method was determined by a recovery study conducted at 3 different levels, and the average recovery was found to be 99.09% for phyllanthin, 99.27% for hypophyllanthin, 98.69% for gallic acid, and 100.49% for ellagic acid. The proposed HPTLC method was found to be simple, precise, specific, sensitive, and accurate and can be used for routine quality control of raw material of P. amarus and formulations containing P. amarus. It also has the applicability in quantitating any of these marker compounds in other drugs.     

A green synthesis of quinoline-4-carboxylic derivatives using p-toluenesulfonic acid as an efficient organocatalyst under microwave irradiation and their docking,molecular dynamics,ADME-Tox and biological evaluation

P-Toluenesulfonic acid, being an efficient, nonhazardous, and fast accessible organocatalyst, was used for the preparation of quinoline-4-carboxylic acid derivatives via a one-pot three-component reaction of aromatic benzaldehyde, substituted aniline, and pyruvic acid under microwave irradiation. After completion of the reaction, the pure products were isolated by column chromatography. Here, to achieve the desired synthesis, various catalytic and solvent conditions were applied to perform a comparison study. We are using higher yield, simple work-up process, avoiding the use of hazardous organic solvents, short reaction time and higher advantages of the present protocol in the study. Biological activities of synthesized compounds were tested against various antibacterial, antifungal, antimalarial, and antituberculosis strains. Compounds 4a and 4c (MIC 50 μg/mL) and compounds 4d and 4n (MIC 62.5 μg/mL) were found active against the Escherichia coli strain, compounds 4c and 4p (MIC 25 μg/mL) were found active against the Staphylococcus aureus strain, and compounds 4c and 4d were found active against the Plasmodium falciparum strain. Molecular docking revealed that ligands and proteins fitted exactly in the binding pocket and had significant correlation with the biological activity. We have also tested molecular dynamics and ADME-Tox parameters for the synthesized compounds.