Quantitative determination of reserpine, ajmaline, and ajmalicine in Rauvolfia serpentina by reversed-phase high-performance liquid chromatography

A sensitive and reproducible reversed-phase high-performance liquid chromatography (HPLC) method using photodiode array detection is established for the simultaneous quantitation of important root alkaloids of Rauvolfia serpentina, namely, reserpine, ajmaline, and ajmalicine. A Chromolith Performance RP-18e column (100 x 4.6-mm i.d.) and a binary gradient mobile phase composed of 0.01 M (pH 3.5) phosphate buffer (NaH(2)PO(4)) containing 0.5% glacial acetic acid and acetonitrile are used. Analysis is run at a flow rate of 1.0 mL/min with the detector operated at a wavelength of 254 nm. The calibration curves are linear over a concentration range of 1-20 microg/mL (r = 1.000) for all the alkaloids. The various other aspects of analysis (i.e., peak purity, similarity, recovery, and repeatability) are also validated. For the three components, the recoveries are found to be 98.27%, 97.03%, and 98.38%, respectively. The limits of detection are 6, 4, and 8 microg/mL for ajmaline, ajmalicine, and reserpine, respectively, and the limits of quantitation are 19, 12, and 23 microg/mL for ajmaline, ajmalicine, and reserpine, respectively. The developed method is simple, reproducible, and easy to operate. It is useful for the evaluation of R. serpentina.     

Sensitivity analysis for generalized strongly monotone variational inclusions based on the -resolvent operator technique

Sensitivity analysis for generalized strongly monotone variational inclusions based on the (A,η)-resolvent operator technique is investigated. The results obtained encompass a broad range of results.     

Design, synthesis, and biological evaluation of a potent, PKC selective, B-ring analog of bryostatin

[structure: see text] The first member of a new class of five-membered B-ring analogs of bryostatin has been synthesized and tested for its ability to bind and translocate protein kinase C (PKC). This synthesis extends the utility of our previously introduced macrotransacetalization strategy to the formation of five-membered dioxolane B-ring analogs. This analog exhibits potent, single-digit nanomolar affinity to PKC and selectively translocates novel PKC isozymes.     

A Physiologically Regulated Multidomain Cystatin of Wheat Shows Stage-Dependent Immunity Against Karnal Bunt (Tilletia indica)

To identify novel components of basal resistance against the Tellitia indica of wheat, breeding for disease resistance was carried out on resistant and susceptible genotype of Karnal Bunt. The different members of wheat cystatin gene families were cloned, and their role in triggering differential resistance through co-expression was analyzed in our lab. The multidomain wheat cystatin (WCM) is a proteinase inhibitor characterized by cloning the gene from susceptible (WH542) and resistant genotype (HD 29). A WCM cDNA was isolated from both genotypes and sequenced. The WCM had a highly conserved N-terminal cystatin domain and a long C-terminal extension containing a second region, which exhibited similarity to the cystatin domain. The expression level was significantly (P?>?0.001) higher in resistant compared to susceptible genotype at all the physiological stages of wheat spikes. In order to characterize the biochemical properties of WCM, the coding sequence was expressed in Escherichia coli using pET expression vector. The recombinant WCM was purified from soluble fraction of the cell extract by using affinity chromatography. WCM, with 23 KDa molecular mass, showed cysteine proteinase inhibitory activity against papain (Ki 3.039?×?10^?7?M) as determined by using BAPNA as substrate. Furthermore, it was able to arrest the fungal mycelial growth of T. indica. Hyphae growth was inhibited, and morphological changes such as swelling and fragmentation of the fungus were observed. Overall, these observations suggest an endogenous high expression of cystatin, possibly associated with the resistance of wheat against Karnal bunt.     

High pressure studies on the electrical resistivity of As–Te–bond Si glasses and the effect of network topological thresholds

The variation of resistivity in an amorphous As₃₀Te_70?x Si _x system of glasses with high pressure has been studied for pressures up to 8 GPa. It is found that the electrical resistivity and the conduction activation energy decrease continuously with increase in pressure, and samples become metallic in the pressure range 1.0–2.0 GPa. Temperature variation studies carried out at a pressure of 0.92 GPa show that the activation energies lie in the range 0.16–0.18 eV. Studies on the composition/average co-ordination number ? r? dependence of normalized electrical resistivity at different pressures indicate that rigidity percolation is extended, the onset of the intermediate phase is around ? r?=2.44, and completion at ? r?=2.56, respectively, while the chemical threshold is at ? r?=2.67. These results compare favorably with those obtained from electrical switching and differential scanning calorimetric studies.     

Hybrid inexact proximal point algorithms based on RMM frameworks with applications to variational inclusion problems

A new application-oriented notion of relatively A-maximal monotonicity (RMM) framework is introduced, and then it is applied to the approximation solvability of a general class of inclusion problems, while generalizing other existing results on linear convergence, including Rockafellar’s theorem (1976) on linear convergence using the proximal point algorithm in a real Hilbert space setting. The obtained results not only generalize most of the existing investigations, but also reduce smoothly to the case of the results on maximal monotone mappings and corresponding classical resolvent operators. Furthermore, our proof approach differs significantly to that of Rockafellar’s celebrated work, where the Lipschitz continuity of M ^?1, the inverse of M:X→2 ^X , at zero is assumed to achieve a linear convergence of the proximal point algorithm. Note that the notion of relatively A-maximal monotonicity framework seems to be used to generalize the classical Yosida approximation (which is applied and studied mostly based on the classical resolvent operator in the literature) that in turn can be applied to first-order evolution equations as well as evolution inclusions.     

Chemoselective and Chemospecific Protection and Deprotection of a Carbonyl Group Using Polystyrene Divinylbenzene Sulfonic Acid

Chemospecific protection of one carbonyl group of two identical carbonyls of 2,2-dialkyl-1,3-cyclohexanedione and chemoselective protection of aliphatic or aromatic carbonyls in the presence of conjugated carbonyl compounds using cross-linked polystyrene divinyl benzene sulfonic acid (SPS) as a heterogeneous catalyst has been demonstrated.     

Effect of cationic surfactants on the enzymatic activity of α-chymotrypsin

The hydrolysis of p-nitrophenyl benzoate catalyzed by α-chymotrypsin in the presence of cetyltriphenylphosphonium bromide, cetyltributylphosphonium bromide and cetyltrimethylammonium bromide (pre and post micellar regions) has been studied. The ester is hydrolyzed readily by α-chymotrypsin in all the surfactants with the highest activity shown in cetyltributylphosphonium bromide. The dependences of the Michaelis constant and the catalytic constant with surfactant concentration have also been discussed.     

Seven and higher-membered oxygen heterocycles: Metal and non-metal

The investigation of methods for the chemical synthesis is a growing area of interest due to increasing environmental issues. The use of catalysts in organic reactions has gained extensive interest. Metal and nonmetal catalysts provided a new improved alternative to traditional methods in modern synthetic chemistry. The aim of present review is to focus on the applications of metals and nonmetals for the synthesis of seven and higher-membered O-heterocycles.     

Characterization of Weyl operator in terms of Mehler–Fock transform

In this paper, we define the windowed-Mehler–Fock transform and introduce the corresponding Weyl transform. Further, we examine the boundedness of windowed-Mehler–Fock transform in Lebesgue space and establish some of its fundamental properties. Also, we give the criteria of boundedness and compactness of Weyl transform in Lebesgue space.