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31.
Gantait Arunava Sahu Amita Venkatesh Pichairajan Dutta Pradeep K. Mukherjee Pulok K. 《平面色谱法杂志一现代薄层色谱法》2010,23(5):323-325
JPC – Journal of Planar Chromatography – Modern TLC - Coccinia grandis (L). Voigt (family: Cucurbitaceae) is widely used in the Indian system of medicine for various skin diseases,... 相似文献
32.
Jana Shibu Narayan Sing Dilip Banerjee Subhadip Haldar Pallab Kanti Dasgupta Barun Kar Amit Sharma Nanaocha Bandyopadhayay Rajib Mukherjee Pulok K. 《平面色谱法杂志一现代薄层色谱法》2021,34(6):521-530
JPC – Journal of Planar Chromatography – Modern TLC - Piperine is the most important alkaloid molecule present in Piper nigrum. In this study, a simple, rapid, quantitative... 相似文献
33.
Maity N Nema NK Sellamuthu MK Sarkar BK Mukherjee PK 《Natural product research》2012,26(20):1939-1941
A RP-HPLC method was developed (λ (max)?=?280) to quantify hydroxychavicol and chlorogenic acid in Piper betel Linn. The method was validated for linearity, limit of detection (LOD?=?3:1σ/S), limit of quantification (LOQ?=?10:1σ/S), precision, accuracy and ruggedness. The response was linear with good correlation between concentration and mean peak area through a coefficient of determinants (r (2)) of 0.9940, y?=?1.98e?+?004x?+?5.19e?+?004 and 0.9945, y?=?2.76e?+?004x?+?1.40e?+?005 with LOD 1.6?μg?mL(-1), 1.0?μg?mL(-1) and LOQ 5.0?μg?mL(-1) and 3.0?μg?mL(-1), respectively, for hydroxychavicol (28.56% w/w) and chlorogenic acid (0.40% w/w). The %RSD of precision and recovery of hydroxychavicol and chlorogenic acid were <2.0%. The proposed method was simple, accurate, specific, precise and reproducible. 相似文献
34.
A mild and convenient ring opening of epoxides with thiophenol and its derivatives takes place at room temperature in the presence of magnesium chloride as catalyst to afford the corresponding β-hydroxy sulfides along with minor amounts of 2-chlorocycloalkanols in good yields. When the crude reaction mixtures are treated with aqueous sodium hydroxide solution, pure 2-arlythiocycloalkanols are obtained in good yields. 相似文献
35.
Mohapatra DK Pattanayak MR Das PP Pradhan TR Yadav JS 《Organic & biomolecular chemistry》2011,9(16):5630-5632
A convergent synthesis of the macrolactone core of amphidinolactone A has been achieved, in a 10 step linear sequence with 32% overall yield, through a ring-closing metathesis reaction as the macrolactonization step. The RCM precursor was obtained by the union of acid and alcohol fragments derived from (R)-epichlorohydrin and (R)-2,3-O-isopropylidene glyceraldehyde, respectively. 相似文献
36.
Iodocyclization and Prins-type macrocyclization: an efficient formal synthesis of leucascandrolide A
The formal total synthesis of leucascandrolide A has been achieved in 20 steps from a known epoxide with an overall yield of 11.5% following a recently developed strategy for the construction of trans-2,6-disubstituted-3,4-dihydropyrans and a Lewis acid catalyzed intramolecular Prins-cyclization of an aldehydic homoallylic alcohol to generate the tetrahydropyran ring with three stereogenic centers and macrocycle concomitantly. 相似文献
37.
Subrat Kumar Pattanayak 《Molecular physics》2013,111(21):3297-3310
The effects of salt concentrations on the structure, dynamics and hydrogen bond structural relaxation properties of ~1.10 M aqueous N-methylacetamide (NMA) solution at 308 K are studied by classical molecular dynamics simulations. We have considered the concentration range of salts solution from 0.222 to 3.756 M to investigate the behaviour of aqueous environment of peptide bonds in the presence of concentrated NaCl and KCl solution. It is found that the addition of salt solution facilitates the structural breaking of aqueous NMA hydrogen bonds, as a result the number of hydrogen bonds per NMA molecule and their stability decreases. The water and NMA molecule shows slower translational and rotational dynamics with increasing salt concentrations due to additional ion atmospheric friction. Our result shows that the cation–ONMA radial distribution function decreases whereas the Cl?─HNMA radial distribution function increases with ion concentration. On the other hand, the cation–Owater and Cl?─Hwater radial distribution function shows very negligible change with respect to ion concentration. We have also calculated NMA–water and water–water hydrogen bond structural relaxation times. It is observed that the hydrogen bond structural relaxation of ONMA─Hwater is comparatively slower than the HNMA─Owater hydrogen bond, which can be attributed to higher number and greater stability of the former hydrogen bond than the latter. The change of the dynamical quantities observed here is more prominent in addition of NaCl rather than the KCl solution. 相似文献
38.
Samita Pattanayak B. N. Parida Piyush R. Das R. N. P. Choudhary 《Applied Physics A: Materials Science & Processing》2013,112(2):387-395
The polycrystalline Bi1?x Gd x FeO3 (BGFO) (x=0.0, 0.05, 0.10, 0.15, 0.20) materials were synthesized by a solid-state reaction (mixed oxide) technique. Preliminary X-ray structural analysis of the compounds confirmed the formation of single-phase polycrystalline samples. Room temperature scanning electron micrographs of the materials revealed the size, type and distribution of grains on the surface of samples. Studies of impedance, electrical modulus and electric conductivity of the materials in a wide frequency (10–1000 kHz) and temperature (30–500 °C) range using a complex impedance spectroscopy technique have provided considerable vital information on contribution of grains, grain boundary and interface in these parameters. A strong correlation between these electrical parameters and microstructures (bulk, grain boundary, nature of charge carrier, etc.) of the materials was established. The frequency dependence of electric modulus and impedance of the material shows the presence of non-Debye type of relaxation. 相似文献
39.
Joydeb Chanda Pulok K. Mukherjee Amit Kar Prasanta Kr. Maitra Seha Singha Pallab Kanti Halder Rahul Gajbhiye Ravichandiran Vishnuvardh 《Biomedical chromatography : BMC》2020,34(12):e4950
Coccinia grandis is an important food crop of the Cucurbitaceae family, widely used for culinary purposes in India. It is reported to possess hypoglycemic, hypolipidemic and antioxidant activities. The current study was aimed to explore the inhibition kinetics as well as major constituents of the active fraction of C. grandis against α-glucosidase. The kinetic study was performed through spectrophotometric assay, with p-nitrophenyl-α-d -glucopyranoside as a substrate with varying concentrations. An in vitro antioxidant study was performed by DPPH assay. In addition, UPLC–QTOF–MS analysis was carried out for metabolite profiling of the bioactive fraction of C. grandis. The results showed that the difference between the α-glucosidase inhibitory activity of the ethyl acetate fraction of C. grandis (EFCG) (IC50 2.43 ± 0.27 mg/ml), and standard inhibitor, acarbose (2.08 ± 0.19 mg/ml), was not statistically significant at a P-value of 0.05. The enzyme kinetics confirmed the inhibition mode in a mixed manner. The EFCG also showed the highest antioxidant activity (101.74 ± 1.95 μg/ml) among all of the fractions. A significant correlation between antioxidant and α-glucosidase inhibitory activity of EFCG was observed. The LC–QTOF–MS study of the EFCG putatively identified 35 metabolites, which may be responsible for its antioxidant and α-glucosidase inhibitory properties. Thus, C. grandis fruits can serve as a functional food to address diabetes-related disorders associated with α-glucosidase. 相似文献
40.
Binding interaction of transition metals copper, cadmium, and mercury with heme proteins were explored using isothermal calorimetry. Consequent conformational changes of the native proteins analyzed by circular dichroic spectroscopy revealed differential structural alteration of heme proteins. But, significant distortion in myoglobin structure was noted due to bioconjugation with mercury whose greater ionic radius may be responsible for this preferential behavior. 相似文献