Hussain Gulab

Development of microwave assisted spectrophotometric method for the determination of glucose

A spectrophotometric method was developed based on the microwave assisted synthesis of Maillard product. Various conditions of the reaction were optimized by varying the relative concentration of the reagents, operating temperature and volume of solutions used in the reaction in the microwave synthesizer. The absorbance of the microwave synthesized Maillard product was measured in the range of 360-740 nm using UV-Visible spectrophotometer. Based on the maximum absorbance, 370 nm was selected as the optimum wave length for further studies. The LOD and LOQ of glucose was found 3.08 μg mL(-1) and 9.33 μg mL(-1) with standard deviation of ±0.05. The developed method was also applicable to urine sample.

One-pot synthesis, characterization, DNA binding and enzymatic studies of 4-methyl trans-cinnamate zinc(II)-mixed ligand complexes

Four new zinc(II) complexes formulated as [Zn(L)2] (1), [Zn(L)2(phen)] (2), [Zn(L)2(bipy)H2O] (3), and [Zn(en)2(H2O)2](L)2(H2O)2 (4), where HL = 4-methyl trans-cinnamic acid, bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline, and en = ethylenediamine, have been synthesized and characterized by FT-IR and NMR spectroscopy. Single-crystal XRD revealed distorted square-pyramidal structure for 3 and octahedral for 4. The complexes were screened for DNA interaction via viscommetry and UV–visible spectroscopy. The apparent binding constants were calculated to be 1.18 × 104, 1.26 × 105, 4.64 × 104, and 1.89 × 104 for 1–4, respectively. The binding propensity to salmon sperm DNA was in the order: K2 > K3 > K4 > K1. Furthermore, these complexes demonstrated efficient inhibition of alkaline phosphatase, which was attributed to the binding of zinc(II) to the enzyme’s active site. Graphical abstract pictogram

Physicochemical Investigation of Some Thiobarbiturate Derivatives and Their Binding Study with Deoxyribonucleic Acid

Due to the gradual increase in genetic related disease worldwide, the synthesis, characterization and physicochemical investigation of medicinal compounds such as thiobarbiturates and their derivatives is a highly desired area of research. Keeping their importance as medicinal compounds in mind, herein we report the synthesis and physicochemical characterization of five selected thiobarbiturate samples namely (MKA20 MKA21, MKA22, MKA23, MKA24) by using various physicochemical techniques. All the selected thiobarbiturates and their derivatives were synthesized by the reaction of diethyl thiobarbituric acid with different aromatic aldehydes. The synthesized thiobarbiturates and their derivatives were analyzed by various electroanalytical techniques, which gave us valuable information about the nature of thiobarbiturates and their derivatives. Further, the preliminary interaction of these thiobarbiturate with Deoxyribonucleic acid in aqueous solution was also investigated by using Ultraviolet-Visible spectrometry. On the basis of various results obtained, it can be said that most of their properties and extent of interaction with Deoxyribonucleic acid are varying with changing the alkyl groups on one hand and the functional groups on the other hand.

Development of Spectrophotometric Method for the Determination of Azoxystrobin Fungicide after Derivatization

A UV-Visible spectrophotometric method has been developed for the determination of azoxystrobin fungicide. Complexation reaction of the azoxystrobin fungicide was carried out with the Ferric (III) chloride in presence of hydroxylamine hydrochloride in alkaline medium resulting in a reddish-brown color complex. The absorbance of the complex was measured at 513 nm using UV-visible spectrophotometer. Different parameters affecting the derivatization reactions were carefully studied and optimized. Beer’s law was obeyed in the concentration range of 1-12 μg mL-1. The molar absorptivity, limit of detection and limit of quantification were calculated and found to be 4.3 × 10-4 L mol-1 cm-1, 0.38 μg mL-1 and 1.26 μg mL-1 respectively. Similarly, the mean limit of detection and limit of quantification were calculated for residue determination and were found to be 3.8 ± 1.02 μg mL-1 and 3.98 ± 1.4 μg mL-1, respectively. The proposed method was successfully applied for the determination of azoxystrobin in pure form and in commercial formulations.

Production of a highly potent epoxide through the microbial metabolism of 3β-acetoxyurs-11-en-13β,28-olide by Aspergillus niger culture

Abstract Context 3β-Acetoxyurs-11-en-13β,28-olide (I), a triterpenoid, is found in most plant species. Pharmacologically triterpenes are very effective compounds with potent anticancer, anti-HIV and antimicrobial activities. Objectives Microbial transformation of 3β-acetoxyurs-11-en-13β,28-olide (I) was performed in order to obtain derivatives with improved pharmacological potential. Materials and methods Compound (I, 100 mg) was incubated with Aspergillus niger culture for 12 d. The metabolite formed was purified through column chromatography. Structure elucidation was performed through extensive spectroscopy (IR, MS and NMR). In vitro α- and β-glucosidase inhibitory, and antiglycation potentials of both substrate and metabolite were evaluated. Results Structure of metabolite II was characterized as 3β-acetoxyurs-11,12-epoxy-13β,28-olide (II). Metabolite II was found to be an oxidized product of compound I. In vitro α- and β-glucosidases revealed that metabolite II was a potent and selective inhibitor of α-glucosidase (IC50 value = 3.56 ± 0.38 μM), showing that the inhibitory effect of metabolite II was far better than compound I (IC50 value = 14.7 ± 1.3 μM) as well as acarbose (IC50 value = 545 ± 7.9 μM). Antiglycation potential of compound II was also high with 82.51 ± 1.2% inhibition. Thus, through oxidation, the biological potential of the substrate molecule can be enhanced. Conclusion Biotransformation can be used as a potential tool for the production of biologically potent molecules.

Development and Validation of a New Spectrophotometric Method for the Determination of Cephalexin Monohydrate in Pure Form and Pharmaceutical Formulations

A simple, fast, sensitive and accurate spectrophotometric method has been developed for the quantitative determination of cephalexin monohydrate in dosage form and in commercial formulations. The method involves the addition of CeIV to cephalexin in acidic medium, followed by the determination of residual CeIV by reacting with a fixed amount of methyl orange, and the absorbance was measured at 510 nm. Beers law was obeyed in the concentration range of 0.6-20 µg mL-1 with correlation coefficient of 0.992. The molar absorptivity was calculated and was found to be 9.8 × 104 L mol-1 cm-1. Different variables affecting the reaction conditions such as concentration and volume of CeIV, type and concentration of acids used, reaction time and temperature were carefully studied and optimized. The limit of detection (LOD) and limit of quantification (LOQ) were calculated and found to be 0.221 and 0.736 µg mL-1, respectively. The proposed method was found to have good reproducibility with a relative standard deviation of 4.4% (n = 9). The interference effects of common excipients found in pharmaceutical preparations were studied. The developed method was validated statistically by performing recoveries studies and successfully applied for the determination of cephalexin in bulk powder and pharmaceutical preparations. Percent recoveries were calculated and found to range from 90.6 to 102.9% for bulk powder and from 98.7 to 104.8% for pharmaceutical preparations.