Ayaz Ali Memon

Determination of free phenolic acids and antioxidant capacity of methanolic extracts obtained from leaves and flowers of camel thorn (Alhagi maurorum)

The present study comprises the determination of some phenolic acids from the leaves and flowers of Alhagi maurorum by HPLC-DAD, confirmed by LC-MS-APCI. The antioxidant properties and measurements of the total phenolic contents of the extracts were assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and Folin–Ciocalteu methods, respectively. It was found that the leaf extract had higher antioxidant potential (83.5%) than the flower extract (72.3%). The antioxidant properties and total phenolic contents of the leaves were higher than those of the flowers.

The GC determination of cisplatin as platinum(II) from pharmaceutical preparations and blood sample of cancer patients

SummaryA capillary gas chromatographic method is described for the determination of cisplatin based on the complexation of platinum(II) with bis(isovalerylacetone) ethylenediimine (H2IVA2en) and extraction in chloroform. The chromatography was carried out on a BP1 or a BP5 column with an FID. Copper(II), nickel (II) and palladium(II) separated completely and did not affect the determination of platinum(II). The method was applied of the determination of cisplatin in a pharmaceutical preparation and blood samples of cancer patients after infusion of cisplatin. The amounts of cisplatin in blood were found to be within 246–283 ng mL−1 with a C.V. of 2.35–4.26%.

Phenolic compounds and seed oil composition of Ziziphus mauritiana L. fruit

Phenolic Compounds and Seed Oil Composition of Ziziphus mauritiana L. Fruit Ber is a tropical fruit which grows from the tree species, Ziziphus mauritiana Lamk. The pericarp of this fruit is consumed either fresh or dried while its seeds are usually discarded as waste. The present study was undertaken to evaluate the antioxidant activity and phenolic content of the fruit, and to evaluate if any potential value-added phytochemicals can be extracted from seed waste. The edible portion of the fruit was extracted with 60% aqueous methanol by sonication and then assayed for total phenolic content, antioxidant activity, and individual phenolic compounds by HPLC-DAD. The seed oil extracted with n-hexane was assayed for fatty acid composition, sterols, and tocopherols content by GC-MS. The total phenolic content of the fresh fruit was 12.8 mg/g as gallic acid equivalent, with an antioxidant activity of 0.5 μmol/g as quercetin equivalent by Folin-Ciocalteu and DPPH assays respectively. Hydroxybenzoic acid, vanillin, ortho- and para-coumaric acid, epicatechin, quercetin, and naringenin were tentatively identified by matching retention time and UV spectra with those of commercial reference standards. GC-MS analysis of the TMS derivative of fruit extract showed the presence of following compounds: propanoic, hexanoic, heptanoic, octanoic, nonanoic, decanoic, dodecanoic, n-pentadecanoic, hexadecanoic, benzoic, and trihydroxybenzoic acids. In addition, D-fructose, galactofuranoside, gluconic acid, and β-sitosterol were also detected. In seed oil of ber, the fatty acids such as, hexanoic, octanoic, 7-octadecenoic, 9,12-octadecendoic, eicosanoic, 11-eicosenoic, and docosanoic acid with 7-octadecenoic acid, were found to make up 55% of total fatty acids. Squalene, γ-tocopherol and stigmasterol were identified as minor constituents in the unsaponifiable fraction of seed oil. Current study shows that ber fruit is a good source of healthy phytochemicals.

Simultaneous determination of some basic dyes using p-tetranitrocalix[4]arene-appended silica-based HPLC column

This study focuses on the synthesis, characterization and application of p-tetranitrocalix[4]arene-appended silica-based material as a stationary phase in high-performance liquid chromatography for the simultaneous separation of some basic dyes such as methyl violet, methyl green and methylene blue. The effect of the pH of mobile phase on the retention, separation and selectivity of these compounds was investigated. The method was validated for system efficiency, linearity, accuracy, precision, limit of detection and quantification. The limits of detection were 0.1, 0.5 and 0.3 mg L−1; whereas, the limits of quantification were observed to be 1, 1.2 and 0.9 mg L−1 for methyl violet, methyl green and methylene blue, respectively. The separation efficiency of the p-tetranitrocalix[4]arene-appended silica-based column was also compared to that of the octadecylsilane column.

Copper sorption efficiency of p-tetranitrocalix[4]arene based high performance liquid chromatographic column

AbstractPresent study deals with the sorption characteristics of p-tetranitrocalix[4]arene (3) appended silica-based high-performance liquid chromatographic (HPLC) column utilized for preconcentration, determination, and purification of Cu2+ from water. The sorption characteristics of the HPLC column were investigated for Cu2+ in column agreement. The experiments were performed in five steps that were monitored using UV–visible diode-array detector. However, all the HPLC experimental results were reconfirmed by using atomic absorption spectrophotometer. The effect of concentration on the sorption efficiency of the column was evaluated for Cu2+ and data obtained was investigated using Langmuir and Freundlich sorption isotherms. The value of coefficient of determination (R2), i.e. 0.99, suggested that the Freundlich sorption isotherm was found to be the best fit model for Cu2+. The developed method was validated for system efficiency, accuracy, and precision, while the data obtained revealed that the develo...

Optimization of HPLC method for determination of cefixime using 2-thiophenecarboxaldehyde as derivatizing reagent: A new approach

The determination of cefixime 1 has clinical and analytical importance due to its broad spectrum antimicrobial activity and stability. Cefixime is a significant member of orally active third generation cephalosporin and has excellent activity against many pathogens. It is for first time that we have developed a new HPLC–DAD method for analysis of imine derivative 3 of cefixime by using reflux method at 100 °C for 50 min without any buffer solution. 2 Thiophenecarboxaldehyde (2TCA) 2 was used first time as a derivatizing reagent for cefixime drug. Furthermore, separation of three components, i.e. drug (cefixime), reagent (2TCA) and derivative was carried out using kromasil 100 C-18 (15 mm × 0.46 mm, 5 μm) column with isocratic elution of methanol: 0.1% aqueous formic acid (70:30 v/v) with flow rate of 1 ml min−1 at retention time of 1.8, 2.4 and 3.3 min, respectively; while, total run time was 5 min. The developed method was repeatable with a relative standard deviation (RSD) of 0.81–1.88% for imine derivative. The limit of detection and quantification of imine derivative 3 were obtained within the range of 0.132–0.401 μg ml−1 and compared with cefixime drug as 0.30–0.90 μg ml−1, respectively. However, the formation of imine derivative 3 was confirmed by comparing peak height, retention time and spectral changes. The method is rapid, simple, very stable and accurate for the separation and determination of imine derivative 3 of cefixime 1.

Removal of ciprofloxacin from aqueous solution using wheat bran as adsorbent

ABSTRACT Current study describes sorption of antibiotic drug (ciprofloxacin) by using nontoxic and biocompatible carrier, i.e., wheat bran (WB). For sorption study, various parameters were optimized and Freundlich, Dubinin–Radushkevich, Langmuir, and Temkin isotherm models were applied to demonstrate the mechanism of sorption, while kinetics study for sorption was evaluated using diffusion models, pseudo-first-order kinetic (Langergren) and pseudo-second-order (Ho and McKay) kinetic models. In addition, thermodynamics study was also carried out. However, sorption of ciprofloxacin was pH depended and it showed 75% drug release in alkaline medium (at pH = 1.5) indicating the good release ability of WB for ciprofloxacin.

Improved Solubility of Morin Using p-sulphonatocalix[4]arene as Encapsulating Agent: HPLC Analysis and their Molecular Modelling

GRAPHICAL ABSTRACT ABSTRACT This study reports the use of water-soluble p-sulphonatocalix[4]arene (pSC-3) as solubilizing agent to improve the water solubility of morin, an exceptional antioxidant. Stoichiometry, stability constant, and mechanism of complex were investigated by UV-Vis and HPLC analysis and characterized by FTIR spectroscopy. Results indicate that 25% morin was encapsulated on pSC-3 at pH 7.3 and phase solubility study suggested 10 fold increase in water solubility of morin while 1:1 stoichiometric ratio was confirmed by Jobs plot. Binding constant for inclusion complex was found to be 6.67 × 104 M−1 calculated by using the Benesi–Hildebrand equation. In order to study the detailed structural properties of the complex, molecular mechanism approach was applied to calculate different energies associated with complex.

Synthesis, Characterization, and Exploration of Antimicrobial Activity of Copper Complex of Diamide Derivative of p-tert-butylcalix[4]arene

ABSTRACT Calixarenes are a versatile class of compounds, which possesses wide applications in various fields including biological as well as pharmaceutical sciences. In the present study, amide derivative of calix[4]arene (3) was synthesized and characterized by modern analytical techniques such as elemental analysis and Fourier transform infrared spectroscopy (FT-IR). Complexation property of 3 with essential metals was explored by UV-Vis spectroscopy. The results revealed that 3 shows good selectivity toward Cu2+. Jobs plot analysis suggests that 3 forms complex with Cu2+ in 1:2 stoichiometric ratio. Antimicrobial activity of 3 and its Cu2+ complex was also determined and it was observed that 3 is more efficient against R. stolonifer as compared to its action against bacteria, because for fungus it shows “Minimum Inhibitory Concentration” (MIC) value equal to 1.5 µg/mL, while for bacteria MIC is 3 µg/mL. However, it was found that complex is more efficient in action than 3. Oxidation state of metal, overtone concept, and Tweedys chelation theory justifies the increased activity of metal complex. Cu2+ complex shows higher antimicrobial activity toward Escherichia coli (E. coli) (Gram-negative) bacteria by showing MIC value 0.37 µg/mL. While for Staphylococcus albus (S. albus) (Gram-positive) bacteria and Rhizopus stolonifer (R. stolonifer) fungal species, it shows MIC value equal to 0.75 µg/mL.

Cuscuta reflexa as a Rich Source of Bioactive Phenolic Compounds

ABSTRACT Free and bound phenolic acids in flowers and stems of Cuscuta reflexa were extracted by sonication using two extraction procedures and analyzed by reverse-phase high-performance liquid chromatography coupled with a photodiode array detector (RP-HPLC-DAD). The HPLC profiling revealed the presence of 16 phenolic compounds including 13 phenolic acids and 3 aldehyde derivatives, possessing a greater fraction of bound phenolic acids than free ones. The results from both procedures revealed that caffeic and p-coumaric acids were the dominant constituents in both flowers and the stem of the plant. Five phenolic acids, i.e., gallic, gentisic, 2,4,6-trihydoxybenzoic acid (THBA), β-resorcinolic, and vanillic acids were identified only as bound phenolic acids, while the others were present in both forms. The radical scavenging potential and total phenolics content were greater in the stem than flowers, while total flavonoids and tannins were more prominent in flowers.