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Abstract  

This work concerns the study of Al–Ni bimetallic nanoparticles synthesized by gamma-radiolysis of aqueous solution containing aluminium chloride hexahydrate, nickel chloride hexahydrate, polyvinyl alcohol for capping colloidal nanoparticles, and isopropanol as radical scavenger. While the Al/Ni molar ratio is kept constant, size of the nanoparticles can be well controlled by varying the radiation dose. The products were characterized by UV–vis spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD). Observations of UV–vis absorption spectra and TEM images showed that as the radiation dose increases from 50 to 100 kGy the particle size decreases and the number particles distribution increases. It may be explained due to the competition between nucleation and aggregation processes in the formation of metallic nanoparticles under irradiation. The EDX and XRD analysis confirmed directly the formation of Al–Ni bimetallic nanoparticles in form of alloy nanoparticles.

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Summary

A densitometric HPTLC method for analysis of cordifolioside A both in 60% methanolic extract of Tinospora cordifolia and in a commercial formulation has been established and validated. Cordifolioside A was separated on aluminum-backed silica gel 60 F254 plates with chloroform-methanol 85:15 (%, v/v) as mobile phase. A compact band was obtained for cordifolioside A at R F 0.52 ± 0.03. The limits of detection (LOD) and quantification (LOQ) were 20.12 and 60.36 ng per band, respectively. The highly precise and accurate method was used for analysis of cordifolioside A.

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JPC - Journal of Planar Chromatography - Modern TLC
Authors:
Omer A. Basudan
,
Perwez Alam
,
Nasir A. Siddiqui
,
Mohamed F. Alajmi
,
Adnan J. Alrehaily
,
Saleh I. Alqasoumi
,
Maged S. Abdel-Kader
,
Prawez Alam
, and
Abd El Raheim M. Donia

A simple and sensitive high-performance thin-layer chromatographic (HPTLC) method was developed for the evaluation of biomarker β-amyrin in the leaves of fve different species of genus Ficus (Ficus carica, Ficus nitida, Ficus ingens, Ficus palmata, and Ficus vasta) grown in the Kingdom of Saudi Arabia. Chromatography was performed on glass-backed silica gel 60 F254 HPTLC plates with solvents toluene–methanol (9:1, v/v) as the mobile phase. After development, the HPTLC plate was derivatized with p-anisalde-hydereagent to give well-resolved and compact spot of β-amyrin. Scanning and quantifcation were done at 550 nm. The system was found to give compact spot for β-amyrin at R F = 0.58. The linear regression analysis data for the calibration plots showed good linear relationship with r 2 = 0.998 with respect to area in the concentration range of 100–900 ng. The regression equation for β-amyrin standard was found to be Y = 5.835X + 87. The precisions (n = 6) for β-amyrin were found to be 1.64–1.77% and 1.68–1.84%, respectively, for intra-day and inter-day batches, and the recovery values were found to be 97.6–98.3%. β-Amyrin was found to be present in three species, i.e., F. carica (0.29%, w/w), F. nitida (0. 5 4% w/w), and F. p almata (0.31%, w/w), while it was absent in F. vasta and F. ingens. The statistical analysis proves that the developed method for the quantifcation of β-amyrin is reproducible; hence, it can beemployed for the determination of β-amyrin in plasma and other biological fuids as well as in fnished products avai lable in the market.

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Reaction Kinetics, Mechanisms and Catalysis
Authors:
Shakeel Ahmed
,
Faizur Rahman
,
Adnan M. J. Al-Amer
,
Eid M. Al-Mutairi
,
Uwais Baduruthamal
, and
Khurshid Alam

Abstract

A series of metal incorporated M-MCM-41 (M = Ce, Mo, and/or V) mesoporous materials were synthesized by the hydrothermal method. The synthesized mesoporous materials were characterized by the XRD, BET, TPR and EPR techniques. The extent of mesoporous structural ordering was evident from the XRD pattern of M-MCM-41. The catalytic properties of the metal containing MCM-41 catalysts were evaluated for oxidative dehydrogenation of propane and n-butane in a fixed-bed micro-reactor. The results showed higher activity in case of V-MCM-41 catalyst as compared to that of Mo-MCM-41 catalysts over a temperature range of 500–600 °C at atmospheric pressure. Cerium containing MCM-41 catalyst showed high selectivity (78%) for butadiene at moderate conversion of about 4%. The major products include ethylene, propylene and butanes. Propane conversion of about 20% with corresponding propylene selectivity of around 30% was obtained at 575 °C over V-MCM-41 catalyst. A small amount of H2 besides COx was also produced during catalytic runs under the conditions of catalyst performance evaluation.

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Summary

The aim of this study was to develop a validated high-performance thin-layer chromatography (HPTLC) procedure for resolution of chemical constituents and identification and quantification of two selected natural anticancer compounds, stigmasterol (PD-1) and cinnamic acid (PD-2), in Pluchea dioscoridis chloroform fraction (PDCF). The chromatographic estimations were conducted on normal HPTLC (20 cm × 10 cm glass-backed silica gel 60 F254) plates with chloroform-methanol-acetic acid (93:5:2, V/V) used as the mobile phase. para-Anisaldehyde was used for the derivatization of the developed plate, and compact spots were scanned at λmax = 513 nm. A well resolved, compact, and intense peaks of PD-1 and PD-2 were recorded at R F = 0.57 and 0.19, respectively. The proposed analytical method for both biomarker compounds was found to be handy, simple, precise, linear (%RSD = 1.03–1.45), accurate (98.91–99.14%), reliable, and sensitive for the analysis of both bio-markers. The LOD/LOQ (ng) for PD-1 and PD-2 were recorded as 38.73/117.37 and 42.58/129.04, respectively, in the linearity range of 200–1400 ng per spot. The obtained result showed maximum quantities of PD-1 and PD-2 (5.36 and 16.98 μg mg−1, respectively). The developed HPTLC was found to be suitable for the routine analysis of these 2 biomarkers in the chloroform fraction of Pluchea dioscoridis and can be further employed in the process quality control of herbal formulations containing the said biomarkers.

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Acta Chromatographica
Authors:
Mohammed Hamed Alqarni
,
Mohamad Ayman Salkini
,
Prawez Alam
,
Mazen Talal Alanazi
,
Maged Saad Abdel-Kader
, and
Samah M. El Sohafy

Abstract

Plants secondary metabolites undergoes qualitative and quantitative variation due to environmental and growth factors. It is a crucial factor to select the proper time for collection of medicinal plants to assure maximum content of active components reflected as maximum efficacy. Olive leaves (Olea europaea L.) are known traditionally for their antidiabetic effect. The secoiridoid glycoside oleuropein is the main active component of Olive leaves responsible for the biological activity. The current study was conducted to monitor the seasonal variation of oleuropein in Olives leaves collected from the same location. To achieve this goal a validated HPLC method following the ICH guidelines was established. Separation was conducted using RP18 column and a mobile phase consisted of ultrapure water containing 20% acetonitrile and 1% acetic acid. Detection was performed at 254 nm with 1 mL/min flow rate. The method was simple, linear, accurate, precise, specific and robust. The analyses revealed considerable variations in the level of oleuropein throughout the year. This variation cannot be explained by temperature variation during the year. Two points of high levels of oleuropein were detected prior to flowering stage and ripening of the fruits. The levels of growth regulators most likely is responsible for the increased production of oleuropein. It is recommended that leaves intended for medicinal use to be collected during the fruiting stage prior to fruit ripening.

Open access

In this study, we have developed a validated high-performance thin-layer chromatographic (HPTLC) method for the simultaneous quantification of two phenolic biomarkers, protocatechuic acid (compound 1) and quercetin 4ʹ-O-β-d-glucopyranoside (compound 2) in antimicrobial and antioxidant active A. cepa ethyl acetate extract (ACEAE). The quantitative analysis was carried out on normal-phase HPTLC (glass-backed silica gel 60 F254) plates with solvents toluene, ethyl acetate, and formic acid in the ratio of 3:6:1, v/v (as the mobile phase). Well-resolved, compact, and intense peaks of compound 1 (R F = 0.56 ± 0.001) and compound 2 (R F = 0.05 ± 0.001) were found at λ max = 275 nm. The linear regression equation / r 2 for compound 1 (Y = 8.89X + 250.71 / 0.994) and compound 2 (Y = 6.64X + 209.34 / 0.998) in the concentration range of 100–700 ng spot−1 indicated good linear relationship. The low values of percent relative standard deviation (%RSD) for intra-day / inter-day precision of compound 1 (1.14–1.26 / 1.08–1.23) and compound 2 (0.97–1.18 / 0.93–1.16) suggested that the method is precise. The (%) recoveries for compound 1 / compound 2 were found as 98.07–99.55 / 98.20–99.89 which confirms the good accuracy of the proposed method. The quantities (%w/w) of compound 1 / compound 2 in ACEAE were found as 18.84% / 13.64% of the dried weight of the extract. In vitro 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay showed the promising free radical scavenging activity of ACEAE (69.00 ± 2.99%) and compound 2 (63.86 ± 2.02%) which were comparable to ascorbic acid tested at 400 μg mL−1. ACEAE was found to be highly active against all tested bacterial strains, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa; however, Candida albicans was found to be susceptible to both compound 2 and ACEAE. The presence of compound 2 in high quantity in the ethyl acetate fractions of A. cepa peel (ACEAE) validated its antimicrobial and antioxidant property. The above developed HPTLC method can be further employed in the analysis of these markers in marketed formulations and in the quality control of herbal drugs.

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