Bio: Fadhil Jasim is an academic researcher from University of Baghdad. The author has contributed to research in topics: Thermal decomposition & Persulfate. The author has an hindex of 13, co-authored 64 publications receiving 372 citations.
Papers published on a yearly basis
TL;DR: In this paper, a sensitive and rapid spectrofluorometric method for determination of micro-amounts of curcumin in turmeric spices and related flavors has been developed, which involves dissolving Curcumin samples in dry acetone, irradiating the resulting clear solution at λE = 424 nm, and measuring the stable intense green-yellow fluorescence at ǫ = 504 nm.
Abstract: A sensitive and rapid spectrofluorometric method for determination of microamounts of curcumin in curcumin spices and related flavors has been developed. It involves dissolving curcumin samples in dry acetone, irradiating the resulting clear solution at λE = 424 nm, and measuring the stable intense green-yellow fluorescence at λF = 504 nm. The fluorescent solution shows no change in λE or λF or in fluorescence intensity for at least 1 month under ambient conditions. Beer's law is followed over the range 0.0–500 ppb of curcumin. The sensitivity and detection limit ( S N = 2 ) are 4.7 and 0.34 ppb of curcumin per fluorescence unit, respectively. The RSD and recovery for a series of concentrations (0.01–0.3 ppm) are 1.13–2.03 and 98.96–100%, respectively. Temperature control is needed; pH adjustment and O2 removal from test solution are unnecessary. Under the specified conditions, water is the only quencher for curcumin fluorescence. Direct calibration determination is satisfactory and therefore there is no need to use a rather lengthy standard additions technique.
TL;DR: In this paper, the authors evaluated the performance of 12 curcumin-solvent nonaqueous systems in terms of λmax, molar absorptivity, durability, sensitivity, limit of detection, linearity, precision and accuracy.
Abstract: Curcumin (Turmeric Yellow) dissolves in various polar and nonpolar organic solvents (Table 1) and gives sensitive and stable yellow to greenish-yellow (depending on the solvent) colors. λmax, molar absorptivity, durability, sensitivity, limit of detection, linearity, precision, and accuracy have been evaluated for each of the 12 curcumin-solvent nonaqueous systems.
TL;DR: In this paper, a specific spectrophotometric method for the determination of (0.01-15) ppm of curcumin in spices using acetone-bicarbonate buffer (pH 11) is described.
Abstract: A specific spectrophotometric method for the determination of (0.01–15) ppm of curcumin in spices using acetone-bicarbonate buffer (pH 11) is described. The effects of various experimental conditions such as pH of solutions, volume ratio of acetone-buffer solution, and interferences have been discussed. The detection limit and molar absorptivity have been found to be 1 ng ml−1 and 46,000 liters mol−1 cm−1, respectively. RSD and relative accuracy percentages have been determined to be 2.67-2.0 and 2.70-2.50% for 1 and 15 ppm curcumin, respectively.
TL;DR: Factors such as sample nature, matrix and heating programme have been found to influence both the sensitivity and precision of the determination of vanadium by electrothermal AAS.
Abstract: Factors such as sample nature, matrix and heating programme have been found to influence both the sensitivity and precision of the determination of vanadium by electrothermal AAS. The reciprocal sensitivity, detection limit and precision (RSD) are 55 pg, 86 pg and 4%, respectively for aqueous solutions and 88 pg, 80 pg and 4% for organic solutions. Only tungsten and nitric acid have been found to interfere appreciably. Moderately concentrated sodium chloride solutions (⩽6%) can be analysed for vanadium (⩾0.05 μg/ml) without background correction, as can the acid digests of phosphate rocks and crude petroleum samples.
TL;DR: The intracellular curcumin showed more fluorescence in tumor cells than in normal cells and fluorescence spectroscopy could be used to monitor its preferential localization in the membrane of tumor cells and the possibility of developingCurcumin, as a bimolecular sensitive fluorescent probe is discussed.
Abstract: Curcumin, with its recent success as an anti-tumor agent, has been attracting researchers from wide ranging fields of physics, chemistry, biology and medicine. The chemical structure of curcumin has two o-methoxy phenols attached symmetrically through α,β-unsaturated β-diketone linker, which also induces keto–enol tautomerism. Due to this, curcumin exhibits many interesting photophysical and photochemical properties. The absorption maximum of curcumin is ∼408–430 nm in most of the organic solvents, while the emission maximum is very sensitive to the surrounding solvent medium (460–560 nm) and the Stokes’ shift varied from 2000 to 6000 cm−1. The fluorescence quantum yield in most of the solvents is low and reduced significantly in presence of water. The fluorescence lifetime is short (<1 ns) and displayed multi-exponential decay profile. The singlet excited states of curcumin decay by non-radiative processes contributed mainly by intra- and intermolecular proton transfer with very low intersystem crossing efficiency. Polarity, π-bonding nature, hydrogen bond donating and accepting properties of the solvent influence the excited state photophysics of curcumin in a complex manner. The triplet excited states of curcumin absorb at 720 nm and react with oxygen to produce singlet molecular oxygen. The photodegradation of curcumin produces smaller phenols and the photobiological activity of curcumin is due to the generation of reactive oxygen species. Being lipophilic in nature, the water solubility of curcumin could be enhanced upon the addition of surfactants, polymers, cyclodextrins, lipids and proteins. Changes in the absorption and fluorescence properties of curcumin have been found useful to follow its interaction and site of binding in these systems. Curcumin fluorescence could be employed to follow the unfolding pattern and structural changes in proteins. The intracellular curcumin showed more fluorescence in tumor cells than in normal cells and fluorescence spectroscopy could be used to monitor its preferential localization in the membrane of tumor cells. This review, presents the current status of research on the photophysical, photochemical and photobiological processes of curcumin in homogeneous solutions, bio-mimetics and living cells. Based on these studies, the possibility of developing curcumin, as a bimolecular sensitive fluorescent probe is also discussed.
TL;DR: In this paper, an antisolvent precipitation method was used to synthesize a mixture of Zein and Curcumin composite colloidal particles, where the average particle size could be controlled down to 100-150 nm, depending on the solvent system and the ratio of zein and curcumin used in the synthesis.
Abstract: Zein–curcumin composite colloidal particles were synthesized using an antisolvent precipitation method The average particle size could be controlled down to 100–150 nm, depending on the solvent system and the ratio of zein and curcumin used in the synthesis In all cases, spherical particles were obtained, as confirmed by transmission electron microscopy Depending on the preparation conditions, curcumin load and encapsulation efficiency varied from 16 to 41% and 711 to 868%, respectively Solid state characterization by differential scanning calorimetry and X-ray diffraction indicated the amorphous nature of entrapped curcumin An UV irradiation study confirmed enhanced photostability of curcumin due to the entrapment of curcumin in the biopolymeric matrix The particles were also found to have good colloidal stability at a broad range of physiologically relevant pH (12, 45, 67 and 74) and in simulated gastro-intestinal conditions Results from an in vitro mucoadhesion study showed retention of more than 60% curcumin for 150 minutes The mucoadhesion property was further confirmed from a mucin association study carried out on Caco-2 cells
TL;DR: The curcumin encapsulated in casein nanoparticles had higher biological activity, as assessed by antioxidant and cell proliferation assays, than pristineCurcumin, likely due to the improved dispersibility.
Abstract: In this work, a novel encapsulation method was studied by spray-drying a warm aqueous ethanol solution with codissolved sodium caseinate (NaCas) and lipophilic food components, using curcumin as a model compound. The encapsulation caused the loss of crystallinity of curcumin. After hydration of spray-dried powder and centrifugation, 137 μg/mL curcumin was dispersed in the transparent dispersion, which was 4 decades higher than its water solubility. Dynamic light scattering and atomic force microscopy results showed that curcumin-loaded casein nanoparticles were bigger than those of NaCas processed at encapsulation conditions but were smaller than those of the native NaCas. The increased nanoparticle dimension, together with fluorescence and FTIR spectroscopy results, suggested that curcumin was entrapped in the nanoparticle core through hydrophobic interactions. The curcumin encapsulated in casein nanoparticles had higher biological activity, as assessed by antioxidant and cell proliferation assays, than pristine curcumin, likely due to the improved dispersibility. This simple approach may be applied to encapsulate various lipophilic bioactive compounds.
TL;DR: The previous databases for 150 compounds have been expanded to encompass 339 compounds for which absorption spectra, fluorescence spectra and references to the primary literature have been included where available (552 spectra altogether).
Abstract: The design of new molecules for photochemical studies typically requires knowledge of spectral features of pertinent chromophores beginning with the absorption spectrum (λabs ) and accompanying molar absorption coefficient (e, m-1 cm-1 ) and often extending to the fluorescence spectrum (λem ) and fluorescence quantum yield (Φf ), where the fluorescence properties may be of direct relevance or useful as proxies to gain insight into the nature of the first excited singlet state. PhotochemCAD databases, developed over a period of 30 years, are described here. The previous databases for 150 compounds have been expanded to encompass 339 compounds for which absorption spectra (including e values), fluorescence spectra (including Φf values) and references to the primary literature have been included where available (552 spectra altogether). The compounds exhibit spectra in the ultraviolet, visible and/or near-infrared spectral regions. The compound classes and number of members include acridines (21), aromatic hydrocarbons (41), arylmethane dyes (11), azo dyes (18), biomolecules (18), chlorins/bacteriochlorins (16), coumarins (14), cyanine dyes (19), dipyrrins (7), heterocycles (26), miscellaneous dyes (13), oligophenylenes (13), oligopyrroles (6), perylenes (5), phthalocyanines (11), polycyclic aromatic hydrocarbons (16), polyenes/polyynes (10), porphyrins (34), quinones (24) and xanthenes (15). A database of 31 solar spectra also is included.
TL;DR: Stability of curcumin in solutions, spectroscopy characteristics ofCurcumin (UV, IR, Raman, MS, and NMR), polymorphism forms, method of analysis in both of biological and nonbiological samples, and metabolite studies of Curcumin are summarized.
Abstract: Curcumin and its two related compounds, that is, demethoxycurcumin and bis-demethoxycurcumin (curcuminoids) are the main secondary metabolites of Curcuma longa and other Curcuma spp. Curcumin is commonly used as coloring agent as well as food additive; curcumin has also shown some therapeutic activities. This review summarizes stability of curcumin in solutions, spectroscopy characteristics of curcumin (UV, IR, Raman, MS, and NMR), polymorphism forms, method of analysis in both of biological and nonbiological samples, and metabolite studies of curcumin. For analysis of curcumin and its related compounds in complex matrices, application of LC–MS/MS is recommended.