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Determination of curcuminoid content in turmeric using fluorescence spectroscopy
摘要： The potential of fluorescence spectroscopy is exploited for the characterization and comparison of different turmeric varieties based on curcuminoids content in turmeric powders. Fluorescence spectra from turmeric powders has been acquired by using excitation wavelengths from 300 to 470 nm with step of 10 nm to investigate the effect of excitation wavelengths on the emission of valuable ingredients for their characterization. Emission spectra revealed that fresh wet turmeric rhizomes show emission bands at 571 nm which is due to curcumin. It is found that main ingredient of turmeric powder is curcumin and best excitation wavelength is 467 nm for its maximum emission intensity. High Pressure Liquid Chromatography (HPLC) was used as alternate standard technique for determination of curcuminoid content in the reference samples. The curcumin content in the commercially available local turmeric brands were also evaluated, one brand showed significant covariance from standard fluorescent spectra of turmeric meaning this particular brand contained minimum curcumin content or have been severely adultered. In the next step the powders were heated at different temperatures from 60 ℃ to 150 ℃ (Normal cooking & frying temperatures) to observe the difference in emission spectra particularly keeping in view the molecular composition and curcuminoid content in turmeric. The results indicate that curcumin content gradually decreases above 90 ℃. Principal component analysis (PCA) has been employed on all the data to statistically differentiate small molecular changes and adulteration by covariance calculations.
关键词： Anti-inflammatory.,Turmeric,Fluorescence emission spectroscopy,Anti-oxidant,Curcumin
更新于2025-09-23 15:22:29
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Ionic Radii and Concentration Dependency of RE <sup>3+</sup> (Eu <sup>3+</sup> , Nd <sup>3+</sup> , Pr <sup>3+</sup> and La <sup>3+</sup> ) Doped Cerium Oxide Nanoparticles for Enhanced Multi-Enzyme Mimetic and Hydroxyl Radical Scavenging Activity
摘要： The anti-oxidant activity of cerium oxide nanoparticles (CNPs) depends on the concentration of oxygen vacancies and Ce3+ active sites. In the present work, we report the impact of 5 mol% tri-valent rare earth doped (RE3+ = Eu3+, Nd3+, Pr3+ and La3+) CNPs on the oxidation state modulation and anti-oxidant property with respect to ionic radii. An increase in lattice parameter, strain and oxygen vacancy concentration was observed as a function of ionic radii. Among the various dopants in CNP, La3+ with higher ionic radii having smaller crystallite size (7.9 nm) and higher vacancy displayed better peroxidase, oxidase and hydroxyl radical (HO?) scavenging activity. The kinetic parameters for the peroxidase and oxidase activity was found to be superior with Km = 0.217 mM and 0.261 mM, respectively, for 5 mol% La3+ doped CNPs. In order to divulge the role of dopants concentration on structural properties, we also explored using 10 and 20 mol% La3+ doping in CNP. Due to smaller crystallite size (6.7 nm) and higher defect level (3.12 x 1021 cm-3), 20% La3+ doping showed superior peroxidase and oxidase activity as shown by the low Km values. CNPs exhibit both peroxidase and oxidase activity in a concentration dependent manner. Moreover, CNPs exhibit a concentration dependent peroxidase and oxidase activity that can be selectively activated for various theranostic applications. Thus, our results demonstrate the crucial role of ionic radii and concentration of RE3+ dopants on the defect formation in cerium oxide nanoparticles for improved anti-oxidant properties of ceria.
关键词： ionic radii,RE3+ doping,oxygen vacancies,peroxidase activity,oxidase activity,hydroxyl radical scavenging,cerium oxide nanoparticles,anti-oxidant properties
更新于2025-09-04 15:30:14