Determination of water-soluble vitamins in multivitamin dietary supplements and in artichokes by micellar electrokinetic chromatography

Cyclodextrin-modified graphene quantum dots as a novel additive for the selective separation of bioactive compounds by capillary electrophoresis

Highly reliable separation and determination of various biologically active compounds were achieved using capillary electrophoresis (CE) based on β-cyclodextrin-functionalized graphene quantum dots (βcd-GQDs) as the background electrolyte additive. βcd-GQDs improve the separation efficiency between peaks of all analytes. No addition of surfactants or organic solvents was needed in the running buffer containing βcd-GQDs. Up to eight consecutive runs were acquired with high precision for the separation of resveratrol, pyridoxine, riboflavin, catechin, ascorbic acid, quercetin, curcumin, and even of several of their structural analogs. Baseline separation was achieved within just 13 min as a result of the effective mobility of the analytes along the capillary owing to the differential interaction with the additive. The proposed analytical method displayed a good resolution of peaks for all species selecting two absorption wavelengths in the diode array detector. Detection limits lower than 0.28 µg mL^-1 were found for all compounds and precision values were in the range of 2.1-4.0% in terms of the peak area of the analytes. The usefulness of the GQD-assisted selectivity-enhanced CE method was verified by the analysis of food and dietary supplements. The applicability to such complex matrices and the easy and low-cost GQD preparation open the door for routine analyses of food and natural products. The concept of using such a dual approach (macromolecules and nanotechnology) has been explored to tackle the separation of various bioactive compounds in nutritional supplements and food. Schematic illustration of the electrophoretic separation of the bioactive molecules in the capillary which is filled with the running solution without (top) and with βcd-GQDs (bottom). The fused silica capillary with negatively ionizable silanol groups at the wall. The voltage is applied at positive polarity at the outlet. R, riboflavin; r, resveratrol; P, pyridoxine; C, catechin; c, curcumin; A, ascorbic acid; Q, quercetin.

Separation of some vitamins in reversed-phase thin-layer chromatography and pressurized planar electrochromatography with eluent containing surfactant

The separation of some water- and fat-soluble vitamins via micellar systems of reversed-phase high-performance thin-layer chromatography (HPTLC) and pressurized planar electrochromatography (PPEC) was subjected to research. Hence, the influence of the mobile phase composition (surfactant and acetonitrile concentration, eluent buffer pH) on the migration distances and zone separation of some vitamins (thiamine, riboflavin, niacin, pyridoxine, cyanocobalamin, folic acid, ergocalciferol and α-tocopherol) was investigated. Our results indicated that the applied technique has an impact on the solute order. Comparing the system capacity of HPLC and PPEC (measured as height of the theoretical plate) for the mobile phase systems with and without surfactant shows differences, especially for fat-soluble vitamin. The variances and reproducibilities (% RDS) values of the vitamin are less in PPEC than in TLC. Moreover, the migration distances of water-soluble vitamins are longer than fat-soluble ones. Overall, eluent consisting of 50% acetonitrile, 18.75 mM SDS, the buffer of pH 6.99 via the PPEC technique was most appropriate for determining the investigated vitamins in the artificial mixture and the two commercially available vitamin combinations.

Recent trends in analytical methods for water-soluble vitamins

In this review, recent advances in the analysis of water-soluble vitamins (WSVs) have been reported considering the advantages and disadvantages of various extraction, separation and detection techniques, commonly used for their quantification. Acid hydrolysis, enzyme treatment, SPE based methods and some other extraction methods have been discussed. Particular attention has been devoted to the analytical techniques based on liquid chromatography and electrophoresis. Furthermore, suitability and selectivity of hydrophilic interaction liquid chromatography (HILIC) for WSVs has been discussed in detail. Problems related to these techniques and their possible solutions have also been considered. Special focus has been given to the applications of liquid chromatography (since 2014-2019) for the simultaneous analysis of WSVs and their homologous in complex food samples.

Synergistic Effects of Jerusalem Artichoke in Combination with Pegylated Interferon Alfa-2a and Ribavirin Against Hepatic Fibrosis in Rats

BACKGROUND

Complementary and alternative medicine has been highly appreciated as a supportive regimen for classical treatment strategies. Here we offer a nutrition-based adjuvant therapy for liver fibrosis, a major risk factor for cirrhosis and hepatocellular carcinoma.

AIM OF THE STUDY

To evaluate the possible hepatoprotective effects of Jerusalem artichoke tubers (JAT) in combination with interferon and ribavirin.

MATERIALS AND METHODS

Twelve groups of rats were administered JAT, interferon and ribavirin either separately or in combination from day one of CCL4 administration until the end of the study. Animals were killed after 8 weeks of CCL4- induced hepatotoxicity.

RESULTS

Hepatocytes from rats treated with triple combination of interferon, ribavirin, and JAT showed more less normal architecture compared to CCL4- treated rats. We also detected significantly higher hepatic protein expression levels of p53, BAX and transforming growth factor-β (TGF-β) in the CCl4- intoxicated group compared to normal controls, as evidenced by immunohistochemical staining and western blotting analyses. Addition of JAT as a supportive regimen improved response to ribavirin and interferon and effectively participated in retaining normal histopathological and biochemical criteria and significantly lowered protein expression of p53, BAX, and TGF-β.

CONCLUSIONS

We suggest that addition of JAT as a supportive regimen to interferon and ribavirin effectively potentiates their anti-fibrotic effects.

Multicomponent analysis of fat- and water-soluble vitamins and auxiliary substances in multivitamin preparations by qNMR

A nuclear magnetic resonance (NMR) spectroscopic method was tested to control 12 vitamins and accompanying substances in multivitamin preparations. The limits of detection (LODs) and limits of quantification (LOQs) varied in the 9.0-77.0 mg/kg and in the 34.5-93.5 mg/kg range, respectively. The coefficients of variation (CVs) ranged between 0.9% and 12%. The (1)H NMR spectra showed linearity for the 140-260 mg sample weight (R(2) > 0.918). The NMR spectra of multivitamin preparations showed the presence of different degradation products of ascorbic acid. The NMR method was applied to 13 different multivitamin preparations including tablets, capsules, and effervescent tablets with average recovery rates between 85% and 132%. A number of accompanying substances (citric acid, mannitol, saccharin, cyclamate, sum of steviol glycosides, and butylhydroxytoluene) were additionally identified and quantified. NMR was found to be suitable for the simultaneous qualitative measurement of water- and fat-soluble vitamins and accompanying substances and shows some promise for quantitative determination of at least 5 vitamins (B1, B3, B5, B6, and E) in multivitamin preparations.