Evaluating four modes of extraction to analyze bioactive compounds in Garcinia brasiliensis (bacupari) by high-performance liquid chromatography diode-array detection (HPLC-DAD).

The prior study of the extraction path is fundamental to optimize the required time and to define the most suitable solvent to extract and determine an analyte of interest in a complex sample. This study aimed to evaluate four extraction modes; solvent sequence in Soxhlet equipment (SES), and by maceration (SEM), direct extraction with ethanol by maceration (EEM), and in Soxhlet equipment (EES), and determine Garcinia brasiliensis bioactive compounds using a validated high-performance liquid chromatography diode-array detection (HPLC-DAD) method. Fukugetin, fukugetina-7''-O-ß-D-glucoside, norathyriol, guttiferone A, and 7-epiclusianone were identified and quantified with authentic standards. Among all four modes applied to extract the main bioactive. From HPLC profile, it was observed that the highest levels of 7-epiclusianone (344.1 mg/g) and guttiferone A (142.8 mg/g) were found in the N-hexane fraction using SEM mode, whereas the highest levels of fukugetin (44.95 mg/g) and norathyriol (3.95 mg/g dry weight) in the ethyl acetate fraction using SES mode.

Development and validation of a micellar electrokinetic chromatography method for quantitative determination of butenolides in Piper malacophyllum (C. Presl) C. DC.

INTRODUCTION: A large number of natural and synthetic compounds having butenolides as a core unit have been described and many of them display a wide range of biological activities. Butenolides from P. malacophyllum have presented potential antifungal activities but no specific, fast, and precise method has been developed for their determination. OBJECTIVE: To develop a methodology based on micellar electrokinetic chromatography to determine butenolides in Piper species. METHODOLOGY: The extracts were analysed in an uncoated fused-silica capillaries and for the micellar system 20 mmol/L SDS, 20% (v/v) acetonitrile (ACN) and 10 mmol/L STB aqueous buffer at pH 9.2 were used. The method was validated for precision, linearity, limit of detection (LOD) and limit of quantitation (LOQ) and the standard deviations were determined from the standard errors estimated by the regression line. RESULTS: A micellar electrokinetic chromatography (MEKC) method for determination of butenolides in extracts gave full resolution for 1 and 2. The analytical curve in the range 10.0-50.0 µg/mL (r(2) = 0.999) provided LOD and LOQ for 1 and 2 of 2.1/6.3 and 1.1/3.5 µg/mL, respectively. The RSD for migration times were 0.12 and 1.0% for peak area ratios with 100.0 ± 1.4% of recovery. CONCLUSIONS: A novel high-performance MEKC method developed for the analysis of butenolides 1 and 2 in leaf extracts of P. malacophyllum allowed their quantitative determined within an analysis time shorter than 5 min and the results indicated CE to be a feasible analytical technique for the quantitative determination of butenolides in Piper extracts.

Mixture-designed electrolytes for the MEKC separation of natural and synthetic steroids.

In this work, the separation of 11 natural and synthetic steroids was studied using MEKC electrolytes modified by property-selected organic solvents: ethanol, ACN, and THF. The interplay between electrophoretic behavior and structural features was disclosed and the effects of organic modifiers to modulate retention and to alter selectivity were discussed in terms of system linear solvation energy relationships (LSER). The LSER indicated the total organic solvent percentage in the electrolyte as a major parameter to control retention and as a minor contribution, the hydrogen bond acidity. By evaluating the electropherograms obtained from mixture-designed electrolytes, a favorable separation condition for all solutes was achieved in ca. 25 min with an electrolyte composed of 20 mmol/L sodium tetraborate at pH 9.4, 20 mmol/L SDS and 20% EtOH (0.80% CV for migration time and 2.5% CV for peak area, n = five consecutive injections). The applicability of the proposed separation condition was demonstrated by the inspection of estrogens in urine sample (puberty stage).

Determination of folic acid in tablets by microemulsion electrokinetic chromatography.

A microemulsion electrokinetic chromatography (MEEKC) method has been developed and validated for the determination of folic acid, a water-soluble vitamin, in a commercial tablet formulation. The analysis was performed using a microemulsion containing 0.5% (w/w) ethyl acetate, 1.2% (w/w) butan-1-ol, 0.6% (w/w) sodium dodecyl sulfate, 15% (v/v) 2-propanol and 82.7% (w/w) 10 mmol L(-1) sodium tetraborate aqueous buffer at pH 9.2. Direct UV detection at 214nm led to an adequate sensitivity without interference from sample excipients. For quantitative purposes, niacin was used as internal standard. Acceptable precision (<1.2% relative standard deviation (R.S.D.)), linearity (r = 0.9992; range from 160.0 to 240.0 microg/mL), sensitivity (limit of detection (LOD) = 2.98 microg/mL; limit of quantification (LOQ) = 9.05 microg/mL) and recovery (99.8 +/- 1.8% at three concentration levels) were obtained. Based on the performance characteristics, the proposed methodology was found suitable for the determination of folic acid in tablet formulations.