Biomedical subjects

F J Señoráns

Publications and source records attributed to F J Señoráns.

8 recordsLinked to original sources

PubMed2006

Supercritical carbon dioxide extraction of compounds with antimicrobial activity from Origanum vulgare L.: determination of optimal extraction parameters.

Oregano leaves were extracted using a pilot-scale supercritical fluid extraction plant under a wide range of extraction conditions, with the goal of determining the extraction and fractionation conditions to obtain extracts with optimal antimicrobial activity. In this investigation, the essential oil-rich fractions were selectively precipitated in the second separator, and their chemical composition and antimicrobial activity were investigated. Gas chromatography-mass spectrometry analysis of the various fractions resulted in the identification of 27 compounds of the essential oil. The main components of these fractions were carvacrol, trans-sabinene hydrate, cis-piperitol, borneol, terpinen-4-ol, and linalool. Antimicrobial activity was investigated by the disk diffusion and broth dilution methods against six different microbial species, including two gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), two gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), a yeast (Candida albicans), and a fungus (Aspergillus niger). All of the supercritical fluid extraction fractions obtained showed antimicrobial activity against all of the microorganisms tested, although the most active fraction was the one obtained in experiment 5 (fraction was obtained with 7% ethanol at 150 bar and 40 degrees C). C. albicans was the most sensitive microorganism to the oregano extracts, whereas the least susceptible was A. niger. Carvacrol, sabinene hydrate, borneol, and linalool standards also showed antimicrobial activity against all of the microorganisms tested, with carvacrol being the most effective. Consequently, it was confirmed that essential oil from experiment 5, with the best antimicrobial activity, also presented the highest quantity of carvacrol.

Anti-Bacterial Agents↗

PubMed2005

Chemical composition and antimicrobial activity of Rosmarinus officinalis L. essential oil obtained via supercritical fluid extraction.

The chemical composition and antimicrobial activity of essential oil-rich fractions obtained by supercritical CO2 extraction from Rosmarinus officinalis L. were investigated. Gas chromatography-mass spectroscopy analysis of these fractions resulted in the identification of 33 compounds of the essential oil. The main components of these fractions were alpha-pinene, 1,8-cineole, camphor, verbenone, and borneol, constituting ca. 80% of the total oil. The antimicrobial activity was investigated by the disc diffusion and broth dilution methods against six microbial species, including gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), a yeast (Candida albicans), and a fungus (Aspergillus niger). All of the essential oil-rich fractions obtained showed antimicrobial activity against all of the microorganisms tested, with inhibition zones and minimal bactericidal and fungicidal concentration values in the range of 17 to 33 mm and 2.25 to 0.25 mg/ml, respectively. The most active fraction was the one obtained in experiment 4 (4% ethanol as modifier; extraction pressure, 25 MPa; extraction temperature, 60 degrees C). S. aureus was found to be the most sensitive bacteria to the rosemary extracts, whereas the least susceptible was A. niger. alpha-Pinene, 1,8-cineole, camphor, verbenone, and borneol standards also showed antimicrobial activity against all the microorganisms tested, borneol being the most effective followed by camphor and verbenone. In that way, it was confirmed that essential oil from experiment 4, with the best antimicrobial activity, presented the highest quantity of camphor, borneol, and verbenone.

Anti-Bacterial Agents↗

PubMed2003

Truffle aroma characterization by headspace solid-phase microextraction.

In the present study, a headspace solid-phase microextraction (HS-SPME) combined to gas chromatography-mass spectrometry (GC-MS) has been used to fully characterize aroma of truffles of different species. A fiber of medium polarity (for flavors) was used to avoid discrimination towards very non-polar and polar volatile compounds. In a previous work, extraction conditions were optimized by means of an experimental design leading to the following conditions that were used in the present study: extraction temperature, 53 degrees C; extraction time, 13.6 min; and equilibrium time, 5 min. A comparison among different truffles species has been established in terms of qualitative and quantitative differences on volatile composition. By using the optimal extraction conditions and GC-MS it was possible to identify 89 compounds in two different truffle species such as Tuber aestivum and Tuber melanosporum. An attempt has been made in order to be able to determine the influence of different geographical origins on the aroma fraction of such fungi.

Ascomycota↗

PubMed2001

Countercurrent supercritical fluid extraction and fractionation of alcoholic beverages.

A procedure for the recovery of aromatic extracts from distilled alcoholic beverages by means of a countercurrent supercritical fluid extraction (CC-SFE) on a pilot plant scale is studied. The beverage is directly in contact with the carbon dioxide current in a packed column, and the extracts are recovered in two different fractionation cells, where the depressurization occurs. The proposed method allows the selective extraction of aromatic components of the brandy flavor, rendering a high-value concentrated extract and a colored residue without brandy aroma. The content in ethanol of the aromatic extract can be modified by tuning the extraction/fractionation conditions, rendering from 15 to 95% recovery. The effect of the main variables, including extraction pressure and quality of extracting CO(2), has been tested.

Alcoholic Beverages↗

PubMed2001

Isolation of antioxidant compounds from orange juice by using countercurrent supercritical fluid extraction (CC-SFE).

Antioxidants from orange juice are isolated by the use of countercurrent supercritical fluid extraction (CC-SFE) and characterized by reversed-phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) and diode-array detection (DAD). A pilot-scale SFE plant equipped with a packed column has been employed for countercurrent extraction and fractionation of raw orange juice with carbon dioxide. Several experiments have been performed in order to study the effect of the countercurrent conditions on the content of antioxidative compounds. In this study, the main variable that has been considered is the solvent-to-feed ratio (S/F) because it plays an essential role in the extraction efficiency. The values tested covered a wide range of sample and solvent (CO(2)) flow rates. In each experimental run, two different extracted fractions and the residual nonextracted juice were obtained and characterized. Different flavonoids have been identified in the fractions obtained after CC-SFE. The possibility of using this process for antioxidant compounds enrichment is discussed.

Antioxidants↗

PubMed2000

Tuning of mobile and stationary phase polarity for the separation of polar compounds by SFC.

The separation of polar compounds by supercritical-fluid chromatography (SFC) is reviewed. New developments in mobile and stationary phase tuning are reviewed for packed and packed capillary SFC. In terms of mobile phase polarity adjustment, new pure and multiple component fluids are presented. The approach of tuning the polarity of the stationary phase as a way of increasing the range of polar compounds analyzed by SFC using pure CO(2) is discussed using either silica-based or new materials as stationary phase. Chiral, liquid crystal and polymer-based stationary phases coated on particles are widely covered in this review as an interesting approach to separate polar compounds avoiding the major drawbacks associated to the use of modifiers in SFC.

Amines↗

PubMed2000

Liquid chromatographic-mass spectrometric analysis of supercritical-fluid extracts of rosemary plants.

A two-step supercritical fluid extraction process of rosemary leaves, on a pilot plant scale, is proposed to divide the oleoresin into two fractions with different antioxidant activities and essential oil composition. Rosemary leaves were extracted by using different conditions of pressure and temperature as well as different conditions for fractionation of the extracts. Conditions can be tuned to selectively extract one antioxidant fraction with almost no residual aroma. In the present investigation, the antioxidant fraction was exhaustively studied in terms of antioxidant activity measurements as well as of chemical composition. An LC-MS method was adapted to perform the analysis and identification of the compounds responsible for the antioxidant activity of the extracts. Different extraction and fractionation conditions were studied in order to correlate the process conditions with the antioxidant activities obtained.

Antioxidants↗

PubMed2000

Combined use of supercritical fluid extraction, micellar electrokinetic chromatography, and reverse phase high performance liquid chromatography for the analysis of antioxidants from rosemary (Rosmarinus officinalis L.).

Antioxidants from rosemary were determined by the combined use of supercritical fluid extraction (SFE) prior to reverse-phase high-performance liquid chromatography (RP-HPLC) or micellar electrokinetic chromatography (MEKC). The separation of antioxidants found in the SFE fractions was achieved by using a new MEKC method and a published HPLC procedure, both with diode array detection. The characterization of the different antioxidants was further done by HPLC-mass spectrometry. Advantages and drawbacks of HPLC and MEKC for analyzing the antioxidants found in the different extracts are discussed. From the results it is concluded that HPLC renders higher peak area and is better in its reproducibility than MEKC; both techniques provide similar analysis time reproducibility. The main advantage of MEKC is its much higher separation speed, which is demonstrated to be useful for the quick adjustment of SFE conditions, allowing rosemary fractions of higher antioxidative power to be obtained quickly. Moreover, the possibilities of this approach for following the degradation of antioxidants are discussed.

Antioxidants↗