Jairo René Martínez

Chemical composition and antiprotozoal activities of Colombian Lippia spp essential oils and their major components

The chemical composition and biological activities of 19 essential oils and seven of their major components were tested against free and intracellular forms of Leishmania chagasi and Trypanosoma cruzi parasites as well as Vero and THP-1 mammalian cell lines. The essential oils were obtained from different species of Lippia, a widely distributed genus of Colombian plants. They were extracted by microwave radiation-assisted hydro-distillation and characterised by GC-FID and GC-MS. The major components were geranial, neral, limonene, nerol, carvacrol, p-cymene, gamma-terpinene, carvone and thymol. The essential oil of Lippia alba exhibited the highest activity against T. cruzi epimastigotes and intracellular amastigotes with an IC50 of 5.5 microg/mL and 12.2 microg/mL, respectively. The essential oil of Lippia origanoides had an IC50 of 4.4 microg/mL in L. chagasi promastigotes and exhibited no toxicity in mammalian cells. Thymol (IC50 3.2 +/- 0.4 microg/mL) and S-carvone (IC50 6.1 +/- 2.2 microg/mL), two of the major components of the active essential oils, were active on intracellular amastigotes of T. cruziinfected Vero cells, with a selective index greater than 10. None of the essential oils or major components tested in this study was active on amastigotes of L. chagasi infected THP-1 cells.

Comparative study of Colombian citrus oils by high-resolution gas chromatography and gas chromatography-mass spectrometry

Abstract Essential oils from fruit peel and leaves of colombian lemon ( Citrus volkameriana ), mandarin ( C. reticulata ) and orange ( C. sinensis ) were obtained by steam distillation and/or cold pressing. The extracts were analysed by high-resolution gas chromatography using either a flame ionization detector or a mass selective detector (electron impact ionization, 70 eV). The oil constituents were identified according to their mass spectra and Kova´ts retention indices determined on both polar and non-polar stationary phase capillary columns. The concentration of volatile secondary metabolites was maximum when the citrus fruits were at an intermediate maturation stage characterized by a greenish yellow coloration (45–75% green). While citrus peel oils contained from 94.01 to 98.66% of monoterpenes (C 10 H 16 ), limonene as a major component and from 0.82 to 5.84% of oxygenated compounds, the extracts from citrus leaves contained only 65.26, 31.23 and 79.43% of monoterpenes (C 10 H 16 ) in lemon, mandarin and orange, respectively. Oxygenated compounds in these oils represented 33.08, 68.47 and 16.38%, respectively.

Solid-phase microextraction with on-fibre derivatisation applied to the analysis of volatile carbonyl compounds

We have used a fast, sensitive and efficient method for the analysis of volatile carbonyl compounds (saturated aliphatic and unsaturated aldehydes) based on solid-phase microextraction with on-fibre derivatisation. Pentafluorophenylhydrazine was absorbed onto a poly(dimethylsiloxane)/divinylbenzene-coated fibre and exposed to the vapours of aldehyde-containing matrices. The hydrazones formed on the fibre were desorbed into the gas chromatograph injection port and quantified by means of electron-capture detection with high sensitivity (10-90 fmol) and good reproducibility (RSD<10%). The method was applied to the headspace-sampling of volatile carbonyl compounds released during the thermally-induced degradation of sunflower oil.

Inhibitory effect of essential oils obtained from plants grown in Colombia on yellow fever virus replication in vitro.

BackgroundAn antiviral drug is needed for the treatment of patients suffering from yellow fever. Several compounds present in plants can inactive in vitro a wide spectrum of animal viruses.AimIn the present study the inhibitory effect of essential oils of Lippia alba, Lippia origanoides, Oreganum vulgare and Artemisia vulgaris on yellow fever virus (YFV) replication was investigated.MethodsThe cytotoxicity (CC50) on Vero cells was evaluated by the MTT reduction method. The minimum concentration of the essential oil that inhibited virus titer by more than 50% (MIC) was determined by virus yield reduction assay. YFV was incubated 24 h at 4°C with essential oil before adsorption on Vero cell, and viral replication was carried out in the absence or presence of essential oil. Vero cells were exposed to essential oil 24 h at 37°C before the adsorption of untreated-virus.ResultsThe CC50 values were less than 100 μg/mL and the MIC values were 3.7 and 11.1 μg/mL. The CC50/MIC ratio was of 22.9, 26.4, 26.5 and 8.8 for L. alba, L origanoides, O. vulgare and A. vulgaris, respectively. The presence of essential oil in the culture medium enhances the antiviral effect: L. origanoides oil at 11.1 μg/mLproduced a 100% reduction of virus yield, and the same result was observed with L. alba, O. vulgare and A. vulgaris oils at100 μg/mL. No reduction of virus yield was observed when Vero cells were treated with essential oil before the adsorption of untreated-virus.ConclusionThe essential oils evaluated in the study showed antiviral activities against YFV. The mode of action seems to be direct virus inactivation.

High-resolution gas-chromatographic analysis of the secondary metabolites obtained by subcritical-fluid extraction from Colombian rue (Ruta graveolens L.).

Subcritical (CO(2)) extraction, carried out in a J&W Scientific High Pressure Soxhlet Extractor, was used to isolate secondary metabolites from leaves, flowers, stems and roots of Colombian rue (Ruta graveolens L.). The various extracts were analyzed by capillary chromatography, on an HP-5 (30 m) column, using nitrogen-phosphorus, flame ionization, and mass selective detection systems. Kováts indexes and mass spectra (electron impact, 70 eV) were employed for compound identification. The extracts from the various parts of rue studied had different compositions. The number of compounds detected at concentrations above 0.01% (w/w) in the extracts from leaves, flowers, stems and roots, was 78, 45, 25 and 24, respectively. 2-Nonanone (8.9%), 2-undecanone (13.4%), chalepensin (13.0%), and geijerene (19.3%) were the main constituents found in the extracts from rue leaves, flowers, stems and roots, respectively. Furanocoumarins, furoquinolines, hydrocarbons and benzodioxol derivatives were the main compound families found in all extracts, at total concentrations between 3.7 and 33.9%, depending on the part of the plant. The extraction method used has low environmental impact and produced solvent-free extracts in good yield with no pigments, waxes, resins, or high-molecular weight compounds which may interfere with the isolation and analysis of the alkaloids responsible for rues biological activity, which were extracted in relatively high yield.

Lippia origanoides chemotype differentiation based on essential oil GC-MS and principal component analysis.

Chromatographic (GC/flame ionization detection, GC/MS) and statistical analyses were applied to the study of essential oils and extracts obtained from flowers, leaves, and stems of Lippia origanoides plants, growing wild in different Colombian regions. Retention indices, mass spectra, and standard substances were used in the identification of 139 substances detected in these essential oils and extracts. Principal component analysis allowed L. origanoides classification into three chemotypes, characterized according to their essential oil major components. Alpha- and beta-phellandrenes, p-cymene, and limonene distinguished chemotype A; carvacrol and thymol were the distinctive major components of chemotypes B and C, respectively. Pinocembrin (5,7-dihydroxyflavanone) was found in L. origanoides chemotype A supercritical fluid (CO(2)) extract at a concentration of 0.83+/-0.03 mg/g of dry plant material, which makes this plant an interesting source of an important bioactive flavanone with diverse potential applications in cosmetic, food, and pharmaceutical products.

Comparison of extraction methods and detection systems in the gas chromatographic analysis of volatile carbonyl compounds

High-resolution gas chromatography (HRGC) with electron-capture detection (ECD), nitrogen-phosphorus detection (NPD), flame ionization detection (FID) or with mass spectrometry-selected ion monitoring (MS-SIM) was used in the analysis of volatile carbonyl compounds. Eighteen carbonyl compounds that are typically produced during lipid peroxidation were derivatized quantitatively with pentafluorophenylhydrazine (PFPH) at room temperature, to afford their corresponding water-insoluble hydrazones. These derivatives were extracted into non-polar phases by means of either liquid-liquid extraction (LLE) (hexane) or solid-phase extraction (SPE) on 3 ml C18 octadecyl-bonded phase cartridges. Detection limits of 10(-14) and 10(-12) mol/ml per aldehyde were achieved with the ECD and MS-SIM systems, respectively. The effects of extraction conditions on sensitivity and recovery were determined by performing parallel HRGC-ECD and HRGC-MS-SIM analyses of pentafluorophenylhydrazones of the eighteen compounds under study. Recoveries of 51.4-78.9 +/- 1.2-4.5 and 80.9-98.3 +/- 1.0-3.5% were obtained with LLE and SPE, respectively. The method was applied to the analysis of the volatile carbonyl compounds in various heated vegetable oils (corn, palm or sunflower) and to the analysis of volatile aldehydes in human urine.

Sampling flower scent for chromatographic analysis

The analysis of flower volatiles requires special methods for their isolation with enrichment. Living flowers show a continuous change in their volatile profile that depends on intrinsic (genetic) and external (light, temperature, hydric stress) factors. Excised flowers suffer rapid deterioration and loss of volatiles. While industrial isolation methods for flower volatiles are well established, those at the laboratory-scale experience progressive development, in the search for higher sensitivity, reproducibility, and simplicity. This review covers the flower scent sampling methods most commonly employed during the last decade, and includes comments on their strengths and limitations. The strengths of headspace solid-phase microextraction (HS-SPME) for in vivo monitoring are emphasized with the examples of monitoring the circadian variation of Brugmansia suaveolens flower scent and of volatile aldehyde detection in flower scent using on-fiber derivatization.

HRGC/FID and HRGC/MSD Analysis of the Secondary Metabolites Obtained by Different Extraction Methods from Lepechinia schiedeana, and in Vitro Evaluation of Its Antioxidant Activity

Steam distillation (SD), simultaneous distillation-solvent extraction (SDE), microwave-assisted solvent extraction (MWE), and supercritical (CO2) extraction (SFE) were used to isolate secondary metabolites from Lepechinia schiedeana. The various extracts were analyzed by capillary gas-chromatography, on poly (dimethylsiloxane) (DB-1) and poly(ethyleneglycol) (INNOWAX), 60 m columns, using FID or MSD (EI, 70 eV). Kovats indexes, mass spectra, or standard compounds were employed for compound identification. 43, 61, 67, and 79 compounds at concentrations above 0.01% were detected in the SD, SDE, MWE, and SFE extracts, respectively. Ledol, C15H26O, was the major constituent (20.04–36.87%) in all extracts. Oxygenated sesquiterpenes (24.36–43.14%), C10H16, monoterpenes (27.70–39.87%), and C15H24, sesquiterpenes (10.04–22.22%) were the main groups of compounds present in SD, SDE, MWE, and SFE extracts. Heavy hydrocarbons (Cn > 15), diterpenoids, and phytosterols were found only in MWE and SFE extracts. The antioxidant activity of Lepechinia schiedeana was measured by the HRGC quantification of the volatile carbonyl compounds, final products of lipoxidation, released in a model lipid system (sunflower oil) by the effect of the Fenton reagent. The concentration of volatile carbonyl compounds decreased by 65% when lipid oxidation was induced in the presence of macerated Lepechinia plant. The protection of polyunsaturated acids in sunflower oil was also studied by measuring their concentrations after heating of the oil (180°C, 2 h) with and without macerated Lepechinia plant.

Chromatographic and mass spectrometric characterization of essential oils and extracts from Lippia (Verbenaceae) aromatic plants

Analytical methodologies based on GC and HPLC were developed for the separation and quantification of carnosic acid, ursolic acid, caffeic acid, p-coumaric acid, rosmarinic acid, apigenin, luteolin, quercetin, kaempferol, naringenin, and pinocembrin. These methods were used to characterize essential oils and extracts obtained by solvent (methanol) and by supercritical fluid (CO(2)) extraction from stems and leaves of Lippia (Verbenaceae family) aromatic plants (Lippia alba, Lippia origanoides, Lippia micromera, Lippia americana, Lippia graveolens, and Lippia citriodora). Supercritical CO(2) extraction isolated solely pinocembrin and narigenin from three L. origanoides chemotypes. Solvent extracts possessed a more varied composition that additionally included apigenin, quercetin, and luteolin. Solvent extraction afforded higher overall flavonoid yields from all species in comparison with supercritical CO(2) extraction. Pinocembrin was determined in L. origanoides extract at a concentration of 30 mg/g of plant material, which is more than ten times higher than the amount at which polyphenols are regularly found in aromatic plant extracts.