Eduardo Cassel

Extraction of essential oils from lime (Citrus latifolia Tanaka) by hydrodistillation and supercritical carbon dioxide

Neste trabalho o oleo essencial de lima acida foi extraido por hidrodestilacao e CO2 supercritico. No caso da hidrodestilacao, os parâmetros avaliados foram o tempo de processo e caracteristicas do material vegetal. Em extracao supercritica, os parâmetros avaliados foram temperatura, pressao e fluxo do CO2, tempo de processo e caracteristicas do material. Considerando o conteudo de citral, os melhores resultados para hidrodestilacao foram obtidos em um tempo de processo de 3 horas utilizando-se cascas inteiras. Os melhores resultados para extracao supercritica foram obtidos a 60oC, 90 bar, a um fluxo de CO2 de 1 mL/ min para 30 minutos de processo utilizando-se cascas moidas. Os melhores resultados em termos de rendimento de oleo essencial foram obtidos por hidrodestilacao (5,45% p/p) e extracao supercritica (7,93% p/p), para cascas moidas.

Supercritical extraction of carqueja essential oil: experiments and modeling

Baccharis trimera is a native Brazilian plant which has medicinal properties. In this work a method of supercritical extraction was studied to obtain the popularly essential oil from Baccharis trimera, known as carqueja. The aim was to obtain experimental data and to compare two mathematical models used in the simulation of carqueja (Baccharis trimera) oil extraction by supercritical CO2. The two mathematical models are based on mass transfer. One of the models, proposed by Reverchon, is solved numerically and requires two adjustable parameters from the experimental data. The other model chosen is the one proposed by Sovova. This model is solved analytically and requires four adjustable parameters. Numerical results are presented and discussed for the adjusted parameters. The experimental results are obtained in a temperature range of 313.15 K to 343.15 K at 90 bar. The extraction yield of carqueja essential oil using supercritical carbon dioxide ranged between 1.72 % (w/w) at 323.15 K and 2.34 % (w/w) at 343.15 K, 90 bar with a CO2 flow rate of 3.34.10-8 m3/s for a 0.0015 kg sample of Baccharis trimera.

Supercritical fluid extraction of volatile and non-volatile compounds from Schinus molle L.

Schinus molle L., also known as pepper tree, has been reported to have antimicrobial, antifungal, anti-inflammatory, antispasmodic, antipyretic, antitumoural and cicatrizing properties. This work studies supercritical fluid extraction (SFE) to obtain volatile and non-volatile compounds from the aerial parts of Schinus molle L. and the influence of the process on the composition of the extracts. Experiments were performed in a pilot-scale extractor with a capacity of 1 L at pressures of 9, 10, 12, 15 and 20 MPa at 323.15 K. The volatile compounds were obtained by CO2 supercritical extraction with moderate pressure (9 MPa), whereas the non-volatile compounds were extracted at higher pressure (12 to 20 MPa). The analysis of the essential oil was carried out by GC-MS and the main compounds identified were sabinene, limonene, D-germacrene, bicyclogermacrene, and spathulenol. For the non-volatile extracts, the total phenolic content was determined by the Folin-Ciocalteau method. Moreover, one of the goals of this study was to compare the experimental data with the simulated yields predicted by a mathematical model based on mass transfer. The model used requires three adjustable parameters to predict the experimental extraction yield curves.

Extraction of tannin by Acacia mearnsii with supercritical fluids

Studies were carried out on solvent and supercritical extraction to obtain natural tannins. The results showed that the best co-solvent to extract tannin with CO2 supercritical was water with a concentration of 5.0% and the best trap rinse solvent was methanol.

Antidepressant-like effect of Valeriana glechomifolia Meyer (Valerianaceae) in mice

The antidepressant-like effect of a supercritical CO2 (SCCO2) Valeriana glechomifolia extract enriched in valepotriates was investigated in a mice tail suspension test (TST) and forced swimming test (FST). The SCCO2 extract decreased mice immobility in the FST (0.5-20 mg/kg p.o.) and elicited a biphasic dose-response relationship in the TST (1-20 mg/kg p.o.) with no alterations in locomotor activity and motor coordination (assessed in the open-field and rota-rod tests, respectively). The anti-immobility effect of the SCCO2 extract (5 mg/kg, p.o.) was prevented by mice pre-treatment with yohimbine (1 mg/kg, i.p., an α2 adrenoceptor antagonist), SCH 23390 (15 μg/kg, s.c., D1 dopamine receptor antagonist) and sulpiride (50 mg/kg, i.p., D2 dopamine receptor antagonist). However, mice pre-treatments with prazosin (1 mg/kg, i.p., α1 adrenoceptor antagonist) and p-chlorophenilalanine methyl ester (4×100 mg/kg/day, i.p., a serotonin synthesis inhibitor) were not able to block the anti-immobility effect of the SCCO2 extract. Administration (p.o.) of the SCCO2 extract (0.25 mg/kg) and imipramine (10 mg/kg), desipramine (5 mg/kg) and bupropion (3 mg/kg) at sub-effective doses significantly reduced mice immobility time in the FST. These data provide the first evidence of the antidepressant-like activity of V. glechomifolia valepotriates, which is due to an interaction with dopaminergic and noradrenergic neurotransmission.

Supercritical fluid extraction and high performance liquid chromatographic determination of benzopyrans and phloroglucinol derivative in Hypericum polyanthemum

The aerial parts of Hypericum polyanthemum Klotzsch ex Reichardt (Guttiferae) were successively extracted with supercritical carbon dioxide (SC CO(2)) under pressures of 90, 120, 150 and 200 bar at different temperatures (40, 50 and 60 degrees C), and compared with the n-hexane extract obtained by ultrasound-assisted extraction. The samples obtained were examined regarding extraction yield and HPLC quantification of the main secondary metabolites, the benzopyrans HP1 (6-isobutyryl-5,7-dimethoxy-2,2-dimethylbenzopyran), HP2 (7-hydroxy-6-isobutyryl-5-methoxy-2,2-dimethyl-benzopyran) and HP3 (5-hydroxy-6-isobutyryl-7-methoxy-2,2-dimethyl) and the phloroglucinol derivative, uliginosin B. SFE presented higher selectivity than the n-hexane maceration, and the best condition to extract the target metabolites has been determined to be at 50 degrees C and for the high molecular-weight compound, uliginosin B, higher pressures were required.

Black Wattle Tannin As Steel Corrosion Inhibitor

−1 Na2SO4 (pH 6.0 and 2.5). The black wattle tannin when used as a corrosion inhibitor is more effective at acidic pH, its efficiency being dependent on its concentration. At the higher pH value (pH 6.0), a blue-black film (ferric tannate) with a short-term protection against corrosion was formed in aerated aqueous solution. At pH 2.5, this blue-black film was not observed.

Supercritical extraction of phloroglucinol and benzophenone derivatives from Hypericum carinatum: Quantification and mathematical modeling

The aerial parts of Hypericum carinatum (Guttiferae) were extracted with supercritical carbon dioxide under constant temperature (40, 50 or 60°C) and gradual pressure increase (90, 120, 150 and 200 bar) aiming at the recovery of enriched fractions containing uliginosin B, cariphenone A and cariphenone B, compounds of pharmaceutical interest. The yields of these substances were determined by high-performance liquid chromatography and compared with those obtained with n-hexane maceration. The supercritical-fluid extraction showed higher selectivity than the conventional solvent extraction method. After defining 40°C and 90 bar as the best conditions to obtain the target compounds, a mathematical model was used for the extraction process and a good correlation was achieved with the experimental data.

Determination of antibacterial activity of vacuum distillation fractions of lemongrass essential oil

Essential oils are natural substances composed of terpenoids and phenylpropanoid molecules that have many biological activities. Because of their activity, essential oils are widely used in foods, cosmetics, and pharmaceutical products, but new applications of such mixtures are still dependent on separation processes that are able to produce compounds with specific standardized and reproducible compositions. This work studies the fractionation of lemongrass essential oil by vacuum distillation with the goal of obtaining an antimicrobial fraction that acts against Salmonella choleraesuis, Pseudomonas aeruginosa and Staphylococcus aureus. The samples were analyzed by gas chromatography–mass spectrometry and evaluated for antimicrobial activity using the indirect bioautography method and minimum inhibitory concentrations. Vacuum distillation was found to be an efficient method for obtaining distinct fractions with increased antimicrobial activity. The fractions that showed the best response against the three microorganisms tested were F3b, F3a1, F2, F3a2 and F1, with the most effective being F3a2, which also presented the highest yield.

Gallic acid reduces the effect of LPS on apoptosis and inhibits the formation of neutrophil extracellular traps

Apoptosis and NETosis of neutrophils are two major mechanisms of programmed cell death that differ in their morphological characteristics and effects on the immune system. Apoptosis can be delayed by the presence of pathogens or chemical components such as lipopolysaccharide (LPS). Neutrophils have other antimicrobial strategy, called neutrophil extracellular traps (NETs), which contributes to the elimination and control of the pathogen. NETosis is induced by infection, inflammation or trauma and represents an innate immune activation mechanism. The objective of this study was to evaluate the effect of gallic acid (GA) in the modulation of apoptosis and NETs release. The results show that GA decreased the anti-apoptotic effect of LPS, blocked the induction of NETs and prevented the formation of free radicals induced by LPS. These findings demonstrate that the GA is a novel therapeutic agent for decreasing the exacerbated response of the body against an infectious agent.