Novel method for isolation of major phenolic constituents from cashew (Anacardium occidentale L.) nut shell liquid

Commercially available cashew (Anacardium occidentale L.) nut shell liquid (CNSL) mainly contains the phenolic constituents anacardic acid, cardol, and cardanol. These phenolic constituents are themselves heterogeneous, and each of them contains saturated, monoene, diene, and trienes in the fifteen-carbon side chain. This communication describes the separation of anacardic acid, cardol, and cardanol for industrial application. Anacardic acid was selectively isolated as calcium anacardate. The acid-free CNSL was treated with liquor ammonia and extracted with hexane/ethyl acetate (98:2) to separate the mono phenolic component, cardanol. Subsequently, ammonia solution was extracted with ethyl acetate/hexane (80:20) to obtain cardol.     

Isolation of anacardic acid from natural cashew nut shell liquid (CNSL) using supercritical carbon dioxide

Solvent extracted cashew nut shell liquid (CNSL), conventionally known as natural CNSL, is a mixture of several alkenyl phenols. One of these alkenyl phenols is anacardic acid, which is present at the highest concentration. In view of anticipated industrial applications of anacardic acid, the objective of this work was to isolate anacardic acid from natural CNSL by supercritical carbon dioxide (scCO 2). In this study, the solubility data for natural CNSL in scCO 2 under a range of operating conditions of pressure (100, 200, and 300 bar), temperature (40 and 50 degrees C), and CO 2 flow rate (5, 10, and 15 g min (-1)) were established. The best scCO 2 working conditions were found to be 50 degrees C and 300 bar at a flow rate of 5 g min (-1) CO 2. Using 3 g of sample (CNSL/solid adsorbent = 1/2) under these scCO 2 conditions, it was possible to quantitatively isolate high purity anacardic acid from crude natural CNSL (82% of total anacardic acid) within 150 min. The anacardic acid isolated by scCO 2 was analyzed by different spectroscopic techniques (UV-vis, FT-IR, and (1)H NMR) and HPLC analysis, indicating that the anacardic acid isolated by scCO 2 has better quality than that obtained through a conventional method involving several chemical conversion steps.     

Comparison of methodology for determination of ethylene dibromide in grains and grain-based foods

Three commonly used methods for determination of ethylene dibromide (EDB) in grains and grain products have been compared. EDB residues were extracted by soaking in hexane, triple co-distillation with hexane from an aqueous sample solution, and soaking in acetone-water (5 + 1). Each method was used for triplicate analyses of 12 samples containing incurred residues of EDB ranging from about 10 to 1000 ppb and representing whole grains (wheat and oats) and intermediate grain-based products such as corn meal and flour. The 4-day hexane soaking method extracted the least EDB. In some cases, this was half of the amount determined by the other methods. Levels from soaking in acetone-water were equal to, or up to 25% greater than, those from distillation. Although soaking for 2 days is required for whole grains in the method, a period of only 16 h was found acceptable for ground products. Results were obtained faster with the distillation method, but more analyst time per sample was required. A single distillation recovered about 80% (40-60% from wheat) of total EDB extracted by triple distillation. Foaming was reduced by the addition of concentrated H2SO4 to the aqueous hexane-sample mixture, plus stirring during distillation, thereby allowing complete recovery of the hexane.     

Enhanced selective extraction of hexane from hexane/soybean oil mixture using binary gas mixtures of carbon dioxide

Carbon dioxide (CO2) can effectively separate hexane from a mixture of soybean oil (SBO) and hexane with a slight coextraction of SBO. Previous research demonstrated that CO2 entrained with helium significantly reduced SBO solubility in CO2. In this study, CO2 was mixed with three gases (He, N2, or Ar) (0.5-30 vol %) to decrease SBO solubility while attempting to maintain hexane solubility. The binary gas mixtures (at 25 degrees C and 9.31 MPa) were passed through a 25 wt % hexane/SBO mixture inside a 2.5 m fractionation column. Coextracted SBO was inversely proportional to binary gas concentration, whereas residual hexane in the raffinate was proportional to binary gas concentration. The 10% binary mixture of N2 or Ar was the best compromise to obtain both low residual hexane levels (i.e., 26 ppm) and low SBO coextraction (i.e., only 40 mg). This carry-over of SBO represents a 95% reduction in SBO carry-over compared to neat CO2.     

Mixture approach for optimizing lycopene extraction from tomato and tomato products

A simple mixture process design based on the comparison of both quadratic and special cubic models and involving three mixture components (hexane/acetone/ethanol) as a solution for extracting lycopene from raw tomato, tomato sauce, and tomato paste was used to confirm the hypothesis that lycopene extraction rates are a function of the solvent used during the extraction process. Conventional criteria (p 相似文献   

Irreversible competitive inhibitory kinetics of cardol triene on mushroom tyrosinase

Cardol triene was first purified from cashew (Anacardium occidentale L.) nut shell liquid and identified by gas chromatography coupled to mass spectroscopy and nuclear magnetic resonance. The effects of this compound on the activity of mushroom tyrosinase were studied. The results of the kinetic study showed that cardol triene was a potent irreversible competitive inhibitor and the inactivation was of the complexing type. Two molecules of cardol triene could bind to one molecule of tyrosinase and lead to the complete loss of its catalytic activity. The microscopic rate constants were determined for the reaction of cardol triene with the enzyme. The anti-tyrosinase kinetic research of this study provides a comprehensive understanding of inhibitory mechanisms of resorcinolic lipids and is beneficial for the future design of novel tyrosinase inhibitors.     

Radioimmunoassay of deoxynivalenol in wheat and corn

With the availability of antibody against deoxynivalenol triacetate (DON-triacetate), a radioimmunoassay (RIA) for DON in wheat was developed. DON is extracted from the sample with acetonitrile-water (84 + 16), defatted with hexane, and then reacted with acetic anhydride to form DON-triacetate. The reaction mixture is loaded onto a C-18 cartridge to remove excess reagents and impurities. Acetylated DON is eluted from the cartridge with 50% methanol in water, and then analyzed by radioimmunoassay utilizing antiserum against DON-triacetate and tritiated DON-triacetate. Overall recovery for DON added to wheat between 50 and 5000 ppb was 86% with a standard deviation of 7% and coefficient of variation of 8%. The limit of detection for DON was about 20 ppb. Analysis of 12 naturally contaminated wheat, corn, and mixed feed samples for DON revealed that RIA results agreed well with thin layer chromatographic analyses performed by other laboratories.     

Quality of Corn Oil Obtained by Sequential Extraction Processing

Sequential extraction processing (SEP) is a new approach to fractionating dried, flaked corn using 95% ethanol. In the original process, corn oil was extracted at 76°C in a countercurrent mode while simultaneously dehydrating the ethanol. This resulted in 20% of the protein (predominantly zein) coextracting with the oil. The process was modified to reduce the amount of coextracted protein. One modification (mSEP1) was to use a blend of 30% hexane and 70% ethanol at 56°C. A second modification (mSEP2) used a longer extraction column (L/D ratio 15) to replace the column with L/D 2 used in the original SEP system. To determine the effect of the modifications on oil quality, the quality of the crude corn oils produced from the modified SEP processes were compared with the quality of oil from the original SEP. To evaluate the quality of the three crude oils produced by SEP with the process typically used in industry, they were compared with the quality of laboratory hexane‐extracted corn oil. The results of the three SEP oils exhibited larger concentrations of fatty acids, phospholipids, and carotenoids, smaller concentrations of triacylglycerols, and darker red color than the hexane‐extracted oil. The oils from the two modified SEP processes contained smaller concentrations of free fatty acids and phospholipids and larger concentrations of triacylglycerols and carotenoids than the original SEP oil. In spite of the improvements to the oil through process modifications, the mSEP1 and mSEP2 oils exhibit greater refining losses than hexane‐extracted oil.     

Analysis of free and esterified ergosterol in tomato products

A new extraction and chromatographic procedure to quantify free and esterified ergosterol in tomato products was devised. The extraction solution was composed of a dichloromethane/methanol mixture in a 2:1 (v/v) ratio. This extraction solvent allowed for higher ergosterol recovery from tomato products (an average of 25% more) compared to hexane, which is frequently employed for ergosterol extraction. Both free and esterified ergosterol were determined by HPLC reverse-phase chromatography employing a Nova-Pak C-18 column (300 x 3.9 mm), filled with 4 mm average particle size and a guard column of the same material. The elution was performed at a flow rate of 1 mL. min(-1) with a linear gradient of solvent A (methanol/water, 80:20, v/v) and solvent B (dichloromethane). The gradient, starting at sample injection, was from 0 to 50% B for 20 min for the free ergosterol analysis and additional 15 min at 50% B to analyze the ergosterol esters. This technique has proven to be more sensitive for ergosterol determination than other reported chromatographic procedures. Moreover, ergosterol esters, extracted from various fungal sources, separated well and were easily quantified.     

Combined extraction-cleanup column chromatographic procedure for determination of dicofol in avian eggs

Dicofol in avian eggs was completely oxidized to dichlorobenzophenone (DCBP) when a hexane Soxhlet extraction procedure was used. This degradation did not occur with other avian tissues (muscle and liver). For this reason, a combined extraction-cleanup column chromatographic procedure, without added heat, was developed for the determination of dicofol in avian eggs. Homogenized subsamples of eggs were mixed with sodium sulfate, and the mixture was added as the top layer on a column prepacked with Florisil. The dicofol and other compounds of interest were then eluted with ethyl ether-hexane. The extracts, relatively free from lipids, were quantitated on a gas chromatograph equipped with a 63Ni electron-capture detector and a methyl silicone capillary column. Recoveries from chicken eggs, fortified with dicofol and other DDT-related compounds, averaged 96%. Analysis of eggs of eastern screech-owls, fed a meat diet containing 10 ppm technical Kelthane, showed that both dicofol and DCBP were present. Results were confirmed by gas chromatography/mass spectrometry. This method is rapid and reliable, involves a minimum of sample handling, and is well suited for high volume determination of dicofol in eggs and other avian tissues.     

New qualitative approach in the characterization of antioxidants in white wines by antioxidant free radical scavenging and NMR techniques

The aim of this study was to obtain new information on antioxidant compounds in white wines. For this purpose, white wine degradation was promoted by a forced aged protocol, and six normally aged white wines from different vintages were analyzed. Both normal and forced aged wines were sequentially extracted using hexane and ethyl acetate. Apolar antioxidants were removed using hexane, and polar antioxidants were extracted with ethyl acetate. This last residue was subject to partial re-extraction with hexane and acetone. The antioxidant capacity of the wines and of each fraction was evaluated by two free radical methods, ABTS and DPPH. Normal aging provides a decrease in the total antioxidant capacity of wines. The antioxidant activity of ethyl acetate/acetone extracts was approximately 95% higher than that found for the hexane extracts. Concerning the forced aged wines, results showed that the wine submitted to a temperature of 60 degrees C for 21 days had higher antioxidant activity than that submitted to a temperature of 20 degrees C. With regard to the ethyl acetate/acetone extracts, oxygen and temperature treatment leads to a decrease in their antioxidant activity. NMR analysis was performed in the highest antioxidant capacity organic fractions (ethyl acetate/acetone extracts) and in the aqueous fraction of the control wine (T = 20 degrees C), in order to attempt the characterization of species involved in oxygen protection. Possible structures of antioxidant compounds in white wines were proposed. Two of these are tyrosol-like structures. This molecule is a well-known phenolic compound in wine, and it is reported to have antioxidative effects.     

Organic compounds in soils and sediments from unlined waste disposal pits for natural gas production and processing

Samples of soil in dry waste pits and of sediment from waste pits currently in-use for natural gas production in the San Juan Basin of northwest New Mexico were collected for characterization of the presence and concentration of organic compounds. Samples were dried at 25 °C and about 50 g were extracted successively in a Soxhlet apparatus using hexane, benzene, and methanol. Extracts were filtered and condensed to 10 mL. Analyses of hexane extracts of samples using high-resolution gas chromatography showed presence of a complex mixture of 40 to 50 organic compounds in dry soil and in sediment from in-use pits. The range of size for compounds was C₁₀ to C₂₅. Although no compounds were detected in GC analyses of subsequent benzene and methanol extracts of the same soil samples, these extracts were highly colored and contained 5 to 10% of total absorptivity at 254 nm. Total extractable residues in the hexane extracts ranged from 49 to 110 mg g^?1 of soil. Polycyclic aromatic hydrocarbons were detected in hexane extracts at concentrations of 270 to 870μg g^?1 of dry sample.     

Gas chromatographic determination of pentachlorophenol in gelatin: collaborative study

Eleven collaborators participated in this study of a gas chromatographic method for the determination of pentachlorophenol (PCP) in gelatin. Following acid hydrolysis of a 2 g sample, PCP is extracted with hexane and partitioned into KOH solution. After reacidification, PCP is again extracted with hexane for determination by electron capture gas chromatography on a 1% SP-1240DA column. Three duplicate practice samples (0.0, 0.5, and 1.5 ppm) and 5 blind duplicate collaborative samples (0.0, 0.02, 0.1, 0.5, and 2.0 ppm) were analyzed by each collaborator. Mean recoveries of PCP in the collaborative samples ranged from 88% at the 0.02 ppm fortification level to 102% at the 0.1 ppm level; the overall mean recovery was 96%. Interlaboratory coefficients of variation ranged from 16.4% for the 0.1 ppm fortification level to 22.9% for the 0.5 ppm level; the overall interlaboratory coefficient of variation was 19.5%. The method has been adopted official first action.     

Determination of oxolinic acid residues in salmon muscle tissue by liquid chromatography with fluorescence detection

The present paper describes a method for determination of oxolinic acid in salmon muscle tissue. Tissue (0.5-2 g) mixed with 2 g anhydrous sodium sulfate is extracted twice with ethyl acetate, centrifuged, and the extract evaporated. The residue is partitioned in a mixture of hexane and 0.01M oxalic acid and the aqueous phase chromatographed using fluorescence detection at 327 nm excitation and 369 nm emission. Calibration and standard curves are linear from 10-200 ppb and 100-2000 ppb at different sensitivity settings. Recoveries ranged from 71-83% in spiked blanks, with a CV of 4-10.3% over a 2-week period. Preliminary results in treated salmon were variable, possibly because some fish refused to eat medicated feed.     

In vitro cytotoxicity of nonpolar constituents from different parts of kava plant (Piper methysticum)

Kava (Piper methysticum), a perennial shrub native to the South Pacific islands, has been used to relieve anxiety. Recently, several cases of severe hepatotoxicity have been reported from the consumption of dietary supplements containing kava. It is unclear whether the kava constituents, kavalactones, are responsible for the associated hepatotoxicity. To investigate the key components responsible for the liver toxicity, bioassay-guided fractionation was carried out in this study. Kava roots, leaves, and stem peelings were extracted with methanol, and the resulting residues were subjected to partition with a different polarity of solvents (hexane, ethyl acetate, n-butanol, and water) for evaluation of their cytotoxicity on HepG2 cells based on the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and lactate dehydrogenase and aspartate aminotransferase enzyme leakage assays. Organic solvent fractions displayed a much stronger cytotoxicity than water fractions for all parts of kava. The hexane fraction of the root exhibited stronger cytotoxic effects than fractions of root extracted with other solvents or extracts from the other parts of kava. Further investigations using bioassay-directed isolation and analysis of the hexane fraction indicated that the compound responsible for the cytotoxicity was flavokavain B. The identity of the compound was confirmed by (1)H and (13) C NMR and MS techniques.     

Development of a rapid method for the sequential extraction and subsequent quantification of fatty acids and sugars from avocado mesocarp tissue

Methods devised for oil extraction from avocado (Persea americana Mill.) mesocarp (e.g., Soxhlet) are usually lengthy and require operation at high temperature. Moreover, methods for extracting sugars from avocado tissue (e.g., 80% ethanol, v/v) do not allow for lipids to be easily measured from the same sample. This study describes a new simple method that enabled sequential extraction and subsequent quantification of both fatty acids and sugars from the same avocado mesocarp tissue sample. Freeze-dried mesocarp samples of avocado cv. Hass fruit of different ripening stages were extracted by homogenization with hexane and the oil extracts quantified for fatty acid composition by GC. The resulting filter residues were readily usable for sugar extraction with methanol (62.5%, v/v). For comparison, oil was also extracted using the standard Soxhlet technique and the resulting thimble residue extracted for sugars as before. An additional experiment was carried out whereby filter residues were also extracted using ethanol. Average oil yield using the Soxhlet technique was significantly (P < 0.05) higher than that obtained by homogenization with hexane, although the difference remained very slight, and fatty acid profiles of the oil extracts following both methods were very similar. Oil recovery improved with increasing ripeness of the fruit with minor differences observed in the fatty acid composition during postharvest ripening. After lipid removal, methanolic extraction was superior in recovering sucrose and perseitol as compared to 80% ethanol (v/v), whereas mannoheptulose recovery was not affected by solvent used. The method presented has the benefits of shorter extraction time, lower extraction temperature, and reduced amount of solvent and can be used for sequential extraction of fatty acids and sugars from the same sample.     

Phosphorus Releasing Characteristics of Ogun Phosphate Rock Acidulated with Cashew Nutshell Liquid

The phosphorus (P) release characteristic of Ogun rock phosphate (OPR) acidulated with cashew nutshell liquid (CNSL), an industrial waste, was studied under laboratory conditions for ten weeks. The results showed that the acidulation of phosphate rock with cashew nutshell liquid at a ratio of 4 to 1 released the highest quantity of available P. There was a general increase in the amount of P extracted from the phosphate rock under the influence of cashew nutshell liquid and this was more spontaneous in alkaline media. The peak of phosphorus release occurred at the 56 days of incubation following a form of stoichiometric order. We found the use of the cashew nutshell liquid in this regard as a win-win approach to not only recycle a major waste of cashew processing industries, which will help to maintain a healthy environment, but to deploy the complementary use of this waste in crop production.     

Evaluation of fatty acid extraction methods for Thraustochytrium sp. ONC-T18

Various extraction methods were assessed in their capacity to extract fatty acids from a dried biomass of Thraustochytrium sp. ONC-T18. Direct saponification using KOH in ethanol or in hexane:ethanol was one of the most efficient techniques to extract lipids (697 mg g(-1)). The highest amount of fatty acids (714 mg g(-1)) was extracted using a miniaturized Bligh and Dyer extraction technique. The use of ultrasonics to break down cell walls while extracting with solvents (methanol:chloroform) also offered high extraction yields of fatty acids (609 mg g(-1)). Moreover, when the transesterification mixture used for a direct transesterification method was doubled, the extraction of fatty acids increased approximately 77% (from 392 to 696 mg g(-1)). This work showed that Thraustochytrium sp. ONC-T18 has the ability to produce over 700 mg g(-1) of lipids, including more than 165 mg g(-1) of docosahexaenoic acid, which makes this microorganism a potential candidate for the commercial production of polyunsaturated fatty acids. Finally, other lipids, such as myristic, palmitic, palmitoleic, and oleic acids, were also produced and recovered in significant amounts (54, 196, 123, and 81 mg g(-1)), respectively.     

Evaluation of the light-sensitive cytotoxicity of Hypericum perforatum extracts, fractions, and pure compounds

Hypericum perforatum (Hp) is known for possessing antidepressant and antiviral activities. Despite its use as an alternative to conventional antidepressants, the identification of the cytotoxic chemicals derived from this herb is incomplete. In this study, the cytotoxicity of Hp extracts prepared in solvents ranging in polarity, fractions of one extract, and purified compounds were examined in three cell lines. All extracts exhibited significant cytotoxicity; those prepared in ethanol (no hyperforin, 3.6 microM hypericin, and 134.6 microM flavonoids) showed between 7.7 and 77.4% cell survival (p < 0.0001 and 0.01), whereas the chloroform and hexane extracts (hyperforin, hypericin, and flavonoids not detected) showed approximately 9.0 (p < 0.0001) and 4.0% (p < 0.0001) survival. Light-sensitive toxicity was observed primarily with the ethanol extracts sequentially extracted following removal of material extracted in either chloroform or hexane. The absence of light-sensitive toxicity with the Hp extracts suggests that the hypericins were not playing a prominent role in the toxicity of the extracts.     

Quality Comparison of Rice Bran Oil Extracted with d‐Limonene and Hexane

d‐Limonene, a safe agricultural by‐product, was used to extract rice bran oil and compared against hexane, a petroleum product widely used as a solvent for extracting edible oil. The yield of crude rice bran oils extracted with both solvents in percentage by weight was obtained. The quality of crude rice bran oil was analyzed. The yield and quality of crude rice bran oil from the limonene‐based solvent extraction were almost equivalent to those from the hexane‐based operation. The optimum solvent‐to‐rice bran ratio and extraction time required for d‐limonene extraction of oil, based primarily on crude rice bran oil yield, have been determined to be 5:1 and 0.5 hr, respectively. Despite the absence of antioxidants during the limonene recovery step with vacuum evaporation, the quantity of the oxidation products in the recovered limonene was <1% (wt) of the original limonene solvent. The application of d‐limonene solvent as an alternative to hexane in edible oil extraction could potentially eliminate the safety, environmental, and health issues associated with the use of hexane.