Ethanol polyphenolic extraction

Monophasic action potential. Glycerin/ ethanol extract of the fresh leaf, administered intragastrically to dogs at a dose of 30 mg/kg, increased duration of ventricular monophasic action potential (16%) . Mutagenic activity. Ethanol (100%) extract of the fresh leaf, on agar plate, was active on Salmonella typhimurium T1530 . Natural-killer cell enhancement. Fixed oil of embryos, administered orally to adults, was inactive . Nonsaponifiable fraction of fruit fixed oil and seed oil, administered to rats at a dose of 0.3% of diet, were active. The polyphenol stripped seed oil was inactive . 

The powdered plant material maximizes polyphenolic extraction because of its high contact area with solvent and easy destruction of biological cell walls. Ethanol may be employed instead of methanol in routine extractions to avoid the toxic properties of methanol. The main advantage of methanol over ethanol is its lower boiling point. 

Polyphenolic extract of fenugreek seed acts as a protective agent against ethanol-induced abnormalities in the liver and the effects are comparable with those of a known hepatoprotective agent, silymarin (Kaviarasan and Anuradha, 2007). 

Data of polyphenols extracted from skins of Pinot noir and Barbera grapes using ethanol/H20/HCl 70 30 1 (v/v/v), tartrate buffer-12% ethanol containing Na2S205 2g/L and ethanol/H20/acetic acid 70 30 1 (v/v/v) solutions, are reported in Tables 2.2 and 2.3, respectively. 

Green tea polyphenol extract (10 g, Upton Company) was dissolved in 95% ethanol solution and the solution loaded onto a Sephadex LH-20 column (38 mm i.d. X 45 mm). After being eluted with 95% ethanol and monitored by TLC [chloroform-methanol-water (3 1 0.2) as eluent], 700 mg EGC and 1300 mg EGCG were yielded. 

Another recently described methodology for the extraction of polyphenols is the use of superheated ethanol-water extraction (SEWE). This technique is a variation of SWE in which water-ethanol mixtures (20 80 or 40 60, v/v) are used in static extractions at high temperatures (180 C-240 C) and pressure (4 MPa). As for SWE, this method allows modification of the extract composition by changing the operation conditions (working pressure, temperature, and water/ethanol ratios). SEWE has been applied for the extraction of phenolic compounds from winery by-products with extraction efficiencies superior to those of conventional... 

The most common solvents used for the extraction of polyphenolics from plant material are methanol, ethanol, acetone, ethyl acetate, and their aqueous solvents. Aqueous methanol is a popular choice of solvent because it is efficient, has a high boiling point, and is eco-... 

Besides solid-phase extraction, column chromatography is also often used for cleanup and purification of polyphenolics from plant material. Ionic adsorbants (polyvinylpyrrolidone or PVP, polyamides, and Sephadex LH-20) and Amberlite XAD-2 resin have been used to isolate and purify polyphenolics from crude extracts. For the separation of polyphenolics from plant material, column chromatography using Sephadex LH-20, a gel-filtration matrix, is often used with various eluting solvents (Park and Lee, 1996). The most widely used solvents for column chromatography are aqueous methanol and aqueous ethanol. 

Table 40.2 displays the results of measured AOA of water and water-ethanol extracts of selected fruits and vegetables. The study of extract AOA allows concluding that AOA of water-ethanol extracts is higher than AOA of water extracts. It results from the fact that polyphenols, main antioxidants in plants, are better extracted by ethanol than by water. 

Cichoric acid is believed to contribute to the immunostimulatory activity, but the compound tends to decompose through enzymatic degradation during extractions (Bauer, 1997) thus, the variability in cichoric acid levels found by many researchers may be due to the extraction methodology and not to the plant species or origin. Bauer (1999b) evaluated the cichoric acid content of six commercially available expressed juice preparations of E. purpurea. The thermally treated preparations had higher cichoric acid than ethanol-preserved preparations. The inactivation of polyphenol oxidase by heat may account for the difference found between heated and nonheated preparations. 

Two different sample preparation methods by size-exclusion and reverse-phase chromatography were proposed for analysis of PCs and PAs in wine. In the former, a volume of 5 mL of dealcoholized wine is passed through a Fractogel Toyopearl TSK gel HW-50 (F) (12 x 120 mm) column. The stationary phase is washed with 25 mL of water and the simple polyphenols are eluted with 50 mL of an ethanol/water/trifluo-roacetic acid 55 45 0.005 (v/v/v) solution. The polymeric fraction is recovered with 50mL of acetone/H20 60 40 (v/v). Figure 6.19 shows the LC/ESI-MS extracted ion chromatograms of dimers and trimers in a wine (Fulcrand et al., 1999). 

Our analytical procedure consists of stepwise acetone extraction followed by cyclohexane. Subsequently, the acetone-soluble fraction is partioned between hexane/aqueous ethanol (12,15), and the soluble components are freed of solvents and determined gravimetrically. For lack of specific nomenclature, the botanochemicals isolated by this technique have been referred to as "whole plant oil," "polyphenol," and "polymeric hydrocarbon." Actually, components from these extracts need to be further characterized. However, petroleum refinery processes may be sufficiently insensitive to allow use of carbon-hydrogen rich compounds represented by a broad spectrum of structures. For example, consider the diverse chemicals ranging from methanol to natural rubber which have been converted to gasoline (16). Thus, chemical species may be important if chemical intermediates are being generated but may be nonconsequential for production of fuels, solvents, carbon black, and other basic chemicals. 

The rather simple solvent classification schemes yield complex fractions of botanochemicals. Their detailed composition depends not only on the species but also on maturity of the plant and the method of extraction (1 5, ). The polar fraction isolated by acetone extraction and readily soluble in 87.5% aqueous ethanol, termed "polyphenol" by Buchanan and coworkers (11,12), no doubt consists of phenolics and a wide variety of other substances. For plants of high tannin content, (e.g., Rhus g/aubra) the polyphenol fraction might well be called tannin (24)... 

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