Article

Solubility of Gallic Acid in Methanol, Ethanol, Water, and Ethyl Acetate

Journal of Chemical & Engineering Data (Impact Factor: 2.04). 02/2008; 53(3). DOI: 10.1021/je700633w

ABSTRACT

The solubility of gallic acid in methanol, ethanol, water, and ethyl acetate was measured at a temperature range of (298.2 to 333.2) K. The gallic acid solubility in different solvents increases smoothly with temperature. The relative solubility of gallic acid in the solvents was found as: wmethanol > wethanol > wwater > wethyl acetate. The temperature dependence of the solubility data was correlated by the modified Apelblat model. The calculated solubilities show good agreement with the experimental data in the temperature range studied.

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    • "The solubility of GE, EA, and GA was observed to be the highest in intestinal fluids (SIF: pH 6.8, FaSSIF: pH 6.5, and FeSSIF: pH 5) and the least in gastric fluid (SGF: pH 1.2). This could be due to the acidic nature of the compounds (Ascacio-Valdes et al., 2011; Daneshfar et al., 2008; Przewloka & Shearer, 2002). "
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    ABSTRACT: Natural products play a vital role in the discovery of leads for novel pharmacologically active drugs. Geraniin (GE) was identified as the major compound in the rind of Nephelium lappaceum L. (Sapindaceae), while ellagic and gallic acids have been shown to be its main metabolites. GE and its metabolites possess a range of bioactive properties including being an anti-infective, anticarcinogenic, antihyperglycemic, and antihypertensive. GE and its metabolites were investigated to establish its gastrointestinal absorption and physicochemical properties. GE was purified from N. lappaceum rind extract using reverse-phase C18 column chromatography. Lipophilicity (log P) was determined using the 1-octanol/water shake-flask method. Equilibrium solubility of GE and its metabolites (20 mg) was determined in water and four biorelevant media: simulated gastric, simulated intestinal, fasted state-simulated intestinal, and fed state-simulated intestinal after 72 h. The purification yield was 10.8%; where a 97-99% pure GE was obtained. Log P values for GE, ellagic, and gallic acids were established as -0.73 ± 0.17, 0.11 ± 0.06, and 0.71 ± 0.21, respectively, establishing them as polar compounds. All three compounds were found to exhibit poor solubility in gastric (0.61-8.10 mg/mL) but good solubility in intestinal fluids (3.59-14.32 mg/mL). The above results indicate that the compounds have limited gastrointestinal absorption due to its polarities. To consider these compounds as oral drug candidates, formulation strategies are being developed.
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    • "In some recent works (Lu and Lu, 2007; Daneshfar et al., 2008; Noubigh et al., 2007 a,b; Noubigh et al., 2008 a,b), solubilities of vanillin in several pure solvents have been measured as a function of temperature. However, to our knowledge no experimental or theoretical study concerning the solubility of vanillin in (ethanol+ water) binary solvents has been reported in the literature. "
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    ABSTRACT: The aim of this study was to investigate the solubilities of vanillin (Van) in water + ethanol solvents mixtures from (278.15 to 308.15) K at atmospheric pressure using a thermostatted reactor and UV/vis spectrophotometer analysis. The effects of binary solvents composition and temperature on the solubility were discussed. The solubility data were correlated with the modified Apelblat equation and semi-empirical Buchowski-Ksiazczak λh equation. The calculated solubilities show good agreement with the experimental data in the temperature range studied. Using the experimentally measured solubilities, the thermodynamic properties of dissolution of the vanillin such as Gibbs energy ( ), molar enthalpy of dissolution ( ), and molar entropy of dissolution ( ) were calculated. Therefore, the experimental solubility and correlation equation in this work can be used as essential data and models in the purification process of vanillin.
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    • "In this study, methanol was used to dilute the gallic acid standard because gallic acid showed higher solubility in methanol compared to water and other solvents (eg. ethanol) (Daneshfar et al., 2008). The total phenolic contents among the different varieties were expressed in terms of gallic acid equivalents using the standard curve equation y = 0.0012x + 0.0007, r 2 = 0.998 (Fig 2). "
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    ABSTRACT: The study of antioxidants from natural sources has gained popularity in the recent years. Six Ipomoea batatas leafy varieties namely Batu Kelantan, Batu Biasa, Biru Putih, Oren, Vitato and Indon were compared to assess the total phenols, flavonoids, reducing power and antioxidant activity. In this study, the Indon variety showed the highest level of total phenolic contents at 5.35 ± 0 g GAE/100 g DW. The flavonoid contents in the leaves ranged from 96 ± 47.6 µg/ g in Indon variety to 263.5 ± 43.5 µg/g in Batu Biasa variety. 1,1-diphenyl-2-picryl hydrazyl (DPPH) was used to determine the radical scavenging activity in leaves, in which the Indon and Biru Putih variety had the highest and lowest scavenging activities of 372.4 µg/ ml (IC 50) and 597.61 µg/ ml (IC 50), respectively. All varieties, except Biru Putih, showed the high radical scavenging activity compared to the ascorbic acid standard. Besides, all the leaf varieties also showed increment in their reducing power with increasing concentrations. Thus, Ipomoea batatas leaves can be used as a potential source of natural antioxidants.
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