Papers by Keyword: Phenolic Compound

Abstract: Madhuca longifolia (J.Koenig ex L.) Macbr. belongs to the Sapotaceae family. This research work focused on the determination of gallic acid and quercetin in an aqueous leaf extract of M. longilolia. The development and validation of the analytical method using HPLC-DAD have been performed. The validated method was applied to determine both compounds in the leaves of M. longifolia. Optimized HPLC conditions were developed and validated for specificity, linearity, sensitivity, precision and accuracy. The linearity ranges and linear regression value were 3.125 to 100 μg/mL with r²=1 for gallic acid and 0.78 to 50 μg/mL with r²=0.9999 for quercetin, respectively. The LOD and LOQ were 0.24 and 0.73 μg/mL for gallic acid and 0.21 and 0.63 μg/mL for quercetin. Intra and inter-day precision were in the range of 0.18 to 1.76. The recovery percentage were 103.86% to 104.98% for gallic acid and 100.10% to 102.97% for quercetin. The concentration ranges of gallic acid and quercetin in the extracts were 207.95 to 405.79 mg/100 g and 7.31 to 20.56 mg/100 g, respectively. The developed HPLC method was considered to be accurate, precise and reliable for the determination of gallic acid and quercetin in M. longifolia aqueous leaf extract. This may be the first-time report for HPLC-DAD method development for the determination of bioactive phenolic compounds in Madhuca longifolia from Myanmar.

Abstract: Mimosa pudica and Phyllanthus niruri were used as the traditional medicines in Thailand. Both plants were very useful for various pharmacological and biological activities. In the present study, the bioactivities of Mimosa pudica and Phyllanthus niruri extracts were investigated. The amounts of total phenolic compounds were analyzed using gallic acid as standard compound and the antioxidant activities were evaluated using ABTS assay. The phenolic content of Mimosa pudica extracts revealed that AEE1 contained the maximum phenolic content and that of Phyllanthus niruri extracts exhibited the same result of maximum phenolic content in AEE2. The antioxidant activity were performed and found that WE1 from Mimosa pudica and WE2 from Phyllanthus niruri exhibited prominent ABTS radical scavenging activities. Interestingly, AEE1, AEE2 and EAE2 specifically exhibited the high cytotoxicity against the colon cancer cell line (SE620).

Abstract: Fast pyrolysis is an attractive thermal conversion process to generate the alternative liquid fuel. However, the bio-oil obtained from biomass pyrolysis has polarity, instability and low energy density due to contained oxygenated compound. Hydrodeoxygenation (HDO) process is the most promising route for bio-oil upgrading through oxygen elimination. The products are suitable for co-feeding into the existing refineries. Metal catalyst and operating conditions play an important role in HDO efficiency. A summary of HDO process has been conducted with various metal catalysts, type of reactors, and reaction mechanisms. It also raises some challenges in improving catalyst efficiency, reducing hydrogen consumption, and effort to understand the HDO kinetics.

Abstract: The aim of this study was to determine the changes of antioxidant activity and antioxidative compounds during table olive preparing by different procedures. The extraction of antioxidants from table olive is studied considering different debittering procedure (alkali treated or brine treated) to investigate the selectivity of the process. The radical-scavenging activity (RSA) of 1,1-diphenyl-2-picrylhydrazyl (DPPH•) and determination of the antioxidant compounds (total phenol, ascorbic acid and tocopherol) are applied to evaluate the antioxidant activity and antioxidative compounds of table olive. The active compounds and DPPH-RSA decreased during table olive preparation. A large amount of the active compounds lost during “alkali treated” except tocopherol. Little amount of the active compounds remained in “brine treated” table olive.

Abstract: Ultrasonic technology was applied for phenolic compounds extraction from the Pinus koraiensis bark （PKB） and response surface methodology (RSM) was used to optimize the effects of processing parameters on phenolic compounds yields. When ultrasonic power 160W,three independent variables were ultrasonic extraction time (X1 20-40min), ratio of water to raw material (X2 1:20-1:40 g/mL)and ethanol concentration(X3 20％-60％), respectively.The optimal extraction conditions of phenolic compounds were determined as follows: Ultrasonic extraction time 30.61 min, ratio of water to raw material 30.79 mL/g and ethanol concentration 42.2%. Under these conditions, the experimental yield of phenolic compounds was 8.2409 ± 0.0648‰, well matched with the predicted models with the coefficients of determination (R2) of 0.9920, which was agreed closely with the predicted value (8.2963‰).

Abstract: The ability of Cr-bentonite prepared using synthetic wastewater containing chromium was investigated for adsorptive removal of 4-aminophenol and 4-chlorophenol from aqueous solution in a batch system at 25 °C. The physic-chemical parameters including pH value of solution and contact time were studied. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of sorption. The equilibrium sorption data for 4-aminophenol and 4-chlorophenol were well fitted to Langmuir adsorption isotherm and the monolayer sorption capacity was found to be 26.53 and 23.81 mg/g at 25 °C, respectively. The sorption energy calculated from Dubinin-Redushkevich (D-R) isotherm are 8.31 and 8.20 kJ/mol for the uptake of 4-aminophenol and 4-chlorophenol respectively which indicates that both the sorption processes are chemical in nature. The kinetic data were analyzed using pseudo-first order, pseudo-second order kinetic equation and intraparticle diffusion model. The experimental data fit very well the pseudo-second order kinetic model. Intraparticle diffusion affects 4-aminophenol and 4-chlorophenol uptake. Sorption studies carried out using industrial wastewater samples containing phenolic compounds show that there is significant potential for Cr-bentonite as an adsorbent material for phenollic compounds removal from aqueous solutions.