探究了用福林-酚法测秋葵汁中总多酚含量的最佳条件,并对此方法进行分析评价。通过实验结果可知,用这种方法检测多酚含量时的最优条件为：测定波长为730 nm,7.5%的碳酸钠溶液3 m L,福林试剂0.7 m L,样品溶液0.5 m L,反应温度为25℃,反...探究了用福林-酚法测秋葵汁中总多酚含量的最佳条件,并对此方法进行分析评价。通过实验结果可知,用这种方法检测多酚含量时的最优条件为：测定波长为730 nm,7.5%的碳酸钠溶液3 m L,福林试剂0.7 m L,样品溶液0.5 m L,反应温度为25℃,反应时间为50 min。在0~100μg范围内吸光度与多酚线性关系R2=0.9993,加标回收率为98.3%,相对标准偏差为2.68%（n=5）。另外,该方法精密度、稳定性都比较好,适合用于测定总多酚含量。展开更多
AIM:To investigate the antioxidant activity and total phenolic content from the crude extracts and crude fractions of ten species of Phellinus mushrooms collected from northeast Thailand.METHODS:The samples were teste...AIM:To investigate the antioxidant activity and total phenolic content from the crude extracts and crude fractions of ten species of Phellinus mushrooms collected from northeast Thailand.METHODS:The samples were tested for their radical scavenging activity toward 2,2-diphenyl-1-pricylhydrazyl (DPPH) radical (DPPH method) and total phenolic content (Folin-Ciocalteu method).RESULTS:Some of the investigated extracts exhibited potent radical scavenging activity with the IC 50 ranging from (7.30±0.34) to (19.80±0.13) μg·mL-1.IC 50 were in the range of the standard antioxidant used;quercetin,ascorbic acid and butylated hydroxytoluene (BHT).The strongest scavenging activity as comparable to quercetin was found in the crude 80% EtOH extract of P.torulosus.The crude EtOAc fraction of P.pini showed the highest total phenolic content with a value of 87.76±1.00 equivalent gallic acid (EGA) while the samples with potent antioxidant activity were also determined to have high amount of total phenolics (78.34±0.27 to 51.01±0.38) EGA.CONCLUSION:These results indicated that crude extracts from Phellinus mushrooms have a potential to be natural antioxidant source.展开更多
This study presents an optimization of the Folin-Ciocalteu spectrophotometric method for the determination of total phenol content. Multivariate optimization using factorial planning 22 with a central point and centra...This study presents an optimization of the Folin-Ciocalteu spectrophotometric method for the determination of total phenol content. Multivariate optimization using factorial planning 22 with a central point and central composite planning was constructed to evaluate the influence of variables in the process and maximize radiation absorption with minimal radiation scattering caused by solid formation. X-ray fluorescence and X-ray diffraction spectrometry were used to evaluate the chemical composition of solids formed and nephelometric and spectrophotometric studies were also used to evaluate whether the type, origin, dilution and dry extract contents of commercial propolis extracts would significantly influence the increase in radiation scattering and absorption. The optimized methodology added several advantages, such as reduction of reagents, time analysis, and higher accuracy.展开更多
文摘探究了用福林-酚法测秋葵汁中总多酚含量的最佳条件,并对此方法进行分析评价。通过实验结果可知,用这种方法检测多酚含量时的最优条件为：测定波长为730 nm,7.5%的碳酸钠溶液3 m L,福林试剂0.7 m L,样品溶液0.5 m L,反应温度为25℃,反应时间为50 min。在0~100μg范围内吸光度与多酚线性关系R2=0.9993,加标回收率为98.3%,相对标准偏差为2.68%（n=5）。另外,该方法精密度、稳定性都比较好,适合用于测定总多酚含量。
基金supported by Center of Excellence for Innovation in Chemistry (PERCH-CIC) and Faculty of Science,Mahasarakham University
文摘AIM:To investigate the antioxidant activity and total phenolic content from the crude extracts and crude fractions of ten species of Phellinus mushrooms collected from northeast Thailand.METHODS:The samples were tested for their radical scavenging activity toward 2,2-diphenyl-1-pricylhydrazyl (DPPH) radical (DPPH method) and total phenolic content (Folin-Ciocalteu method).RESULTS:Some of the investigated extracts exhibited potent radical scavenging activity with the IC 50 ranging from (7.30±0.34) to (19.80±0.13) μg·mL-1.IC 50 were in the range of the standard antioxidant used;quercetin,ascorbic acid and butylated hydroxytoluene (BHT).The strongest scavenging activity as comparable to quercetin was found in the crude 80% EtOH extract of P.torulosus.The crude EtOAc fraction of P.pini showed the highest total phenolic content with a value of 87.76±1.00 equivalent gallic acid (EGA) while the samples with potent antioxidant activity were also determined to have high amount of total phenolics (78.34±0.27 to 51.01±0.38) EGA.CONCLUSION:These results indicated that crude extracts from Phellinus mushrooms have a potential to be natural antioxidant source.
文摘This study presents an optimization of the Folin-Ciocalteu spectrophotometric method for the determination of total phenol content. Multivariate optimization using factorial planning 22 with a central point and central composite planning was constructed to evaluate the influence of variables in the process and maximize radiation absorption with minimal radiation scattering caused by solid formation. X-ray fluorescence and X-ray diffraction spectrometry were used to evaluate the chemical composition of solids formed and nephelometric and spectrophotometric studies were also used to evaluate whether the type, origin, dilution and dry extract contents of commercial propolis extracts would significantly influence the increase in radiation scattering and absorption. The optimized methodology added several advantages, such as reduction of reagents, time analysis, and higher accuracy.
