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Antiradical Activity (antiradical + activity)
Selected AbstractsA validated spectrophotometric method for quantification of prenylated flavanones in pacific propolis from TaiwanPHYTOCHEMICAL ANALYSIS, Issue 2 2010Milena Popova Abstract Introduction , Because of its chemical diversity, the only way to standardise propolis is to specify multiple standards for different propolis types according to the corresponding chemical profile. So far, this has been done only for European propolis. Objective , To develop a rapid low-cost spectrophotometric procedure for quantification of bioactive prenylated flavanones in Taiwanese propolis. Methodology , The proposed method quantifies the total flavanones on the basis of their absorption as coloured phenylhydrazones formed by interaction with 2,4-dinitrophenylhydrazine. The procedure was validated through model mixture of compounds representing the composition of Taiwanese propolis according to previous studies. The major flavanones of the propolis samples (propolins C, D, F and G) were quantified by HPLC. Antiradical activity against DPPH was also measured. The DNP (dinitrophenylhydrazine) spectrophotometric method is applied for the first time for quantification of prenylated flavanones. Results , Spectophotometric procedure applicable to new type propolis (Macaranga type) was developed with recovery between 105 and 110% at the concentration range of 0.573,1.791,mg/mL. Six propolis samples were analysed by spectrophotometry using the procedure developed and validated, and by HPLC as the results demonstrated satisfactory agreement. Neither the spectrophotometric data nor the values measured by HPLC showed significant correlation with the antiradical activity against DPPH. Conclusion , The proposed spectrophotometric procedure is useful for routine analyses of Macaranga -type propolis, because of its simplicity, repeatability and acceptable accuracy. Its application to a number of commercial samples could be used as a basis for standardisation and quality control of Pacific propolis. Copyright © 2009 John Wiley & Sons, Ltd. [source] Antimutagenic and antioxidant activities of cascalote (Caesalpinia cacalaco) phenolicsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2004Rafael A Veloz-García Abstract There is an increasing awareness and interest in the antioxidant behaviour and potential health benefits of phenolic acids. The identification of novel sources of phenolic acids has been also of scientific interest. Cascalote (Caesalpinia cacalaco) pods are known to be a good source of ,tannins', the name by which industry in Mexico recognizes phenolic extract. Phenolics were determined as gallic acid equivalents g,1. The antimutagenic activity against aflatoxin B1 and the antioxidant activity, using two different methods, of the extract were also evaluated. Gallic acid accounts for almost 90% of the phenolic extract of cascalote, the remaining 10% was tannic acid. Antimutagenic activity of cascalote phenolics was dose-dependent, showing an inhibition level of 64.42% at the highest dose assayed. Antioxidant and antiradical activities were also dose-dependent. The highest antioxidant activity showed by cascalote phenolics was 73.5%, higher than that of Trolox. The highest antiradical activity of cascalote phenolics was 75.3%, higher than that of BHT and Trolox. Cascalote pods are an outstanding source of gallic and tannic acids. Copyright © 2004 Society of Chemical Industry [source] Free-radical scavenging activity of wormwood (Artemisia absinthium L) extractsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2005Jasna M Canadanovic-Brunet Abstract In an effort to discover new antioxidant natural compounds, wormwood (Artemisia absinthium L) an aromatic-bitter herb, was screened. The sequential extraction was realized with five solvents of different polarities (70% methanol, petroleum ether, chloroform, ethyl acetate, n -butanol). The antioxidative activity was tested by measuring their ability to scavenge stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and reactive hydroxyl radical during the Fenton reaction trapped by 5,5-dimethyl-1-pyrroline- N -oxide (DMPO), using electron spin resonance (ESR) spectroscopy. Results demonstrated that the antiradical and antioxidative activity depend on the type and concentration of applied extracts and increased in the order ethyl acetate > methanol > n -butanol > chloroform > petroleum ether > remaining water extracts. The investigation showed that the antiradical activity increased with increasing concentration of all extracts. The high contents of total phenolic compounds (25.6 mg g,1) and total flavonoids (13.06 mg g,1) indicated that these compounds contribute to the antiradical and antioxidative activity. In a model system, the formation of o -semiquinone radicals from quercetin and chlorogenic acid was obtained to prove the mechanism (hydrogen donating and/or one-electron reduction) of free-radical scavenging activity. Copyright © 2004 Society of Chemical Industry [source] Correlation between antiradical activity and stability of betanine from Beta vulgaris L roots under different pH, temperature and light conditionsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2001A Pedreño Abstract When the antiradical activity and stability of betanine were studied at pH values of 3.5 and 8.5 and temperatures of 25, 50 and 75,°C, the results showed that the antiradical activity was greater at acidic pH and lower at higher temperatures. At basic pH the activity of betanine correlated well with its stability at the three temperatures assayed, suggesting that the degradation products, betalamic acid (BA) and cyclo DOPA 5- O -,- D -glucoside (CDG), did not contribute to this activity under the experimental conditions used. However, at acidic pH the degradation product, CDG, did seem to contribute to the antiradical activity. Furthermore, at pH 3.5, betanine stability was so great that light conditions had no effect on the antiradical activity. At basic pH, too, light had no effect on betanine activity owing to the high instability of the pigment. © 2001 Society of Chemical Industry [source] A validated spectrophotometric method for quantification of prenylated flavanones in pacific propolis from TaiwanPHYTOCHEMICAL ANALYSIS, Issue 2 2010Milena Popova Abstract Introduction , Because of its chemical diversity, the only way to standardise propolis is to specify multiple standards for different propolis types according to the corresponding chemical profile. So far, this has been done only for European propolis. Objective , To develop a rapid low-cost spectrophotometric procedure for quantification of bioactive prenylated flavanones in Taiwanese propolis. Methodology , The proposed method quantifies the total flavanones on the basis of their absorption as coloured phenylhydrazones formed by interaction with 2,4-dinitrophenylhydrazine. The procedure was validated through model mixture of compounds representing the composition of Taiwanese propolis according to previous studies. The major flavanones of the propolis samples (propolins C, D, F and G) were quantified by HPLC. Antiradical activity against DPPH was also measured. The DNP (dinitrophenylhydrazine) spectrophotometric method is applied for the first time for quantification of prenylated flavanones. Results , Spectophotometric procedure applicable to new type propolis (Macaranga type) was developed with recovery between 105 and 110% at the concentration range of 0.573,1.791,mg/mL. Six propolis samples were analysed by spectrophotometry using the procedure developed and validated, and by HPLC as the results demonstrated satisfactory agreement. Neither the spectrophotometric data nor the values measured by HPLC showed significant correlation with the antiradical activity against DPPH. Conclusion , The proposed spectrophotometric procedure is useful for routine analyses of Macaranga -type propolis, because of its simplicity, repeatability and acceptable accuracy. Its application to a number of commercial samples could be used as a basis for standardisation and quality control of Pacific propolis. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||