Kratchanova Maria, Denev Petko, Ciz Milan, Lojek Antonin, Mihailov Atanas
Institute of Organic Chemistry with Centre of Phytochemistry, Plovdiv, Bulgaria.
Acta Biochim Pol. 2010;57(2):229-34. Epub 2010 Jun 9.
This study investigates the influence of extraction system on the extractability of polyphenol compounds and antioxidant activity of various medicinal plants. Oxygen radical absorbance capacity (ORAC) and total polyphenol content of 25 Bulgarian medicinal plants subjected to water or 80 % acetone extractions were investigated and compared. The type of extragent significantly influenced the efficiency of the polyphenol extraction and the antioxidant activity. In all cases ORAC results and total polyphenol content were higher for acetone extraction than for water extraction. The acetone extract of peppermint had the highest ORAC value - 2917 micromol Trolox equivalent (TE)/g dry weight (DW) and polyphenol content - 20216 mg/100 g DW. For water extraction thyme exhibited the highest ORAC antioxidant activity - 1434 micromol TE/g DW. There was a significant linear correlation between the concentration of total polyphenols and ORAC in the investigated medicinal plants. It can be concluded that the solvent used affects significantly the polyphenol content and the antioxidant activity of the extract and therefore it is recommended to use more than one extraction system for better assessment of the antioxidant activity of natural products. Several of the investigated herbs contain substantial amounts of free radical scavengers and can serve as a potential source of natural antioxidants for medicinal and commercial uses.
本研究调查了提取系统对各种药用植物中多酚化合物提取率和抗氧化活性的影响。对25种保加利亚药用植物进行水提取或80%丙酮提取后，对其氧自由基吸收能力（ORAC）和总多酚含量进行了研究和比较。提取剂的类型显著影响多酚提取效率和抗氧化活性。在所有情况下，丙酮提取的ORAC结果和总多酚含量均高于水提取。薄荷的丙酮提取物具有最高的ORAC值——2917微摩尔 Trolox 当量（TE）/克干重（DW）和多酚含量——20216毫克/100克DW。对于水提取，百里香表现出最高的ORAC抗氧化活性——1434微摩尔TE/克DW。在所研究的药用植物中，总多酚浓度与ORAC之间存在显著的线性相关性。可以得出结论，所用溶剂对提取物的多酚含量和抗氧化活性有显著影响，因此建议使用多种提取系统以更好地评估天然产物的抗氧化活性。几种被研究的草药含有大量自由基清除剂，可作为药用和商业用途天然抗氧化剂的潜在来源。
