向日葵茎髓醇提物中不同溶剂萃取部位总酚、总黄酮含量与抗氧化活性的相关性

依次用石油醚、乙酸乙酯、正丁醇对向日葵茎髓乙醇提取物进行萃取，得到不同极性萃取部位， 测定石油醚萃取部位（PE）、乙酸乙酯萃取部位（EE）和正丁醇萃取部位（BE）的总酚和总黄酮含量及其 体外抗氧化活性，并分析其相关性。结果表明：EE中总酚和总黄酮含量均最高，分别为（1.60±0.10）mg/g 和（20.50±1.55）mg/g；且其1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl，DPPH）自由基清 除率（半抑制浓度（2.56±0.10）mg/mL）、2,2’-二氮-双（3-乙基苯并噻唑-6-磺酸）二铵盐（2,2’-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid)，ABTS）自由基清除率（半抑制浓度（52.00±1.97）μmol/g）和铁离子还原能 力（半抑制浓度（120.57±0.74）μmol/g）也最好；总酚、总黄酮含量与抗氧化活性的相关性分析结果表明，各向 日葵茎髓萃取部位的DPPH自由基清除率、ABTS＋·清除能力及铁离子还原能力与其总酚和总黄酮含量均呈极显著 正相关（P＜0.01）。

Correlation between Total Phenols and Total Flavonoids Contents and Antioxidant Activity of Different Fractions from Ethanol Extract of Sunflower Stalk Pith

The total phenols, total flavonoids contents and in vitro antioxidant activities of petroleum ether (PE), ethyl acetate (EE) and n-butanol (BE) soluble fractions from the ethanol extract of sunflower stalk pith were evaluated and correlated with each other. Results showed that EE contained the highest amount of total phenols (1.60 ± 0.10) mg/g calculated as gallic acid equivalent and total flavonoids (20.50 ± 1.55) mg/g calculated as rutin equivalent. EE also had the highest antioxidant activity among three extracts, with half maximal inhibitory concentration of (2.56 ± 0.10) mg/mL, (52.00 ± 1.97) μmol/g and (120.57 ± 0.74) μmol/g for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and total reducing power (the latter two were calculated as Trolox equivalent), respectively. The correlation analysis showed that for all three extracts, there were significant correlations between the contents of total phenols and total flavonoids and DPPH and ABTS radical scavenging activity and ferric reducing antioxidant power (P < 0.01).