桃金娘根提取物体外抗氧化活性研究

Antioxidant activity of extracts from Myrtle root in Vitro

桃金娘根含有酚类、鞣质、三萜类、多糖等化学成分,其中三萜类、鞣质、桃金娘多糖在体外具有一定的抗氧化活性。采用DPPH·法及Fe3+还原力法对桃金娘根提取物的抗氧化活性进行了研究,分别测定桃金娘根乙醇提取物、石油醚提取物、氯仿提取物、乙酸乙酯提取物、正丁醇提取物、水提粗多糖及碱提粗多糖的抗氧化作用,同时以Vc作为阳性对照。结果表明:桃金娘根提取物具有较强的抗氧化活性,尤其是乙酸乙酯提取物、正丁醇提取物及水提粗多糖;它们对DPPH·的清除作用与Vc相当,其中乙酸乙酯提取物IC50值为2.8μg/mL,活性高于Vc,同时以上提取物对Fe3+也具有很强的还原能力。综上而得,桃金娘根提取物抗氧化活性大小为:乙酸乙酯提取物>Vc≈正丁醇提取物>水提粗多糖>乙醇提取物>氯仿提取物>碱提粗多糖>石油醚提取物。

Ferrocenyl-terminated hyperbranched polyesters/epoxy resin （HBPE-Fc/E-51） composites with mechanical and electromagnetic performance were prepared with the third generation of epoxidized hyperbranched polyesters （EHBP） toughened epoxy resin as matrix material, and ferrocenyl-terminated hyperbranched polyesters （HBPE-Fc） as microwave-absorber. The mechanics and electromagnetic properties of the composites were investigated by mechanics performance tests, SEM and the vector network analyzer. The results indicate that lower content of HBPE-Fc can improve the tensile and impact performance of epoxy resin. Compared with base curing system. When the mass fraction of G4 HBPE-Fc is 2%, the tensile strength, tensile rupture elongation and impact strength increase by 21.81%, 34.32% and 15.41%, respectively. The analysis of tensile fracture surfaces shows that the composites with HBPE-Fc were judged for ductile fracture with the glass transition temperatures for the composites of 105.29-130.27 ℃, and the composites also possess certain electromagnetic properties.