簕竹属竹叶中黄酮类成分分析及其抗氧化活性

Quantification and Antioxidant Activity of Flavonoids in Bamboo Leaves Extract of Bambusa

为探索簕竹属主要竹种竹叶提取物中黄酮类成分的开发利用,以簕竹属10个竹种的竹叶为原料,提取、分离和纯化后得到竹叶提取物,建立了测定竹叶提取物中5种黄酮类成分的HPLC方法,采用DPPH法和ABTS法对竹叶提取物的抗氧化活性进行评价。竹叶中5种黄酮类成分异荭草苷、荭草苷、牡荆苷、异牡荆苷和木犀草苷的HPLC方法为:采用YMC-Pack ODS-A色谱柱(250 mm×4.6 mm,5μm),以0.5%乙酸/水溶液(A)和乙腈(B)为流动相,14%B等梯度洗脱40 min,进样量10μL,流速1 mL/min,柱温30℃,检测波长340 nm。此条件下,5种黄酮类成分在40 min内实现完全分离,分离度均大于1.2,其质量浓度与峰面积具有良好的线性相关性,相关系数R2>0.999,加标回收率在94.36%~105.37%之间,相对标准偏差(RSD)在0.98%~3.48%之间,表明该方法稳定可靠。测得的10种簕竹属竹叶提取物中5种黄酮类成分的总量为62.30~223.24 mg/g,其中凤尾竹竹叶提取物中的质量分数最高,为223.24 mg/g。10种簕竹属竹叶提取物对DPPH自由基(DPPH·)的半抑制质量浓度(IC_(50))值为28.58~44.37 mg/L,对ABTS自由基(·ABTS^(+))的IC_(50)值为8.58~11.07 mg/L,清除能力均略弱于Vc和BHT。对DPPH·清除效果较好的竹种为大眼竹(IC_(50)=28.58 mg/L)、青皮竹(IC_(50)=28.68 mg/L)和凤尾竹(IC_(50)=31.65 mg/L),对·ABTS^(+)清除效果较好的竹种为凤尾竹(IC_(50)=8.58 mg/L)、银丝竹(IC_(50)=9.11 mg/L)和青皮竹(IC_(50)=9.27 mg/L)。其中青皮竹、凤尾竹是清除效果最好、最具有开发利用价值的2个竹种。

To explore the development and utilization of flavonoids in the leaves of the main bamboo species of Bambusa,extracts of leaves from ten bamboo species were obtained by extraction,separation and purification,using bamboo leaves from Bambusa as the materials.A HPLC method was established for the determination of 5 flavonoids in extract of bamboo leaves,and the antioxidant activities of those extracts were evaluated by DPPH and ABTS assays.The HPLC method for the determination of 5 flavonoids isoorientin,orientin,vitexin,isovitexin and luteoside in extract of bamboo leaves was using YMC-Pack ODS-A column(250 mm×4.6 mm,5μm)with 0.5%acetic acid/water(A)and acetonitrile(B)as the mobile phases,elution with 14%B for 40 min,the injection volume 10μL,the flow rate 1 mL/min,the column temperature 30℃and the detection wavelength at 340 nm.Under these conditions,the five flavonoids were completely separated within 40 min,the degree of separation was greater than 1.2,and the concentration had a good linear correlation with the peak area(R~2>0.999).The recovery rate was 94.36%-105.37%,and the relative standard deviation(RSD)was 0.98%-3.48%.These results indicated that the method was stable and reliable.The total contents of 5 flavonoids in extract of leaves from 10 bamboo species of Bambusa measured under these conditions were 62.30-223.24 mg/g,and the mass fraction of bamboo leaves extract from B.multiplex f.fernleaf was the highest(223.24 mg/g).The half inhibitory mass fraction(IC_(50))values of DPPH·and·ABTS^(+)were 28.58-44.37 mg/L and 8.58-11.07 mg/L,respectively,slightly higher than those of Vc and BHT.The bamboo species with better DPPH·scavenging rate were B.eutuldoides(IC_(50)=28.58 mg/L),B.textilis(IC_(50)=28.68 mg/L)and B.multiplex f.fernleaf(IC_(50)=31.65 mg/L).The bamboo species with better ABTS·^(+)scavenging rate were B.multiplex f.fernleaf(IC_(50)=8.58 mg/L),B.multiplex f.silverstripe(IC_(50)=9.11 mg/L)and B.textilis(IC_(50)=9.27 mg/L).The IC_(50)values of B.multiplex f.fernleaf and B.textilis of two kinds of radicals were lower,which were the two bamboo species with the best removal effect and the most value of development and utilization.