Zhou Chunhua, Sun Chongde, Chen Kunsong, Li Xian
College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China; E-Mail:
Int J Mol Sci. 2011;12(5):2935-45. doi: 10.3390/ijms12052935. Epub 2011 May 4.
Flavonoids and phenolics are abundant in loquat flowers. Methanol had the highest extraction efficiency among five solvents, followed by ethanol. Considering the safety and residue, ethanol is better as extraction solvent. The average content of flavonoids and phenolics of loquat flower of five cultivars were 1.59 ± 0.24 and 7.86 ± 0.87 mg/g DW, respectively, when using ethanol as extraction solvent. The contents of both bioactive components in flowers at different developmental stages and in the various flower tissues clearly differed, with the highest flavonoids and phenolics content in flowers of stage 3 (flower fully open) and petal, respectively. The antioxidant capacity was measured using FRAP, DPPH, and ABTS methods. The values of ABTS method was highest, followed by DPPH, the lowest was FRAP, when using vitamin C equivalent antioxidant capacity (VCEAC) as unit. Correlation analysis showed that the ABTS method showed the highest correlation coefficients with flavonoids and phenolics, i.e., 0.886 and 0.973, respectively.
黄酮类化合物和酚类物质在枇杷花中含量丰富。在五种溶剂中，甲醇的提取效率最高，其次是乙醇。考虑到安全性和残留量，乙醇作为提取溶剂更佳。当使用乙醇作为提取溶剂时，五个品种枇杷花中黄酮类化合物和酚类物质的平均含量分别为1.59±0.24和7.86±0.87毫克/克干重。不同发育阶段的花以及花的各个组织中这两种生物活性成分的含量明显不同，黄酮类化合物含量在第3阶段（花完全开放）的花中最高，酚类物质含量在花瓣中最高。使用FRAP、DPPH和ABTS方法测定抗氧化能力。以维生素C等效抗氧化能力（VCEAC）为单位时，ABTS方法的值最高，其次是DPPH，FRAP最低。相关性分析表明，ABTS方法与黄酮类化合物和酚类物质的相关系数最高，分别为0.886和0.973。
