宜昌绿肉猕猴桃果肉中叶绿素的结构鉴定及其抗氧化活性

为探究猕猴桃中叶绿素组分及其抗氧化活性,以宜昌绿肉猕猴桃果肉为实验材料,利用溶剂提取法和柱层析等手段分离纯化得到包括叶绿素a在内的6种高纯度物质,通过质谱得到了它们[M+H]⁺的准确分子质量,结合核磁共振数据推测了5种叶绿素相关物质的结构。其中C₁为叶绿素a,得到物质A₁的[M+H]⁺的分子质量为927.6967,分子式C₅₅H₈₄O₇N₄;物质B₁的[M+H]⁺的分子质量为588.4304,分子式C₃₄H₃₃O₅N₄;物质D₁的[M+H]⁺的分子质量为601.1116,分子式C₃₅H₃₄O₅N₄,推测结构可知为脱镁叶绿酸a;物质E₁的[M+H]⁺的分子质量为927.6985,分子式C₅₅H₈₄O₇N₄;物质F₁的[M+H]⁺的分子质量为701.5039,分子式C₃₇H₃₈O₉N₄。同时通过DPPH法和Fe³⁺还原力法对其单品进行了抗氧化活性研究,结果显示,在质量浓度为0.12 mg/mL时,清除率分别为93.14%和93.39%,略低于V_C的96.49%,且在质量浓度为1.0 mg/mL时,物质E₁与F₁的吸光值均为1.92,仅次于V_C的1.95。通过研究发现并推测了5种叶绿素相关物质的结构,并且都具有一定的抗氧化活性,其中E₁与F₁的活性最强。

Structure Identification and Antioxidant Activity of Chlorophyll in Yichang Green Meat Kiwifruit

To explore the chlorophyll component and its antioxidant activity in kiwifruit,taking Yichang green meat kiwi fruit pulp as experimental material. Using solvent extraction and column chromatography,6 kinds of high-purity substances including chlorophyll a were obtained through separation and purification. The molecular weights of[M+H]+ were obtained by mass spectrometry.Combined with nuclear magnetic resonance data,the structure of five kinds of chlorophyll-related substances was speculated,in which C₁ was chlorophyll a. The molecular weight of [M+H]+ of the material A₁ was 927.6967,the molecular formula was C₅₅H₈₄O₇N₄;the molecular weight of[M+H]+ of the substance B₁ was 588.4304,the molecular formula was C₃₄H₃₃O₅N₄;the molecular weight of[M+H]+ of the substance D₁ was 601.1116,the molecular formula C₃₅H₃₄O₅N₄,the structure was estimated to be pheophorbide a;the molecular weight of[M+H]+ of the substance E₁ was 927.6985,the molecular formula was C₅₅H₈₄O₇N₄;the molecular weight of[M+H]+ of the substance F₁ was 701.5039,and the molecular formula was C₃₇H₃₈O₉N₄.At the same time,the antioxidant activity of the single product was studied by DPPH method and Fe3+ reduction method. The results showed that when mass concentration was 0. 12 mg/mL,the clearance rates were 93.14% and 93.39%,respectively,which was slightly lower than the 96.49% clearance rate of V_C. At a mass concentration of 1.0 mg/mL,the absorbance values of the substances E₁ and F₁ were both 1.92,which was second only to 1.95 of V_C. The structure of five chlorophyll-related substances was discovered and presumed,and all of them had certain antioxidant activities,among which E₁ and F₁ were the most active.