不同叶型五指毛桃皮中游离酚和结合酚的提取及其组成差异分析

Extraction and composition analysis of free phenols and bound phenols in Ficus hirta Vahl. root cortex with different leaf types

  • 摘要: 【目的】 优化不同叶型五指毛桃皮中游离酚和结合酚的提取工艺,并分析酚类化合物在不同叶型五指毛桃皮中的组成和含量差异,为五指毛桃品种选育及深加工利用提供参考依据。【方法】 以不同叶型(一指、三指、五指)五指毛桃皮为试验材料,通过单因素试验确定五指毛桃皮中游离酚和结合酚的提取方式,采用超高效液相色谱—质谱联用法(UPLC-MS)分析不同叶型五指毛桃皮中酚类化合物的组成和含量,并通过主成分分析(PCA)和偏最小二乘法判别分析(PLS-DA)筛选不同叶型五指毛桃皮的差异酚类化合物。【结果】 五指毛桃皮中游离酚和结合酚的提取方式:溶剂为60%丙酮,料液比为1∶20,25 ℃下超声提取10 min可得到游离酚;残渣中加入15 mL 2 mol/L氢氧化钠,75 ℃水浴4 h,再用乙酸乙酯萃取、真空旋转蒸发至干,得到结合酚。一指、三指、五指叶型五指毛桃皮中的游离型总多酚含量分别为7.41、9.50和8.59 mg/g,结合型总多酚含量分别为11.46、9.96和8.80 mg/g,游离型总多酚和结合型总多酚含量在3种叶型间均具有显著差异(P<0.05)。UPLC-MS分析结果表明,在游离酚中共检测出50种酚类化合物,在结合酚中共检测出49种酚类化合物;3-O-对香豆酰奎宁酸、芝麻素、儿茶素、芦丁和异荭草素仅存在游离型,而表儿茶素没食子酸酯、儿茶素没食子酸酯、咖啡酸和山柰素仅存在结合型。在游离酚中,补骨脂素含量最高,在一指、三指和五指叶型中的含量分别为11868.37、14909.63和14050.10 μg/g;在结合酚中,含量较高的有松柏苷、阿夫儿茶精、阿魏酸、柚皮素和伞形花内酯。PCA和PLS-DA分析结果表明,游离型圣草酚、游离型松柏苷、游离型隐绿原酸、游离型阿夫儿茶精、游离型绿原酸、游离型柚皮素、游离型补骨脂素、游离型佛手柑内酯、结合型松柏苷、结合型阿魏酸和结合型香豆酸是3种叶型五指毛桃皮的主要差异酚类化合物,其中游离型补骨脂素是最重要的差异化合物。【结论】 酚类化合物在不同叶型五指毛桃皮中的组成和含量有明显差异,叶型可作为区分品质的依据之一;且五指毛桃皮中有大量的结合酚,可注重对结合酚的利用,以提高五指毛桃的附加值。

     

    Abstract: 【Objective】 The aim of the study was to optimize the extraction process of free phenols and bound phenols from Ficus hirta Vahl. root cortex with different leaf types, and analyze the composition and content differences of phenolic compounds in Ficus hirta Vahl. root cortex with different leaf types, which could provide reference for the breeding, deep processing and utilization of Ficus hirta Vahl. varieties.【Method】 Ficus hirta Vahl. root cortex with different leaf types (no-lobed, three-lobed, five-lobed) were used as experiment materials. The extraction methods of free phenols and bound phenols were determined by single factor experiment. The compositions and contents of phenolic compounds in Ficus hirta Vahl. root cortex with different leaf types were determined by ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS). Finally,principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) were used to screen the differential phenol compounds in Ficus hirta Vahl. root cortex with different leaf types.【Result】 The extraction methods of free phenols and bound phenols from Ficus hirta Vahl. root cortex: the solvent was 60% acetone, ratio of solid to liquid was 1∶20,free phenol was obtained by ultrasonic extraction at 25 ℃ for 10 min; 15 mL of 2 mol/L sodium hydroxide was added to the residue, and hydrolysis was conducted at 75 ℃ in a water bath for 4 h, then, residue was extracted by ethyl acetate, and dried by vacuum rotary evaporation, and bound phenol was obtained. The contents of free total polyphenols in no-lobed,three-lobed and five-lobed Ficus hirta Vahl. root cortex were 7.41,9.50, and 8.59 mg/g,and the contents of bound total polyphenols were 11.46,9.96, and 8.80 mg/g. The contents of free total polyphenols and bound total polyphenols showed significant difference among the three leaf types (P<0.05). The results of UPLC-MS analysis showed that, a total of 50 phenolic compounds were detected in free phenols and 49 phenolic compounds were detected in bound phenols. 3-O-p-coumaroylquinic acid, sesamin, catechin, rutin, and isoorientin existed only in free type, while epicatechin gallate, catechin gallate, caffeic acid, and kaempferol existed only in bound type. The content of psoralen in free phenol part was the highest,which were 11868.37,14909.63, and 14050.10 μg/g in Ficus hirta Vahl. root cortex with no-lobed,three-lobed and five-lobed respectively. Among the bounding polyphenols,coniferin,afcatechin,ferulic acid,naringin and umbelliferolactone were the most abundant. The results of PCA and PLS-DA analysis showed that, free sericol,free coniferin,free cryptochlorogenic acid,free afcatechin,free chlorogenic acid,free naringin,free psoralen,free bergamolide,bound coniferin,bound ferulic acid, and bound coumaric acid were the main differential phenolic compounds in Ficus hirta Vahl. root cortex. Among them, free psoralen was the most important phenolic compound.【Conclusion】 The compositions and contents of phenolic compounds in root cortex of Ficus hirta Vahl. with different leaf types vary greatly. Leaf type can be used as one of the criteria for distinguishing quality; moreover, there is a large amount of bound phenols in root cortex of Ficus hirta Vahl., and it is important to focus on the utilization of the bound phenols to increase the added value of Ficus hirta Vahl.

     

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