不同干燥方式对鸡屎藤中酚类代谢物及抗氧化活性的影响

Effects of different drying methods on phenolic metabolites and antioxidant activity in Paederia scandens

【目的】分析不同干燥方式处理鸡屎藤后酚类代谢物的变化和抗氧化活性差异,为鸡屎藤的开发利用提供理论依据。【方法】采用冷冻干燥和热烘干燥2种方式处理鸡屎藤,比较不同干燥方式处理鸡屎藤后酚类物质的抗氧化能力,并应用非靶向代谢组学方法对鸡屎藤酚类化合物进行定性分析,采用偏最小二乘法判别分析(PLS-DA)筛选酚类差异代谢物后,对其进行层次聚类分析和KEGG代谢通路富集分析,同时分析不同干燥方式处理后鸡屎藤差异代谢物与抗氧化活性之间的相关性。【结果】冷冻干燥和热烘干燥2种方式对鸡屎藤总酚和总黄酮含量均无显著影响(P>0.05);冷冻干燥鸡屎藤的1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力、2,2-联氮-双(3-乙基苯并噻唑啉-6-磺酸)二铵盐(ABTS)阳离子自由基清除能力和铜离子还原能力均高于热烘干燥。采用超高效液相色谱串联傅里叶变换质谱仪对2种干燥方式处理的鸡屎藤均鉴定出99种酚类化合物,其中黄酮类54种,香豆素及其衍生物15种,肉桂酸及其衍生物13种,酚类9种,异黄酮类6种,黄酮醇类2种。主成分分析和层次聚类分析结果表明不同干燥方式处理的鸡屎藤酚类代谢物具有显著差异(P<0.05,下同),且热烘干燥方式有15种差异代谢物表达量显著高于冷冻干燥方式。应用PLS-DA共筛出25种极显著差异代谢物(P<0.01),其中10种代谢物上调,15种代谢物下调,变化显著的主要有黄酮类、酚类和香豆素及其衍生物。KEGG代谢通路富集分析发现,不同干燥方式下鸡屎藤差异代谢物富集代谢通路有7条,富集程度最高的前5条通路分别为类黄酮生物合成、苯丙烷生物合成、多种次生代谢产物的生物合成1、酪氨酸代谢及二苯乙烯类、二芳基庚烷类和姜辣素生物合成。25种酚类差异代谢物与DPPH自由基清除能力和铜离子还原能力均表现出显著相关性,其中有10种酚类差异代谢物与这2个指标呈显著正相关,15种酚类差异代谢物呈显著负相关。【结论】不同干燥方式处理鸡屎藤未改变酚类化合物种类,但对酚类化合物的含量及抗氧化活性均有明显影响。鸡屎藤发挥功能活性不是单一代谢物作用,而是多种代谢物协同作用的结果。

【Objective】The study aimed to analyze the changes in phenolic metabolites and differences in antioxidant activity of Paederia scandens after different drying methods,providing theoretical basis for the development and utilization of P.scandens.【Method】Two drying methods,freeze drying and heat drying,were used to treat P.scandens,and the antioxidant capacity of phenolic substances in P.scandens after different drying methods was compared.Non-targeted metabolomics was applied for the qualitative analysis of phenolic compounds in P.scandens.After screening for differential phenolic metabolites using partial least squares discriminant analysis(PLS-DA),hierarchical clustering analysis and KEGG metabolic pathway enrichment analysis were conducted.Additionally,the correlation between the differential metabolites and antioxidant activity of P.scandens after treatment with different drying methods was analyzed.【Result】Freeze drying and heat drying had no significant effect on the total phenol and total flavonoid contents of P.scandens(P>0.05).The 1,1-diphenyl-2-trinitrophenylhydrazine(DPPH)radical scavenging capacity,2,2-azino-bis(3-ethyl-benzothiazole-6-sulfonic acid)diammonium salt(ABTS)cation radical scavenging capacity and copper ion reduction capacity of freeze-dried P.scandens were all higher than those of the heat-dried samples.Using ultra-high-performance liquid chromatography coupled with Fourier transform mass spectrometry,99 phenolic compounds were identified in P.scandens treated with two drying methods,including 54 flavonoids,15 coumarins and their derivatives,13 cinnamic acids and their derivatives,9 phenolics,6 isoflavonoids,and 2 flavonols.The results of principal component analysis and hierarchical cluster analysis showed that the phenolic metabolites of P.scandens treated with different drying methods were significantly different(P<0.05,the same below).The expression levels of 15 differential metabolites in the heat drying method were significantly higher than those in the freeze drying method.A total of 25 extremely significant differential metabolites were screened out using PLS-DA(P<0.01),among which 10 metabolites were up-regulated and 15 metabolites were down-regulated.Significant changes were mainly observed in flavonoids,phenols,and coumarins and their derivatives.KEGG metabolic pathway enrichment analysis revealed that there were 7 metabolic pathways enriched with differential metabolites of P.scandens under different drying methods.The top 5 most enriched pathways were flavonoid biosynthesis,phenylpropane biosynthesis,biosynthesis of multiple secondary metabolites 1,tyrosine metabolism,and biosynthesis of stilbenes,diarylheptanes and gingerol.The 25 phenolic differential metabolites showed significant correlations with both DPPH radical scavenging capacity and copper ion reduction capacity,with 10 phenolic differential metabolites exhibiting significant positive correlations with the two indicators and 15 phenolic differential metabolites showing significant negative correlations.【Conclusion】Different drying methods applied to P.scandens do not change the types of phenolic compounds,but they have obvious effect on the content of phenolic compounds and antioxidant activity.The functional activity of P.scandens is not the result of a single metabolite,but rather the synergistic effect of multiple metabolites.