Phenylalanin ammonia-lyase(PAL) plays a pivotal role in the production of phenolic compounds,which are responsible for the success of the defense strategies in harsh environments in response to different stimuli.Measu...Phenylalanin ammonia-lyase(PAL) plays a pivotal role in the production of phenolic compounds,which are responsible for the success of the defense strategies in harsh environments in response to different stimuli.Measurements of the PAL activity,total phenolics,total flavonoids and anthocyanin contents were performed in flowers,leaves and fruits of three pistachio cultivars "Ahmadaghaii","Ohadi" and "Kallehghuchi".The results showed that PAL activity was different in cultivars and in plant organs of pistachio trees(flowers,leaves and fruits).The highest activity rate of their compounds was observed in Ahmadaghaii cultivar.A positive correlation was observed between PAL activity,total phenolics and total flavonoids in leaves,and a negative correlation between PAL activity and anthocyanin contents in leaves and flowers of Ahmadaghaii cultivar.PAL activity and total phenolics in fruits of pistachio suffered a decrease when the maturation processes began.It is suggested that the hulls of the pistachio fruits,containing high level of phenolic compounds(especially in Ahmadaghaii cultivar),may function as a protective layer of defense chemicals against ultraviolet radiation and pathogens.The final concentration of phenolic compounds,flavonoids and antocyanins in the kernel depend on PAL activity in the kernel's cultivar.The results led to the conclusion that increase in PAL activity,phenolic compounds and flavonoids in Ahmadaghaii can help the plant to cope with the stresses better than the other cultivars.Since phenolic compounds are antioxidant and scavenge free oxygen,it is postulated that Ahmadaghaii is the most resistant cultivar to the environmental stresses.展开更多
乳酸菌发酵可以促进食品中多酚等活性物质的生物转化,改善其功能活性。为探究乳酸菌发酵对铁皮石斛中酚类化合物的影响,该研究选用3种常见乳酸菌对云南省5个地区的铁皮石斛进行发酵,测定发酵前后铁皮石斛的总酚和总黄酮含量及体外抗氧...乳酸菌发酵可以促进食品中多酚等活性物质的生物转化,改善其功能活性。为探究乳酸菌发酵对铁皮石斛中酚类化合物的影响,该研究选用3种常见乳酸菌对云南省5个地区的铁皮石斛进行发酵,测定发酵前后铁皮石斛的总酚和总黄酮含量及体外抗氧化活性,并采用高效液相色谱和超高效液相色谱-串联质谱对其酚类成分和代谢物组成进行分析。结果表明:3种乳酸菌发酵均可提高铁皮石斛的总酚、总黄酮含量和抗氧化活性,其中云南文山产铁皮石斛经保加利亚乳杆菌发酵48 h的增效作用最为明显,该条件下发酵的铁皮石斛总酚、总黄酮含量分别为120.67和23.39 mg/g,其2,2’-联氮-双-3-乙基苯并噻唑啉-6-磺酸阳离子自由基(ABTS)和1,1-二苯基-2-三硝基苯肼自由基清除能力(DPPH)以及铁还原能力(FRAP)最高,分别为288.51、34.34和136.32 mg/g,较发酵前增加了0.81、2.11和0.52倍。选取该条件下发酵的铁皮石斛,利用高效液相色谱对其16种酚类化合物进行定量分析,发现丁香酸和香草酸含量显著增加,表没食子儿茶素没食子酸酯含量显著降低,而水杨酸仅在发酵后铁皮石斛中被检测到。进一步的非靶向代谢组学分析表明,所检测到的1 298种共有代谢物中,发酵后下调的代谢物显著多于上调代谢物。相关性分析表明,抗氧化活性与酚类化合物高度相关。分别在正负离子模式下筛选出75和76个上调、103和89个下调的酚类化合物,表明乳酸菌发酵促使铁皮石斛中的酚类化合物发生了生物降解或转化。采用京都基因与基因组百科全书(kyoto encyclopedia of genes and genomes,KEGG)对铁皮石斛发酵过程中的代谢通路进行富集,结果表明:蛋白质的消化和吸收、苯丙氨酸代谢、丙烷生物碱生物合成、各种次生代谢产物的生物合成-第二部分、黄酮类生物合成和ABC运输通路是最有可能的代谢通路。综上,乳酸菌尤其是保加利亚乳杆菌发酵可显著改善铁皮石斛的抗氧化活性,这可能与其酚类化合物在发酵过程中的转化释放有关。该研究可为利用乳酸菌对铁皮石斛进行发酵增效提供新的思路。展开更多
基金Shahid Bahonar University for providing research funds and Iran's Pistachio Research Institute (IPRI) for providing the research material
文摘Phenylalanin ammonia-lyase(PAL) plays a pivotal role in the production of phenolic compounds,which are responsible for the success of the defense strategies in harsh environments in response to different stimuli.Measurements of the PAL activity,total phenolics,total flavonoids and anthocyanin contents were performed in flowers,leaves and fruits of three pistachio cultivars "Ahmadaghaii","Ohadi" and "Kallehghuchi".The results showed that PAL activity was different in cultivars and in plant organs of pistachio trees(flowers,leaves and fruits).The highest activity rate of their compounds was observed in Ahmadaghaii cultivar.A positive correlation was observed between PAL activity,total phenolics and total flavonoids in leaves,and a negative correlation between PAL activity and anthocyanin contents in leaves and flowers of Ahmadaghaii cultivar.PAL activity and total phenolics in fruits of pistachio suffered a decrease when the maturation processes began.It is suggested that the hulls of the pistachio fruits,containing high level of phenolic compounds(especially in Ahmadaghaii cultivar),may function as a protective layer of defense chemicals against ultraviolet radiation and pathogens.The final concentration of phenolic compounds,flavonoids and antocyanins in the kernel depend on PAL activity in the kernel's cultivar.The results led to the conclusion that increase in PAL activity,phenolic compounds and flavonoids in Ahmadaghaii can help the plant to cope with the stresses better than the other cultivars.Since phenolic compounds are antioxidant and scavenge free oxygen,it is postulated that Ahmadaghaii is the most resistant cultivar to the environmental stresses.
文摘乳酸菌发酵可以促进食品中多酚等活性物质的生物转化,改善其功能活性。为探究乳酸菌发酵对铁皮石斛中酚类化合物的影响,该研究选用3种常见乳酸菌对云南省5个地区的铁皮石斛进行发酵,测定发酵前后铁皮石斛的总酚和总黄酮含量及体外抗氧化活性,并采用高效液相色谱和超高效液相色谱-串联质谱对其酚类成分和代谢物组成进行分析。结果表明:3种乳酸菌发酵均可提高铁皮石斛的总酚、总黄酮含量和抗氧化活性,其中云南文山产铁皮石斛经保加利亚乳杆菌发酵48 h的增效作用最为明显,该条件下发酵的铁皮石斛总酚、总黄酮含量分别为120.67和23.39 mg/g,其2,2’-联氮-双-3-乙基苯并噻唑啉-6-磺酸阳离子自由基(ABTS)和1,1-二苯基-2-三硝基苯肼自由基清除能力(DPPH)以及铁还原能力(FRAP)最高,分别为288.51、34.34和136.32 mg/g,较发酵前增加了0.81、2.11和0.52倍。选取该条件下发酵的铁皮石斛,利用高效液相色谱对其16种酚类化合物进行定量分析,发现丁香酸和香草酸含量显著增加,表没食子儿茶素没食子酸酯含量显著降低,而水杨酸仅在发酵后铁皮石斛中被检测到。进一步的非靶向代谢组学分析表明,所检测到的1 298种共有代谢物中,发酵后下调的代谢物显著多于上调代谢物。相关性分析表明,抗氧化活性与酚类化合物高度相关。分别在正负离子模式下筛选出75和76个上调、103和89个下调的酚类化合物,表明乳酸菌发酵促使铁皮石斛中的酚类化合物发生了生物降解或转化。采用京都基因与基因组百科全书(kyoto encyclopedia of genes and genomes,KEGG)对铁皮石斛发酵过程中的代谢通路进行富集,结果表明:蛋白质的消化和吸收、苯丙氨酸代谢、丙烷生物碱生物合成、各种次生代谢产物的生物合成-第二部分、黄酮类生物合成和ABC运输通路是最有可能的代谢通路。综上,乳酸菌尤其是保加利亚乳杆菌发酵可显著改善铁皮石斛的抗氧化活性,这可能与其酚类化合物在发酵过程中的转化释放有关。该研究可为利用乳酸菌对铁皮石斛进行发酵增效提供新的思路。
