College of Science, Sichuan Agricultural University, Ya'an 625014, China.
College of Science, Sichuan Agricultural University, Ya'an 625014, China.
J Chromatogr A. 2020 Jun 7;1620:461036. doi: 10.1016/j.chroma.2020.461036. Epub 2020 Mar 19.
Leaves, flowers, fruits and stems (44 sample groups) were collected from mature Camptotheca acuminate during 2017.3-2018.3 and classified by ultra-high performance liquid chromatography coupled with quadrupole-time of flight-mass spectrometry based metabolomics. One hundred metabolites including forty-seven alkaloids, fifteen terpenes, thirty-two polyphenols and six other metabolites were rapidly identified through the in-house database alignment at first glance. Thirty-three alkaloids classified into five groups including camptothecin group (CG1-13), pumiloside group (PG1-5), strictosidinic acid group (SG1-3), vincosamide group (VG1-7), and a new hybrid group, vincosamide-camptothecin group (VC1-5) were mined and further characterized by MS/MS analyses. The identification of two untapped biosynthetic precursors, 2-hydroxypumiloside (PG2) and 16‑hydroxy‑15, 16-dihydrocamptothecoside (CG3), along with sixteen new alkaloids enables us for a better understanding of camptothecin biogenetic reasoning. The underlying enzymes involved in camptothecin biosynthesis were also proposed according to the guiding metabolic map, thus purposefully mining of enzymes involved in the downstream biosynthetic pathway of camptothecin could be initiated with the help of this map.
于 2017.3-2018.3 期间,采集了成熟喜树的叶、花、果实和茎(44 个样品组),并通过基于超高效液相色谱与四极杆飞行时间质谱联用的代谢组学方法进行了分类。通过内部数据库比对,我们初步快速鉴定了 100 种代谢产物,包括 47 种生物碱、15 种萜类化合物、32 种多酚类化合物和 6 种其他代谢产物。我们挖掘并进一步通过 MS/MS 分析鉴定了 33 种生物碱,它们分为五个组:喜树碱组(CG1-13)、喜树苷组(PG1-5)、斯替可苷酸组(SG1-3)、长春酰胺组(VG1-7)和一个新的杂种组,长春酰胺-喜树碱组(VC1-5)。同时,还鉴定了两种未开发的生物合成前体,2-羟基喜树苷(PG2)和 16-羟基-15,16-二氢喜树碱(CG3),以及 16 种新的生物碱,这使我们能够更好地理解喜树碱的生物合成推理。根据指导代谢图谱,还提出了参与喜树碱生物合成的潜在酶,因此,借助该图谱可以有针对性地挖掘喜树碱下游生物合成途径中涉及的酶。