Characteristic ion clusters as determinants for the identification of pyrrolizidine alkaloid N-oxides in pyrrolizidine alkaloid-containing natural products using HPLC-MS analysis
作者:Jianqing Ruan、Na Li、Qingsu Xia、Peter P. Fu、Shuying Peng、Yang Ye、Ge Lin
DOI:10.1002/jms.2969
日期:2012.3
the massspectra of 10 PA N-oxides and the corresponding PAs were systemically investigated using HPLC-MS to define the characteristic mass fragment ions specific to PAs and PA N-oxides. Massspectra of toxic retronecine-type PA N-oxides exhibited two characteristic ion clusters at m/z 118-120 and 136-138. These ion clusters were produced by three unique fragmentation pathways of PA N-oxides and were
含吡咯烷核生物碱(PA)的植物在世界范围内分布广泛。PA具有肝毒性,影响牲畜和人类。PA N氧化物通常与PA一起存在于植物中,还具有肝毒性,但效力较低。HPLC-MS通常用于分析含PA的草药,尽管在大多数情况下不提供PA参考。但是,迄今为止,没有参考标准,HPLC-MS方法无法将PA N-氧化物与PA区别开来,因为它们在质谱图中都会产生相同的特征离子。在本研究中,使用HPLC-MS系统研究了10种PA N-氧化物和相应PA的质谱,以定义对PAs和PA N-氧化物特有的特征质量碎片离子。有毒逆转录酶型PA N氧化物的质谱在m / z 118-120和136-138处显示两个特征性离子簇。这些离子簇是通过PA N-氧化物的三个独特的断裂途径产生的,并且在其相应的PA中未发现。类似地,无毒的platynecine型PA N氧化物也通过三种相似的途径断裂,从而在m / z 120-122和138-
Culvenor; Smith, Australian Journal of Chemistry, 1957, vol. 10, p. 464,470
作者:Culvenor、Smith
DOI:——
日期:——
Human Intestinal Bacteria Mediate Reduction of the N-Oxides of Isoline and Monocrotaline to the Corresponding Parent Alkaloids
The role of human intestinal bacteria in the biotransformation of pyrrolizidine alkaloid N-oxides was investigated. Two naturally-occurring hepatotoxic pyrrolizidine alkaloids, isoline and monocrotaline and their N-oxides were incubated with a human fecal suspension in an in vitro model, respectively. The metabolites were isolated and purified by chromatographic techniques and identified by the spectral analyses and the metabolic profiles were further analyzed by a specific TLC method. Human intestinal bacteria showed high reduction effects on the pyrrolizidine alkaloid N-oxides but not on the resultant tertiary alkaloids, suggesting that IB may play a partial role in the cyclic conversion between each pyrrolizidine alkaloid and its N-oxide in vivo. This evidence implied the potential risk of the pyrrolizidine alkaloid-containing Chinese medicinal herbs to human health when used in decoctions.
Kinetic characterization of a flavin-dependent monooxygenase from the insect food crop pest, Zonocerus variegatus
作者:Sydney B. Johnson、Kathryn Paasch、Starlina Shepard、Pablo Sobrado
DOI:10.1016/j.abb.2024.109949
日期:2024.4
grasshopper, is a foodcroppest endemic in Western and Central Africa. Agricultural industries in these regions rely heavily on natural defense mechanisms to control the grasshopper population such as plant-secreted alkaloid compounds. In recent years, the population has continued to rise due to acquired resistance to alkaloids. Here we focus on the kineticcharacterization of a flavin-dependent monooxygenase