A stable isotope dilution tandem mass spectrometry method of major kavalactones and its applications

Kava is regaining its popularity with detailed characterizations warranted. We developed an ultraperformance liquid chromatography high-resolution tandem mass spectrometry (UPLC-MS/MS) method for major kavalactones (kavain, dihydrokavain, methysticin, dihydromethysticin and desmethoxyyangonin) with excellent selectivity and specificity. The method has been validated for different matrices following the Food and Drug Administration guidance of analytical procedures and methods validation. The scope of this method has been demonstrated by quantifying these kavalactones in two kava products, characterizing their tissue distribution and pharmacokinetics in mice, and detecting their presence in human urines and plasmas upon kava intake. As expected, the abundances of these kavalactones differed significantly in kava products. All of them exhibited a large volume of distribution with extensive tissue affinity and adequate mean residence time (MRT) in mice. This method also successfully quantified these kavalactones in human body fluids upon kava consumption at the recommended human dose. This UPLC-MS/MS method therefore can be used to characterize kava products and its pharmacokinetics in animals and in humans.

卡瓦（Kava）正重拾人气，对其开展细致表征的需求愈发迫切。本研究建立了一种针对主要卡瓦内酯类成分——包括卡瓦内酯（kavain）、二氢卡瓦内酯（dihydrokavain）、麻醉椒素（methysticin）、二氢麻醉椒素（dihydromethysticin）以及去甲氧基扬波素（desmethoxyyangonin）——的超高效液相色谱-高分辨串联质谱（ultraperformance liquid chromatography high-resolution tandem mass spectrometry, UPLC-MS/MS）分析方法，该方法具备优异的选择性与专属性。本方法依据美国食品药品监督管理局（Food and Drug Administration, FDA）的分析程序与方法验证指南，针对不同基质完成了方法学验证。本方法的适用范围已通过以下应用得到验证：对两款卡瓦制品中的上述卡瓦内酯类成分进行定量分析、表征其在小鼠体内的组织分布与药代动力学特征，以及检测人体摄入卡瓦后尿液与血浆样本中的该类成分存在情况。正如预期，两款卡瓦制品中各卡瓦内酯类成分的含量存在显著差异。在小鼠体内，所有成分均表现出较大的表观分布容积、广泛的组织亲和力以及适中的平均驻留时间（mean residence time, MRT）。本方法还成功在按推荐人体剂量摄入卡瓦后的人体体液中，对上述卡瓦内酯类成分完成了定量检测。因此，该超高效液相色谱-高分辨串联质谱（UPLC-MS/MS）方法可用于卡瓦制品的质量表征，以及卡瓦内酯类成分在动物与人体内的药代动力学研究。