# Signals of Diagnostic Product Ions of Kavalactones in Their ESI Mass Spectra—Implications for Isomer Differentiation and Identification of Kavalactone Conjugates

## TL;DR

This paper studies the mass spectrometry fragmentation of kavalactones to help identify and differentiate their isomers and conjugates.

## Contribution

The study reveals diagnostic product ions and structure–fragmentation relationships for kavalactone isomer differentiation and identification.

## Key findings

- Diagnostic ions were identified for differentiating isomeric kavalactones.
- Structure–fragmentation relationships were established for kavalactone conjugates.
- Findings can aid in the identification of kavalactone dimers and glycosides.

## Abstract

Kavalactones are psychoactive substances that naturally occur in some plants, such as Piper methysticum, Alpinia zerumbet, and Achyrocline satureioides, which are considered to have a significantly positive effect on human organisms. For example, Alpinia zerumbet is classified as a life-expanding plant. Although high-pressure liquid chromatography–mass spectrometry has been used for kavalactone analysis in plant material, the fragmentation pathways of protonated kavalactone molecules are not fully known and require further detailed study. In this paper, the fragmentation pathways of [M+H]+ ions of twelve kavalactones, including three pairs of isomers, are discussed in detail. Special emphasis has been placed on diagnostic product ions, which are characteristic of kavalactone structures. It has been demonstrated that diagnostic ions and structure–fragmentation relationships enable the differentiation of isomeric kavalactones and may be useful for the identification of other kavalactone conjugates, such as kavalactone dimers or kavalactone glycosides.