Targeted Enrichment and Characterization of Diester Diterpenoid Alkaloids in Aconitum Herbs Using Gas–Liquid Microextraction Coupled with High-Resolution Mass Spectrometry

TL;DR

A new method using gas-liquid microextraction and mass spectrometry improves detection of toxic and active compounds in aconite herbs.

Contribution

A novel GLME-MS strategy is introduced for rapid, selective, and sensitive detection of diterpenoid diester alkaloids in Aconitum herbs.

Findings

GLME enhanced DDA mass spectrometric signals by 3–4 orders of magnitude.

27 alkaloids were identified, including 3 potential new compounds.

Raw Caowu showed the highest DDA response, which decreased after processing.

Abstract

Diterpenoid diester alkaloids (DDAs) are the primary toxic constituents in aconite herbs, while also being the key pharmacologically active components. Consequently, establishing rapid enrichment and highly sensitive analytical methods for DDAs is of critical importance. Herein, we developed and constructed a gas–liquid microextraction (GLME) device, which enables the rapid and selective enrichment of DDAs from complex matrices. The enriched extract can be directly analyzed by high-resolution Orbitrap mass spectrometry without requiring any further pretreatment. A comparative analysis of six commonly used Aconitum herbs medicines and their processed derivatives was conducted. Notably, GLME enhanced the mass spectrometric signals of DDAs by 3–4 orders of magnitude, facilitating the identification of 27 alkaloids, including 3 potential new compounds (15-Ethyl-13-deoxyanhydroaconitine, 13-Hydroxy-15-ethylanhydroaconitine and 8-eicosapentaenoic-benzoylmesaconine). It was found that among the tested samples, the DDAs response intensity of raw Caowu was the highest, and the DDA signals decreased significantly after processing. This result chemically validates the detoxification efficacy of traditional methods. The proposed GLME-MS strategy has the advantages of being green, economical, easy to operate, and highly selective (>1000-fold), which provides a technical reference for the rapid detection, safety assessment, and quality control of Aconitum herbs.

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