Qualitative and quantitative analysis of pyrrolizidine alkaloids in crude extracts of industrial interest

Pyrrolizidine alkaloids (PA) are reported as the most widely distributed naturally occurring secondary metabolites of high toxicological relevance. More than 660 compounds have been detected in floriferous plants. Their high occurrence and toxicity have triggered the development of different PA quantitative methodologies based on commercially available PAs. However, a limiting amount of standards are currently available and the effectiveness of the pre-purification steps used for their quantification remain uncertain.

The aim of our study is to shed light on the variability and the distribution of PAs in herbal extracts of industrial interest and to propose a validated quantification methodology for the evaluation of the total PA content excluding the pre-purification steps. Herein, we performed a comparative PA screening of eleven

crude and SPE enriched extracts obtained from Boraginaceae, Fabaceae and Asteraceae families.

In total, 105 PAs were tentatively identifiedthrough a meticulous dereplication study of UHPLC-HRMS^e analyses by comparing our data with customized in-house libraries and literature data. In addition, a previously published quantification method was optimized to assess the total PA-content expressed as retronecine-equivalent, directly from their crude matrices assuring high sensitivity, recovery and reproducibility.

Our findings highlight a more accurate and exhaustive retronecine-based PA quantification methodology which may advantageously be exploited for the analysis of extracts of industrial interest. In addition, the effectiveness of the pre-purification steps, which are widely recommended in the literature for its benefits in both reducing matrix load and concentrating PAs from complex matrices, resulted ambiguous in relation to major PAs in the extracts.

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Artikel online veröffentlicht:
13. Dezember 2021