Quantitative analysis of total retronecine esters-type pyrrolizidine alkaloids in plant by high performance liquid chromatography

• Published in: Analytica chimica acta Vol. 605; no. 1; pp. 94 - 101
• Main Authors: Zhang, Fang, Wang, Chang-hong, Xiong, Ai-zhen, Wang, Wan, Yang, Li, Branford-White, Christopher J., Wang, Zheng-tao, Bligh, S.W. Annie
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 12.12.2007; Elsevier
• Subjects: Analytical chemistry; Carcinogens - analysis; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography, High Pressure Liquid - methods; Dimethylaminobenzaldehyde; Esters - analysis; Exact sciences and technology; High performance liquid chromatography–mass spectrometry; Molecular Structure; Mutagens - analysis; Other chromatographic methods; Plant Preparations - chemistry; Plants - chemistry; Pyrrolizidine alkaloids; Pyrrolizidine Alkaloids - analysis; Retronecine; Senecio - chemistry; Senecio scandens; Sensitivity and Specificity; Spectrometric and optical methods; Senecio scandens; Dimethylaminobenzaldehyde; Retronecine; Pyrrolizidine alkaloids; High performance liquid chromatography–mass spectrometry; Trace analysis; Human; High performance liquid chromatography-mass spectrometry; HPLC chromatography; Foodstuff; NMR spectrometry; Marker; Derivatization; Calibration standards; Electrospray; Chemical ionization; Ester; Alkaloid; Sensitivity; Sample preparation; Pyrrolizidine derivatives; Detection limit; Chloranil; Mass spectrometry; Quantitative analysis
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2007.10.021

Pyrrolizidine alkaloids (PAs) are alkaloids which typically contain a necine (7-hydroxy-1-hydroxymethyl-6,7-dihydro-5H-pyrrolizidine) base unit, and they can be found in one third of the higher plants around the world. They are hepatotoxic, mutagenic and carcinogenic and pose a threat to human health and safety. A specific, quick and sensitive method is therefore needed to detect and quantify the PAs sometimes in trace amount in herbs, tea or food products. Based on high performance liquid chromatography with prior derivatization of the alkaloids using o-chloranil and Ehrlich's reagent, we report an improved method for quantitative analysis of the total amount of retronecine esters-type pyrrolizidine alkaloids (RET-PAs) in a plant extract. The total quantitation of RET-PAs is achieved because of a common colored retronecine marker, a 7-ethoxy-1-ethoxylmethyl retronecine derivative, is produced with all the different RET-PAs during the derivatization reaction. The chemical identity of the common retronecine marker was characterized on-line by positive mode electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy. The limit of detection using the improved method is 0.26 nmol mL −1 and the limit of quantitation is 0.79 nmol mL −1. The advantages of this method are much enhanced sensitivity in detection and quantitation, and, no restriction on the choice of RET-PA as a calibration standard. Application of the developed method to the quantitation of total RET esters-type PAs in Senecio scandens from different regions of China is also reported.