1 H qNMR Quantification of Annonaceous Acetogenins in Crude Extracts of Annona muricata L. Fruit Pulp.

INTRODUCTION: Annonaceous acetogenins (AAGs) constitute a group of environmental neurotoxins, possibly implicated in sporadic atypical Parkinsonism/dementia complexes. The recent evidencing of complex mixtures of AAGs in edible fruits and derived food products requires efficient and practical analytical tools for an estimation of human exposure.

OBJECTIVE: To develop a simple method for the direct quantitation of the majority of AAGs (sub-types 1a and 1b) within crude extracts, using commonly available1 H-NMR spectrometers, for food control.

METHODOLOGY: Method development was carried out on 400 MHz and 300 MHz spectrometers, for routine application on fruits crude extracts of Annona muricata L. The method was validated with annonacin and squamocin as reference compounds. Two internal standards (ISs), fumaric acid and dimethyl fumarate, were successfully used, in deuterated methanol (CD3 OD) and deuterated chloroform (CDCl3 ), respectively.

RESULTS: Quantitation was carried out using signals corresponding to the deshielded ethylenic protons characterising most AAGs, at δ 7.18 or δ 6.98 ppm in CDCl3 . The limit of quantification (LOQ) was 2.5 mM, with acceptable accuracy, and the limit of detection (LOD) was 0.5 mM. The AAGs contents measured in seven distinct fruit samples of Annona muricata ranged from 14 μmol to 226 μmol of AAGs per 100 g fresh pulp (i.e. 0.14 mmol to 1.3 mmol of AAGs per fruit).

CONCLUSION: A simple, accurate and specific method for quantification of AAGs content was developed and validated for routine application to fruit pulp crude extracts. Copyright © 2017 John Wiley & Sons, Ltd.