Estudio de métodos analíticos para determinar las aflatoxinas B1, B2, G1 y G2, a niveles de trazas, en plantas medicinales

Author

Mulero Raichs, Mar

Abstract

Aflatoxins are secondary metabolites produced by filamentous fungi of the genus Aspergillus, particularly A.flavus, A. parasiticus and A.nomius in determined stress conditions of temperature and humidity. Aflatoxins B1, B2, G1, and G2 are the most common and studied aflatoxins due to their genotoxic and carcinogenic effects, and natural occurrence as contaminants in agricultural products such as plants. Medicinal plants are widely used as home remedies and raw materials for pharmaceutical industries. During harvesting, storage or distribution processes, they are subjected to contamination by fungi, responsible for production of aflatoxins. Due to the increasing consumption of medicinal plants and the lack of a global legislation that establish maximum permitted levels of each aflatoxin in herbal drugs, their use has become a problem of public health concern. The European (EP), British (BP) and German Pharmacopoeia (GP) have implemented the strictest maximum permitted levels for the presence of aflatoxins in herbal drugs, no more than 2 μg kg-1 of aflatoxin B1 and 4 μg·kg-1 for the sum of aflatoxins B1, B2, G1, and G2. However, there are no official methods available for quantifying aflatoxins in low concentrations (ppb) in complex matrices such as plants.
In this study, an analytical method has been developed and validated for the simultaneous analysis of the aflatoxins B1, B2, G1, and G2 in different medicinal plants acquired from local herbal stores (Menta piperita, Rosmarinus officinalis and Eucalyptus globulus). The extraction and purification steps were established by optimizing the extraction mode, temperature, solvent ratio, sample weight, and SPE and immunoaffinity (IAC) columns. The optimized procedure was based on accelerated solvent extraction (ASE) using MeOH:H2O (3:2), followed by IAC clean-up. The extracts were analyzed by liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), achieving a limit of quantification of 1 μg·kg-1. The method was validated by evaluating: linearity, precision (intra-day and inter-day variation), accuracy, and sensibility (limit of quantification, LOQ). No trace level has been found in studied samples.

Director

Gotor Navarra, Gemma
Broto Puig, Francesc  

Degree

IQS SE - Master’s Degree in Analytical Chemistry

Date

2020-09-13