How gamma-rays and electron-beam irradiation would affect the antimicrobial activity of differently processed wild mushroom extracts?

M.J Alves,A Moura,A.R Ribeiro,J.C.M Barreira,D Fernandes,I Lourenço,J Salgado,Â Fernandes,I.C.F.R Ferreira,A Antonio

doi:10.1111/jam.12718

Abstract

The effects of irradiation (gamma-rays and electron-beams), up to 10 kGy, in the antimicrobial activity of mushroom species (Boletus edulis, Hydnum repandum, Macrolepiota procera and Russula delica) differently processed (fresh, dried, freeze) were evaluated. Clinical isolates with different resistance profiles from hospitalized patients in Local Health Unit of Mirandela, Northeast of Portugal, were used as target micro-organisms. The mushrooms antimicrobial activity did not suffer significant changes that might compromise applying irradiation as a possible mushroom conservation technology. Two kGy dose (independently of using gamma-rays or electron-beams) seemed to be the most suitable choice to irradiate mushrooms. This study provides important results in antimicrobial activity of extracts prepared from irradiated mushroom species.

Highlights

The interest of the scientific community for mushrooms has been increasing due to their potential in prevention or treatment of different diseases of the modern world
Centering the discussion in the antimicrobial activity of mushroom extracts, a primary observation allows concluding that the Gram positive bacteria presented more susceptibility, in agreement with other reports (Barros et al 2007; Barros et al 2008a, b; Venturini et al 2008; Alves et al 2012b), despite the results obtained by Ozen et al (2011), which indicated that H. repandum extracts had a maximal antibacterial activity against a Gram negative bacteria (Pseudomonas aeruginosa)
The results reported for dried R. delica extracts indicate slightly higher antibacterial activity, namely against P. mirabilis and MRSA, than those obtained in our laboratory with the same species (Alves et al 2012b)

Summary

Introduction

The interest of the scientific community for mushrooms (extracts and derived compounds) has been increasing due to their potential in prevention or treatment of different diseases of the modern world. Several authors reported the antimicrobial activity of extracts prepared from different mushroom species including Boletus edulis Bull. A short shelf life (1-3 days at room temperature) is one of the disadvantages for their distribution and marketing as a fresh product. Our research group has been investigating the effects of mushrooms (including the above mentioned species B. edulis, H. repandum, M. procera and R. delica) irradiation by evaluating their nutritional, physical and chemical parameters, concluding that these parameters are not affected in high extension with this preservation technology (Fernandes et al 2013a-c, 2014a-c). In the present study, the antibacterial properties of extracts prepared from irradiated (gamma radiation and electron-beam) wild mushrooms were assessed against clinical isolates with different resistance profiles from hospitalized patients in Local Health Unit of Mirandela, Northeast of Portugal

Methods

Results

Conclusion