Antibacterial Activity of Spent Substrate of Mushroom Pleurotus ostreatus Enriched with Herbs

Nallely Rivero Perez,Armando Zepeda-Bastida,Marcos Meneses Mayo,Deyanira Ojeda Ramírez,Maricela Ayala Martínez,Sergio Soto Simental

doi:10.5539/jas.v7n11p225

Abstract

The recurrent use of antibiotics has given the guideline so that bacteria will develop resistance to drugs used in medicine, which is why recent investigations have been directed to evaluate natural sources such as plants or fungi, which can fight the bacteria. Here the antibacterial activity of spent substrate of Pleurotus ostreatus combined with medicinal plants was evaluated. We designed six mixtures (barley straw, barley straw/Chenopodium ambrosioides L., barley straw/Mentha piperita L., barley straw/Rosmarinus officinalis L., barley straw/Litsea glaucescens Kunth and barley straw/Tagetes lucid Cav) to be used as a substrate of cultivation of mushroom. These were recovered after the harvest. We obtained aqueous extracts from spent substrates and resuspended them to different concentrations (25, 50 and 100 mg mL-1). These were tested for antibacterial activity against Staphylococcus epidermidis, Bacillus subtilis and Escherichia coli; as a positive control we used azithromycin, cephalexin and dicloxacillin. The protocol was a completely randomized assay with a factorial arrangement design. The data were analyzed with PROC GLM, SAS. The spent substrate from Pleurotus ostreatus that contained Mentha piperita L. presented the largest zone of inhibition against Staphylococcus epidermidis (40.00 mm) which was similar to control antibiotics (40.00 mm). Second in toxicity was the spent substrate from barley straw extract (33.33 mm). In conclusion, the results suggest that it is possible to use the spent substrate of Pleurotus ostreatus as source of extracts with antibacterial activity, being the best option the combination of barley straw with Mentha piperita L.

Highlights

The indiscriminate use of antimicrobials has generated serious problems on global health, since the bacteria have developed resistance to them, both in veterinary medicine as well as in human medicine, so the World Health Organization is considering infections caused by drug-resistant bacteria as an emergent global disease and a major public health problem
The spent substrate extracts combined with Chenopodium ambroioides L. and Litsea glauescens Kunth showed the greater inhibition against Escherichia coli (16.67 and 16.94 mm, respectively) and Chenopodium ambroioides L., Litsea glauescens Kunth and Tagetes lucida Cav showed the highest inhibition against Bacillus subtilis (13.61, 15.83 and 14.72 mm, respectively); the barley straw extract showed greater inhibition against Staphylococcus epidermidis (25.27 mm)
We show that aqueous extract of spent substrate from Pleurotus ostreatus cultures combined with barley straw has antibacterial activity against S. epidermidis, showing a greater inhibition at a concentration of 50 mg mL-1 (33.33 mm) and intermediate antibacterial activity at a concentration of 50 mg mL-1 against E. coli and B. subtilis (13.33 mm), similar to that obtained using extracts of mushroom Pleurotus ostreatus obtained with different organic solvents (24.56 and 14 mm) for Gram positive and Gram negative bacteria (Nehra et al, 2012); It has a concentration of 25 mg mL-1 not be found antibacterial activity against B. subtilis

Summary

Introduction

The indiscriminate use of antimicrobials has generated serious problems on global health, since the bacteria have developed resistance to them, both in veterinary medicine as well as in human medicine, so the World Health Organization is considering infections caused by drug-resistant bacteria as an emergent global disease and a major public health problem. Despite the urgent need to find new antibacterial products, many pharmaceutical companies have abandoned antibiotic drug discovery programs. For this reason, pharmacological alternatives have been sought, such as the use of fungi and medicinal plants (Roca et al, 2015). Fungi have an important role in the degradation of organic matter (Chang & Miles, 1984). In addition these are a source of bioactive substances to produce antibiotics or pharmaceutical drugs, such as functional food and additives in feeding stuffs (Santoyo, Ramírez-Anguiano, Reglero, & Soler-Rivas, 2009). Their organic waste can be used as a source of food with high protein content and as an alternative pharmaceutical treatment; Pleurotus ostreatus is a fungus that grows on agricultural wastes, accelerates biodegradation and recycling, and prevents trash burning and the subsequent environmental pollution (Varnero, Quiroz, & Álvarez, 2010)

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Conclusion