Antibacterial activity of Pleurotus spp. hexanic extracts

Mushrooms are a nutritionally functional food and a source of secondary metabolites with physiologically activity [1]. A few studies have been reported on the antimicrobial activity of edible mushroom Pleurotus and its bioactive compounds. Hexane extracts of four Pleurotus spp. strains (IE200, IE201, ECS127 and RP) were evaluated for antibacterial activity by the single disk method [2]. Antibacterial activity was tested against the pathogenic Gram-positive strains of Bacillus subtilis and Staphylococcus aureus or Gram-negative strains Enterobacter agglomerans, Shigella dysenteriae, Yersinia enterocolitica, Klebsiella rhinoescleromatis, and K. pneumoniae. The edible mushrooms strains were cultivated on straw substrate to obtain fruiting bodies, the fine dried mushroom powder (20 mesh) sample (10g) was then extracted with hexane and extracts concentrated to dryness in rotary evaporator under vacuum. All bacteria were grown (1.5×10⁸ CFU/mL, 0.5 McFarland) in nutrient broth incubated at 37°C for 24h and plated, onto Petri dishes containing Müeller-Hinton agar. At the same time, sterile discs of 5mm diameter were embedded with 20µL (4mg/mL) of hexane extracts of each strain – experimental group – or with the solvent or chloramphenicol (30 mcg) – control groups – and added to the cultured dishes. Toxicity of the mushrooms extracts against microorganisms was determined after 24h by measuring the diameter of the halo around the discs, oneway ANOVA was applied. All the strains revealed antimicrobial activity showing different selectivity (Duncan, p<0.05), the IE200 and IE 201 white strains showed better results than pink strains (ECS127 and RP).

Acknowledgements: Supported by SIP 20070922, IPN, 2007–2008.

References: 1. Wasser S.P., Weis, A.L. (1999) Int. J. Med. Mushrooms 1: 31–62.

2. Indu M.N. et al. (2006) Braz. J. Microbiol. 37: 153–158.