International Journal of Medicinal Mushrooms, 16(1): 77–84 (2014) 77 1045-4403/14/$35.00 © 2014 Begell House, Inc. www.begellhouse.com Antimicrobial Effect of the Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Higher Basidiomycetes) and Its Main Compounds Mahdi Vazirian, 1 Mohammad Ali Faramarzi, 2 Seyed Esmaeil Sadat Ebrahimi, 3 Hamid Reza Monsef Esfahani, 1 Nasrin Samadi, 4 Seyed Aboulfazl Hosseini, 1 Ali Asghari, 1 Azadeh Manayi, 1 Ali Mousazadeh, 5 Mohammad Reza Asef, 6 Emran Habibi, 1 & Yaghoub Amanzadeh 1, * 1 Department of Pharmacognosy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; 2 Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, Tehran, Iran; 3 Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; 4 Department of Drug and Food Control, Faculty of Pharmacy and Pharmaceutical Quality Assurance Research Center, Tehran University of Medical Sciences, Tehran, Iran; 5 Agriculture and Natural Research Center of Mazandaran, Passand Forest and Rangeland Research Station, Behshahr, Iran; 6 Department of Botany, Iranian Research Institute of Plant Protection, Tehran, Iran *Address all correspondence to: Yaghoub Amanzadeh, Department of Pharmacognosy, Faculty of Pharmacy, Tehran University of Medical Sciences, Enqelab Ave., Tehran 14155-6451, Iran; Tel: +98-21-66954706; amanzadehyaghoub@yahoo.com. ABSTRACT: Mushrooms are considered one of the richest sources of natural antibiotics, and various species of them inhibit the growth of a wide diversity of microorganisms. Ganoderma lucidum, a well-known medicinal mushroom. has many pharmacological and biological activities including an antimicrobial effect, although few studies have investigated the antibacterial and antifungal effects of its puriied compounds. The chemical structure of the puriied compounds from the hexane fraction was elucidated as ergosta-7,22-dien-3β-yl acetate, ergosta-5,7,22-trien-3β-yl acetate (isopyrocalciferol acetate), ergosta-7,22-dien-3-one, ergosta-7,22-dien-3β-ol, and ergosta-5,7,22-trien-3β- ol (ergostrol). In addition, the structure of ganodermadiol was demonstrated after puriication from the chloroform fraction. The fractions inhibited Gram-positive bacteria and yeast, with minimum inhibitory concentration values of 6.25 mg/mL, but were ineffective against Gram-negative bacteria in the tested concentrations. The results were comparable for isolated compounds, whereas the mixture of ergosta-7,22-dien-3β-yl acetate and isopyrocalciferol acetate was weakly effective against Escherichia coli (minimum inhibitory concentration, 10 mg/mL). It could be assumed that the antimicrobial effect of crude fractions is the consequence of mixing triterpenoid and steroid compounds. KEY WORDS: medicinal mushrooms, Ganoderma lucidum, nonpolar fractions, steroids, triterpenoids, antimicrobial effect ABBREVIATIONS: ATCC, American Type Culture Collection; 13 C, carbon-13; dd, doublet of doublets; 1 H, hydrogen-1; MIC, minimum inhibitory concentration; NMR, muclear magnetic resonance; TLC, thin layer chromatography; UV, ultraviolet. I. INTRODUCTION Natural products have long attracted a great deal of interest among researchers in isolation of antibac- terial agents. 1 This is mainly due to the spread of resistance among microorganisms and the toxicity of synthetic/semisynthetic medications that are in many instances major hindrances to gaining suc- cessful therapeutic outcomes. 2 A number of natu- rally occurring components from herbs and medici- nal mushrooms, mainly terpenes, steroids, saponins, lavones, xanthones, coumarins, and alkaloids, are reported to have antimicrobial effects. 3 Mushrooms have been considered a rich source of natural antibiotics, and various species inhibit the growth of a wide diversity of microorganisms. For instance, some species of mushrooms produce sev- eral bioactive metabolites that have potential me-