Objective：To explore a new natural antibiotic. Methods：The chemical composition of the essential oil from Ganodermajaponicum （G. japonicum）mycelia was analyzed by gas chromatography-mass spectrometry（GC-MS）, The antimicrobial activity of the oil was evaluated against eighteen microorganisms, including bacteria, mildew and yeast by using a disc diffusion method. Furthermore, the minimum inhibitory concentrations（MIC） and the minimum bactericidal concentrations（MBC） of the essential oil against twelve clinical pathogens were determined. Results：The main components of the oil were nerolidol, decadienal, linalool and benzyl alcohol. The antimicrobial results indicated that the oil inhibited all the tested bacterium, especially Methicillin-resistant Staphylococcus aureus （MRSA） in which the antibacterial activity exhibited a MBC of 1.03 mg/ml. Conclusion： The essential oil of G. japonicum mycelium has significant inhibitory activity. It is a potential medicinal resource that can be used as a natural antibiotic.
Dandan LiuZheng HuZhigang LiuBo YangWenjuan TuLiang Li
An antibacterial protein was isolated from the cultured mycelia of Cordyceps sinensis, and was designated as Cordyceps sinensis Antibacterial Protein （CSAP）. CSAP was single-chained, with an apparent molecular mass of 35 × 10^3 revealed by SDS-PAGE and a novel hydrophobic N-terminal sequence N-ALATQHGAP. The antimicrobial assays showed CSAP could inbibit the growth of Gram-positive and Gram-negative bacteria but no significant inhibition against fungi or yeasts. Further more, the antibacterial activity of CSAP was not bactericidal but bacteriostatic. It was the first time that an antibacterial protein was described in the Cordyceps species, which might involve in the chemical defense mechanism of the hosts.
HU ZhengYE MaoqingXIA LiqiuTU WenjuanLI LiangZOU Guolin
