title: Identification of antifungal compounds produced by Lactobacillus casei AST18.
abstract: Lactobacillus casei AST18 was screened as an antifungal lactic acid bacteria which we have reported before. In this research, the antifungal properties of cell-free culture filtrate (CCF) from L. casei AST18 were detected, and the antifungal compounds of CCF were prepared by ultrafiltration, and semi-preparative HPLC, and then determined by GC-MS. CCF was sensitive to pH and heat treatment but it was not affected by the treatment of trypsin and pepsin. Through the treatment of ultrafiltration and semi-preparative HPLC there were two parts of CCF which showed antifungal activities: part 1 and part 4. Lactic acid was identified as the main antifungal compound in part 1. In part 4, three small molecular substances were detected with GC-MS. The three potential antifungal substances were cyclo-(Leu-Pro), 2,6-diphenyl-piperidine, and 5,10-diethoxy-2,3,7,8-tetrahydro-1H,6H-dipyrrolo[1,2-a;1',2'-d]pyrazine. The antifungal activity of L. casei AST18 was a synergistic effect of lactic acid and cyclopeptides.
authors.affiliation: Key Laboratory of Agricultural Product Processing and Quality Control, Institute of Agro-food Science and Technology, Chinese Academy of Agricultural Sciences, Haidian District, Beijing, People's Republic of China.
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Li
authors.forename: Lu
authors.initials: L
authors.lastname: Liu
authors.forename: Shuwen
authors.initials: S
authors.lastname: Zhang
authors.forename: Wenming
authors.initials: W
authors.lastname: Cui
authors.forename: Jiaping
authors.initials: J
authors.lastname: Lv
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media / Q000737:chemistry; D004151:Dipeptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D007780:Lacticaseibacillus casei / Q000378:metabolism*; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010880:Piperidines / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D011719:Pyrazines / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D013696:Temperature; D014462:Ultrafiltration
chemical_list: D000935:Antifungal Agents; D003470:Culture Media; D004151:Dipeptides; D010456:Peptides, Cyclic; D010880:Piperidines; D011719:Pyrazines; C445694:cyclo(leucyl-prolyl); D019344:Lactic Acid