Antifungal compounds from cultures of dairy propionibacteria type strains

Abstract

Antifungal compounds from cultures of five type strains of dairy propionibacteria, as well as from the cultivation medium, were studied. Cell-free supernatants and medium were fractionated by C(18) solid phase extraction. The aqueous 95% acetonitrile fractions were analyzed by GC-MS or subjected to reversed-phase HPLC, to identify, quantify or isolate antifungal substances. The resulting HPLC fractions were screened for antifungal activity against the mold Aspergillus fumigatus and the yeast Rhodotorula mucilaginosa. Active fractions were further separated by HPLC and the structures of the compounds were determined by spectroscopic and chromatographic methods. All five strains produced 3-phenyllactic acid, at concentrations ranging from 1.0 microg mL(-1) (Propionibacterium freudenreichii ssp. shermanii) to 15.1 microg mL(-1) (Propionibacterium thoenii), and at L/D -ratios ranging from 2 : 3 (Propionibacterium acidipropionici) to 9 : 1 (Propionibacterium freudenreichii). A number of active compounds found in cultures of propionibacteria were also present in noninoculated growth medium: two antifungal diketopiperazines, cyclo(L-Phe-L-Pro) and cyclo(L-Ile-L-Pro), and seven antifungal linear peptides. Three of the linear peptides corresponded to sequences found in the medium component casein, suggesting their origin from this component, whereas the diketopiperazines were suggested to be formed from medium peptides by heat treatment.

One stain-many compounds (OSMAC) method for production of phenolic compounds using Camarops sp., an endophytic fungus from Alibertia macrophylla (Rubiaceae)

“…in Czapek's liquid medium from which seven compounds were obtained. The compounds were identified as p-hydroxyphenyllactic acid (1) 7,8 , p-hydroxybenzoic acid (2) 8,9 , p-hydroxybenzaldehyde (3) 10 , phenyllactic acid (4) 11 , n-butyl-3,4-dihydroxybenzoate (5) 11,12 , n-hexyl-3,4-dihydroxybenzoate (6) 11, 12 and n-octyl-3,4-dihydroxybenzoate (7) 11, 12 ( Figure 1). The NMR 1 H spectra of p-hydroxyphenyllactic acid (1) ( Table 1) , bearing a characteristic coupling constant of a para hydrogen, depicting a disubstituted aromatic ring system.…”

“…The structures of the esters 5-7 were confirmed by mass spectrometry (ESI-MS) which showed the presence of [M-H] -ion peaks at m/z 209.23 (n-butyl-3,4-dihydroxybenzoate); 237.19 (n-hexyl-3,4--dihydroxybenzoate) and 265.27 (n-octyl-3,4-dihydroxybenzoate) (Figure 2). 11,12 The data obtained from sequencing and BLAST analysis of the 28S rDNA showed that the isolated AM-02 had 95% sequence identity with several species within the genus Camarops (Ascomycota: Boliniales, Boliniaceae). Ecologically, Camarops spp.…”

Dairy Propionibacteria: Less Conventional Probiotics to Improve the Human and Animal Health

“…Propionibacteria also produce other peptides and organic acids (2-pyrrolidone-5-carboxylic acid, 3-phenyllactic acid, hydroxyphenyl lactic acid 3-phenyllactic acid) with antiviral, antiyeasts and antifungal activities [91][92][93].…”

Rapid identification, by use of the LTQ Orbitrap hybrid FT mass spectrometer, of antifungal compounds produced by lactic acid bacteria

“…Other metabolites from these bacteria have been identified as the source of the antifungal activity. These include cyclic dipeptides, proteinaceous compounds, fatty acids and a variety of other low-molecular-weight compounds [3,4,[11][12][13][14][15][16]. The individual MIC of these metabolites are much higher than the amounts detected in culture broths.…”