Antimicrobial effect of 4-hydroxybenzoic acid ester with glycerol.

WHAT IS KNOWN AND OBJECTIVES: Parabens have been commonly used as preservatives in pharmaceutical and cosmetics industries for almost 50 years. These compounds are thermostable, pH-stable and inexpensive and have a wide antimicrobial effect. The antimicrobial activity of parabens in emulsion system is limited by their poor solubility in water phase, which is increasing with the length of their alkyl chain. The aim of this work was preparation of 1-O-(4-hydroxybenzoyl)-glycerol, more hydrophilic and naturally occurring analogue of parabens, and comparison of its antimicrobial activity with commercially used parabens (4-hydroxybenzoic acid, methylparaben, ethylparaben, propylparaben). METHODS: 1-O-(4-Hydroxybenzoyl)-glycerol was obtained by the transesterification reaction of methyl paraben with glycerol. Purity was confirmed by determination of melting point and by GC/MSD. Antimicrobial activity of 1-O-(4-hydroxybenzoyl)-glycerol and commercially used parabens was determined by spectrophotometrical monitoring of microbial growth in media containing the testing substances, using spectrophotometers PowerWave XS and Cary 50 Conc. RESULTS AND DISCUSSION: 1-O-(4-Hydroxybenzoyl)-glycerol was prepared with purity >99%. This compound showed antimicrobial activity against all tested microorganisms (Staphylococcus aureus, Escherichia coli, Saccharomyces cerevisiae and Fusarium culmorum). In comparison with other tested substances, 1-O-(4-hydroxybenzoyl)-glycerol showed less inhibitory activity at the highest concentration of 20 mmol/L, with the maximum inhibitory activity ca. 70%. On the other hand, antimicrobial activity of 1-O-(4-hydroxybenzoyl)-glycerol at the lower concentrations (2·5 mmol/L, 1·25 mmol/L) was the same or, in some cases, even higher (S. aureus) in comparison with commercially used parabens. WHAT IS NEW AND CONCLUSION: A novel hydrophilic analogue of parabens was synthetized and tested for its antimicrobial activity against selected microorganisms in model system. This study confirms antimicrobial potential of 1-O-(4-hydroxybenzoyl)-glycerol, which is comparable with other commercially used parabens. Unlike commercial parabens, it is possible to expect more significant antimicrobial activity of 1-O-(4-hydroxybenzoyl)-glycerol in real emulsion systems due to the increased solubility of this substance in water phase and also the lower skin irritation.

Short communication: Polymorphism of casein cluster genes in Czech local goat breeds.

The 4 casein loci were evaluated as haplotypes in 2 dairy goat breeds kept in the Czech Republic. Analysis of 41 White Shorthaired (WSH) trio families and 44 Brown Shorthaired (BSH) trio families revealed 14 and 20 haplotypes, respectively. Various genomic techniques were used to type the casein loci. Twenty-two different combinations of these alleles (casein haplotypes, in the order CSN1S1-CSN2-CSN1S2-CSN3) were found. Only 5 haplotypes in the WSH breed and 6 haplotypes in the BSH breed occurred at frequencies >0.05. For the WSH breed, the most common haplotype was FCFB (0.260), whereas for the BSH breed, the most common haplotype was FCFA (0.217). The information on the haplotype variability in both breeds could be used in breeding programs aimed at preserving biodiversity or selecting animals for specific protein production and cheesemaking.