Paleic acid, a fatty acid from Paenibacillus sp.: taxonomy, fermentation, isolation, structure determination, and anti-Mannheimia and -Pasteurella activity
Paleic acid (1), an antibiotic, was obtained from a fermentation broth of Paenibacillus sp. BMK771-AF3. The compound is a fatty acid (9Z,16R)-16-hydroxy-9-octadecenoic acid ((R)-16-hydroxyoleic acid), whose isolation required protection of its polar functional groups. Mosher esters of paleic acid yielded information on the absolute configuration of secondary alcohol, and well-resolved 1H NMR peaks around the double bond suggested that olefin adopted a Z geometry. Paleic acid showed potent antibacterial activity and narrow spectrum against Mannheimia haemolytica with MIC values ranging between 0.78 and 1.56âμgâmlâ1.
alkylation of an aldehyde using a chiral titanium sulfonamide complex and the cis double bond was installed using a Wittig reaction. This synthetic route was also applied to the preparation of structurallyrelated analogs, which were used in structure–activity relationship studies for antibacterial activity.