INHIBITION OF BACTERIA BY 5-FLUORONICOTINIC ACID AND OTHER ANALOGUES OF NICOTINIC ACID

Abstract

Several compounds related to 5-fluoronicotinic acid (5-FNA) inhibit Streptococcus sp. (viridans group), Staphylococcus aureus, Escherichia coli and Lactobacillus plantarum in vitro. The most active compounds were 5- FNA and 5-fluoronicotinamide (5- FNAM). The growth of Streptococcus sp. was inhibited more than 50% by 0.05 [mu]g/ml of 5-FNA or 0.5 [mu]g/ml of 5-FNAM. The inhibition of Streptococcus sp. from 1 part of 5-FNA or 5-FNAM was reversed by 4 and 2 parts of nicotinic acid, respectively. The inhibition of E. coli from 100 parts of 5- FNA or 5- FNAM was reversed by 1 part of nicotinic acid. Inhibitions by most other active compounds could be reversed by nicotinic acid. In experiments with mice eight compounds related to 5- FNA had activity against S. pyogenes; 5-FNA, 5-FNAM and 5-fluoro-N-dimethyl-aminomethylnicotinamide protected all mice at 83 mg/kg given twice subcutaneously. The action of 200 mg/kg given twice of 5- FNA was reversed by 20 mg/kg given twice of nicotinic acid. The activity of 5- FNA was not increased by modifications at the number 3 or 5 positions on the pyridine ring or by any other structural changes.