Antibacterial activity of pure flavonoids isolated from mosses.

Seven pure flavonoids were isolated and identified from five moss species. The flavonoids were the flavones apigenin, apigenin-7-O-triglycoside, lucenin-2, luteolin-7-O-neohesperidoside, saponarine and vitexin; and the biflavonoid bartramiaflavone. Some of these flavonoids were shown to have pronounced antibacterial effects against Enterobacter cloaceae, E. aerogenes and Pseudomonas aeruginosa (minimal bacteriostatic concentration MIC in the range of 4-2048 micrograms/ml). Because of their antibacterial spectrum mainly active against Gram negative bacterial strains, responsible for severe opportunistic infections and resistant to common antibacterial therapy, these flavonoids may be important tools in antibacterial strategies.