ABSTRACT
Lythrum salicaria extracts showed activity against the phytopathogenic fungus Cladosporium cucumerinum and activity against the bacteria Staphylococcus aureus, Proteus mirabilis and Microccocus luteus. Bioautography on thin-layer chromatograms was used to isolate the two antifungal triterpenoids oleanolic and ursolic acid. The hexahydroxydiphenoyl ester vescalagin was isolated as active principle of the antibacterial activity. Furthermore, the flavon-C-glucosides vitexin, isovitexin, orientin and isoorientin were isolated.
Subject(s)
Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Bacteria/drug effects , Cladosporium/drug effects , Lythrum , Phytotherapy , Plant Extracts/pharmacology , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/therapeutic use , Antifungal Agents/administration & dosage , Antifungal Agents/therapeutic use , Humans , Microbial Sensitivity Tests , Micrococcus luteus/drug effects , Plant Components, Aerial , Plant Extracts/administration & dosage , Plant Extracts/therapeutic use , Proteus mirabilis/drug effects , Staphylococcus aureus/drug effectsABSTRACT
A dichloromethane and a methanol extract of the liverwort Bazzania trilobata showed antifungal activity against the phytopathogenic fungi Botrytis cinerea, Cladosporium cucumerinum, Phythophthora infestans, Pyricularia oryzae and Septoria tritici. Bioautography on thin-layer chromatograms was used to isolate six antifungal sesquiterpenes: 5- and 7-hydroxycalamenene, drimenol, drimenal, viridiflorol, gymnomitrol and three bisbibenzyls: 6 ',8'-dichloroisoplagiochin C, isoplagiochin D and 6'-chloroisoplagiochin D. Furthermore we report the isolation of gymnomitr-8(12)-en-4-one and the new coumarin 7,8-dihydroxycoumarin-7-O-beta-D-glucuronide. Their structures have been elucidated based on extensive NMR spectral evidence.
Subject(s)
Antifungal Agents/isolation & purification , Antifungal Agents/pharmacology , Hepatophyta/chemistry , Antifungal Agents/chemistry , Hepatophyta/classification , Inhibitory Concentration 50 , Magnetic Resonance Spectroscopy , Molecular StructureABSTRACT
Fire blight, a devastating bacterial disease in pome fruits, causes severe economic losses worldwide. Hitherto, an effective control could only be achieved by using antibiotics, but this implies potential risks for human health, livestock and environment. A new approach allows transient inhibition of a step in the flavonoid pathway, thereby inducing the formation of a novel antimicrobial 3-deoxyflavonoid controlling fire blight in apple and pear leaves. This compound is closely related to natural phytoalexins in sorghum. The approach does not only provide a safe method to control fire blight: Resistance against different pathogens is also induced in other crop plants.
