Structure and anti-TB activity of trachylobanes from the liverwort Jungermannia exsertifolia ssp. cordifolia.

In the critical search for new antituberculosis lead compounds, bryophytes represent a largely untapped resource of chemically diverse structures. From the liverwort Jungermannia exsertifolia subsp. cordifolia, 11 new trachylobane diterpene derivatives, as well as three known compounds, were isolated. Their structures were elucidated by spectroscopic means, and full (1)H NMR spin analysis of one model compound confirmed the relative configurational assignments of the congeners. Four of the isolates exhibited noticeable activity against virulent Mycobacterium tuberculosis H(37)Rv with minimal inhibitory concentrations of 61-24 microg/mL. This finding suggests that bryophytes in general and trachylobanes in particular deserve further attention in the search for new antimycobacterial leads.

Bioactivity guided isolation of antimicrobial compounds from Lythrum salicaria.

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.

Bioactivity guided isolation of antifungal compounds from the liverwort Bazzania trilobata (L.) S.F. Gray.

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.

Bazzanins L-R, chlorinated macrocyclic bisbibenzyls from the liverwort Lepidozia incurvata.

Seven new chlorinated bisbibenzyls (bazzanins L-R), of the isoplagiochin C type, as well as isoplagiochin C have been isolated from the liverwort Lepidozia incurvata. The structures have been elucidated based on extensive NMR spectral evidence and by mass spectrometry.

Lignan derivatives from the liverwort Bazzania trilobata.

Eight lignan derivatives trilobatin D-K, as well as jamesopyrone were isolated from the liverwort Bazzania trilobata. Their structures have been elucidated based on extensive NMR spectral evidence.