A cytotoxic diterpenoid and antifungal phenolic compounds from Frullania muscicola steph
A novel ent -labdane type diterpenoid, muscicolone ( 1 ), as well as two bibenzyls ( 2 , 3 ) and four flavonoids ( 4 - 7 ) were isolated from the liverwort Frullania muscicola Steph. Their structures were established by analysis of the spectral data of IR, UV, 1D-, 2D-NMR, and ORD. The stereostructure of 1 was confirmed by X-ray crystallographic analysis. Bioassay experiments showed that compound 3 and 4 have potent inhibitory effects against some fungi while 1 showed cytotoxic effects to some human tumor cells.
An antifungal bibenzyl from the New Zealand liverwort, Plagiochila stephensoniana. Bioactivity-directed isolation, synthesis, and analysis.
The bioactivity-directed isolation of 4-hydroxy-3'-methoxybibenzyl [1] from a New Zealand liverwort, Plagiochila stephensoniana, is described. Compound 1 exhibited antifungal and antibacterial activity. Compound 1 is not considered to be a useful taxonomic marker. Syntheses of 1, stilbenes 2 and 3, and some derivatives were made and the biological activities were compared.
Optimization of the derivatization method for the liquid-chromatographic determination of carboxylic acids in wines
Abstract Several reagents and experimental conditions were tested to optimize the yield of the derivatization procedure for determining carboxylic acids in wines. Two techniques were applied for optimization: a modified sequential simplex method and a simultaneous modelling method. The results obtained were similar; advantages of the latter method are discussed. The optimized conditions (phenacyl bromide as reagent with 18-crown-6 as catalyst with a reaction time of 90 min at 90 ° C) were used to determine the main carboxylic acids in several varietal wines of the Tarragona region.