PARTE UTILIZADA= Used part: Resina.

ACCIÓN FARMACOLÓGICA= Pharmacological action: Astringente, hemostática, cicatrizante, antiartrítica. 

COMPOSICIÓN QUÍMICA= Chemical composition: Three flavonoids, (2R,3R)-5,4`;-dihydroxy-3' ;-O-methyl-7- (gamma, gamma; -dimethylallyloxy)dihydroflavonol 1, (2R,3R)-5,7,4`;- trihydroxy-3`;-O-methyl-6-(alpha,alpha;-dimethylallyl)dihydroflavonol 2, and (2R,3R)-5,7,4`;-trihydroxy-6-(alpha;,alpha;-dimethylallyl) dihydroflavonol 3, together with three known flavonoids (4-6), were isolated from the aerial parts of Pterocaulon alopecuroides. The structures of the compounds were determined by mass and by 1 D and 2 D NMR spectroscopy. Screening of the antibacterial activity of all six compounds was conducted by a disc diffusion test against Bacillus cereus, Bacillus subtilis, Salmonella typhimurium and Proteus mirabilis. The minimum inhibitory concentration (MIC) of the active compounds (2, 3, 4, 6) was determined by a microdilution assay. These compounds were active only against both Gram (+) bacteria with MIC values equal or bigger 200 ug/mL. 

ZONA GEOGRÁFICA= Geografical zone: S de Brasil, Uruguay, N., centro y NE. de Argentina hasta las Islas del Caribe. 

ÚLTIMOS AVANCES EN LA QUÍMICA Y ACTIVIDADES BACTERIOLÓGICAS EN LAS PLANTAS MEDICINALES= Medicinal plants, last advances on chemistry and bacteria activities on the medicinal herbs

1) Fractionation of antifungal hexane exts. of the aerial parts of three Pterocaulon spp., Pterocaulon alopecuroides, Pterocaulon balansae and Pterocaulon polystachyum (Asteraceae) from South Brazil traditionally used to treat animal mycoses, afforded the coumarins 5-methoxy-6,7-methylenedioxycoumarin, 7-(2',3'-epoxy-3'-methylbutyloxy)-6-methoxycoumarin, 6,7-methylenedioxycoumarin (ayapin), along with a mixt. of 6-hydroxy-7-(3'-methylbutyl-2'-en-oxy)-coumarin (prenyletin) and 6-methoxy-7-(3'-methylbutyl-2'-en-oxy)-coumarin (prenyletin-methyl-ether).  Among the different components of the active exts., only the mixt. of prenyletin and prenyletin-methyl-ether isolated from Pterocaulon polystachyum showed activity against Cryptococcus neoformans, Microsporum gypseum, Trichophyton rubrum and Trichophyton mentagrophytes.  Nevertheless their MIC values were higher than the MIC of the original exts., suggesting that the mixt. but not only one compd. would be the responsible for the activity detected in these Pterocaulon species.

2) Based on informal interview, ethnoveterinary information about plants used in the treatment of skin diseases were obtained.  Plants from the genus Pterocaulon (Asteraceae) known as "quitoco" are used to treat problems popularly diagnosed as "mycoses", which can have both fungic and bacterial etiology.  In order to validate this traditional practice, the crude methanolic extracts and fractions from the aerial parts of three species of Pterocaulon (Pterocaulon alopecuroides (Lam.) D.C., Pterocaulon balansae Chodat. and Pterocaulon polystachyum D.C.) grown in southern Brazil were analyzed for the in vitro antifungal activity against a panel of standardized and clinical opportunistic pathogenic yeasts and filamentous fungi including dermatophytes by the agar dilution method.  The crude methanolic extract of Pterocaulon alopecuroides was the most active followed by the extract of Pterocaulon polystachyum.  Pterocaulon balansae crude methanolic extract was the less active but its lipophilic fractions showed remarkable activity mainly against the dermatophytes.

1) TOURSARKISSIAN, Martín. Plantas medicinales de Argentina : sus nombres botánicos, vulgares, usos y distribución geográfica. Buenos Aires : Hemisferio Sur, 1980, 178p.

2) ALARCÓN, R.; et al. Flavonoids from Pterocaulon alopecuroides with antibacterial activity. Planta Médica . 2008, vol.74, nº12, p.1463-1467.
 
3) STEIN, Ana Cristina, et al. Antifungal activity of some coumarins obtained from species of Pterocaulon (Asteraceae).  Journal of Ethnopharmacology . 2006, vol.107, nº1, p.95-98.
 
4) STEIN, Ana Cristina, et al. Ethnoveterinary medicine in the search for antimicrobial agents: antifungal activity of some species of Pterocaulon (Asteraceae).  Journal of ethnopharmacology . 2005, vol.99, nº2, p.211-214.