PARTE UTILIZADA: Corteza.

ACCIÓN FARMACOLÓGICA: Medicinal (corteza).

COMPOSICIÓN QUÍMICA: This in vitro study evaluated the antimicrobial activity of exts. obtained from Rheedia brasiliensis fruit (bacupari) and its bioactive compd. against Streptococcus mutans. Hexane, ethyl-acetate and ethanolic exts. obtained (concns. ranging from 6.25 to 800 ug/mL) were tested against S. mutans UA159 through MIC/MBC assays. S. mutans 5-days-old biofilms were treated with the active exts. (100 x MIC) for 0, 1, 2, 3 and 4h (time-kill) and plated for colony counting (CFU/mL). Active exts. were submitted to exploratory chem. analyses so as to isolate and identify the bioactive compd. using spectroscopic methods. The bioactive compd. (concns. ranging from 0.625 to 80 ug/mL) was then tested through MIC/MBC assays. Peel and seed hexane exts. showed antimicrobial activity against planktonic cells at low concns. and were thus selected for the time kill test. These hexane exts. reduced S. mutans biofilm viability after 4 h, certifying of the bioactive compd. presence. The bioactive compd. identified was the polyprenylated benzophenone 7-epiclusianone, which showed a good antimicrobial activity at low concns. (MIC: 1.25-2.5 ug/mL; MBC: 10-20 ug/mL). The results indicated that 7-epiclusianone may be used as a new agent to control S. mutans biofilms; however, more studies are needed to further elucidate the mechanisms of action and the anticariogenic potential of such compd. found in R. brasiliensis. .

ZONA GEOGRÁFICA: E. de Brasil y NE de Argentina. 

ÚLTIMOS AVANCES EN LA QUÍMICA Y ACTIVIDADES BACTERIOLÓGICAS EN LAS PLANTAS MEDICINALES

The structures of 3 new prenylated xanthones, isolated from the root bark ext. of R. brasiliensis, were established as 4'',5''-dihydro-1,5-dihydroxy-6',6'-dimethylpyrano(2',3':6,7)-4'',4'',5''-trimethylfurano(2'',3'':3,4)xanthone, 1,3,5-trihydroxy-6',6'-dimethylpyrano(2',3':6,7)-4-(1,2-dimethylprop-2-enyl)xanthone, and 1,3,5,6-tetrahydroxy-4-(1,1-dimethylprop-2-enyl)-7-(3-methylbut-2-enyl)xanthone.

1) TOURSARKISSIAN, Martín. Plantas medicinales de Argentina : sus nombres botánicos, vulgares, usos y distribución geográfica. Buenos Aires : Hemisferio Sur,1980, p.60 .

2) ALMEIDA, L. S. B., et al. Antimicrobial activity of Rheedia brasiliensis and 7-epiclusianone against Streptococcus mutans. Phytomedicine. 2008, vol.15, nº10, p.886-891.
 
3) DELLE MONACHE, Giuliano, et al. Chemical investigation of the genus Rheedia, IV.  Three new xanthones from Rheedia brasiliensis.  Journal of Natural Products. 1984, vol.47, nº4, p.620-625.