Two new benzofuranes from Eupatorium aschenbornianum and their antimicrobial activity.

Through a bioassay-guided fractionation, from the aerial parts of the medicinal plant Eupatorium aschenbornianum were isolated two new benzofurane compounds, 5-acetyl-3beta-angeloyloxy-2beta-(1-hydroxyisopropyl)-2,3-dihydrobenzofurane ( 1) and 5-acetyl-3beta-angeloyloxy-2beta-(1-hydroxyisopropyl)-6-methoxy-2,3-dihydrobenzofurane ( 2) in addition to 4-hydroxy-3,5-diprenylacetophenone, espeletone ( 3), encecalinol ( 4), beta-sitosterol and stigmasterol. The antimicrobial evaluation of these natural products showed that 1 [MIC = 200 microg/mL against T. mentagrophytes and 100 microg/mL against T. rubrum], 2 [MIC = 50 microg/mL towards both] and 3 [MIC = 100 microg/mL against both] were active against dermatophytes, while 4 was active against all of microorganisms assayed [MIC = 12.5 microg/mL ( T. mentagrophytes), 12.5 microg/mL ( T. rubrum), 100 microg/mL ( C. albicans) and 200 microg/mL ( A. niger)].