Eucalyptus botryoides' resin and its new 2-O-galloyl-1,6-O-di-trans-p-coumaroyl-β-D-glycopyranoside compound display good antimicrobial activity.

Fungal resistance to different therapeutic drugs has become a growing challenge. This crucial health problem requires new effective drug alternatives. Herein, we report the study of Eucalyptus botryoides' resin used in folk medicine as antimicrobial. Thus, E. botryoides' resin was extracted with aqueous-ethanol and fractionated using Sephadex chromatography, furnishing its major compounds. The crude extracts and the isolated compounds were evaluated for their in vitro antimicrobial activity against bacteria and yeasts. The crude extract displayed MIC of 25 μg/mL against S. salivarius, and for C. albicans, C. glabrata, and C. tropicalis the MIC were between 2.9 and 5.9 μg/mL. The 7-O-Methyl-aromadendrin was the most effective against C. glabrata and C. krusei (MIC = 1.6 μg/mL). 2-O-Galloyl-1,6-O-di-trans-p-coumaroyl-β-D-glycopyranoside, first time reported, showed MIC of 3.1 μg/mL against C. glabrata and C. krusei. Overall, this work gave promising results, indicating that Eucalyptus botryoides' resin and its compounds have the potential for developing anti-yeast products.