Antibacterial activity and mode of action of metabolites purified from Tripodanthus acutifolius

SOBERON, J. R.; SGARIGLIA, M. A.; SAMPIETRO D.A.; VATTUONE, M. A.

Tafi del Valle

Congreso; XXVI Annual Scientific Meeting of Tucuman Biology Association; 2009

Tucuman Biology Association

Tripodanthus acutifolius (Ruiz & Pav¨®n) Van Tieghem leaves have water-soluble phenolic metabolites with antibacterial activities. Five antibacterial phenolic compounds (against Staph. aureus ATCC 25923 and Ps. aeruginosa ATCC 27853), were purified from infusion, and identified as: rutin, nicotiflorin, isoquercitrin, hyperoside (flavonoids), and tripodantoside (an unussual phenylbutanoid glycoside). Bioautography and broth microdilution assays were employed to assess the antibacterial activity of samples on TLC plates and to obtain the MIC and MBC values respectively. Tripodantoside and its aglycone showed high antibacterial activities against the assayed strains (CIM/CBM =2.98/2.98 ¦Ìmol . mL-1 for both strains). Flavonoids showed low antibacterial activities against the assayed strains (CIM/CBM ranging from 6.02-8.61/6.02-13.46 ¦Ìmol . mL-1). Spectrophotometric assays, Sytox green staining and transmission electron microscopy studies suggested a bacteriolytic effect for tripodantoside aglycone against both strains. The structural knowledge of antibacterial substances and their mode of action represents a contribution to the present antibacterial therapies and the development of new leader drugs.