Antibacterial activity of extracts and compounds isolated from the Andean medicinal plant Azorella cryptantha (Clos) Reiche, Apiaceae

AGÜERO, MB; SÁNCHEZ, M; LIMA, B; FERESIN, GE; PALERMO, JA; TAPIA, A

Industrial Crops and Products

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 64 p. 152 - 157

0926-6690

tAzorella cryptantha (Clos) Reiche, Apiaceae, vernacular name ?yerba del soldado or cuerno de cabra?is a medicinal herb that grows in the Andean mountains (Argentina). An infusion or decoction of theleaves is employed as cholagogue and digestive, usually to treat food-borne illnesses associated withenterobacteria. Extracts and compounds from two Argentinean populations were subjected to antibac-terial assays against pathogenic bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidisand Yersinia enterocolitica) and Gram (+) Staphylococcus aureus methicillin-sensitive and methicillin-resistant microorganisms. The antibacterial activity-guided fractionation against a panel of ATCC andclinically isolated bacteria was done according to CLSI protocols. The petroleum ether extracts fromboth populations showed strong antibacterial activity against S. enteritidis with MIC values from 125to 250 g/ml, and also towards methicillin-sensitive Staphylococcus aureus, and Gram negative strainsE. coli, P. aeruginosa, Salmonella sp. and Yersinia enterocolítica-PI, (MICs between 400 and 1000 g/ml).Fractions from the petroleum extracts showed strong antimicrobial activity, against Escherichia coliATCC 25922, E. coli-LM1, E. coli-LM2, and Salmonella enteritidis-MI, with MICs values between 31.2 and125 g/ml. The bioassay-guided fractionation of the petroleum ether extracts led to the isolation ofnine terpenes: azorellolide (1), mulinol (2), stachytriol (3),1,10,4,5-diepoxy-7-germacran-6-ol(4), 1,10,4,5-diepoxy-7-germacran-6-ol (5), 1,2,3,3,4,5,6,7,8,8-decahydro-7-(1-hydroxy-1-methylethyl)-1,4-dimethylazulene-3,8-diol (6), madreporanone (7), yaretol (8) and chrysotol or6,10-epoxy-4-hydroxyguaiane (9). Compounds 3, 5, 6 and 9 are reported here for the first timefrom A. cryptantha. Their structures and relative configurations have been determinated by means 1Dand 2D NMR techniques. Chrysothol (9), madreporanone (7), and stachytriol (3) showed strong antimi-crobial activities (MICs = 50?100 g/ml) against enterobacteria E. coli and S. enteritidis. The antibacterialactivity found for some of the isolated compounds supports least in part, the commercial exploited ofthis species to treat food-borne illnesses associated with Gram negative pathogenic bacteria.