A Novel Antibacterial Iridoid and Triterpene from Caiophora coronata

Abstract

Bioassay-guided fractionation of the antibacterial CH(2)Cl(2)-MeOH extract obtained from the aerial parts of the Argentinean plant Caiophora coronata led to the isolation of a new triterpene, 1beta,3beta-dihydroxyurs-12-en-27-oic acid, 1, and a new iridoid, 1alpha-methoxy-6alpha,10-dihydroxyisoepiiridomyrmecin (caiophoraenin), 2, along with the known iridoid isoboonein 3. Their structures were established by spectroscopic techniques (1D and 2D NMR, HRFABMS, FTIR). The MIC values of isolated compounds were determined against methicillin-sensitive (MSSA) and -resistant (MRSA) strains of Staphylococcus aureus, Bacillus subtilis (BS), vancomycin-resistant Enterococcus faecium (VREF), Escherichia coli (EC), E. coli imp (ECimp), and Candida albicans (CA). Compound 1 was found active against BS, MSSA, MRSA, VREF, and ECimp with MIC values of 2, 4, 4, 4, and 16 microg/mL, respectively.

Pentacyclic triterpene derivatives possessing polyhydroxyl ring A inhibit Gram-positive bacteria growth by regulating metabolism and virulence genes expression

“…aureus [10], while 1β,3β-dihydroxyurs-12-en-27-oic acid showed an MIC of 2 µg/mL against B. subtilis [34]. However, fewer studies reported on pentacyclic triterpenes bearing three hydroxyl groups in positions of C-1, C-2 and C-3, respectively, which M A N U S C R I P T…”

Caracteristicas fitoquímicas y capacidad antioxidante in vitro de Aloe vera, Plukenetia volubilis, Caiophora carduifolia, Cecropia membranácea

“…Sin embargo, Khera y col. (19) identificaron triterpenos, en la especie Caiophora coronata; además, observando efectos antibacterianos, estos datos coinciden con los resultados obtenidos en la marcha fotoquímica. Se presume que la presencia de saponinas, flavonoides y aminoácidos libres contribuyen a alcanzar altos potenciales de inhibición mediante el método de DPPH y ABTS (20) ; con ello contribuyen a la capacidad antioxidante in vitro.…”

Isolation, antimicrobial activity, and absolute configuration of the furylidene tetronic acid core of pestalotic acids A–G

“…The inhibition was calculated and plotted versus test concentrations to afford the IC 50 , whereas the MIC was defined as the lowest concentration that completely inhibited the growth of the test organism. 25…”