Subscribe to RSS
DOI: 10.1055/s-0034-1382550
MRSA and VRE active dimeric isobutyrlphloroglucinol from Ivesia gordonii
Bioassay-guided fractionation of the CHCl3 soluble fraction the native plant Ivesia gordonii led to the isolation of a new dimeric acylphloroglucinol, 3,3′-diisobutyryl-2,6′-dimethoxy-4,6,2′4′-tetrahydroxy-5,5′dimethyl- diphenyl methane (ivesinol) (1), together with a known monomeric acylphloroglucinol, 1,5-dihydroxy-2-(2′-methylpropionyl)-3-methoxy-6-methylbenzene (2). Ivesinol showed potent activity against SA and MRSA with IC50/MIC/MBC values of 0.10/1.25/> 20 µg/mL and 0.05/0.31/> 20 µg/mL, respectively, while the monomer 2 was found to be less active. Compound 1 also demonstrated strong activity against VRE with IC50/MIC/MBC values of 0.22/1.25/> 20 µg/mL, whereas the reference standard ciprofloxacin was found to be inactive against this strain. In addition, compound 2 showed moderate activity against two specis of Candida and Cryptococcus neoformans, while 1 was inactive against these fungi. In order to evaluate the influence of the acyl group(s) in phloroglucinol (3) as a ligand, the mono- (4) and diacetylphloroglucinol (5) were prepared from 3, and evaluated for in vitro SA, MRSA, and VRE activities; 2,4-diacetylphloroglucinol (5) showed potent activity, like 1, against SA, MRSA, and VRE with IC50/MIC values of 0.3/2.5, 0.23/2.5, and 0.86/2.5 µg/mL, respectively, while 4 was inactive.
[This work was supported by the USDA-ARS SCA No. 58 – 6408 – 1-603.]