Antimicrobial phenolic compounds from Anabasis aphylla L.

Bioassay-guided fractionation of an ethyl acetate extract from the aerial parts of Anabasis aphylla, a Chenopodiaceous species widely distributed in the northwest of China, led to the isolation of six phenolic compounds, which were identified by means of spectrometric analysis as 1-(2-hydroxy-4,6-dimethoxyphenyl)-ethanone (1), 3,4-dihydroxy cinnamic acid tetracosyl ester (2), 4-hydroxy-3-methoxy benzoic acid (3), 2-hydroxy benzoic acid (4), 3,4-dihydroxy cinnamic acid methyl ester (5) and 4-hydroxy benzoic acid pentadecane ester (6). These compounds were further screened for their minimum inhibitory concentration (MIC) and median inhibitory concentration (IC50) by use of the micro-dilution-MTT assay for antimicrobial activity against one Gram-positive bacterium (Bacillus subtilis), three Gram-negative bacteria (Agrobacterium tumefaciens, Pseudomonas lachrymans, and Xanthomonas vesicatoria), and one yeast (Candida albicans). Apart from compound 6, which had no activity against any of the tested microorganisms, the other compounds showed selective inhibitory activity. This is the first report on the antimicrobial activity of the phenolic compounds isolated from A. aphylla. The obtained results provide promising baseline information for the potential use of the extract and some isolated compounds from this plant as antimicrobial agents to control plant and animal diseases.