Antibacterial activity of propolis from rincón, catamarca, argentina. Isolation of bioactive compounds

Abstract

Pevious paper reported the antioxidant and antimicrobial activities of different NOA propolis extracts but very little has been reported about their chemistry. The aim of this study was the isolation and identification of bioactive compounds from ethanolic extracts of propolis from “Del Monte” phytogeographical region (Catamarca, Argentina) against Staphylococcus aureus resistant to methycillin (MRSA). Through high-resolution chromatographic techniques (HPLC), twelve flavonoids with different degrees of hydroxylation and methoxylation were isolated and their structures were elucidated by spectroscopic analysis. Isolation was bioguided by antibacterial activity against MRSA. The compounds 2´,4´- dihydroxychalcone, 2´,4´-dihydroxy-3-methoxychalcone, 2´,4´,4-trihydroxy- 6´-methoxychalcone, 5-hydroxy-4’,7-dimethoxyflavone, 4’,5-dihydroxy- 3,7,8- trimethoxyflavone and 7-hydroxy-5,8- dimethoxyflavone were the most active with values of minimal inhibitory concentration (MIC50) of 10 μg/ml. This is the first report of the isolation of metabolites with antibacterial activity of propolis from Catamarca, Argentina.