In vitro assays for bioactivity-guided isolation of antisalmonella and antioxidant compounds in Thonningia sanguinea flowers

Abstract

Bioguided fractionation of the aqueous extract of Thonningia sanguinea flowers, used traditionally in the treatment of microbial diseases, led to the isolation of two phenolic compounds. The structure of these compounds was elucidated by 1H, 13C 1D NMR and mass spectrometry experiments. The antibacterial activity against Salmonella strains and antioxidant activity of the crude extract, fractions and isolated compounds was evaluated using the DPPH method. The isolated compounds identified as brevifolin carboxylic acid and gallic acid demonstrates moderate antibacterial activity against Salmonella enteritidis, Salmonella typhimurium, and Salmonella abony. The results indicated that the two isolated compounds, gallic acid (IC50 = 13.5 iM) and brevifolin carboxylic acid (IC50 = 18.0 iM) were mainly responsible for the good scavenging activity of the aqueous extract.