Cytotoxicity and antibacterial activity of scutellarein and carajurone-enriched fraction obtained from the hydroethanolic extract of the leaves of Fridericia chica (Bonpl.) L.G. Lohmann

The hydroethanolic extract obtained from the dry leaves of Fridericia chica (HEFc) underwent several fractionations by different chromatographic techniques. The ethyl acetate and dichloromethane fraction were subjected to phytochemical analysis, resulting in the identification and isolation of scutellarein (1) and in a fraction rich in carajurone (2). They were tested for cytotoxicity in CHO-K1 and the antibacterial activity and mode of action by in vitro assays. The HEFc and scutellarein (1) presented no cytotoxicity. The results showed good antibacterial effect of HEFc against Streptococcus pyogenes and Staphylococcus aureus and moderate activity for Staphylococcus epidermidis, Pseudomonas aeruginosa and Salmonella typhimurium. The fraction containing the compound carajurone (2) showed good activity against Staphylococcus aureus and Staphylococcus epidermidis and moderate activity against Streptococcus pyogenes. Scutellarein (1) showed no activity against the bacteria tested. HEFc antibacterial mode of action appeared to be associated with changes in the permeability of bacterial membranes and nucleotide leakage.