Polyphenolic composition of Lantana camara and Lippia chevalieri, and their Antioxidant and Antimicrobial Activities

In the present study, the antioxidant and antibacterial activities of methanolic extracts of two Verbenaceae (Lantana camara L. and Lippia chevalieri Moldenke: aerial part) were investigated. Their polyphenolic composition in the ethyl acetate and aqueous fractions were characterized by HPLC-DAD. The antioxidant capability of the methanolic extracts was assessed by the Ferric Reducing Antioxidant Power (FRAP) and the scavenging activity of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The Minimum Inhibitory Concentrations (MIC) of the methanolic extracts (25 µg mL-1), and the minimum bactericidal concentrations (MBC) (12.5 µg mL-1) against 13 pathogenic bacteria and four serotyped bacteria from the American Type Culture Collection (ATCC) were also determined by the agar-well diffusion method. The results indicated that the L. chevalieri extracts are rich in phenolic compounds (among the 27 polyphenolic compounds detected, 20 belong to L. chevalieri) and showed the highest antioxidant activities, simultaneously on iron (III) to iron (II)-reducing activity and the radical scavenging activity. However, L. camara displayed the best and the broadest antimicrobial spectrum, especially on Shigella flexneri and Pantoea sp. (two Gram-negative strains of bacteria). The nature of polyphenolics compounds detected (phenol acid and flavone) in the L. camara can justify this activity.Key words: Verbenaceae, HPLC-DAD, antioxidant activity, antimicrobial activity, polyphenolic compound