DPPH-scavenging and antimicrobial activities of Asteraceae medicinal plants on uropathogenic bacteria

Abstract

AbstractAsteraceae species were widely applied in traditional medicines in Asia countries as sources of natural antioxidants and antimicrobial agents. This study aimed to evaluate DPPH-scavenging capacities and antimicrobial activities of nine Asteraceae species collected from Southern Vietnam. Antioxidant and antimicrobial activities were determined by standard protocols. Essential oils fromAgeratum conyzoides, Helianthus annuus, Artemisia vulgarisindicated significant inhibitory effects onStaphyloccocus aureusandCandidaspp.. Crude extracts and fractions fromTaraxacum officinale, Chrysanthemum morifolium, Ageratum conyzoides, Tagetes erectashowed inhibitory ability on at least one testing bacterial strains includingS. aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa. Study on clinical isolates, ethyl acetate fraction fromA. conyzoidesdisplayed the most potent effect on uropathogenicE. coliandK. pneumoniaewith MIC at 1.25-10 mg/ml and 5-12.5 mg/ml, respectively. DPPH scavenging assay indicated thatTagetes erectaextract had the lowest IC50(17.280 μg/ml) and 2.5 times higher than vitamin C (7.321 μg/ml). This study revealed thatA. conyzoideshas good potential against uropathogenicE. coliandK. pneumoniae, and could, therefore, apply to prophylactic urinary tract infection.