ABSTRACT
Objective: To compare with the antimicrobial activities of chlorogenic acid and its 13 main metabolites in vivo. Methods: Main metabolites were detected by broth microdilution method against clinical isolated strains including methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), non ESBLs-producting Escherichia coli (E-), extended-spectrum β-lactamase Escherichia coli (E+), Klebsiella pneumoniae (E-/E+), Acinetobacter baumannii, and Pseudomonas aeruginosa to compare with the minimal inhibitory concentrations value of chlorogenic acid. Results: For the most tested strains, the antibacterial activities of some major metabolites were enhanced, ranging from four to 66 times higher than chlorogenic acid. Benzoic acid, p-hydroxybenzoic acid, p-coumaric acid, dihydrocaffeic acid, and gallic acid were stronger than the other metabolites. Moreover, the antibacterial actions of dihydrocaffeic acid and gallic acid against MSSA and MRSA was increased 33-66 times respectively. Conclusion: Some main metabolites presented more potent antibacterial activities than chlorogenic acid, and chlorogenic acid may exert antibacterial effects through some of its metabolites.
ABSTRACT
Objective: To study the chemical constituents from Glechoma longituba and their anti-oxidant activity in vitro. Methods: The chemical constituents were isolated and purified by solvent extraction, repeated silica gel column chromatography, and reverse phase preparative HPLC. Their structures were identified on the basis of ESI-MS and NMR spectra. The anti-oxidant activities of these compounds were screened by DPPH free radical scavenging assay in vitro. Results: Ten compounds were isolated and elucidated as cosmosiin (1), dihydrocaffeic acid (2), caffeic acid (3), isololiolide (4), vomifoliol (5), glecholone (6), apigenin (7), aurantiamide (8), (+)-lariciresinol (9), and (-)-syringaresinol (10). Conclusion: Compounds 2, 4, and 8-10 are isolated from the plants in Glechoma L. for the first time; Compounds 9 and 10 are lignans firstly obtained from this plant. DPPH free radical scavenging assays show that compounds 2, 3, 9, and 10 exhibit potential anti-oxidant activity.