title: Antimicrobial, resistance-modifying effects, antioxidant and free radical scavenging activities of Mezoneuron benthamianum Baill., Securinega virosa Roxb. &Wlld. and Microglossa pyrifolia Lam.
abstract: Mezoneuron benthamianum, Securinega virosa and Microglossa pyrifolia are used in folk medicine in Ghana for the treatment of dermal infections and wounds. Petroleum spirit, chloroform and ethanol extracts of the plants were tested for antimicrobial activity against a battery of organisms using the agar well diffusion technique and a serial dilution microassay. The resistance modifying activities of these extracts on standard antibiotics against Staphylococcus aureus possessing efflux mechanisms of resistance have also been assessed. A 4-fold potentiation of the activity of norfloxacin was observed for ethanol and chloroform extracts of M. benthamianum and S. virosa, respectively, whilst the petroleum spirit extract resulted in a 2-fold potentiation with minimum inhibitory concentration (MIC) values in the range 8-16 microg/mL. Ethanol extracts of all three species, the petroleum spirit extract of M. benthamianum and the chloroform extracts of M. benthamianum and S. virosa, showed interesting antimicrobial activities. Antioxidant and free radical scavenging activities using DPPH spectrophotometric and TBA lipid peroxidation assays were also conducted. Of the five extracts that showed antioxidant activities, the petroleum spirit and chloroform extracts of M. benthamianum rated most highly by displaying strong free radical scavenging activity with IC50 values of 15.33 and 19.72 microg/mL, respectively. Lipid peroxidation inhibition provided by the same two extracts also produced the lowest IC50 values for all the extracts tested, of 23.15 and 30.36 microg/mL. These findings therefore give some support to the ethnopharmacological use of the plants in the treatment of various skin diseases and wounds, as well as demonstrating the potential of some of the plants as sources of compounds possessing the ability to modulate bacterial multidrug resistance.
authors.affiliation: Pharmacognosy Research, Pharmaceutical Sciences Research Division, KCL, 150 Stamford Street, London SE1 9NH, UK.
authors.forename: R A
authors.initials: RA
authors.lastname: Dickson
authors.forename: P J
authors.initials: PJ
authors.lastname: Houghton
authors.forename: P J
authors.initials: PJ
authors.lastname: Hylands
authors.forename: S
authors.initials: S
authors.lastname: Gibbons
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D019659:Asteraceae / Q000737:chemistry*; D001921:Brain; D002417:Cattle; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects; D019665:Euphorbiaceae / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D024301:Plant Bark / Q000737:chemistry; D010936:Plant Extracts / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry*; D012997:Solvents
chemical_list: D000890:Anti-Infective Agents; D000975:Antioxidants; D016166:Free Radical Scavengers; D010936:Plant Extracts; D012997:Solvents