Modulation of drug resistance in staphylococcus aureus by a kaempferol glycoside from herissantia tiubae (malvaceae)

Abstract

In an ongoing project to evaluate natural compounds isolated from plants from the Brazilian biodiversity as modulators of antibiotic resistance, kaempferol-3-O-beta-d-(6''-E-p-coumaroyl) glucopyranoside (tiliroside), isolated from Herissantia tiubae (Malvaceae) was investigated using the strain SA-1199B of Staphylococcus aureus, which overexpresses the norA gene encoding the NorA efflux protein which extrudes hydrophilic fluorquinolones and some biocides, such as benzalkonium chloride, cetrimide, acriflavine and ethidium bromide. The minimum inhibitory concentrations (MICs) of the antibiotics and biocides were determined by the microdilution assay in the absence and in the presence of sub-inhibitory concentration of tiliroside. Although tiliroside did not display relevant antibacterial activity (MIC = 256 microg/mL), it modulated the activity of antibiotics, i.e. in combination with antibiotics a reduction in the MIC was observed for norfloxacin (16-fold), ciprofloxacin (16-fold), lomefloxacin (four-fold) and ofloxacin (two-fold), and an impressive reduction in the MICs for the biocides (up to 128-fold). The results presented here represent the first report of a kaempferol glycoside as a putative efflux pump inhibitor in bacteria. The present finding indicates that H. tiubae (and broadly Malvaceae) could serve as a source of plant-derived natural products that modulate bacterial resistance, i.e. a source of potential adjuvants of antibiotics.

Synergistic antibacterial effects of herbal extracts and antibiotics on methicillin-resistant Staphylococcus aureus: A computational and experimental study

“…It increased the activity of norfloxacin 16 times, ciprofloxacin 16 times, lomefloxacin 4 times, and ofloxacin by 2 times. 54 Thus, tiliroside could be a constituent of D. genkwa capable of producing a synergistic effect with oxacillin against MRSA in this study. The potential mechanism could be related to the binding of PBP2a or PBP4, as indicated by the high binding scores calculated in this study.…”

The Essential Oil from <b><i>Origanum vulgare</i></b> L. and Its Individual Constituents Carvacrol and Thymol Enhance the Effect of Tetracycline against <b><i>Staphylococcus aureus</i></b>

“…These findings indicate that the compounds tested inhibit the activity (or even the expression) of TetK efflux protein, but not of NorA and Msr efflux proteins. This activity may be related to the lipophilicity of the assayed plant compounds, which is a common feature of several putative EPIs, such as methoxylate flavonoids [12], natural amphipathic compounds [13] or even synthetic compounds [14]. …”

Free Radical-Scavenging, Anti-Inflammatory, and Antibacterial Activities of Water and Ethanol Extracts Prepared from Compressional-Puffing Pretreated Mango (Mangifera indicaL.) Peels

“…Bioactive compounds in mango peel are generally extracted via the following methods: extraction with 80% ethanol by sonication for 3 days at room temperature [18]; extraction performed three times with methanol, for 3 h per time [19]; extraction with 95% ethanol three times, 72 h per time [20]; extraction with acetone or ethyl acetate for up to 20 h [21][22][23]; extraction by microwave-assisted method [24,25]; or extraction with supercritical CO 2 , followed by pressurized ethanol [26]. However, these methods generally involve the use of a large volume of solvents, require a long extraction time, consume a lot of energy, are costly, and sometimes are not eco-friendly.…”