Piperine, a Phytochemical Potentiator of Ciprofloxacin against Staphylococcus aureus

Abstract

Piperine, a trans-trans isomer of 1-piperoyl-piperidine, in combination with ciprofloxacin markedly reduced the MICs and mutation prevention concentration of ciprofloxacin for Staphylococcus aureus, including methicillin-resistant S. aureus. The enhanced accumulation and decreased efflux of ethidium bromide in the wild-type and mutant (CIP r -1) strains in the presence of piperine suggest its involvement in the inhibition of bacterial efflux pumps.Ciprofloxacin, the most frequently used fluoroquinolone, is less effective against gram-positive bacteria, including Staphylococcus aureus, Streptococcus pneumoniae, and Enterococcus faecalis (8). Fluoroquinolones inhibit DNA synthesis by inhibiting the closely related enzymes gyrase and topoisomerase IV. The resistance to this class of antibiotics is caused by changes in the genes coding for DNA gyrase (gyrA or gyrB) or for topoisomerase IV (parC or parE) (11). The regions in which these mutations occur are termed quinolone resistance-determining regions (16,17). However multidrug efflux transporters also play a major role in contributing to the resistance of gram-positive organisms to fluoroquinolones by actively extruding fluoroquinolones and multiple other drugs from cells (4, 12, 21).Piperine, the major plant alkaloid present in black pepper (Piper nigrum) and long pepper (Piper longum), is reported to have bioavailability-enhancing activity for some nutritional substances and for some drugs (1, 3). Piperine has previously been shown to inhibit several cytochrome P450-mediated pathways and phase II reactions in animal models (2,19). It has also been proven to be an inhibitor of human P-glycoprotein (5). In this report, we describe for the first time the potentiating effect of piperine with ciprofloxacin in in vitro combination studies against S. aureus and its suggestive role as an efflux pump inhibitor.S. aureus ATCC 29213 was obtained from the American Type Culture Collection (Manassas, Va.). Methicillin-resistant S. aureus (MRSA) 33, MRSA 450, and MRSA 15187 were obtained as a kind gift from Ranbaxy Research Laboratories (New Delhi, India). Ciprofloxacin powder was obtained from Cadila Pharmaceuticals, Gujarat, India. Piperine of 99% purity was provided by the Pharmacology Division, Regional Research Laboratory, Jammu Tawi, India. Reserpine was obtained from Sigma Aldrich, St. Louis, Mo. Mueller-Hinton broth (Becton Dickinson, Cockeysville, Md.) supplemented with calcium (25 mg/liter) and magnesium (12.5 mg/liter) was used for all susceptibility and killing curve experiments. MuellerHinton agar (Becton Dickinson) was used for mutation studies. Trypticase soy agar (Becton Dickinson) was used for colony counts.In vitro combination studies. Combination studies were performed by a broth checkerboard method (9). The final concentrations ranged from 0.03 g/ml to 64 g/ml for ciprofloxacin and from 0.8 g/ml to 50 g/ml for piperine. The final bacterial inoculum in each well was 5 ϫ 10 5 CFU/ml. The plates were incubated at 37°C for 24 h. Piperine did not show any antiba...

Fluoroquinolone resistant mechanisms in methicillin-resistant Staphylococcus aureus clinical isolates in Cairo, Egypt

“…As inihibitors of the NorA efflux pump, reserpine, omeprazole, and lansprazole can improve fluoroquinolone activity against strains expressing different levels of NorA [16]. Piperine is a major plant alkaloid within the family Piperaceae and has been reported to enhance the accumulation of ciprofloxacin by S.aureus [39]. At concentrations of 12.5 and 25 mg/L, piperine caused a twofold reduction of MIC of ciprofloxacin.…”

Evaluation of the best method to assess antibiotic potentiation by phytochemicals against Staphylococcus aureus

“…Also, several antibiotic adjuvants have been evaluated for their action as resistance-modifying agents (RMAs) (Hemaiswarya et al, 2008), i.e., compounds that can modify or inhibit the bacterial mechanisms of resistance, so that antibiotics can efficiently kill the resistant bacteria. Several RMAs were already described (Chan et al, 2011;Gibbons et al, 2003;Khan et al, 2006;Roccaro et al, 2004;Schmitz et al, 1998;Yam et al, 1998). Efflux pump inhibitors (EPIs) are important examples of RMAs since they can prevent the extrusion of an antibiotic to the exterior of the cell and thus allow the antibiotic to act efficiently against bacteria.…”

In vitro antifungal activities of amphotericin B in combination with acteoside, a phenylethanoid glycoside from Colebrookea oppositifolia

“…There are several reports in the literature where natural products have demonstrated enhancement of antimicrobial activity (Khan et al, 2006;Stavri et al, 2007;Werle, 2008;Kumar et al, 2008;Lechner et al, 2008;Sharma et al, 2010). However, the number of natural compounds behaving synergistically with antifungals is minimal.…”