Punicalagin suppresses methicillin resistance of Staphylococcus aureus to oxacillin

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen that is cross-resistant to most β-lactam antibiotics. We investigated whether oxacillin, which is a β-lactam antibiotic, alone or in combination with punicalagin can affect the penicillin binding protein 2a (PBP2a)-mediated resistance of MRSA. Susceptibility testing of punicalagin with oxacillin was performed using the microdilution and checkerboard assay and the growth curve assay. Binding affinity of punicalagin for cell wall peptidoglycan (PGN) was confirmed by an increased concentration of PGN in bacterial cultures containing punicalagin. The level of PBP2a was analyzed by western blotting. Punicalagin exhibited antimicrobial activity in the viability assay and increased the susceptibility of MRSA to oxacillin. PGN interfered with the antimicrobial activity of punicalagin and prevented the synergistic activity of punicalagin and oxacillin. Increasing the concentration of punicalagin and maintaining a constant concentration of oxacillin resulted in synergistic suppression of the expression of the mec operon (mecA, mecI, and mecR1). The production of PBP2a was suppressed by the addition of punicalagin to oxacillin. Our findings demonstrate that punicalagin potentiates the effect of oxacillin on MRSA by reducing the transcription of mecA (a gene marker for methicillin resistance), which resulted in a reduced level of PBP2a.

Antifungal activity of Punicalagin–nystatin combinations against Candida albicans

“…The combination of natural compounds with antibiotic drugs or antifungal agents has been suggested to enhance the antimicrobial activity of both, including against resistant strains (de Castro et al, 2015;Endo et al, 2010;Mun et al, 2018), with additional reduction of side F I G U R E 2 Percentage of reduction of metabolism activity of Candida albicans ATCC 90028 (a) and C. albicans SC5314 (b), after 24 hr in contact with Punicalagin, Nystatin and in Combination. The percentage of metabolism was calculated from the respective negative control (culture medium).…”

“…The combination of natural compounds with antibiotic drugs or antifungal agents has been suggested to enhance the antimicrobial activity of both, including against resistant strains (de Castro et al., 2015; Endo et al., 2010; Mun et al., 2018), with additional reduction of side effects and toxicity. This therapeutic strategy has been shown to be effective alternatives against Candida species (Cui, Ren, Tong, Dai, & Zhang, 2015; Liu et al., 2017; Mertas et al., 2015; Tabbene et al., 2015).…”

“…Among the active compounds derived from natural products with antimicrobial properties (Anibal, Peixoto, Foglio, & Höfling, 2013), PCG is also highlighted for its antioxidant, hepatoprotective, anti‐inflammatory, antiviral activities (Haidari, Ali, Ward Casscells, & Madjid, 2009; Lin, Hsu, Lin, Hsu, & Hsu, 1998; Nonaka et al., 1990; Yang, Xiu, Zhang, Qin, & Liu, 2012), and antiproliferative effects against human tumor cell lines (Aqil et al., 2012). Moreover, this compound presented synergistic activity when combined with oxacillin and fluconazole (Endo et al., 2010; Mun et al., 2018).…”

“…The addition of these compounds to conventional antifungal formulations may play an important role in the design of novel combination therapy protocols (Nascimento, Locatelli, Freitas, & Silva, 2000). This interaction between drugs is known as synergism, in which the combination of them can reduce the associated side effects, increase the spectrum of drug action, and improve antifungal activity (Liu et al., 2017), including against resistant strains (Mun et al., 2018).…”

“…A therapeutic option to be used in combination with NYS is Punicalagin (PCG), an ellagitannin isolated from Punica granatum Linne (pomegranate), and one of the main active components responsible for its antimicrobial properties (Mun et al., 2018). PCG was also effective acting synergistically with oxacillin and fluconazole against C. albicans and Methicillin‐resistant Staphylococcus aureus (Endo, Garcia Cortez, Ueda‐Nakamura, Nakamura, & Dias Filho, 2010; Mun et al., 2018), suggesting that the use of this compound in combination with other antifungals might be a promising therapeutic strategy for the oral candidiasis treatment. Thus, the present in vitro study aimed to evaluate whether PCG and NYS, in combination, improve the anti‐ Candida action of compounds alone, as well their cytotoxic effects on the human oral cells.…”