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Synergistic Activity of Nanoparticles and Other Antimicrobials Against Pathogenic Bacteria
Published in Mahendra Rai, Patrycja Golińska, Microbial Nanotechnology, 2020
Krystyna I. Wolska, Anna M. Grudniak
Combinations of NPs with plant compounds, mainly essential oils, are studied in the hope of finding a formulation of high antimicrobial potential. The most active plant compounds are phenolics and terpenoids (Wolska et al. 2012). It was proved that phenolics, especially flavones, cause disruption of bacterial membranes, inhibit energy metabolism and quorum sensing and neutralize bacterial toxins (Cushnie and Lamb 2011). Terpenoids influence biofilm formation preferentially in Gram-positive bacteria (Walencka et al. 2007). The literature on synergy between NPs and plant compounds is not abundant. It was shown that a combination of silver nanoparticles and an essential oil (cinnamaldehyde) acted synergistically against spore forming Bacillus cereus and Clostridium perfringens, which are the species releasing cytotoxins in contaminated food. The bactericidal action was very fast and extensive damage of the bacterial cell envelope was observed (Gosh et al. 2013). The spectacular enhancement of bactericidal activity of Drosea binata extract or its pure compound (3-chloroplumbagin) when combined with AgNPs was reported (Krychowiak et al. 2014). The authors suggested that this combination was a possible alternative for antibiotic treatment of burn wound infections caused by resistant S. aureus. It was also demonstrated that the combination of silver nanoparticles and curcumin nanoparticles is more potent in elimination of biofilms formed by P. aeruginosa and S. aureus compared to the individual compounds, and it was shown that none of these compounds was toxic to healthy human bronchial epithelial cells (Loo et al. 2016). The synergistic antibacterial effect of oleoresin from Copaifera multijuga (copaiba oil) and nanoparticles produced by Fusarium oxysporum against planctonic cells and biofilms of Streptococcus agalactiae (group B Streptococcus or GSB) was also demonstrated. This pathogen is a leading cause of neonatal infections as well as an infection in adults. The combination of two compounds resulted in the reduction of minimal inhibitory concentration values of both compounds and therefore can be considered as a new alternative strategy for controlling GBS infections (Otaguiri et al. 2017). Scandorieiro and coworkers (2018) described a synergistic and additive effect of oregano essential oils and biological silver nanoparticles in combination against multidrug-resistant bacterial strains such as MRSA (methicillin-resistant S. aureus) and E. coli and A. baumanii strains producing b-lactamase and carbapenemase (Scandorieiro et al. 2018). Oregano essential oil was extracted from leaves of Oregano vulgare; it was previously shown that its main antibacterial compounds are carvacrol and thymol (Nostro et al. 2004). In another study, bio-AgNPs were prepared according to the modified method of Duran et al. (2005) from Fusarium oxysporum strain 551. It was proved that the combination of these two compounds showed synergistic or additive effect and reduced MIC values and time of action compared to either compound used separately. Moreover, this composition efficiently disrupted S. aureus cells, as was shown by scanning electron microscopy.
Preventive activity of Copaifera langsdorffii Desf. leaves extract and its major compounds, afzelin and quercitrin, on DNA damage in in vitro and in vivo models
Published in Journal of Toxicology and Environmental Health, Part A, 2021
Saulo Duarte Ozelin, Juliana Marques Senedese, Jacqueline Morais Alves, Carla Carolina Munari, Juliana De Carvalho Da Costa, Flávia Aparecida Resende, Débora Leite Campos, Ildercílio Mota De Souza Lima, Augusto Faria Andrade, Eliana Aparecida Varanda, Jairo Kenupp Bastos, Denise Crispim Tavares
The Copaifera genus comprises trees popularly known as copaiba, widely distributed predominantly in South America, where it is considered a medicinal source (Arruda et al. 2019). Copaifera langsdorffii Desf. is known as a folk remedy, whose tea derived from leaves is used to treat kidney stones and gastric ulcers. The majority of studies on Copaifera are related to the trunk oleoresin, and there are only a few studies regarding the aerial parts. C. langsdorffii leaves hydroalcoholic extract showed potential for treatment of urolithiasis (Brancalion et al. 2012), and displayed gastroprotective properties in different animal models of gastric ulcers (Lemos et al. 2015; Motta et al. 2017a).