Modulating Effect of 4,6,6-trimethylbicyclo [3.1.1] hept-3-ene on Antimicrobials Used to Combat Escherichia coli

Felipe Lemos Esteves do Amaral , Ticiane Costa Farias , Siluana Benvindo Ferreira , Savio Benvindo Ferreira c Graduate Student, Center for Teacher Training (CFP), Federal University of Campina Grande (UFCG), Cajazeiras campus, Paraíba, Brazil PhD in Veterinary Medicine, Agricultural Defense Agency of Piauí, Piauí, Brazil. PhD Professor of the Academic Unit of Life Sciences, Center for Teacher Training (CFP), Federal University of Campina Grande (UFCG), Cajazeiras campus, Paraíba, Brazil. . . . Graphical Abstract


Introduction
Currently, the class of antibiotics is at the top of the list of the most prescribed medications in the world, a fact that may be responsible for the development of bacterial resistance. Recent research shows that on average 50% of antimicrobials are not prescribed correctly by doctors, and the number of people who self-medicate without a professional indication is quite significant. Continuing these errors not only increases the selection of resistant strains, but also increases the costs of each patient and the effect of disease and death on a population (LIMA; BENJAMIM; SANTOS, 2017).
In theory, the practice of combining antimicrobial compounds would increase the chance of employing at least one effective agent to treat a given infection. In this case, if there were any resistance to one of the antimicrobials employed, but not to all, the microorganism would be destroyed by the agent (s) that maintained its activity in the scheme, with no resistance evolution (ZIMERMAN, 2010 ). In this context, the use of drugs of natural origin becomes an effective and economical alternative because they provide high chances of obtaining prototype molecules due to the diversity of their phytoconstituents with possibilities of increased antibacterial potential when associated with pathogen antibiotics (DE SOUZA ELLER et al., 2015).
In search of biological materials that interact in this sense, PEDROSA (2014) verified the association of three products, the phytoconstituent thymol, vancomycin and EDTA, which evaluated the sensitivity and the possibility of reducing the doses of the antibiotic cited against E. coli and may reduce the usual dose against this pathogen by up to sixteen times. In addition, other studies have shown that monoterpenes have detrimental effects on the bacterial cell membrane, showing themselves as alternatives to fighting pathogens such as E. coli, which is the subject of this study and is related to approximately 50% of hospital infections and 70 90% of episodes of urinary tract infections (KORB et al., 2013).
Among these monoterpenes is α-pinene, which has shown promise against bacterial biofilm formation and presented growth inhibition halos of E. coli strains. This fact demonstrates the possibility of using this phytoconstituent as an antimicrobial agent alone or in combination with other drugs (FARIAS et al., 2017).

Materials and Methods
Phytoconstituent 4

Results and Discussion
The study results were verified by comparing growth inhibition halos before and after association with the phytoconstituent to demonstrate whether there was a statistically significant change or synergism in this use, as can be seen in Figure 1.
MOL2NET, 2018, 4,ISSN: 2624-5078, ISBN: 978-3-03842-820-6 4 http://sciforum.net/conference/mol2net-05 Escherichia coli ATCC 25922 The following growth inhibitor halo diameters for antimicrobial isolated cell wall inhibitors and monoterpene inhibitors were as follows: (+) -α-pinene: 13.33 mm (± 0.58 mm), Cephalothin: 14.00 mm (± 2.00 mm), Ceftazidime: 25.33 mm (± 1.16 mm), Amoxicillin: 23.33 mm (± 1.16 mm), Amikacin: Applying the classification proposed by Cleeland and Squires (1991) for the effect of interaction between substances, we can classify the effect of the association of phytoconstituent to the antimicrobials Ceftazidime, Amoxicillin, Cefepime and Cefoxitin as a synergistic effect. However, for the other ATMs, there was no statistically significant difference, and the effect of the association was classified as indifferent. Thus, if there was antagonism or indifference in the results for some drugs, the possibilities open for further studies on the resistance and adaptation mechanism of the strain used and how the synergistic associations were able to increase the potential toxic effect against the pathogen..

Conclusions
MOL2NET, 2018, 4,ISSN: 2624-5078, ISBN: 978-3-03842-820-6 5 http://sciforum.net/conference/mol2net-05 Thus, it is concluded that phytoconstituent 4,6,6-trimethylbicyclo [3.1.1] hept-3-ene, having synergistic effects with some drugs tested in this work, can be used as an associated substance and potentiator against E. coli ATCC 25922, provided that it is submitted to tests to verify their allergenic potential against humans. Similarly, the association of this monoterpene with the antibiotics that had antagonistic or indifferent effects in this study should be avoided, not allowing the growth of resistant bacterial strains. Thus, opportunities are created for the reduction of morbidity and mortality associated with resistant microbes and for the reduction of toxicity related to certain commercially available drugs by reducing the doses used.