Int.J.Curr.Microbiol.App.Sci (2020) 9(11): 1053-1058 1053 Original Research Article https://doi.org/10.20546/ijcmas.2020.911.123 In vitro Studies on Potentiation of Enrofloxacin by Phytochemicals Srividya Gullapudi 1* , G. S. Rao 1 , P. Ravikumar 1 , Muralidhar Metta 2 and V. Ramadevi 3 1 Department of Veterinary pharmacology & Toxicology CVSC, Proddatur, YSR Kadapa district, Andhrapradesh-516360, India 2 Department of Animal Genetics and Breeding, 3 Dept of Veterinary Pathology, SriVenkateswara Veterinary University, Tirupati, India *Corresponding author ABSTRACT Introduction Bacterial infections are one of the major clinical implications observed in routine veterinary practice. From the dawn of civilisation so many drugs, antibiotics came into role to treat bacterial infections. Even after the discovery of many antibiotics starting from penicillins to quinolones, treating the bacterial infections has became a challenging issue till to date due to the emergence of resistance by the bacteria to antibacterial agents. Antibiotics and other are used as growth promoters, coccidiostats and various purposes for the production of animal meat for human consumption. Due to over the counter usage, indiscriminate application, failure of following the dosage regimen will sensitize the bacteria to develop resistance. Among several means of resistance development by the bacteria, efflux mediated resistance is of prime importance. International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 9 Number 11 (2020) Journal homepage: http://www.ijcmas.com Enrofloxacin, an antimicrobial fluoroquinolone is most commonly used against majority of gram negative bacterial and mycoplasma infections in majority of livestock. Indiscriminate usage of enrofloxacin in clinical practice leads to resistance development to this quinolne drug. Among the various pathways of resistance, efflux pump mediated drug resistance is one of the important pathways identified in the recent past. Phytochemicals namely, theobromine, glycyrrhetenic acid and glycyrrhizic acid and capsaicin were identified as efflux pump inhibitors. Phytochemicals which possess efflux pump inhibitory activity if combined with classical antimicrobial agents reduces the development of resistance and also improves their therapeutic efficacy. Interaction between enrofloxacin, and capsaicin, theobromine, glycyrrhetenic acid and glycyrrhizic acid were studied by determining MIC and MBC against E.coli, S.aureus, K.pneumoniae and P.aureginosae following CLSI guidelines. There is a significant decrease in MIC and MBC values of enrofloxacin in the presence of phytochemicals. In conclusion, Synergisitic interaction of efflux protein inhibitory phytochemicals capsaicin, theobromine, glycyrrhetenic acid and glycyrrhizic acid with enrofloxacin was noticed in minimum inhibitory concentration (MIC) and minimum bactericidal concentration. Keywords Enroloxacin, Capsaicin, Theobromine, Efflux pump, MIC Accepted: 10 October 2020 Available Online: 10 November 2020 Article Info