title: Camellia sinensis Ameliorates the Efficacy of Last Line Antibiotics Against Carbapenem Resistant Escherichia coli.
abstract: Aquo-ethanolic extract of Camellia sinensis (PTRC-31911-A), standardized using Fourier transform infrared analysis, was found to have seven common functional groups in comparison with pre-identified marker compound 'quercetin'. Phyto-chemical quantitation analysis revealed the presence of 10.65 µg/mg of flavonoids. The bioactivity fingerprint profile of PTRC-31911-A includes IC50 (Hydroxyl radical site specific scavenging)  = 11.36 ± 0.5 µg/mL, IC80 (Hydroxyl radical non-site specific scavenging)  = 26.44 ± 0.5 µg/mL and IC50 (Superoxide ion scavenging)  = 10.141 ± 0.5 µg/mL. The drug combination analysis of PTRC-31911-A with five third-line antibiotics was carried out against carbapenem-resistant Escherichia coli. The analysis of combination of PTRC-31911-A (6.25-1000 µg/mL) and antibiotics (6.25-1000 µg/mL) revealed synergistic behaviour (fractional inhibitory concentration indices < 1) with tigecycline, ertapenem, meropenem, colistin and augmentin. The lead combination of PTRC-31911-A + ertapenem or meropenem showed maximum augmentative potential at 50 and 100 µg/mL, respectively, with nearly five-fold decrease in minimum inhibitory concentrations as compared with respective antibiotics alone. The synergistic effects implied that the antibacterial combinations of PTRC-31911-A and ertapenem, meropenem, colistin, tigecycline or augmentin would be more effective than a single monotherapy with either of the antibacterial agent.
authors.affiliation: Division of CBRN Defence, Institute of Nuclear Medicine and Allied Sciences, Delhi, India.
authors.forename: Pallavi
authors.initials: P
authors.lastname: Thakur
authors.affiliation: Division of CBRN Defence, Institute of Nuclear Medicine and Allied Sciences, Delhi, India.
authors.forename: Raman
authors.initials: R
authors.lastname: Chawla
authors.affiliation: Division of CBRN Defence, Institute of Nuclear Medicine and Allied Sciences, Delhi, India.
authors.forename: Ankita Singh
authors.initials: AS
authors.lastname: Chakotiya
authors.affiliation: Division of CBRN Defence, Institute of Nuclear Medicine and Allied Sciences, Delhi, India.|Department of Medical Elementology and Toxicology, Jamia Hamdard, Delhi, India.
authors.forename: Ankit
authors.initials: A
authors.lastname: Tanwar
authors.affiliation: Division of CBRN Defence, Institute of Nuclear Medicine and Allied Sciences, Delhi, India.
authors.forename: Rajeev
authors.initials: R
authors.lastname: Goel
authors.affiliation: Department of Biotechnology, Jamia Hamdard, Delhi, India.
authors.forename: Alka
authors.initials: A
authors.lastname: Narula
authors.affiliation: Division of CBRN Defence, Institute of Nuclear Medicine and Allied Sciences, Delhi, India.|Office of DG (LS), Defence Research and Development Organisation (DRDO) Bhawan, Delhi, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Arora
authors.affiliation: Division of CBRN Defence, Institute of Nuclear Medicine and Allied Sciences, Delhi, India.
authors.forename: Rakesh Kumar
authors.initials: RK
authors.lastname: Sharma
mesh_terms: D019980:Amoxicillin-Potassium Clavulanate Combination / Q000494:pharmacology; D028241:Camellia sinensis / Q000737:chemistry*; D015780:Carbapenems / Q000494:pharmacology*; D003091:Colistin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D000077727:Ertapenem; D004926:Escherichia coli / Q000187:drug effects*; D005419:Flavonoids / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000494:pharmacology; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D008911:Minocycline / Q000031:analogs & derivatives / Q000494:pharmacology; D064209:Phytochemicals / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D013845:Thienamycins / Q000494:pharmacology; D000078304:Tigecycline; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D015780:Carbapenems; D005419:Flavonoids; D016166:Free Radical Scavengers; D064209:Phytochemicals; D010936:Plant Extracts; D013845:Thienamycins; D047090:beta-Lactams; D000078304:Tigecycline; D019980:Amoxicillin-Potassium Clavulanate Combination; D000077731:Meropenem; D008911:Minocycline; D000077727:Ertapenem; D003091:Colistin
keywords: Camellia sinensis; New Delhi metallo-beta-lactamase-1 (NDM-1) Escherichia coli; fractional inhibitory concentration; multi-drug resistance; synergistic effects