Preprint / Version 1

A saponin-polybromophenol antibiotic (CU1) from Cassia fistula Bark Against Multi-Drug Resistant Bacteria Targeting RNA polymerase

Authors

  • Asit Chakraborty aDepartment of Biotechnology and Biochemistry, Oriental Institute of Science and Technology, Vidyasagar University, Midnapore 721102, India
  • Sourajit Saha bDepartment of Chemistry, Bose Institute, Kolkata 700009, India
  • Kousik Poria aDepartment of Biotechnology and Biochemistry, Oriental Institute of Science and Technology, Vidyasagar University, Midnapore 721102, India
  • Tanmoy Samanta aDepartment of Biotechnology and Biochemistry, Oriental Institute of Science and Technology, Vidyasagar University, Midnapore 721102, India
  • Sudhanshu Gautam dMolecular Biophysical Unit, Indian Institute of Science, Bangalore 560012, India
  • Jayanta Mukhopadhyay bDepartment of Chemistry, Bose Institute, Kolkata 700009, India

Keywords:

Saponin polybromophenol phyto-antibiotic, Cassia fistula bark, RNA polymerase Inhibition, MDR-Bacteria, Anti-TB drug: Antibiotics void

Abstract

Gradual increase of multidrug resistant infections is a threat to the human race as MDR plasmids have acquired.>10 mdr and drug efflux genes to inactivate antibiotics. Plants secret anti-metabolites to retard growth of soil and water bacteria and are ideal source of antibiotics. Purpose Purpose of the study is to discover an alternate phyto-drug from medicinal plants of India that selectively kills MDR bacteria. Methods MDR bacteria isolated from Ganga river water, milk, chicken meat and human hair for testing phyto-extracts. Eighty medicinal plants were searched and six phyto-extracts were selected having good antibacterial activities as demonstrated by agar-hole assays giving 15 ​mm or greater lysis zone. Phyto-extracts were made in ethanol or methanol (1:5 w/v) for overnight and were concentrated. Preparative TLC and HPLC were performed to purify phytochemical. MASS, NMR, FTIR methods were used for chemical analysis of CU1. In vitro RNA polymerase and DNA polymerase assays were performed for target identification. Results CU1 belongs to a saponin bromo-polyphenol compound with a large structure that purified on HPLC C18 column at 3min. CU1 is bacteriocidal but three times less active than rifampicin in Agar-hole assay. While in LB medium it shows greater than fifteen times poor inhibitor due to solubility problem. CU1 inhibited transcription from Escherichia coli as well as Mycobacterium tuberculosis RNA Polymerases. Gel shift assays demonstrated that CU1 interferes at the open promoter complex formation step. On the other hand CU1 did not inhibit DNA polymerase. Conclusion Phyto-chemicals from Cassia fistula bark are abundant, less toxic, target specific and may be a safer low cost drug against MDR bacterial diseases. Keywords: Saponin polybromophenol phyto-antibiotic, Cassia fistula bark, RNA polymerase Inhibition, MDR-Bacteria, Anti-TB drug: Antibiotics void Abbreviations: AMR, Antimicrobial resistance; MDR, Multi-drug resistant; Bla, beta-lactamase; BSA, Bovine serum albumin; EDTA, Ethylene di-amine tetra-acetic acid; Rif, Refampicin; FTIR, Fourier transformed Infrared Spectroscopy; NMR, Nuclear Magnetic Resonance Spectroscopy; DTT, Dithiothreitol; EMSA, Electrophoretic Mobility Shift Assay; Mtb, Mycobacterium tuberculosis; DMSO, Dimethyl sulfoxide; HPLC, HighPerformance Liquid Chromatography; PAGE, Poly-Acrylamide Gel Electrophoresis; ppm, parts per million; Rp0, RNA polymerase open complex

Author Biography

Tanmoy Samanta, aDepartment of Biotechnology and Biochemistry, Oriental Institute of Science and Technology, Vidyasagar University, Midnapore 721102, India

cDepartment of Basic Sciences, IIT-Mandi, Himachal Pradesh 175005, India