1 / 14

Cynthia Amaning Danquah UCL School of Pharmacy London, UK

Synthetic Analogues of Natural Product Disulfides from Allium stipitatum Demonstrate Anti-Tubercular Activities through Drug Efflux Pump and Biofilm Inhibition. Cynthia Amaning Danquah UCL School of Pharmacy London, UK.

sbowman
Download Presentation

Cynthia Amaning Danquah UCL School of Pharmacy London, UK

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Synthetic Analogues of Natural Product Disulfides from Allium stipitatum Demonstrate Anti-Tubercular Activities through Drug Efflux Pump and Biofilm Inhibition Cynthia AmaningDanquah UCL School of Pharmacy London, UK

  2. A rise in drug resistant tuberculosis (TB) • Countries that have reported at least one case of XDR by the end of 2014 • (WHO Global Tuberculosis Report, 2015) XDR cases No XDR cases 9.6 million new TB cases 1.5 million deaths 480,000 MDR-TB cases reported in 2014

  3. Natural sources Natural products as a reservoir for novel anti-infectives drugs Teixobactin Eleftheria terrae Rifampicin Streptomyces mediterranei Paclitaxel (Taxol) Taxus brevifolia Streptomycin Streptomyces griseus

  4. The genus Allium - Allium stipitatum MIC 0.5-8 µg/mL • Three Pyridine-N-oxides alkaloids were isolated: • 2-(methyldithio)pyridine-N-oxide • (2) 2-[(methylthiomethyl)dithio]pyridine-N-oxide • (3) 2,2′-dithio-bis-pyridine-N-oxide Bioactive Pyridine-N-oxide Disulfides from Allium stipitatum Gemma O’Donnell, Rosemarie Poeschl, Oren Zimhony, Mekala Gunaratnam, Joao B. C. Moreira, Stephen Neidle, Dimitrios Evangelopoulos, Sanjib Bhakta, John P. Malkinson, Helena I. Boshoff, Anne Lenaerts and Simon Gibbons J. Nat. Prod., 2009, 72 (3), pp 360–365 Publication Date (Web): December 18, 2008 (Article) DOI: 10.1021/np800572r

  5. Generation of disulphide analogues ES2 ES3 3-(benzylthio)-5-(methyldisulfanyl)-4H-1,2,4-triazol-4-amine 2-(methyldisulfanyl)thieno[2,3-d]pyrimidin-4-amine ES4 7-fluoro-2-(methyldisulfanyl)benzo[d]thiazole ES6 4-ethyl-5-(methyldisulfanyl)-4H-1,2,4-triazol-3-ol ES5 (E)-3-(methyldisulfanyl)-5-styryl-4H-1,2,4-triazole Kitson T.M. and Loomes K.M. (1985) Synthesis of methyl 2- and 4-pyridyl disulfide from 2- and 4-thiopyridone and methylmethanethiosulfonate Analytical Biochemistry Volume 146, Issue 2, 429–430

  6. Biological evaluation: Antimycobacterial activity of the synthesized analogues

  7. Biological evaluation: Cytotoxicity assay Macrophages RAW 264.7 cell line Resazurin fluorescence assay

  8. Biological evaluation: Efflux Pump Inhibition Assay (a, b and c) Efflux pump inhibition assay of ES compounds using M aurum. Ethidium bromide (EtBr) is an efflux pump substrate (used at a final concentration of 0.5 µg/mL) verapamil and chlorpromazine are known efflux pump inhibitors and are used as controls , (d) growth curve with optical density taken at 600nm

  9. Biological evaluation: Biofilm assay Concentration dependent inhibition of biofilm formation by synthesized methyldisulphide ES3 (OD600 3.5) Decreasing biofilm formation Biofilm Biofilm Increasing concentration of ES3 (0.78-50µg/ml) Quantification of biofilm: Crystal violet staining, absorbance measured

  10. Microscopy: Biofilm assay Light Microscope Planktonic cells Biofilm formed 1000X 1000X Scanning Electron Microscope (SEM) (c) Mycobacterium smegmatis cells Planktonic Biofilm matrix 1000X 1000X

  11. Conclusions • Synthesized analogues of bioactive natural product disulfides • They have shown anti-tubercular activity • Effective against other pathogenic bacteria • Efflux pump inhibitory effect • Biofilm inhibitory properties • Cytotoxicity profile of the compounds • These findings indicate that synthetic analogues of naturally occurring disulfides are bioactive and can serve as leads for the development of effective new treatment for Mycobacterial diseases and other pathogenic bacteria.

  12. Future work • Generation of mutants • Amplification of specific genes /regions by PCR or Whole genome sequencing

  13. Acknowledgements Phytochemistry Laboratory (UCL School of Pharmacy) Prof. Simon Gibbons Dr. Proma Khondkhar Mycobacteria Research Laboratory Dr. Sanjib Bhakta Dr. Dimitrios Evangelopoulos Arundhati Maitra Ghana Education Trust Fund British Society of Antimicrobial Chemotherapy

  14. “No one is safe from tuberculosis until everyone is safe..............the search continues’’ Thank you

More Related