Brackman, Gilles

Coenye, Tom

Cos, Paul

Meyer, Evelyne

Risseeuw, Martijn

Van Calenbergh, Serge

Van Hecke, Kristof

Vermote, Arno

English

Ghent University Academic Bibliography

Hamamelitannin analogues potentiate antibiotics in the fight against biofilm-related Staphylococcus aureus infections Arno Vermote,1 Gilles Brackman,2 Martijn Risseeuw,1 Kristof Van Hecke,3 Paul Cos,4 Evelyne Meyer,5 Tom Coenye2  and Serge Van Calenbergh1  1 Laboratory for Medicinal Chemistry (FFW), UGent, Ottergemsesteenweg 460, B-9000 Gent, Belgium 2 Laboratory for Pharmaceutical Microbiology (FFW), UGent, Ottergemsesteenweg 460, B-9000 Gent, Belgium 3 Xstruct Bio-Inorganic Group, UGent, Krijgslaan 281 S3, B-9000, Gent, Belgium 4 Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Universiteitsplein 1 (S7), B-2610 Wilrijk, Belgium 5 Laboratory for Biochemistry, UGent, Salisburylaan 133, B-9820 Merelbeke, Belgium Scheme 1. Reagents and conditions: a) i) MsCl, Et3N, DCM, rt, 3h, ii) NaN3, DMF, 60 °C, 16h, 94% (2 steps); b) DIBAlH, DCM, -78 °C, 4h, 98%; c) aq. CH2O, K2CO3, MeOH, 50 °C, 24h, 84%; d) NaBH4, MeOH, 0 °C, 16h, 93%; e) i) TsCl, pyridine, rt, 3h, ii) 60 °C, 16h, 72%; f) K phthalimide, NaI, DMF, 90 °C, 16h, 86%; g) N2H4.H2O, EtOH, reflux, 4 h, 93%; h) BzCl, Et3N, DCM, 0 °C, 3h, 99%; i) i) PMe3, THF, H2O, ii) RCO2H, EDC.HCl, DIPEA, HOBt, DMF, rt, 16h; j) 35% TFA in H2O. SYNTHETIC ORGANIC CHEMISTRY BIOLOGICAL EVALUATION & X-RAY STRUCTURE In this poster we present a practical synthetic route that allows preparing a library of HAM derivatives with two non-identical aromatic moieties. A selection is given in Scheme 1 and 2.  Scheme 2. Reagents and conditions: a) 2-chlorobenzoic acid, EDC.HCl, DIPEA, HOBt, DMF, rt, 16h, 69%; b) i) PMe3, THF, H2O, ii) RCO2H, EDC.HCl, DIPEA, HOBt, DMF, rt, 16h; c) 35% TFA in H2O. Compound EC50 (µM)   Pretreatment Co-treatment 1 (HAM) 145.5 165.1 2 96.97 93.55 12 0.3890 7.976 13 18.01 21.39 14 13.67 52.62 15 70.42 104.4 18 0.2600 1.268 19 3.376 98.93 20 5.357 28.42 * * 012345678910PBS HAM 12 CEF CEF + HAM CEF + 12Log CFU/g gland • We developed a practical synthetic route that allows preparing a library of HAM analogues.  • Several compounds show promising activity on biofilm susceptibility (Table 1). 5-ortho-chlorobenzamide 12 emerges as one of the strongest potentiators (EC50 = 0.389 µM).  • The potentiators were not cytotoxic up to a concentration of 128µM (highest concentration tested) in MRC-5 lung fibroblast cells, suggesting acceptable therapeutic windows (not shown).  • Ortho-substitution of the benzamide increases activity. Twisting the benzamide group out of the plane (Figure 2) tends to improve interaction with the target. • HAM analogues potentiate the activity of several classes of antibiotics (not shown).  • The most potent analogues (including 12) significantly enhance survival of infected Caenorhabditis elegans (Figure 3).  • In a mouse mastitis model, significantly less CFU are present after treatment with the combination of cefalexin (CEF) and 12, compared to treatment with antibiotic alone (Figure 4).  • In all cases, MIC values were higher than 500 µM, the highest concentration tested (not shown).  Figure 1: Identification of hamamelitannin analogue 12, with exceptional antibiofilm activity in Staphylococcus aureus. Table 1: selection of HAM analogues with in vitro results. Figure 2: asymmetric unit of the crystal structure of 12. Figure 4: Log(CFU)/g mammary gland (average ± sd) of mice infected with S. aureus, reveiving  no treatment, treatment with potentiator, or treatment with cefalexin (CEF) and potentiator.  RESULTS & CONCLUSIONS 0102030405060708090100NI/NT I/NT 100 µM 50 µM 20 µM 5 µM 1 µM 100 µM 50 µM 20 µM 5 µM 1 µM% C. elegans survival (48h p.i.) HAM (1) EC50 = 73.80 µM 12 EC50 = 1.854 µM  Figure 3: C. elegans survival after 48h for uninfected (NI) and infected (I) nematodes receiving no treatment (NT), treatment  with HAM, or treatment with 12. EC50 values are expressed as the concentration needed to increase survival by 50%. arno.vermote@ugent.be ABSTRACT Brackman, G.; Breyne, K.; De Rycke, R.; Vermote, A.; Van Nieuwerburgh, F.; Meyer, E.; Van Calenbergh, S.; Coenye, T. Scientific Reports 2016, 6, 20321. Vermote, A.; Brackman, G.; Risseeuw, M. D. P.; Vanhoutte, B.; Cos, P.; Van Hecke, K.; Breyne, K.; Meyer, E.; Coenye, T.; Van Calenbergh, S. Angewandte Chemie International Edition 2016, 55, 6551-6555. Vermote, A.; Brackman, G.; Risseeuw, M. D. P.; Coenye, T.; Van Calenbergh, S. Bioorganic & Medicinal Chemistry 2016, 24, 4563-4575. Vermote, A.; Brackman, G.; Risseeuw, M. D. P.; Coenye, T.; Van Calenbergh, S. ACS Medicinal Chemistry Letters 2016, submitted.   

Hamamelitannin analogues potentiate antibiotics in the fight against biofilm-related Staphylococcus aureus infections

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Hamamelitannin analogues potentiate antibiotics in the fight against biofilm-related Staphylococcus aureus infections

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