Mannopyranoside Glycolipids Inhibit Mycobacterial Growth, Biofilm and Potentiate Isoniazid Inhibition Activities in M. smegmatis.

Lipomannan and lipoarabinomannan are integral components of mycobacterial cell wall. Our earlier studies demonstrated that synthetic arabinan and arabinomannan glycolipids act as inhibitors of mycobacterial growth, in addition to exhibiting inhibitory activities of mycobacterial biofilm. In the present study, we demonstrate that synthetic mannan glycolipids are better inhibitors of the mycobacterial growth, whereas, lipoarabinomannan has higher inhibition efficiencies to biofilm. Syntheses of mannan glycolipids with graded number of mannan moieties and an arabinomannan glycolipid are conducted by chemical methods and subsequent mycobacterial growth and biofilm inhibition studies are conducted on M. smegmatis. Growth inhibition of 73 ± 3% is observed with a mannose trisaccharide containing glycolipid, whereas this glycolipid did not promote biofilm inhibition activity better than arabinomannan glycolipid. The antibiotic supplementation activities of glycolipids on growth and biofilm inhibitions are evaluated. Fold increases in the growth and biofilm inhibitions are observed when the antibiotic is supplemented with glycolipids, leading to a significant reduction of inhibition concentrations of the antibiotic.