Mycobacteria arabinolipids as potential endotoxins: their activity on mitochondrial oxidative phosphorylation.

Two natural arabinolipids from the cell wall of Mycobacterium tuberculosis (5-mycoloyl-D-arabinose and 5-mycoloyldiarabinoside) and two synthetic arabinolipids (5-mycoloyl-L-arabinose and 5-mycoloyl(2'-hydroxyethyl)L-arabinoside) were tested on rat liver mitochondria. 5-Mycoloyl D- and L-rabinose had the same low activity, while 5-mycoloyldiarabinoside efficiently lowered the ADP/O ratio, inhibited active respiration and increased controlled respiration. The synthetic 5-mycoloyl(2'-hydroxyethyl)arabinoside had an intermediate efficiency. Due to their activity on mitochondria, the arabinolipids of the mycobacterial cell wall can be considered as potential endotoxins.