Chemical Structure and Biochemical Activity of Cord Factor Analogs

By using mycolic acids isolated from virulent tubercle bacillus, two glycolipids, methyl 6‐mycoloyl‐α‐d‐glucopyranoside and 6,6′‐dimycoloyl sucrose, have been prepared. Their toxicity for mice, expressed as LD50, was respectively 187 and 161 μg, compared to 50 μg for 6,6‐dimycoloyl‐α‐d‐trehalose (cord factor). In mitochondria preincubated with these glycolipids, there was a decrease of the P/O ratio in the presence of succinate or pyruvate + malate as substrate, a functional damage at coupling site II, and a stimulation of ATPase activity, to a lesser extent than when mitochondria were preincubated with natural cord factor. In contrast to 6,6′‐dimycoloyl sucrose (and cord factor), methyl 6‐mycoloyl‐α‐d‐glucoside failed to affect the transfer of electrons in the NADH pathway.