Structural elucidation of new phenolic glycolipids from Mycobacterium tuberculosis

From one clinical isolate of Mycobacterium tuberculosis, two new phenolic glycolipids(PGLs) were obtained as its major PGLs. These were dimycocerosyl esters of 2,4-di-O-methyl-fucopyranosyl-(alpha 1-->3)-rhamnopyranosyl-(alpha 1-->3)-2-O-methyl-rhamnopyranosyl-(alpha 1-->)-phenolphthiocerol A and -phenolphthiotriol A, which were produced by this strain at a ratio of about 5:1. Another clinical isolate of this species was found to produce PGL-tb1 and its analogue, 2,3,4-tri-O-methyl-fucopyranosyl-(alpha 1-->3)-rhamnopyranosyl-(alpha 1-->3)-2-O-methyl-rhamnopyranosyl-(alpha 1-->)-phenolphthiotriol A at a ratio of about 1:3. The fact that different strains of M. tuberculosis produce chemically different PGLs as their major PGLs may be related to the diversity of virulence of the clinical isolates of M. tuberculosis.