Mycolic acids (MAs) are distinctive markers of the cell envelope in Mycobacterium tuberculosis and related species. Their unique and complex structures can be extracted using specific organic solvents, such as esters of trehalose or glycerol, or by esterifying the terminal pentaarabinofuranosyl units of arabinogalactan (AG), form an insoluble polysaccharide-peptidoglycan matrix of the cell wall. Both forms are crucial for the atypical structure and impermeability of the cell envelope, contributing to ......