“…Additionally, it must be noted that several activators of ABC transporters share molecular-structural features of ABC transporter inhibitors. For example, tetrahydroisoquinolines (ABCB1) [48] , [62] , [63] and pyrrolopyrimidines (ABCC1) [49] , [64] have been described for both activators [48] , [49] and inhibitors [62] , [63] , [64] of ABCB1 and ABCC1, respectively. Other examples are the compound classes of phenothiazines [65] , [66] and purines [49] , [67] , [68] , which have been described to comprise of ABCC1 activators [49] , [65] , [66] and ABCB1 inhibitors [65] , [66] , [67] , [68] .…”