L-CARNITINE ESTERS AS SOFT, BROAD-SPECTRUM ANTIMICROBIAL AMPHIPHILES

A new class of antimicrobial, ''soft'', quaternary ammonium L-carnitin e esters, of the type (CH3)(3)N+-CH2-CHOCO(R-1)-CH2-COO(R-2) Cl-, has been designed, with R-1 and R-2 being in general long-chain alkyl subs tituents. The series shows good activity against a wide range of bacte ria, yeasts, and fungi. Lipophilicity has been measured by RP-HPLC met hod to give the logarithm of the experimental capacity factor (log k') , and a quantitative relationship has been determined between log k' a nd the theoretical partition coefficient (CLOGP); also, bond-dipole de scriptors have been introduced into calculations by accounting for pol ar moieties present within the apolar cores of the molecules, giving a more refined calculated capacity factor (log k'(calcd)) Finally the l atter has been related to the antimicrobial activity (MIC values). The proposed models are predictive for the best broad-spectrum antimicrob ial compound within the series.