Cytotoxicity to tumors by alpha, beta-dihydric long-chain fatty alcohols isolated from esterolysates of uncytotoxic sheep cutaneous wax: the dependence on the molecular hydrophobicity balance of N- or iso-alkyl moiety bulkiness and two hydroxyl groups

Wool fatty alcohols (WF-Alc; C10-C33), separated by esterolysis of wool grease secreted from sheep sebaceous gland, inhibited growth of mouse Ehrlich ascites carcinoma (EAC) cells in contrast to no inhibition by unesterolysed wool grease. WF-Alc was fractionated by molecular distillation and subsequent octadecylsilica (ODS) gel liquid chromatography, showing that most of the growth-inhibitory activity was found in the most hydrophilic fraction with the lowest boiling-point (MW 200-300; C12-C20), ODS-HPLC of the fraction showed that most of the activity resided in two homogeneous fractions identified by GC-MS and 13C-/1H-NMR as alpha, beta-dihydric saturated fatty alcohols such as 1,2-hexadecanediol (n-C16(OH)2) and 16-methyl-1,2-heptadecanediol (iso-C18(OH)2), respectively. EAC cells implanted into mice were inhibited markedly by n-C16(OH)2 possessing a cytolysing ability and slightly by iso-C18(OH)2, but hardly by other alkyl-alpha, beta-diols (C12-C24) contained in WF-Alc. Thus, the antitumor activity of WF-Alc was exhibited only after saponification of uncytotoxic wool grease, showing necessity of unesterified hydroxyl groups, and was dependent upon the molecular hydrophobicity balance attributed to both hydroxyl groups and n- or iso-alkyl moiety bulkiness specified out of diverse species of fatty alcohols contained in WF-Alc.