Lipophilicity of Flavonoids Estimated by Reversed-Phase High Performance Thin-Layer Chromatography: Chemically Bonded Plates vs. Impregnated Plates with Oils, Animal, and Human Fats

Abstract

Silica gel plates impregnated with a variety of oils (olive oil, sunflower oil, corn oil, trioctylamine, and paraffin oil) and fats (margarine, butter, cod liver fat, pig fat, sheep fat, pullet fat, and human fat) were evaluated and compared with the commercially available reversed-phases TLC plates (RP-18, RP-18 W, and CN). A representative series of flavonoids is employed to evaluate the suitability of oils and fats as reversed-phases for TLC and to provide different lipophilicity indices: RM0, scores corresponding to first principal component of RF and/or RM, arithmetic mean of RF and RM values obtained with solvent mixture containing various concentrations of methanol in water. The retention results were excellent (r > 0.96) and allowed for accurate estimation of lipophilicity of selected flavonoids and to ranking the lipophilicity of oils and fats when comparing with chemically bonded phases. The human fat-impregnated plates provided lipophilicity values closely associated with those obtained for margarine and butter. Moreover, the human fat lipophilic character seems to be placed between pullet and cod fats. Concerning the lipophilicity scale of vegetable oils, it is worth noting that the corn oil presents the highest lipophilicity, closely followed by the sunflower and olive oils.