Figure 7

Clock time-dependent changes of neutral lipids (cholesterol ester, CE; triglyceride, TG; free fatty acid, FFA; free cholesterol, C) and lipid hydroperoxide of lip surface. Certain amount of internal standard elaidic acid methyl ester, which appears between the spots of triglyceride and cholesterol ester in the TLC, was mixed in the PVDF membrane after extraction of lip lipids and co-extracted as shown in Fig. 1. These neutral lipids were developed on TLC with hexane:diethylether:acetic acid (80:30:1) and charred by 50% sulfuric acid at 170°C for nearly 30 min. The TLC patterns were incorporated in computer with scanner, and the charred spots were quantitated in intensity with Scion Image software (Scion Co., Israel) using a gel-plotting macro program. The amounts of the neutral lipids in μg unit were calculated in comparison with the amount of the internal standard, 20 μg of elaidic acid methyl ester, and under the present condition the extent of darkness of charred spot (after conversion to optical density by Scion Image program) was linearly well correlated with amount of neutral lipids. In this case the amount of lipids in lip thus calculated was correspond to the amount of lipids extracted to the PVDF membrane in one wiping event of the lip surface.