WATER-SOLUBLE ELASTIN AS A COSMETIC MATERIAL 17 Figure 3. Chromatograms for HAPA-elastin and its fractions derived from gel fi ltration chromatography. Chromatograms for (a) HAPA-elastin, (b) fraction 1, and (c) fraction 2. Elution times of the molecular mass standards: (i) thyroglobulin (670,000 Da), (ii) γ-globulin (158,000 Da), (iii) ovalbumin (44,000 Da), (iv) myoglobin (17,000 Da), and (v) vitamin B12 (1,350 Da) are indicated with arrows.

JOURNAL OF COSMETIC SCIENCE 18 Da, respectively. As shown in Figure 3, the distinctive peak observed in the chromato- grams for HAPA-elastin and fraction 1 represents a peptide with a molecular weight of 7,000 Da. The intensity of this peak decreased in the chromatogram for fraction 2. It confi rmed that the molecular weight distribution in fraction 2 was different from that in HAPA-elastin and fraction 1. In addition, only fraction 2 showed a broad peak represent- ing a high-molecular-weight peptide. MOISTURE-RETAINING PROPERTY The water content of LabCyte treated with HAPA-elastin, fraction 1, and fraction 2 is shown in Figure 4. The water content of LabCyte was measured to demonstrate the use- fulness of elastin in maintaining the skin moisture. The water content of the control LabCyte was 49.4% ± 10.1%. Treatment of LabCyte surface with HAPA-elastin at elas- tin concentrations of 0.1% (w/w) and 1.0% (w/w) increased the water content signifi - cantly to 58.4% ± 5.7% and 65.7% ± 8.9%, respectively. However, increasing the HAPA-elastin concentration to 8.0% resulted in a LabCyte water content of only 52.4% ± 4.9%. In fact, the highest concentration of HAPA-elastin that induced the highest water content in LabCyte was 1.0% (w/w). Similar results were observed with fractions 1 and 2. The water content of LabCyte was 59.5% ± 4.9%, 65.4% ± 5.7%, and 77.2% ± 7.8% when fraction 1 was applied at con- centrations of 0.02% (w/w), 0.1% (w/w), and 1.0% (w/w), respectively. There were sig- nifi cant differences in the water contents between the control and fraction 1-treated samples at all the concentration levels studied. The water content of LabCyte was 52.5% ± 8.2%, 55.9% ± 6.8%, and 66.6% ± 8.1% at fraction 2 concentrations of 0.02%, 0.1%, and 1.0% (w/w), respectively. A statistically signifi cant difference was detected in the water content between the control LabCyte and that treated with 1.0% fraction 2. The highest water content in LabCyte in the study was 77.2%, which was approximately 1.5-fold higher than that of the control, and was obtained using fraction 1 at a concentration of 1.0% (w/w). INHIBITION OF TYROSINASE ACTIVITY The inhibitory effects of HAPA-elastin and fractions 1 and 2 on the activity of tyrosinase were examined in an in vitro assay using mushroom tyrosinase (Figure 5). Vitamin C (1.0 mg/ml) was used as a positive control and showed 99% ± 0.86% inhibition. HAPA- elastin showed a weak inhibitory effect on tyrosinase activity. At concentrations of 1.0 and 10 mg/ml, HAPA-elastin inhibited the activity of tyrosinase by about 4% and 12%, respectively. These results indicate the concentration-dependent inhibitory effects of HAPA-elastin on tyrosinase activity. At 10 mg/ml, fraction 1 showed a relatively weaker inhibitory effect than HAPA-elastin on tyrosinase activity. Conversely, fraction 2 inhib- ited tyrosinase to about the same extent as HAPA-elastin did. These results clearly indi- cate that the high-molecular-weight fractions in HAPA-elastin have an inhibitory effect on tyrosinase, demonstrating their potential as skin-lightening materials in cosmetics provided the activity can be further enhanced. DISCUSSION In this study, we investigated HAPA-elastin (water-soluble elastin) as a cosmetic material. The molecular weight of HAPA-elastin ranged from 1,350 to 670,000 Da (Figure 3).