JOURNAL OF COSMETIC SCIENCE 338 represented the stronger anti-oxidative ability. Figure 3 shows the effect of anthocyanin extracts on the reducing ability of anthocyanins that were extracted using acidic ethanol and acidic water. The reducing ability of acidic ethanol and water extracts was signifi cantly dif- ferent (p 0.05) at 1.25%, 5%, and 10% of anthocyanin extract content. The relationship between the reducing ability and anthocyanin content was almost linear. Thus, using more anthocyanin extracts resulted in a better reducing ability. Meanwhile, the acidic ethanol-extracted anthocyanins showed a higher reducing ability compared to acidic water-extracted anthocyanins. According to the above results, using more anthocyanin extracts resulted in better DPPH radical scavenging activity, higher total phenolic content, and higher reducing ability. The acidic ethanol-extracted anthocyanins were good anti-oxidative ingredients for the cosmetic cream. Adding anthocyanin extracts to the cosmetic cream not only provides ultra-UV protective ability, but also helps skin against free radicals. Figure 4 shows the UV absorption ability of a cosmetic cream at different wavelengths measured by the spectrophotometric method. The addition of anthocyanin extract dra- matically improves the UV-absorbing ability of the cosmetic cream for both UV-A (350 and 375 nm) and UV-B (300 and 325 nm), with the improvement being more signifi cant for the UV-B. The cosmetic cream with the anthocyanin extract was more effective for UV-B absorbance than for UV-A. The results revealed that anthocyanin extracts are ideal Table II Total Phenolic Content of Acidic Ethanol (AE) and Acidic Water (AW) Extracts of Purple Sweet Potato Total phenolic content (μg gallic acid equivalent/ml sample) Extract added (%) 1.25% 2.5% 5% 10% AE extract 14.08 ± 1.61∗ 27.38 ± 1.83∗ 56.26 ± 7.34 97.26 ± 9.07 AW extract 8.96 ± 1.25 18.60 ± 1.62 47.19 ± 5.16 80.95 ± 8.86 Each value is mean ± SD (n=3). ∗Indicates a signifi cant difference ( p 0.05) between the two groups. Figure 3. Reducing ability of acidic ethanol (AE)- and acidic water (AW)-extracted anthocyanin solutions. Each value is the mean ± SD (n=3) of the experiments performed. *Indicates a signifi cant difference ( p0.05) between the two groups.

PURPLE SWEET POTATO EXTRACTS IN UV PROTECTION 339 ingredients for absorbing UV radiation. Without the addition of anthocyanin extracts, the UV-A and UV-B absorption ability of the cosmetic cream was low. Figure 5 shows the fraction of incident UV radiation that is absorbed by the cosmetic cream. Without the addition of anthocyanin extract, the cosmetic cream absorbed ap- proximately 30% of the UV radiation. When 5 ml of the anthocyanin extract (0.61 mg of Figure 4. The UV absorbance of a cosmetic cream with the UV-A and UV-B regions measured by the spec- trophotometric method ( : no anthocyanin extract added : 0.61 mg/100 g anthocyanin extract added : 1.22 mg/100 g total anthocyanins added). Figure 5. The infl uence of anthocyanin extract on the percentage UV radiation absorbed.