The objectives of this study were to determine inhibitory effect on tyrosinase activity and antioxidant activity of the methanolic extract from grape seeds and to investigate relationships between tyrosinase inhibitory activity and antioxidant activity of the extract. The 80% methanol extracts of grape seeds were fractionated subsequently with hexane, chloroform, ethyl acetate and water. The methanolic extract and fractions from grape seeds inhibited tyrosinase activity in a concentration dependent manner. The methanolic extracts showed the highest inhibitory effects on tyrosinase activity. The inhibitory effects of the ethyl acetate fraction from the methanolic extract on tyrosinase activity was higher than other fractions. The ethyl acetate fraction from methanolic extracts showed higher antioxidant activity and contained higher polyphenolic and flavonoid contents compared to other fractions. The correlation coefficients among the polyphenoilc content of methanolic extracts, ABTS radical cation scavenging activity and inhibitory effect of tyrosinase were relatively high. These results suggest that grape seeds may have potential as a depigmentation agent for cosmetics and functional food products.
Purpose:The aim of this study is to identify Korean high school students' health behaviors and perceived stress and to examine effects of their health behaviors on their stress perception. Methods: The subjects were 33,744 high school students who participated in the 11th Korea youth risk behavior web-based survey 2015 in Korea. Data were analyzed using complex samples analysis with the PASW 18.0 program. The questionnaire utilized in this study is designed to find the subjects' general characteristics, health behaviors, and perceived stress. Results: The prevalence of subjects with high level stress was 38.9% (n=13,137) in this study. There were significant differences in the general characteristics and stress perception among the Korean high school students in terms of gender, grade, school achievement, family's affluence, mother's education, perceived happiness, perceived health status, and stressor. The variables of health behaviors of Korean high school students were significantly different from stress perception. Under complex samples logistic regression, predictive factors of stress for the high school students include gender, grade, father's education, family's affluence, living arrangement, perceived health status, perceived happiness, current smoking, current alcohol experience, and enough sleep. Conclusion: The study suggests multilateral efforts are needed to help high school students' stress management including health behaviors for high school students.
The purposes of this study were aimed to evaluate the antioxidant and antiproliferative activities of water, methanol, and 70% acetone extracts from pepper leaves. The antioxidant activity was evaluated by ABTS and DPPH radical scavenging activities, reducing power, and chelating effect. Moreover, the effects of the extracts on cell proliferation of breast (MCF7), colon (HCT116), and gastric (MKN45) tumor cells were investigated. Higher extraction yields were obtained with methanol than with 70% acetone and water. Among the three different solvents, 70% acetone extract showed the highest polyphenolic contents. 70% acetone extracts showed higher antioxidant activities compared with other extracts. Also, 70% acetone extract of pepper leaves exhibited higher antiproliferative activity (>80%) against HCT116 and MKN45 cells compared with other samples at the concentration of 1 mg/mL. These results indicate that pepper leaves may serve as potential dietary sources of natural antioxidants and antiproliferative substances.
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