In this study, we investigated the protective effects of Ulva lactuca methanol extracts against ultraviolet B (UVB)-induced DNA damage in HaCaT cells. First, the contents of general and antioxidative nutrient contents of Ulva lactuca were measured. The moisture, carbohydrate, crude protein, crude fat and ash were 14.01%, 44.80%, 23.19%, 3.10% and 14.90%, respectively. Magnesium that acts as DNA repair enzyme cofactor was the most abundant mineral followed by Ca, P and Fe. The total phenolic and anthocyanoside contents of Ulva lactuca were 2.69 mg/g and 0.13 mg/g, respectively. Cells treated with Ulva lactuca methanol extracts for 24 hours post UVB exposure increased cell viability in a concentration-dependent manner compared to the non-treated control. Also, Ulva lactuca methanol extracts decreased the levels of UVB-induced DNA damage such as cyclobutane pyrimidine dimer and DNA damage response (DDR) proteins such as p-p53 and p21. These results suggest that Ulva lactuca methanol extracts comprising physiological active substances such as Mg, polyphenols and anthocyanosides promote DNA repair by regulating genes related with DDR.

Abstract
서 론
재료 및 방법
    1. 재료 및 추출물의 제조
    2. 일반성분 분석
    3. 무기성분 분석
    4. 총 폴리페놀 함량 분석
    5. 총 안토시아노사이드 함량 분석
    6. 세포 배양
    7. UV 조사 및 시료처리
    8. MTT assay
    9. Immunodot blot assay (IBD)
    10. Western blot
    11. 통계처리
결과 및 고찰
    1. 일반성분 함량
    2. 무기성분 함량
    3. 총 폴리페놀 및 안토시아노사이드 함량
    4. 세포활성도 측정
    5. IBD
    6. Western blot
요약 및 결론
References

• 정슬아(원광대학교 생물학과) | Seula Jeong (Major in Dept. of Biological Science, Wonkwang University)
• 정유헌(원광대학교 생물학과) | Yuheon Chung (Major in Dept. of Biological Science, Wonkwang University)
• 박종군(원광대학교 생명과학부) | Jong Kun Park (Major in Dept. of Biological Science, Wonkwang University) Corresponding author