Hearing loss is a prevalent sensory disorder in which oxidative stress plays a central role in cochlear damage. This study evaluated the cytoprotective and antioxidant effects of Sargassum thunbergii (Mertens ex Roth) Kuntze(ST) extracts in UB-OC1 cells and investigated the underlying molecular mechanisms. Among the fractions, the water extract (STW) and celluclast-assisted extract (STC) showed low cytotoxicity and significantly attenuated H2O2-induced cell damage, whereas the other fractions showed higher toxicity. STW and STC effectively reduced the intracellular reactive oxygen species (ROS) levels in a dose-dependent manner, indicating direct antioxidant activity. Mechanistically, STW and STC enhanced NRF2 activation, as evidenced by the increased intracellular accumulation and nuclear localization of NRF2. Although Nrf2 mRNA expression showed only modest changes, the downstream target gene HO-1 was significantly upregulated, while keap1 expression was reduced, suggesting enhanced NRF2 stabilization and activation. These findings show that STW and STC protect cochlear hair cell-like cells against oxidative stress-induced damage by suppressing ROS accumulation and activating the NRF2/HO-1 signaling pathway. These results suggest that S. thunbergii may be a promising functional resource for protecting auditory hair cell-like cells against oxidative stress.

Abstract
I. 서 론
II. 연구 내용 및 방법
    1. 소재 준비
    2. 세포배양
    3. 세포 생존율 측정
    4. ROS 측정
    5. 면역세포화학염색(Immunocytochemistry)
    6. Quantitative real-time PCR
    7. 통계 처리
III. 결과 및 고찰
    1. ST 추출물의 UB-OC1 세포 독성 평가
    2. ST 추출물의 H2O2 유도 산화 스트레스에 대한 세포 보호효과
    3. ST 추출물의 활성산소종 생성 억제 효과
    4. ST 추출물의 NRF2 signaling pathway 활성화 효과
IV. 요약 및 결론
감사의 글
Conflict of Interest
References

• 이정은(한국식품연구원, 식품기능연구본부) | Jung-Eun Lee (Food Functionality Research Division, Korea Food Research Institute, Wanju 55365, Republic of Korea)
• 김태연(한국식품연구원, 식품기능연구본부, 전남대학교 식품공학과) | Taeyeon Kim (Food Functionality Research Division, Korea Food Research Institute, Wanju 55365, Republic of Korea, Department of Food Science & Technology, Chonnam National University, Gwangju 61216, Republic of Korea)
• 김윤태(한국식품연구원, 식품기능연구본부, 한국과학기술연합대학원대학교) | Yun-Tai Kim (Food Functionality Research Division, Korea Food Research Institute, Wanju 55365, Republic of Korea, Department of Food Biotechnology, University of Science and Technology, Daejeon 34113, Republic of Korea)
• 이재광(한국식품연구원, 식품기능연구본부, 한국과학기술연합대학원대학교) | Jaekwang Lee (Food Functionality Research Division, Korea Food Research Institute, Wanju 55365, Republic of Korea, Department of Food Biotechnology, University of Science and Technology, Daejeon 34113, Republic of Korea) Corresponding author
• 임승태(한국식품연구원, 식품융합연구본부) | Seung Tae Im (Food Convergence Research Division, Korea Food Research Institute, Wanju 55365, Republic of Korea)
• 강민철(한국식품연구원, 식품융합연구본부) | Min-Cheol Kang (Food Convergence Research Division, Korea Food Research Institute, Wanju 55365, Republic of Korea)