catechol structure on the A ring were able to compensate and become a larger determinant of flavonoid antiradical ... (secondary metabolite) flavonoids In plant product, their relatively low toxicity compared to ohter active ... activity생체 내 anti-oxidant 방어 기전생체가 이용한 산소 중 1-3%는 스트레스로 인해 유해한 ROS(Reactive Oxygen Species)으로 변함.