Specially-treated Soy Sauces Regulate Antioxidant Activity and ROS in Human Astrocyte U373MG Cells

Abstract

Oxidative stress is an outcome of the over-production of reactive oxygen species (ROS) that overwhelms the antioxidant capacities of the cells. Soy sauces have been used for the purpose of prevention and treatment of various diseases in Korea for centuries. Soy sauce is specially fermented and made of special ingredients including bean, wheat, and salt. We investigated the protective effects of soy sauces on ROS production against the H2O2 induced oxidative stress in U373MG cells. We further examined the SOD activity of soy sauces as an antioxidant to determine the effectiveness of bamboo salt (BS) in regard to inhibition of ROS formation. Soy sauces with BS inhibited ROS formation by a factor of 3 to 4 times higher compared with NaCl based soy sauce and even by 1.9 to 2.5 times higher than vitamin E. The SOD activity of BS based soy sauce-pretreated cells, as an antioxidant, were 2.6 to 3.8 times higher than that of vitamin E. On the other hand, NaCl based soy sauce had no significant difference of SOD activity from vitamin E and NaCl. The antioxidant activity of soy sauce is fairly dependent of the quality of the salt used. Therefore, specially treated soy sauce is considered to be an effective antioxidant to inhibit and even eliminate ROS. Consequently, it will not only prevent and treat various oxidative stress-induced diseases, but also delay human brain cell damage-induced aging.