The protective effects of echinochrome A structural analogs against oxidative stress and doxorubicin in AC16 cardiomyocytes

Backgrounds Echinochrome A (6-ethyl-2,3,5,7,8-pen-tahydroxy-1,4-naphthoquinone) is a common naphthoquinone pigment found in the shells, spines, and coelomic fluid of sea urchins. We previously reported that echinochrome A has a cardioprotective function as an antioxidant against reactive oxygen species (ROS) induced by tert-Butyl hydroperoxide and doxorubicin. Methods In the current study, we evaluated the antioxidant activity, ATP production, and oxygen consumption rate (OCR) of seven echinochrome structural analogs (spinochromes) in AC16 human cardiomyocyte cells. The compounds included in the study had various substituents including hydroxyl (Sp B and Sp E), amino (Echm A), methoxyl (TriMeEch A), pentyl (No. 284), and hydroxypentyl (No. 285). We also investigated the effects of one dimeric spinochrome (Binaphthoquinone). Results Spinochromes exhibited enhanced antioxidant activity and ATP production. Interestingly, the hydroxylated compounds significantly enhanced the OCR and had a cardiomyocyte protective effect in the presence of doxorubicin. Conclusion Our findings indicate that echinochrome A structural analogs may have therapeutic potential for cardio-protection.