Oxidative Stress :: Health, Diseases

Oxidative stress plays a critical role in the pathogenesis of various diseases including cancer, atherosclerosis, ischemic injury, inflammation and neurodegenerative diseases such as Parkinson's and Alzheimer's. As oxidative stress might be an important part of many human diseases, the use of antioxidants in pharmaceuticals and nutraceuticals is intensively studied. Natural antioxidants have been the focus of considerable interest in recent times [22]. To date antioxidant activity of E. cava has been extensively studied and documented. E. cava extracts and the isolated compounds exhibited strong antioxidant activity and this proven antioxidant properties of the brown seaweed as a valuable natural antioxidant source have been utilized into several industrial applications [23]. One of the previous studies [10] has shown antioxidant activities of phlorotannins purified from E. cava on free radical scavenging using electron spin resonance (ESR). The potential antioxidant activities of three phlorotannins namely phloroglucinol, eckol and dieckol purified from E. cava were evaluated and all the compounds showed potential radical scavenging activities and potential inhibitory effects on H2O2-mediated DNA damage as well. In addition, promising antioxidant properties of E. cava were reported with novel phlorotannin derivatives [7]. They have isolated and characterized seven phlorotannins from E. cava and according to the results all the phlorotannins exhibited potent antioxidant properties. Kang et al. [24] have investigated the cytoprotective effect of eckol, which was isolated from E. cava, against oxidative stress induced cell damage in V79-4 cells. Further, they suggested that eckol protects V79-4 cells against oxidative damage by enhancing the cellular antio xidant activity and modulating cellular signal pathway. Antioxidative effect of E. cava dried by far infrared radiation drying was reported by Lee et al. [25]. Methanolic extract from E. cava dried by far infrared radiation drying enhanced cell viability and H2O2 scavenging activity in Vero cells. It was also found that dieckol; a phlorotannin was the major antioxidant compound in this work. Interestingly, a study in antioxidant activity of brown algal phlorotannins demonstrated that phlorotannins of E. cava had significant radical scavenging activities against the superoxide anion and DPPH, and were more effective compared to ascorbic acid and ÃŽ ±-tocopherol [26]. Triphlorethol-A phlorotannin found in E. cava, protects V79-4 cells against oxidative stress induced cell death through up regulation of heme oxygenase-1 (HO-1) [27]. Further, they suggested triphlorethol-A augments cellular antioxidant defense capacity through induction of HO-1 via ERK-Nrf2-ARE signaling pathway, thereby protecting cells from oxidative stress. In another stud y cytoprotective effect of triphlorethol-A against ÃŽ ³-ray radiation-induced oxidative stress was reported [28].