Effects of Ecklonia cava Extract on Neuronal Damage and Apoptosis in PC-12 Cells against Oxidative Stress

Abstract

Marine algae (seaweed) encompass numerous groups of multicellular organisms with various shapes, sizes, and colors, and serve as important sources of natural bioactive substances. The brown alga Ecklonia cava Kjellman, an edible seaweed, contains many bioactives such as phlorotannins and fucoidans. Here, we evaluated the antioxidative, neuroprotective, and anti-apoptotic effects of E. cava extract (ECE), E. cava phlorotannin-rich extract (ECPE), and the phlorotannin dieckol on neuronal PC-12 cells. The antioxidant capacities of ECPE and ECE were 1,711.5 and 1,050.4 mg vitamin C equivalents/g in the ABTS assay and 704.0 and 474.6 mg vitamin C equivalents/g in the DPPH assay, respectively. The dieckol content of ECPE (58.99 mg/g) was approximately 60% higher than that of ECE (36.97 mg/g). Treatment of PC-12 cells with ECPE and ECE increased cell viability in a dose-dependent manner. Intracellular oxidative stress in PC-12 cells due to ECPE and ECE decreased dose-independently by up to 63% and 47%, respectively, compared with the stress control (323%). ECPE reduced the production of the pro-apoptotic proteins Bax and caspase-3 more effectively than ECE. Early and late apoptosis in PC-12 cells were more effectively decreased by ECPE than ECE treatments. From the results obtained in this study, we concluded that ECPE, which is rich in phlorotannins, including the marker compound dieckol, may be applied to the development of functional materials for improving cognition and memory.

Neuroprotective activity of macroalgal fucofuroeckols against amyloid β peptide‐induced cell death and oxidative stress

“…By contrast, Lee et al (2019) reported that eckol and dieckol were not toxic up to a concentration of 100 µM. Additionally, Shin et al (2021) reported that dieckol at a concentration of 50 µg mL À1 (approx. 67 µ M) protected PC12 cells against H 2 O 2 (200 µM) (Shin et al, 2021).…”

“…The brain is more vulnerable than other organs to oxidative stress due to the high consumption of oxygen, relatively low levels of endogenous antioxidant capacity and generation of superoxides by the action of various oxidases and nitric oxide synthase (Yavin et al ., 2002). Oxidative stress can impair redox homeostasis and induce mitochondrial dysfunction, leading to damage in neuronal cells (Li et al ., 2020) and H 2 O 2 has previously been used to effectively generate cytosolic oxidative stress (Cai et al ., 2008; Shin et al ., 2021). Our results demonstrated that the fucofuroeckols PFFA and 974‐A were able to prevent H 2 O 2 ‐induced death in PC12 cells, while no protective effects were observed with eckol and dieckol (Fig.…”

“…Additionally, Shin et al . (2021) reported that dieckol at a concentration of 50 µg mL −1 (approx. 67 µ m ) protected PC12 cells against H 2 O 2 (200 µ m ) (Shin et al ., 2021).…”

“…(2021) reported that dieckol at a concentration of 50 µg mL −1 (approx. 67 µ m ) protected PC12 cells against H 2 O 2 (200 µ m ) (Shin et al ., 2021). This variability could be due to the difference in phlorotannin concentrations and/or the PC12 cells, where PC12 cells displaying a semi‐differentiated phenotype with neuronal projections (Ordway subclone) (Dixon et al ., 2005) were used in the present study, whereas these previous studies used undifferentiated cells (Lee et al ., 2019; Shin et al ., 2021).…”