An extract of eisenia bicyclis stimulates mineralized nodule formation by osteoblasts

Diet is an important factor maintaining bone health. Several studies have reported that extracts of brown marine algae containing polyphenols positively regulate bone metabolism. Therefore, we examined the effects of Eisenia bicyclis (Japanese name, Arame), an edible brown marine algae, on cell proliferation, alkaline phosphatase activity, collagenous and non-collagenous bone matrix protein expressions, and mineralized nodule formation using ROS17/2.8 cells as osteoblasts. A thermal extract derived from E. bicyclis was applied to a Diaion HP-20 column, and a portion of the 50% ethanol fraction was used as the E. bicyclis extract. The cells were cultured in the presence or absence of E. bicyclis extract, and cell proliferation and alkaline phosphatase activity were determined. The expressions of type I collagen, bone sialoprotein, and osteopontin were examined at the mRNA level using real-time PCR. Mineralized nodule formation was detected via alizarin red staining. Alkaline phosphatase activity and the expressions of type I collagen, bone sialoprotein, and osteopontin were increased in the presence of E. bicyclis extract, whereas cell proliferation was not affected. The E. bicyclis extract also increased mineralization. Together, these results indicate that the extract induces osteogenic function in osteoblasts.