Stimulatory Effect of Wasabi Leafstalk Extract (Wasabia japonica MATSUM.) on Bone Calcification: Interaction with Bone Anabolic Factors in Mouse Calvaria Tissue in Vitro

Abstract

The stimulatory effect of wasabi leafstalk extract (Wasabia japonica MATSUM.) on bone calcification was compared with the anabolic effect of insulin, insulin-like growth factor I (IGF-I), 17β-estradiol, and genistein. Mouse calvaria tissues were cultured for 48 h in a serum-free Dulbecco’s modified Eagle’s medium (high glucose, 4.5%). The presence of wasabi leafstalk extract (25 μg/ml) caused significant increases in bone calcium content. The combination of 10−10 M 17β-estradiol and 15 μg/ml wasabi leafstalk extract had an additive effect on bone calcium content, while the increasing effect of phyotoestrogen genistein (10−9 or 10−7 M) on this content was not significantly greater in the presence of the same amount of the extract. Insulin (10−8 or 10−7 M) had a significant effect on bone calcium content, and the combination of both 10−8 or 10−7 M insulin with 15 μg/ml wasabi leafstalk extract had an additive effect. Such an effect was not seen in the case of IGF-I (10−8 M), however which increased bone calcium content. The present study demonstrates that wasabi leafstalk extract has an enhancing effect on the anabolic action of 17β-estradiol or insulin, which regulates bone formation and calcification in vitro.