Zeolite a inhibits osteoclast‐mediated bone resorption in vitro

The effects of Zeolite A on Bone resorbing activity of highly purified avian osteoclasts were analyzed. The present study demonstrates that when 100 pg/ml of acid‐treated Zeolite A is added to the media the number of pits per osteoclast is reduced 3‐fold at 24h after treatment. Secreted cathepsin B enzyme activity was also reduced 3‐fold. A similar reduction in pit number per osteoclast was measured following 48 h of treatment with Zeolite A but there appeared to be less reduction of cathepsin B enzyme activity. The effects on pit number and cathepsin B Protein activity were Zeolit dose dependent. The structure of the compound seemed to be responsible for the effects measured since compounds used to represent constituents of Zeolite A (silicon dioxide and aluminum cholride) failed to inhibit bone resorption or reduce the level of secreted cathepsin B enzyme activity. Thus the molicular architecture of Zeolite A or a derivative there of appears to be inportant. In conclusion, the data indicate that Zeolite A can inhibit bone resorption. Together with previous data on osteoblasts, this might suggest a potential positive activity of intact Zeolite A or a partial substructure of Zeolite A on bone turnover. © Wiley‐Liss, Inc.