Inhibitory activity of Drynariae rhizoma extracts on cathepsin having bone resorption activity.
Effects of traditional Korean (Hanbang) medicine, Drynariae rhizoma (DR), on the protease activity of bone loss-initiation in rats and mice were investigated. Ethanol extracts-DR (EE-DR) and water extracts-DR (WE-DR) were identified as potent inhibitor of cathepsins K and L. The original WE-DR inhibits cathepsins K and L with IC50 values of 3.7 microg/ml and 4.5 microg/ml, respectively. EE-DR was more potent than that of WE-DR, because the inhibitions of cathepsin K and L increased to 0.5 microg/ml and 0.8 microg/ml, respectively. The EE-DR was proved to be the most potent. EE-DR was found to be a potent inhibitor of cathepsins K with a Ki value of 5.0 microg/ml for cathepsin K. The activity was increased by 10-fold when the assay is performed in the presence of glutathione at pH 7.0, which favors the formation of a GSH thiolate anion. Thus, it is suggested that this increase in potency is probably due to an enhanced chemical reactivity of the extract mixtures toward the thiolate of the active site of the enzyme. WE-DR exhibited time-dependet inhibition which allowed us to determine the association and dissociation rate constants with cathepsin K. Finally, EE-DR inhibits bone resorption in an in vitro assay involving mouse osteoclasts and bovine bone with an IC50 value of 70 microg/ml. WE-DR represents a new herbal formulation inhibiting cathepsin K and L activity and proteolysis of bone collagen. These results strongly suggest that DR is effective for preventing the development of bone loss induced by cathepsin K. This result also suggested that the DR is effective for bone resorptive action in bone cells.
Jeong
Ji-Cheon
JC
Department of Biochemistry and Internal Medicine, Dongguk University College of Oriental Medicine, MOST, Kyungju, Kyungbuk, Korea.
Yoon
Cheol-Ho
CH
Jeong
Chang-Whan
CW
Lee
Young-Choon
YC
Chang
Young-Chae
YC
Kim
Cheorl-Ho
CH
D000818:Animals; D001665:Binding Sites; D001862:Bone Resorption / Q000201:enzymology*; D056657:Cathepsin K; D056668:Cathepsin L; D002403:Cathepsins / Q000037:antagonists & inhibitors*; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases; D015853:Cysteine Proteinase Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology*; D000431:Ethanol; D020128:Inhibitory Concentration 50; D007723:Korea; D051379:Mice; D008807:Mice, Inbred BALB C; D010006:Osteoblasts / Q000187:drug effects* / Q000201:enzymology; D010936:Plant Extracts / Q000493:pharmacokinetics / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry; D029621:Polypodiaceae; D051381:Rats; D027343:Rhizome / Q000737:chemistry; D014867:Water
D015853:Cysteine Proteinase Inhibitors; D010936:Plant Extracts; D014867:Water; D000431:Ethanol; D002403:Cathepsins; D003546:Cysteine Endopeptidases; D056668:Cathepsin L; C534278:Ctsl protein, mouse; C534280:Ctsl protein, rat; D056657:Cathepsin K; C534132:Ctsk protein, mouse; C534133:Ctsk protein, rat