Osteoporosis is a common metabolic bone-related disease characterized by low bone mass and micro architectural deformation of bone tissue leading to increased bone fragility and fractures. Primary type 1 osteoporosis or postmenopausal osteoporosis takes place most commonly in women after menopause. Primary type 2 osteoporosis or senile osteoporosis is seen in both females and males after age 75.

Bone integrity abnormality and imbalance between bone formation by osteoblasts and bone resorption by osteoclasts are known to result in metabolic bone diseases such as osteoporosis.

Silymarin-rich milk thistle extract (MTE) and its component silibinin enhanced alkaline phosphatase activity of osteoblasts but reduced tartrate-resistant acid phosphatase (TRAP) activity of osteoclasts.

The osteoprotective effects of MTE were comparable to those of estrogenic isoflavone. Low-dose combination of MTE and isoflavone had a pharmacological synergy that may be useful for osteogenic activity.

This study attempted to reveal the suppressive effects of MTE on bone loss. Female mice were ovariectomized (OVX) as a model for postmenopausal osteopenia and orally administered 10 mg/kg MTE or silibinin for 8 weeks. The sham-operated mice served as estrogen controls. The treatment of ovariectomized mice with nontoxic MTE and silibinin improved femoral bone mineral density. In addition, the administration of MTE or silibinin inhibited femoral bone loss induced by ovariectomy. Collectively, oral dosage of MTE containing silibinin in the preclinical setting is effective in preventing estrogen deficiency-induced bone loss.

1. Kim, J-L.,  Kim, Y.H., Kang, M.K., Gong, J.H.,  Han, S.J., & �Kang, Y.H. (2013). Antiosteoclastic Activity of Milk Thistle Extract after Ovariectomy to Suppress Estrogen Deficiency-Induced Osteoporosis. BioMed Research International, 2013, Article ID 919374, 11 pages. Retrieved from http://dx.doi.org/10.1155/2013/919374