Herba Epimedii: An Ancient Chinese Herbal Medicine in the Prevention and Treatment of Osteoporosis.

Herba Epimedii (HEP) known as YinYangHuo in Chinese is the dried leaf of the Epimediium, and has been historically used in combination with other herbs to treat skeletal diseases in traditional Chinese medicine (TCM). Here, we review the historical TCM interpretation of the action of HEP, its use in clinical trials, its main phytochemical constituents and its pharmacological findings. 85 clinical trials were identified which used HEP in TCM prescriptions with other herbs to treat primary and secondary osteoporosis from 2005 to now. More than 60 individual compounds were isolated and characterized from HEP and studied in various animal and cell models. HEP and its constituents exhibited a variety of anti-resorptive and bone formation-stimulating effects, which target different pathways in the bone remodeling cycle. These compounds may provide new perspectives in alternative treatment regimes and reveal novel chemical scaffolds for the development of anti-osteoporotic drugs. These approaches are also useful for guiding our research to employ an integrative therapeutic approach to treat complex diseases such as osteoporosis diseases which could be superior to the conventional single target - single drug approach.