Comparative study of two types of herbal capsules with different Epimedium species for the prevention of ovariectomised-induced osteoporosis in rats

Background/Objective: Epimedii Folium is the most important osteogenic herb formulated for the traditional Chinese Medicine Xian Ling Gu Bao (XLGB) capsule. The present study compared XLGB capsules containing two different Epimedium species, i.e., either Epimedium pubescens (XEP) or Epimedium koreanum (XEK), with the focus being on the chemical constituents and antiosteoporotic efficacy. Methods: Ultra performance liquid chromatography was used to demonstrate the different chemical constituents. Biomechanical tests, histological, and cytological evaluation were performed to characterise and compare the bone mineral density, bone strength, microstructure of bone tissue, and biological activity between XEP and XEK using an established ovariectomised (OVX) rat model. Results: Six flavonoids with different contents between XEK and XEP were identified. As compared with the OVX group, significantly higher bone mineral density, elastic-modulus, and compressive strength were found in both the XEK group and XEP group (p < 0.05 for all, n = 8). Histomorphometric data presented significantly higher osteoblast surface ratio and osteoid area accompanied by significantly lower values of erosion surface and adiopocytes area in two treatment groups (p < 0.05, n = 6). XLGB Fufang with either XEK or XEP all showed significant preventive effects in OVX-induced osteoporosis and deterioration of bone mechanical properties. Conclusion: The significance of the current preclinical experimental study was that these two Epimedium species used for formulating XLGB capsules were equally effective for the prevention of oestrogen-depletion induced osteoporosis.