Autors: Nian H, Qin LP, Chen WS, Zhang QY, Zheng HC and Wang Y

Research Institute: Department of Pharmacognosy, School of Pharmacy, Second Military Medical University, Shanghai (China)

Publication: Acta Pharmacologica Sinica. 2006 June;27(6):728-34

Many postmenopausal women suffer from osteoporosis, caused by reduced serum levels of estrogen. Menopause causes increased bone turnover, imbalance between bone absorption and resorption, and net bone loss. Hormone replacement therapy is widely used to combat this bone loss but is associated with increased risk of some cancers, including breast cancer. Therefore, there is still a need to look for alternative treatments of osteoporosis. The aim of this study was to determine the protective role on bone loss of steroidal saponins from Anemarrhena asphodeloides on ovariectomized rats. Ovariectomized rats are used as model of postmenopausal women because they share similar chracteristics. Anemarrhena asphodeloides is traditionally used for treatment of diabetes, lung disease, fever and constipation. This herb contains more than 5% steroidal saponins. The similarity in structure of steroidal saponins and human estrogens may explain the estrogenic effect of the steroidal saponins.

The rats were treated with nylestriol (drug that is metabolized into ethynyl estriol and estriol) or steroidal saponins during 12 weeks. The researchers found that the steroidal saponins changed serum parameters: the level of alkaline phosphatase increased and the level of osteocalcin decreased. Nylesterol treatment recovered the serum levels of calcium and phosphorus but steroidal saponins only recovered the calcium level. Body weight was not influenced by the treatment. They found that the atrophy of the uterus and decrease of bone mineral density were decreased. Saponins also resulted in increased bone formation. Mophological examination of sections of the proximal tibia bone showed that steroidal saponins improved trabecular thickness and increased the ratio of bone area to tissue area but did not increase the number of osteoclasts. The steroidal saponins demonstrated a mild estrogenic activity by increasing the uterine weight and increasing serum estradiol level. The study concluded that steroidal saponins of Anemarrhena asphodeloides prevented ovariectomized induced bone loss in rats.