Dual roles of QOA-8a in antiosteoporosis: a combination of bone anabolic and anti-resorptive effects

Recent advances in medicinal chemistry of oleanolic acid derivatives

Oleanolic acid (OA), a ubiquitous pentacyclic oleanane-type triterpene isolated from edible and medicinal plants, exhibits a wide spectrum of pharmacological activities and tremendous therapeutic potential. However, the undesirable pharmacokinetic properties limit its application and development. Numerous researches on structural modifications of OA have been carried out to overcome this limitation and improve its pharmacokinetic and therapeutic properties. This review aims to compile and summarize the recent progresses in the medicinal chemistry of OA derivatives, especially on structure-activity relationship in the last few years (2010-2021). It gives insights into the rational design of bioactive derivatives from OA scaffold as promising therapeutic agents.

Evolving Roles of Natural Terpenoids From Traditional Chinese Medicine in the Treatment of Osteoporosis

Osteoporosis (OP) is a systemic metabolic skeletal disease which can lead to reduction in bone mass and increased risk of bone fracture due to the microstructural degradation. Traditional Chinese medicine (TCM) has been applied in the prevention and treatment of osteoporosis for a long time. Terpenoids, a class of natural products that are rich in TCM, have been widely studied for their therapeutic efficacy on bone resorption, osteogenesis, and concomitant inflammation. Terpenoids can be classified in four categories by structures, monoterpenoids, sesquiterpenoids, diterpenoids, and triterpenoids. In this review, we comprehensively summarize all the currently known TCM-derived terpenoids in the treatment of OP. In addition, we discuss the possible mechanistic-of-actions of all four category terpenoids in anti-OP and assess their therapeutic potential for OP treatment.

Oleanolic Acid and Ursolic Acid Improve Bone Properties and Calcium Balance and Modulate Vitamin D Metabolism in Aged Female Rats

Oleanolic acid (OA) and ursolic acid (UA) are the major chemical constituents in Fructus Ligustri Lucidi (FLL), a kidney-tonifying Chinese herb that is previously shown to improve bone properties and enhance calcium balance in aged female rats. The present study was designed to study if OA and UA act as the active ingredients in FLL to exert the positive effects on bone and mineral metabolism in aged rats. Aged (13-month-old) Sprague-Dawley female rats were randomly assigned to four groups with oral administration of drug or vehicle treatment for 12 weeks: medium calcium diet (MCD, 0.6% calcium), high calcium diet (HCD, 1.2% calcium), MCD + FLL (700 mg/kg/day), MCD + OA (23.6 mg/kg/day) + UA (8.6 mg/kg/day). A group of mature (3-month-old) female rats fed with MCD was included as positive control. The results demonstrated that FLL and OA+UA increased bone mineral density and improved microarchitectural properties of aged female rats. The osteoprotective effects of FLL and OA+UA might be, at least in part, associated with their actions on enhancing calcium balance and suppressing age-induced secondary hyperparathyroidism in aged female rats. FLL and OA+UA also significantly induced renal CYP27B1 protein expression and OA+UA treatment decreased CYP24A1 mRNA and protein expressions in aged female rats. In addition, FLL and OA+UA significantly increased the promoter activity, mRNA and protein expressions of renal CYP27B1 in vitro in human proximal tubule HKC-8 cells. The present findings suggest that OA+UA can be regarded as the active ingredients of FLL and might be a potential drug candidate for prevention and treatment of osteoporosis.

Effects of a standard high-fat diet with or without multiple deficiencies on bone parameters in ovariectomized mature rat

The aim of this study was to determine the effects of a standard high fat diet (D12451) with or without vitamin D3, phosphorus, and calcium (i.e., high-fat diet [HFD] or high-fat deficient diet [HFDD]) on the bone parameters of ovariectomized female rats. Six-month-old of female Sprauge Dawley (SD) rats were randomly divided into six study groups: sham operation with standard chow diet (SSCD), sham operation with a HFD (SHFD), sham operation with a HFDD (SHFDD), ovariectomized (OVX), OVX with a HFD (OVX-HFD), and OVX with a HFDD (OVX-HFDD). A bilateral ovariectomy was administered to the OVX, OVX-HFD, and OVX-HFDD rats, while the SSCD, SHFD, and SHFDD rats were only given a laparotomy. Multiple analyses concerning the glucose and insulin tolerance, structure, bone strength, bone matrix, and mineralization of the rats were conducted in order to produce a detailed characterization of the effects of a HFD and a HFDD on postmenopausal osteoporotic rats. Seven months of HFD and HFDD feeding resulted in obesity and insulin resistance in female SD rats. A standard HFD increased the bone calcium content and bone strength of OVX rats. Conversely, the serum N-mid osteocalcin (N-MID-OT) and tartrate-resistant acid phosphatase (TRAP) levels in the OVX-HFDD group were increased, accompanied by a clear decrease in the bone mineral density (BMD), bone mineral content (BMC), bone calcium and bone strength, as well as reduced osteocalcin expression. A HFDD weakened the activity of the osteoblasts while aggravating bone loss and decreasing bone strength in ovariectomized rats, which may be due to the calcium, phosphorus and vitamin D3 deficiencies in the diet.