OBJECTIVE: The aim of this study was to determine the skeletal effect of 6-C-β-d-glucopyranosyl-(2S,3S)-(+)-3′,4′,5,7- tetrahydroxyflavanone (GTDF)/Ulmoside A, a new compound isolated from the extract of Ulmus wallichiana in a rat model of postmenopausal bone loss. METHODS: GTDF (1.0 and 5.0 mg kg-1 d-1) was given orally to ovariectomized (OVx) rats (180-200 g) for 12 weeks. Sham operated + vehicle, ovariectomy + 17β-estradiol (2.5 μg kg-1 d-1), and ovariectomy + vehicle groups served as various controls. Bone mineral density (BMD), trabecular microarchitecture, bone biomechanical strength, levels of bone turnover/resorption markers, uterotropic effect, and plasma pharmacokinetics were studied. One-way analysis of variance was used to test significance of effects. RESULTS: OVx rats treated with both doses of GTDF exhibited significantly higher BMD in the trabecular (distal femur, proximal tibia, and vertebrae) and cortical (femur shaft) regions compared with the ovariectomy + vehicle group. Micro-CT demonstrated that OVx rats treated with 5.0 mg kg -1 day -1 of GTDF had better bone microarchitectural parameters compared with the ovariectomy + vehicle group. Serum osteocalcin and urinary C-terminal teleopeptide of Type I collagen levels in OVx rats treated with GTDF (at both doses) were significantly lower than those in the ovariectomy + vehicle group. At neither of the two doses did GTDF exhibit uterine estrogenicity. A pharmacokinetic study revealed that GTDF achieved maximum plasma concentration (40.67 ng mL-1) at ∼1 hour, indicating its slow absorption. Its absolute bioavailability was found to be 1.04% with a plasma elimination half-life of ∼5 hours. CONCLUSIONS: GTDF, a novel compound isolated from U wallichiana extract, improves bone biomechanical quality through positive modifications of BMD and trabecular microarchitecture without a hyperplastic effect on the uterus.
- Bone strength