1.Synthesis, metabolism, and biological activity of 2-[3-(tetrazolyl)propyl]-1α,25-dihydroxy-19-norvitamin D3.
Takano M1, Yasuda K2, Higuchi E1, Tohyama E2, Takeuchi A3, Sakaki T2, Kittaka A4. J Steroid Biochem Mol Biol. 2015 Jul 29. pii: S0960-0760(15)30029-7. doi: 10.1016/j.jsbmb.2015.07.016. [Epub ahead of print]
Recently, we found that 2α-[2-(tetrazol-2-yl)ethyl]-1α,25-dihydroxyvitamin D3 showed higher osteocalcin promoter transactivation activity in human osteosarcoma (HOS) cells and a greater therapeutic effect in ovariectomized (OVX) rats in vivo than those of active vitamin D3, 1α,25(OH)2D3. We were interested in introducing a heterocyclic ring to the C2 position of the seco-steroidal structure via an alkyl linker, and four novel C2-(3-tetrazolylpropyl) substituted 1α,25-dihydroxy-19-norvitamin D3 analogs, 2α-[3-(tetrazol-1-yl)propyl]-, 2β-[3-(tetrazol-1-yl)propyl]-, 2α-[3-(tetrazol-2-yl)propyl]-, and 2β-[3-(tetrazol-2-yl)propyl]-19-nor-1α,25(OH)2D3 were synthesized. Among them, 2α-[3-(tetrazol-1-yl)propyl]-19-nor-1α,25(OH)2D3 showed weak binding affinity for human vitamin D receptor (hVDR) (2.6% of 1α,25(OH)2D3 and ca. 15% of 19-nor-1α,25(OH)2D3) and weak VDR transactivation activity in HOS cells (EC50 7.3nM, when 1α,25(OH)2D30.23nM). Although the other three compounds could not act as VDR binders by evaluation of the competition assays, 2α-[3-(tetrazol-2-yl)propyl]-19-nor-1α,25(OH)2D3 showed weak transactivation activity (EC50 12.
2.A new suprasterol by photochemical reaction of 1α,25-dihydroxy-9-methylene-19-norvitamin D3.
Kulesza U1, Plum LA2, DeLuca HF2, Mouriño A3, Sicinski RR4. Org Biomol Chem. 2016 Jan 27;14(5):1646-52. doi: 10.1039/c5ob01896j.
The UV-induced photochemical reaction of 1α,25-dihydroxy-9-methylene-19-norvitamin D3 has been investigated. The pentacyclic structure of the isolated product has been unequivocally established by X-ray crystallographic analysis. The possible reaction paths of the examined photochemical transformation are discussed. Biological in vivo and in vitro tests proved that the photoproduct is devoid of calcemic activity.
3.Long-term treatment with eldecalcitol (1α, 25-dihydroxy-2β- (3-hydroxypropyloxy) vitamin D3) suppresses bone turnover and leads to prevention of bone loss and bone fragility in ovariectomized rats.
Takeda S1, Smith SY, Tamura T, Saito H, Takahashi F, Samadfam R, Haile S, Doyle N, Endo K. Calcif Tissue Int. 2015 Jan;96(1):45-55. doi: 10.1007/s00223-014-9937-5. Epub 2014 Dec 4.
The purpose of this study is to estimate the efficacy of eldecalcitol (1α, 25-Dihydroxy-2β- (3-hydroxypropyloxy) vitamin D3; ELD) on bone metabolism after long-term administration. Six-month-old Wistar-Imamichi rats were ovariectomized (OVX) and administered ELD orally at doses of 7.5, 15, or 30 ng/kg daily. Bone mineral density (BMD), urinary excretion of deoxypyridinoline (DPD), a bone resorption marker, and serum total alkaline phosphatase (ALP), a surrogate marker of bone formation, were assessed after 3, 6, and 12 months of treatment. After 12 months of treatment, the biomechanical strength of the L4 lumbar vertebra and femoral shaft was measured, and bone histomorphometry was performed on the L3 lumbar vertebra and the tibia diaphysis. ELD prevented OVX-induced decreases in BMD of the lumbar vertebrae and femur throughout the treatment period. ELD significantly suppressed OVX-induced increases in urinary DPD excretion throughout the treatment period with minimal effects on ALP.
4.Synthesis and properties of 14-epi-1α,25-dihydroxy-19-nortachysterol and its 2-substituted derivatives.
Sawada D, Kittaka A1. Curr Top Med Chem. 2014;14(21):2454-9.
As the first stable tachysterol analogs, 14-epi-19-nortachysterol and its 2-substituted derivatives were synthesized using the Stille coupling reaction between the A-ring precursor (three vinylstannanes) and the CD-ring vinyl trifrate. Among them, the 2-methylidene group was hydrogenated with Wilkinson's catalyst regioselectively to obtain 2α- and 2β-methyl analogs after separation; therefore, five new 14-epi-19- nortachysterols were constructed. All 14-epi-19-nortachysterols showed moderate to strong human vitamin D receptor (hVDR) binding affinity except the 2α-(3-hydroxypropoxy) substituted analog. X-ray cocrystallographic analysis of the [truncated hVDR]-[2-methyl-14-epi-19-nortachysterol] complex exhibited an unusual binding structure that has not been observed previously.