5E-Calcipotriol is a geometric analog of vitamin D derivative calcipotriol. It was shown to enhance anticancer activity of 5-fluorouracil in an in vivo mouse colon cancer model and anticancer activity of imatinib in an in vivo lung cancer model. The compound also demonstrated activity in a subcutaneous MCF-7 model of breast cancer in vivo. The detailed mechanism of action for 5E-calcipotriol is not known.

Cholecalciferol (/ˌkoʊləkælˈsɪfərɒl/) (vitamin D3) is one of the five forms of vitamin D. Cholecalciferol is a steroid hormone that has long been known for its important role in regulating body levels of calcium and phosphorus, in mineralization of bone, and for the assimilation of Vitamin A. The classical manifestation of vitamin D deficiency is rickets, which is seen in children and results in bony deformities including bowed long bones. Most people meet at least some of their vitamin D needs through exposure to sunlight. Ultraviolet (UV) B radiation with a wavelength of 290–320 nanometers penetrates uncovered skin and converts cutaneous 7-dehydrocholesterol to previtamin D3, which in turn becomes vitamin D3. In supplements and fortified foods, vitamin D is available in two forms, D2 (ergocalciferol) and D3 (cholecalciferol) that differ chemically only in their side-chain structure. Vitamin D2 is manufactured by the UV irradiation of ergosterol in yeast, and vitamin D3 is manufactured by the irradiation of 7-dehydrocholesterol from lanolin and the chemical conversion of cholesterol. The two forms have traditionally been regarded as equivalent based on their ability to cure rickets and, indeed, most steps involved in the metabolism and actions of vitamin D2 and vitamin D3 are identical. Both forms (as well as vitamin D in foods and from cutaneous synthesis) effectively raise serum 25(OH) D levels. Firm conclusions about any different effects of these two forms of vitamin D cannot be drawn. However, it appears that at nutritional doses, vitamins D2 and D3 are equivalent, but at high doses, vitamin D2 is less potent. The American Academy of Pediatrics (AAP) recommends that exclusively and partially breastfed infants receive supplements of 400 IU/day of vitamin D shortly after birth and continue to receive these supplements until they are weaned and consume ≥1,000 mL/day of vitamin D-fortified formula or whole milk. Cholecalciferol is used in diet supplementary to treat Vitamin D Deficiency. Cholecalciferol is inactive: it is converted to its active form by two hydroxylations: the first in the liver, the second in the kidney, to form calcitriol, whose action is mediated by the vitamin D receptor, a nuclear receptor which regulates the synthesis of hundreds of enzymes and is present in virtually every cell in the body. Calcitriol increases the serum calcium concentrations by increasing GI absorption of phosphorus and calcium, increasing osteoclastic resorption, and increasing distal renal tubular reabsorption of calcium. Calcitriol appears to promote intestinal absorption of calcium through binding to the vitamin D receptor in the mucosal cytoplasm of the intestine. Subsequently, calcium is absorbed through formation of a calcium-binding protein.

24-Cyclopropyl-1α,3β-BIS(((1,1-Dimethylethyl)dimethylsilyl)oxy)-9,10-secochola-5,7,10(19),22-tetraen-24-ol, (5Z,7E,22E,24S)- is the tert-Butyldimethylsilyl ether conjugate of Calcipotriene (C144200), a vitamin D3 analogue with potential antitumor activities. 24-Cyclopropyl-1α,3β-BIS(((1,1-Dimethylethyl)dimethylsilyl)oxy)-9,10-secochola-5,7,10(19),22-tetraen-24-ol, (5Z,7E,22E,24S)- is used in Calcipotriol synthesis. The physiological and toxicological properties of this compound have not been evaluated.

24R-Calcipotriol (PRI 2202) is an impurity of Calcipotriol. 24R-Calcipotriol shows the strong antiproliferative activity on the human breast cancer cell line MCF-7

MC-1046 (Impurity A of Calcipotriol) is the C22-23-unsaturated 24-ketone, an active metabolite of the synthetic vitamin D analog calcipotriol (calcipotriene, MC 903). Calcipotriene is a ligand of VDR-like receptors approved for topical dermatological use indicated for the treatment of plaque psoriasis. It is approved by FDA in United States under the trade name Dovonex. Calcipotriol displays minimal effects on calcium homeostasis, and regulates cell differentiation, and proliferation exhibiting antiproliferative activity against human HL-60, HL60/MX2, MCF-7, T47D, SCC-25 and mouse WEHI-3 cancer cell lines. Calcipotriol is an effective anti-proliferative agent when applied topically at high concentrations but it is relatively “noncalcemic” in vivo (administered perorally, intravenously or intraperitoneally) because it can be metabolized by a variety of cells to metabolites with reduced biological activity as was demonstrated in vitro using rat and human cell lines from liver, bone, kidney, and keratinocytes. MC1046 is the initial calcipotriol metabolite which concentration reaches a steady state after 4 h of incubation with cells in vitro whereas the concentration of another major MC 903 metabolite MC1080, C22-23-saturated 24-ketone, continues to increase linearly over the time period tested (20 h). These two metabolites have also been detected in vivo in serum from rats and pigs dosed with MC903. MC1046 has the ability to stimulate e VDRE-mediated human growth hormone production in COS-1 cells co-transfected with pSG5hVDR1/3 and (CT4)4TKGH vectors and also binds to VDR although with lower (1/133) binding affinity compared to calcipotriol.