- Photo-conversion of two epimers (20R and 20S) of pregna-5,7-diene-3β, 17α, 20-triol and their bioactivity in melanoma cells
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Pregna-5,7-dienes and their hydroxylated derivatives can be formed in vivo when there is a deficiency in 7-dehydrocholesterol (7-DHC) Δ-reductase function, e.g., Smith-Lemli-Opitz syndrome (SLOS). Ultraviolet B (UVB) radiation induces photoconversion of 7-DHC to vitamin D3, lumisterol3 and tachysterol3. Two epimers (20R and 20S) of pregna-5,7-diene-3β,17α,20-triol (4R and 4S, respectively) were synthesized and their UVB photo-conversion products identified as corresponding 9,10-secosteroids with vitamin D-like and tachysterol-like structures, and 5,7-dienes with inverted configuration at C-9 and C-10 (lumisterol-like). The number and character of the products and the dynamics of the process were dependent on the UVB dose. At high UVB doses, the formation of multiple oxidized derivatives of the primary products, and the formation of 5,7,9(11)-triene, were observed. The production of vitamin D-like, tachysterol-like and lumisterol-like derivatives was also observed in human skin treated with 4R and 4S, and subjected to UV irradiation, as shown by RP-HPLC. Newly synthesized compounds inhibited melanoma growth in dose dependent manner, and some of them showed equal or higher potency than 1,25(OH)2D3. In summary, we have characterized for the first time the products of UV induced conversion of pregna-5,7-diene-3β,17α,20-triols and documented that the newly synthesized compounds have antiproliferative properties against melanoma cells.
- Zmijewski, Michal A.,Li, Wei,Zjawiony, Jordan K.,Sweatman, Trevor W.,Chen, Jianjun,Miller, Duane D.,Slominski, Andrzej T.
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scheme or table
p. 218 - 228
(2009/04/14)
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- Microwave induced selective enolization of steroidal ketones and efficient acetylation of sterols in semisolid state
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Under microwave irradiation steroidal enones, more specifically, position three carbonyls were efficiently and selectively converted to the corresponding enol acetates in the presence of additional enolizable carbonyl functions at other positions, using acetic anhydride and a catalytic amount of toluene-p-sulfonic acid. Acetylation of hydroxyl groups of the sterols, including those at the hindered positions, was near quantitative. Strictly anhydrous conditions were not a pre-requisite for acetylation and the reaction system easily tolerated up to 10% (v/v) moisture.
- Marwah, Padma,Marwah, Ashok,Lardy, Henry A.
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p. 2273 - 2287
(2007/10/03)
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