Abstract: Provided herein are steroidal compounds that are androsta-5,7-dienes or a pregna-5,7-dienes and ultraviolet B (UVB) conversion products thereof which includes pharmaceutical compositions of the steroidal compounds as shown in Tables 1 and 2. Also provided is a method for producing hydroxylated metabolites of cholecalciferol or ergocalciferol via the P450scc (CYP11A1) or CYP27B1 enzyme systems where the hydroxylase has an activity to hydroxylate position C20 of a secosteroid or its 5,7-dieneal precursor and the hydroxylated metabolites so produced. In addition, a method for inhibiting proliferation of either a normally or abnormally proliferating cell by contacting the cell with any of the compounds described herein. A related method is provided of treating a condition associated with the proliferating cell such as a cancer, a skin disorder, a defect in cell differentiation, cosmetic, prophylaxsis, or healthy cell maintenance.

Abstract: Provided herein are steroidal compounds that are androsta-5,7-dienes or pregna-5,7-dienes and ultraviolet B (UVB) conversion products thereof and cholecalciferol derivatives hydroxylated at one or more of C1, C17, C20, C23, C24, C25, and C26 which includes pharmaceutical, cosmeceutical or nutraceutical compositions of the steroidal compounds as shown in Tables 1A, 2A and 3. Also provided is a method for producing hydroxylated metabolites of cholecalciferol via CYP11A1, CYP24, CYP27A1, or CYP27B1 enzyme systems where the hydroxylase has an activity to hydroxylate position C1 or C20 or other position of the sidechain of a secosteroid or its 5,7-dieneal precursor and the hydroxylated metabolites so produced.

Abstract: Provided herein are steroidal compounds that are androsta-5,7-dienes or a pregna-5,7-dienes and ultraviolet B (UVB) conversion products thereof which includes pharmaceutical compositions of the steroidal compounds as shown in Tables 1 and 2. Also provided is a method for producing hydroxylated metabolites of cholecalciferol or ergocalciferol via the P450scc (CYP11A1) or CYP27B1 enzyme systems where the hydroxylase has an activity to hydroxylate position C20 of a secosteroid or its 5,7-dieneal precursor and the hydroxylated metabolites so produced. In addition, a method for inhibiting proliferation of either a normally or abnormally proliferating cell by contacting the cell with any of the compounds described herein. A related method is provided of treating a condition associated with the proliferating cell such as a cancer, a skin disorder, a defect in cell differentiation, cosmetic, prophylaxsis, or healthy cell maintenance.