Stereoselective synthesis of (26R)-26-hydroxydiosgenin and its effect on the regulation of rat ovarian function.

The stereoselective cyclization of a C-16 acetylated 22,26-dioxocholestene derivative to give the spirostane E and F rings, under alkaline conditions, yields exclusively the (26R)-26-hydroxydiosgenin. Both experimental and computational data support the formation of a single diastereoisomer. The effect of diosgenin and (26R)-26-hydroxydiosgenin on rat ovary is also investigated.

-Hydroboration-oxidation products in Δ-steroids a hydroboration--hydroboration mechanism.

Herein, we report for the first time a "-hydroboration-oxidation product" isolated and characterized under traditional hydroboration-oxidation conditions using cholesterol and diosgenin as substrates. These substrates are excellent starting materials because of the rigidity and different structural environments around the double bond. Further investigations based on experimental evidence, in conjunction with theoretical studies, indicate that the formation of this -species occurs a -hydroboration of the major product to generate the corresponding Δ-structure and the subsequent hydroboration by the β-face.

Apoptotic, necrotic, and antiproliferative activity of diosgenin and diosgenin glycosides on cervical cancer cells.

(25R)-spirost-5-en-3β-ol, also known as diosgenin (DSG), exerts antiproliferative activity on diverse cell lines, induces apoptosis, and acts as a chemopreventative agent. However, the relationship between DSG glycosides and apoptotic, necrotic, and antiproliferative activity remains unclear. It is in this regard that we report the antiproliferative, necrotic, and apoptotic activities of DSG and its glycoside derivatives: (25R)-spirost-5-en-3β-yl O-β-D-glucopyranoside (3GD), (25R)-spirost-5-en-3β-yl O-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranoside (3GRD); and (25R)-spirost-5-en-3β-yl O-α-L-rhamnopyranosyl-(1 → 2)-O-[α-L-rhamnopyranosyl-(1 → 4)]-β-D-glucopyranoside), also known as dioscin (DSC), in in vitro assays of cervical HeLa and CaSki cancer cells.

Mimicking natural phytohormones. 26-Hydroxycholestan-22-one derivatives as plant growth promoters.

26-Hydroxycholestan-22-one derivatives with oxygenated functions in the rings A and/or B were successfully synthesized from diosgenin. After the modifications of rings A and B, the spiroketal side chain was selectively opened through a Lewis acid mediated acetolysis to afford the cholestane derivatives. These compounds incorporate pharmacophores, which mimic the activity of natural phytohormones and show high growth promoting activity in Mexican rice cultivars using the rice lamina inclination test.

Regioselective Spirostan E-Ring Opening for the Synthesis of Dihydropyran Steroidal Frameworks.

The regioselective opening of the ring E in spirostan sapogenins provides new dihydropyran derivatives. This novel side chain is obtained after a Lewis acid mediated acetolysis followed by an alkaline workup. The reaction mechanism is analyzed via density functional theory computations, and both experimental and computational data support the formation of an oxacarbenium intermediate.

22-Oxocholestanes as plant growth promoters.

The spirostanic steroidal side-chain of diosgenin and hecogenin was modified to produce 22-oxocholestane derivatives. This type of side-chain was obtained in good yields through a straightforward four-step pathway. These compounds show potent brassinosteroid-like growth promoting activity evaluated via the rice lamina joint inclination bioassay.