1900-53-4Relevant academic research and scientific papers
24β-METHYLCHOLESTA-5,22E,25-TRIEN-3β-OL AND 24α-ETHYL-5α-CHOLEST-22E-EN-3β-OL FROM CLERODENDRUM FRAGRANS
Akihisa, Toshihiro,Ghosh, Parthasarathi,Thakur, Swapnadip,Oshikiri, Satoshi,Tamura, Toshitake,Matsumoto, Taro
, p. 241 - 244 (1988)
Two minor sterols isolated from Clerodendrum fragrans were identified as 24β-methylcholesta-5,22E,25-trien-3β-ol and 24a-ethyl-5α-cholest-22E-en-3β-ol of which the former has so far been detected only in a marine sponge.The other sterols identified in the plant were clerosterol, 22E-dehydroclerosterol and several other common sterols.Key Word Index - Clerodendrum fragrans; Verbenaceae; sterol; 24β-methylcholesta-5,22E,25-trien-3β-ol; 24α-ethyl-5α-cholest-22E-en-3β-ol.
Stereoselective synthesis and NMR characterization of C-24 Epimeric Pairs of 24-Alkyl oxysterols
Ogawa, Shoujiro,Kawamoto, Hiroaki,Mitsuma, Takashi,Fujimori, Hiroki,Higashi, Tatsuya,Iida, Takashi
, p. 197 - 207 (2013)
Two pairs of C-24 epimeric (24R)-/(24S)-24-hydroxy-24-methyl-5α- cholestan-3β-yl acetates and (24R)-/(24S)-25-hydroxy-24-methyl-5α- cholestan-3β-yl acetates as well as some related 24-ethyl oxysterol analogs were stereoselectively synthesized directly from the respective parent 24-alkyl sterols by a remote O-insertion reaction with 2,6-dichloropyridine N-oxide (DCP) in the presence of a catalytic amount of (5,10,15,20- tetramesitylporphrinate) ruthenium(II) carbonyl complex [Ru(TMP)CO] and HBr. 1H- and 13C-NMR signals serving to differentiate each of the two epimeric pairs were interpreted. The C-24 alkyl oxysterols epimeric at C-24 were found to be effectively characterized by the aromatic solvent-induced shift (ASIS) by C5D5N, particularly for the difference in the 13C resonances in the substituted cholestane side chain. A method for differentiating the 1H and 13C signal assignment of the terminal 26-/27-CH3 in the iso-octane side chain was also discussed on the basis of a combined use of the preferred conformational analysis and HMQC and HMBC techniques. The present method may be useful for determining the stereochemical configuration at C-24 of this type of 24-alkyl oxysterols.
Oxidized derivatives of dihydrobrassicasterol: Cytotoxic and apoptotic potential in U937 and HepG2 cells
Kenny, Olivia,O'Callaghan, Yvonne,O'Connell, Niamh M.,McCarthy, Florence O.,Maguire, Anita R.,O'Brien, Nora M.
experimental part, p. 5952 - 5961 (2012/10/07)
The ability of phytosterol compounds to reduce plasma serum cholesterol levels in humans is well investigated. However, phytosterols are structurally similar to cholesterol with a double bond at the C5-6 position and are therefore susceptible to oxidation. Much research has been carried out on the biological effects of cholesterol oxidation products (COPs) in vitro. In contrast, there is less known about phytosterol oxidation products (POPs). From previous studies, it is apparent that oxidized derivatives of the phytosterols, β-sitosterol and stigmasterol, are cytotoxic in vitro but are less potent than their COP counterparts. In the present study, the cytotoxic and apoptotic potential of oxidized derivatives of dihydrobrassicasterol (DHB) including 5α,6α-epoxyergostan-3β-ol (α-epoxide), 5β,6β-epoxyergostan-3β-ol (β-epoxide), ergost-5-en-7-on- 3β-ol (7-keto), ergost-5-ene-3β,7β-diol (7-β-OH), and ergostane-3β,5α,6β-triol (triol) were evaluated in the U937 and HepG2 cell lines. In general, 7-keto, 7-β-OH, and triol derivatives had a significant cytotoxic impact on U937 and HepG2 cells. The oxides appear to be more toxic toward U937 cells. In line with previous findings, the POPs investigated in this study were less potent than the equivalent COPs. The results add to the body of data on the toxicity of individual POPs.
A concise synthesis of β-sitosterol and other phytosterols
Hang, Jiliang,Dussault, Patrick
experimental part, p. 879 - 883 (2010/10/19)
A convenient synthesis of sidechain-modified phytosterols is achieved via a temporary masking of the stigmasterol 5,6-alkene as an epoxide. Following performance of the desired modification, the alkene is regenerated through a mild deoxygenation. The approach is applied to the syntheses of β-sitosterol and campesterol acetate, and suggests a facile route to the (Z)-isomers of Δ22-23 phytosterols.
