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• 111-02-4 2,6,10,15,19,23-hexamethyltetracosa-2,6,10,14,18,22-hexaene 

Relevant academic research and scientific papers

Importance of the methyl group at C(10) of squalene for hopene biosynthesis and novel carbocyclic skeletons with 6/5 + 5/5 + (6) ring system(s)

Squalene-hopene cyclase (matrix presented) Incubation of (6E,10E,14E,18E)-2,6,10,19,23-pentamethyl-tetracosa-2,6,10,14,18,22-hexaene with Alicyclobacillus acidocaldarius hopene cyclase afforded four products having two types of carbocyclic skeletons, i.e., two hopane products and two products having an unprecedented carbocyclic skeleton of 6/5 + 5/5 +6 pentacyclic and 6/5 + 5/5 tetracyclic ring systems. The former two hopane skeletons were formed from the bioconversion of C(15)-desmethylsqualene and the latter two skeletons from that of C(10)-desmethylsqualene.

Investigation of the Effects of Squalene and Squalene Epoxides on the Homeostasis of Coenzyme Q10 in Rats by UPLC-Orbitrap MS

Squalene has been used as a dietary supplement for a long history due to its potential cancer-preventive function. However, the mechanism has not been investigated in detail yet. Therefore, the aim of this study is to see if the plasma coenzyme Q10 (CoQ10) level will be altered by gavage of squalene and oxidosqualenes to rats. In the present work, a sensitive and simple high-performance analytical method based on ultra-high-performance liquid chromatography coupled with an Orbitrap mass spectrometry (UPLC-Orbitrap-MS) was developed for the quantification of CoQ10 in rat plasma. Coenzyme Q9 (CoQ9) was employed as the internal standard. CoQ10 was determined after acetonitrile-mediated plasma protein precipitation using UPLC-Orbitrap-MS in negative ion mode. Intragastric administration of squalene and the two squalene epoxides into rats once daily for several days elevated the level of CoQ10 in their plasma, but there was no significant difference between high-dose (286 mg/kg) and low-dose (143 mg/kg) groups. Intragastric administration of squalene once a day for 5 consecutive days and oxidosqualenes once a day for 3 consecutive days is necessary for reaching the steady-state level of CoQ10. Our present findings indicate that squalene and oxidosqualenes may be useful for stimulating the synthesis of CoQ10 in rats.

Squalene-Hopene Cyclase: On the Polycyclization Reactions of Squalene Analogues Bearing Ethyl Groups at Positions C-6, C-10, C-15, and C-19

Squalene-hopene cyclase (SHC) has been found to convert acyclic squalene into 6,6,6,6,5-fused pentacyclic triterpenes hopene and hopanol. The enzymatic reactions of squalene analogues bearing ethyl groups in lieu of methyl groups at positions C-6, C-10, C-15, and C-19 have been examined to investigate whether the larger ethyl substituents (a C1 unit increment) are accepted as substrates and to investigate how these substitutions affect polycyclization cascades. Analogue 6-ethylsqualene 19a did not cyclize, which indicates that substitution with the bulky group at C-6 completely inhibited the polycyclization reaction. In contrast, 19-ethylsqualene 19b afforded a wide spectrum of cyclization products, including mono-, bi-, tetra-, and pentacyclic products in a ratio of 6:6:1:2. The production of tetra- and pentacyclic scaffolds suggests that the reaction cavity for D-ring formation site is somewhat loosely packed and can accept the 19-ethyl group, and that a robust hydrophobic interaction exists between the 19-ethyl group and the binding site. In contrast to 19b, 10-ethylsqualene 20a and 15-ethylsqualene 20b afforded mainly mono- and bicyclic products, that is, the polycyclization cascade terminated prematurely at the bicyclic reaction stage. Therefore, the catalytic domains for the 10- and 15-methyl binding sites are tightly packed and cannot fully accommodate the Et substituents. The cyclization pathways followed by the ethyl-substituted substrates in the presence of SHC and lanosterol and β-amyrin synthases are compared.

Two concise enantioselective total syntheses of (-)-glabrescol implicate alternative biosynthetic pathways starting from squalene

The C2-symmetric (-)-glabrescol was synthesized in two steps from (10S,11R)-dihydroxy-10,11-dihydrosqualene or squalene with 50% or 10% overall yields, respectively. These highly efficient and biomimetic syntheses employed a base-promoted middl

Squalene-hopene cyclase: Insight into the role of the methyl group on the squalene backbone upon the polycyclization cascade. Enzymatic cyclization products of squalene analogs lacking a 26-methyl group and possessing a methyl group at C(7) or C(11)

To provide deep insight into the polycyclization reaction of squalene, some analogs were synthesized and incubated with the cell-free homogenates of the recombinant Escherichia coli encoding the wild-type squalene cyclase. The presence of C(6)-Me leads to an efficient polycyclization cascade. Substitution of the C(14)-H and the C(18)-H with a methyl group halted the polycylization reaction at the tricyclic ring stage having a 6/6/6-fused ring system and the tetracycle with a 6/6/6/6-fused ring, respectively, both of which were produced according to a Markovnikov closure. Replacement of the C(7)-H and the C(11)-H with a methyl group led to no cyclization. These results, in conjunction with our previous reports, indicated that the methyl positions are important for bringing to completion of the normal polycylization reaction and further demonstrated that the precise steric bulk size at the methyl positions of squalene is critical to the correct folding and the strong binding of the substrate to the squalene cyclase.

New cyclization mechanism for squalene: A ring-expansion step for the five-membered C-ring intermediate in hopene biosynthesis

Three triterpenes having the 6/6/5-fused tri- and 6/6/6/5-fused tetracyclic skeletons were isolated from an incubation mixture of the mutated F601A enzyme, these products being in accordance with a Markovnikov closure. Successful trapping of the tricyclic

Epoxidation of Carbon-Carbon Double Bonds in Terpenes by Linoleic Acid Hydroperoxides

Epoxidation of C=C double bonds in terpenes is achieved by reaction with linoleic acid hydroperoxides (LOOH) exemplified with caryophyllene (3), methyl farnesoate (5) and squalene (8).Linoleic acid (9S)-hydroperoxide was obtained by reaction of linoleic acid (1) with lipoxygenase present in tomato homogenisate.When 18O2-labeled (9S)-LOOH (2) was used 18O was found in the terpene epoxide.While 3 is converted under physiological conditions regioselectivity in high yield into its 4,5-epoxide 4, the yield of epoxidized products from long-chain molecules, e.g. squalene (8), decreases strongly and no regioselectivity was observed. - Key Words: Terpenes/ Epoxides/ Linoleic acid derivatives/ Hydroperoxides/ Labeled compounds, 18O2

Stereospecific Synthesis of Squalenoid Epoxide Vinyl Ethers as Inhibitors of 2,3-Oxidosqualene Cyclase

The stereospecific synthesis of squalenoid epoxide vinyl ethers with an isopentyloxy group is described.The synthesis involves the preparation of the C22 squalenoid aldehyde bromohydrin (15) by a new method via a one-step cleavage of lipophilic epoxides using periodic acid in diethyl ether, and the preparation of (1-isopentyloxyethyl)diphenylphosphine oxide (24).The structure of this compound has been confirmed by X-ray analysis.The configuration of vinyl ethers, synthesized using a Wittig-Horner reaction, has been determined by (13)C n.m.r.Biological results show that vinyl ethers (5) and (27) are competitive inhibitors of 2,3-oxidosqualene cyclase from rat liver.