Number Of Minor Products Research Articles

Lumisterol is metabolized by CYP11A1: Discovery of a new pathway

Lumisterol3 (L3) is produced by photochemical transformation of 7-dehydrocholesterol (7-DHC) during exposure to high doses of ultraviolet B radiation. It has been assumed that L3 is biologically inactive and is not metabolized in the body. However, some synthetic derivatives of L3 display biological activity. The aim of this study was to test the ability of CYP11A1 to metabolize L3. Incubation of L3 with bovine or human CYP11A1 resulted in the formation of three major and a number of minor products. The catalytic efficiency of bovine CYP11A1 for metabolism of L3 dissolved in 2-hydroxypropyl-β-cyclodextrin was approximately 20% of that reported for vitamin D3 and cholesterol. The structures of the three major products were identified as 24-hydroxy-L3, 22-hydroxy-L3 and 20,22-dihydroxy-L3 by NMR. 22-Hydroxy-L3 was further metabolized by bovine CYP11A1 to 20,22-dihydroxy-L3. Both 22-hydroxy-L3 and 20,22-dihydroxy-L3 gave rise to a minor metabolite identified from authentic standard and mass spectrometry as pregnalumisterol (pL) (product of C20–C22 side chain cleavage of L3) and two trihydroxy-L3 products. The capability of tissues expressing CYP11A1 to metabolize L3 was demonstrated using pig adrenal fragments where 20,22-dihydroxy-L3, 22-hydroxy-L3, 24-hydroxy-L3 and pL were detected by LC/MS. Thus, we have established that L3 is metabolized by CYP11A1 to 22- and 24-hydroxy-L3 and 20,22-dihydroxy-L3 as major products, as well as to pL and other minor products. The previously reported biological activity of pL and the presence of CYP11A1 in skin suggest that this pathway may serve to produce biologically active products from L3, emphasizing a novel role of CYP11A1 in sterol metabolism.

Automated approach for ribosomal intergenic spacer analysis of microbial diversity and its application to freshwater bacterial communities.

An automated method of ribosomal intergenic spacer analysis (ARISA) was developed for the rapid estimation of microbial diversity and community composition in freshwater environments. Following isolation of total community DNA, PCR amplification of the 16S-23S intergenic spacer region in the rRNA operon was performed with a fluorescence-labeled forward primer. ARISA-PCR fragments ranging in size from 400 to 1,200 bp were next discriminated and measured by using an automated electrophoresis system. Database information on the 16S-23S intergenic spacer was also examined, to understand the potential biases in diversity estimates provided by ARISA. In the analysis of three natural freshwater bacterial communities, ARISA was rapid and sensitive and provided highly reproducible community-specific profiles at all levels of replication tested. The ARISA profiles of the freshwater communities were quantitatively compared in terms of both their relative diversity and similarity level. The three communities had distinctly different profiles but were similar in their total number of fragments (range, 34 to 41). In addition, the pattern of major amplification products in representative profiles was not significantly altered when the PCR cycle number was reduced from 30 to 15, but the number of minor products (near the limit of detection) was sensitive to changes in cycling parameters. Overall, the results suggest that ARISA is a rapid and effective community analysis technique that can be used in conjunction with more accurate but labor-intensive methods (e.g., 16S rRNA gene cloning and sequencing) when fine-scale spatial and temporal resolution is needed.

A rearrangement in the nitration of 3β, 17β-diacetoxy-7-norandrost-5-ene

The nitration of 3β,17β-diacetoxy-7-norandrost-5-ene by fuming nitric acid leads to 3β,17β-diacetoxy-5β-nitroxy-6α-nitro-7-norandrostane and to the rearrangement product 2. A number of minor products were also identified. The formation of these can be rationalized in terms of a Markownikoff directed diaxial (5β,6α) addition to the Δ5-double bond of the B-norsteroid which contrasts with the 5α,6β-diaxial addition found in the normal steroids.

The fate of an experimental MAO inhibitor, N-cyclopropyl-2-chlorophenoxyethylamine (Lilly 51641) in the rat and in man.

Abstract1. In vivo metabolism studies have shown N-cyclopropyl-2-chlorophenoxy-ethylamine (Lilly 51641) to be extensively metabolized in the rat. Those metabolites identified include 2-chlorophenoxyacetic acid, N-cyclopropyl-4-hydroxy-2-chlorophenoxyethylamine and 4-hydroxy-2-chlorophenoxyethanol, together with a number of minor products. The major route of elimination of these metabolites is through the kidney.2. The major in vitro metabolites of Lilly 51641 have been identified as 2-chlorophenoxyethylamine, 2-chlorophenoxyacetaldehyde, 2-chlorophenoxyacetic acid and 2-chlorophenoxyethanol. It thus appears that this drug is metabolized by the following sequence: N-dealkylation, deamination and aldehyde oxidation or reduction.3. Aromatic hydroxylation was found to be an independent but important mechanism involved in the metabolism of Lilly 51641.4. Human urinary metabolites of Lilly 51641 were separated and identified. The nature of these metabolites indicated that the same mechanisms of detoxication wer...

Chemistry of hop constituents. Part XXXIV. Methylation of some hop resins

The hop resins colupulone and cohulupone have been methylated using diazomethane and methyl iodide. O-Methylation was obtained with diazomethane, colupulone giving mainly 6-isobutyryl-5-methoxy-2,2,4-tri-(3-methylbut-2-enyl)cyclohex-4-ene-1,3-dione, together with a number of minor products probably corresponding to the many enol forms possible. Cohulupone gave a mixture of four mono-O-methyl derivatives corresponding to the four possible mono-enolic forms. Methyl iodide methylation of colupulone gave 5-hydroxy-4-isobutyryl-2-methyl-2,6,6-tri-(3-methylbut-2-enyl)cyclohex-4-ene-1,3-dione, existing as the two possible enol chelates. Methyl iodide methylation of cohulupone gave no recognisable products.

RADIOLYSIS OF CYCLOHEXANONE: I. PURE LIQUID

The G values of the major products of the gamma-radiolysis of liquid cyclohexanone are: hydrogen (0.76), carbon monoxide (0.45), 1-pentene (0.22), 5-hexenal (0.85), cyclohexenone (0.4), cyclohexanol (0.5), "dimer" (1.15), and polymer (1.8 cyclohexanone units). A large number of minor products were also measured.The amount of ring cleavage that occurs in cyclohexanone is much greater than that which occurs in the radiolysis of cyclohexane. The increase has been attributed to the influence of the carbonyl group on the course of the reaction. Ring cleavage occurs preferentially at the C—C bonds to the carbonyl group.Much of the radiolytic reaction appears to occur from energy states higher than those of importance in the photolytic studies.

REACTION OF 2-METHYL-2-NITRO-1,3-PROPANEDIOL WITH ALKALI

Hydrolysis of 2-methyl-2-nitro-1,3-propanediol with strong alkali (20% NaOH) resulted primarily, as expected, in a reverse aldol decomposition, although a small but significant quantity of free nitrite ion was detected. Hydrolysis with alkaline borate (pH 10) gave high yields of nitrite ion. Possible mechanisms to explain these results are presented. The major product formed in the borate hydrolysis was identified as 2-C-methyl glycerol (2-methyl-1,2,3-propanetriol). A number of minor products were also detected by vapor-phase chromatography.