2-Hydroxy lauric acid

A number of fatty acid (palmitic, myristic and lauric) esters (both 3α- and 3β-isomers) of epibrassinolide has been prepared as reference compounds for metabolic studies. Selective protection of the three of four hydroxyl groups of epibrassinolide was successively performed first as cyclic 22,23-methylboronates and then as 2α-benzyl ethers. α,β-Inversion of C-3 hydroxyl group was achieved through a consecutive oxidation-reduction reactions or by a nucleophilic substitution of the 3α-mesylates. Treatment of the 3α- and 3β-alcohols with palmitic, myristinic or lauric acid chlorides gave the corresponding esters. The hydrolysis of 22,23-methylboronates was performed after their transformation into 2-hydroxy-1,3,2-dioxaborolanes using a cation exchange column with DOWEX 50WX8 in NH4(+) form. Hydrogenolysis of the benzyl ethers catalyzed by palladium yielded the target compounds. This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".

The mutagenicity of N-nitrosobis (2-hydroxypropyl) amine (BHP), N-nitrosobis(2-oxopropyl)amine (BOP) and N-nitroso-(2-hydroxy-propyl) (2-oxopropyl) amine (HPOP) was measured in V79 cells. Hepatocytes, used to metabolize (activate) the nitrosamines, were isolated from untreated Syrian hamsters (control) and hamsters treated with clofibrate (CLO) or dehydroepiandrosterone (DHEA) in vivo. BHP and HPOP mutagenicity increased 3- and 2-fold when hepatocytes from CLO- and DHEA-treated hamsters were used. BOP mutagenicity did not increase. 10-Undecynoic acid, a lauric acid hydroxylase inhibitor, inhibited the increase in BHP and HPOP mutagenicity by 80-90% but did not affect that of BOP. Antimycin A1, a fatty acyl coenzyme A beta-oxidase inhibitor did not affect the mutagenicity of these nitrosamines. Lauric acid hydroxylase, probably omega-1 hydroxylase (cytochrome P-450 IVA2), appears to be involved in the activation of BHP and HPOP.

Local velocities of rising bubbles decrease with the increasing concentration in solution of surface-active, water-soluble species. Therefore, it is possible to use this phenomenon to monitor products of enzymatic reactions, which meet such criteria. In this study, hydrolysis of 1,2-dilauroyl-sn-glycero-3-phosphatidylcholine (DLPC) catalyzed by calcium-dependent phospholipase A2 (PLA2) (EC3.1.1.4) from porcine pancreas was used as model reaction. The products of this reaction are lauric acid (LA) and 1-lauroyl-2-hydroxy-sn-glycero-3-phosphatidylcholine (Lyso-PC). DLPC was dispersed in a chloroform/methanol mixture that was spread on a free PLA2 solution surface. Air bubbles were then formed at a capillary orifice and the local velocity of rising bubbles as a function of the distance from the capillary tip was monitored. Local velocity profiles were compared with profiles recorded for solutions of pure enzymatic reaction products and their mixtures. Our experiments showed that the product, which had a dominating effect on bubble motion retardation, was lyso-phosphatidylcholine. This can be explained by differences in the kinetics of lauric acid and lyso-phosphatidylcholine transfer from the spread layer to the solution.