title: 1-Heteroaryl-3-phenoxypropan-2-ones as inhibitors of cytosolic phospholipase A₂α and fatty acid amide hydrolase: Effect of the replacement of the ether oxygen with sulfur and nitrogen moieties on enzyme inhibition and metabolic stability.
abstract: Cytosolic phospholipase A2α (cPLA2α) and fatty acid amide hydrolase (FAAH) are enzymes, which have emerged as attractive targets for the development of analgesic and anti-inflammatory drugs. We recently reported that certain 3-phenoxy-substituted 1-heteroarylpropan-2-ones are inhibitors of cPLA2α and/or FAAH. Starting from 1-[2-oxo-3-(4-phenoxyphenoxy)propyl]indole-5-carboxylic acid (3) and 1-(1H-benzotriazol-1-yl)-3-(4-phenoxyphenoxy)propan-2-one (4), the effect of the replacement of the oxygen in position 3 of the propan-2-one scaffold by sulfur and nitrogen containing moieties on inhibition of cPLA2α and fatty acid amide hydrolase as well as on metabolic stability in rat liver S9 fractions was investigated. As a result of these structure-activity relationship studies it was found that the ether oxygen is of great importance for enzyme inhibitory potency. Replacement by sulfur led to an about 100-fold decrease of enzyme inhibition, nitrogen and substituted nitrogen atoms at this position even resulted in inactivity of the compounds. The effect of the structural variations performed on metabolic stability of the important ketone pharmacophore was partly different in the two series of compounds. While introduction of SO and SO2 significantly increased stability of the ketone against reduction in case of the indole-5-carboxylic acid 3, it had no effect in case of the benzotriazole 4. Further analysis of the metabolism of 3 and 4 in rat liver S9 fractions revealed that the major metabolite of 3 was the alcohol 53 formed by reduction of the keto group. In contrast, in case of 4 beside keto reduction an excessive hydroxylation of the terminal phenoxy group occurred leading to the dihydroxy compound 50. Experiments with enzyme inhibitors showed that the phenylhydroxylation of 4 was catalyzed by tranylcypromine sensitive cytochrome P450 isoforms, while the reduction of the ketone function of 3 and 4 was mainly caused by cytosolic short chain dehydrogenases/reductases (cSDR).
authors: Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstrasse 48, D-48149 Münster, Germany.
authors: Tom
authors: T
authors: Sundermann
authors: Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstrasse 48, D-48149 Münster, Germany.
authors: Jörg
authors: J
authors: Fabian
authors: Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstrasse 48, D-48149 Münster, Germany.
authors: Walburga
authors: W
authors: Hanekamp
authors: Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstrasse 48, D-48149 Münster, Germany. Electronic address: lehrm@uni-muenster.de.
authors: Matthias
authors: M
authors: Lehr
mesh_terms: D000581:Amidohydrolases / Q000037:antagonists & inhibitors* / Q000737:chemistry; D000700:Analgesics / Q000138:chemical synthesis* / Q000737:chemistry; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000138:chemical synthesis* / Q000737:chemistry; D001711:Biotransformation; D001923:Brain Chemistry; D002264:Carboxylic Acids / Q000138:chemical synthesis* / Q000737:chemistry; D004355:Drug Stability; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry; D054513:Group IV Phospholipases A2 / Q000037:antagonists & inhibitors* / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000138:chemical synthesis* / Q000737:chemistry; D008862:Microsomes, Liver / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D051381:Rats; D013329:Structure-Activity Relationship; D013455:Sulfur / Q000737:chemistry; D013552:Swine; D000099252:Fatty Acid Amide Hydrolases
chemical_list: D000581:Amidohydrolases; D000700:Analgesics; D000894:Anti-Inflammatory Agents, Non-Steroidal; D002264:Carboxylic Acids; D004791:Enzyme Inhibitors; D054513:Group IV Phospholipases A2; D007211:Indoles; D007659:Ketones; D009584:Nitrogen; D010100:Oxygen; D013455:Sulfur; D000099252:Fatty Acid Amide Hydrolases
keywords: Aldo–keto reductase; Benzotriazole; Carbonyl reductase; Cytochrome P450; Cytosolic phospholipase A(2)α; Fatty acid amide hydrolase; Indole-5-carboxylic acid; Inhibitors; Metabolic stability; Short chain dehydrogenase/reductase