title: Inhibitory effects of 2-substituted-1-naphthol derivatives on cyclooxygenase I and II.
abstract: Naphthol derivatives, 2-(3'-hydroxypropyl)-naphthalen-1-ol (2), 2-(3'-hydroxy-2'-methylpropyl)-naphthalen-1-ol (3) and 2-(3'-hydroxy-2',2'-dimethylpropyl)-naphthalen-1-ol (7) were synthesized and already reported by our group. Therefore in this paper we described further synthesis of their ether derivatives, 3-(1-methoxy-naphthalen-2-yl)-propan-1-ol (4), 3-(1-methoxy-naphthalen-2-yl)-2methyl-propan-1-ol (5), 3-(1-methoxy-naphthalen-2-yl)-2,2-dimethyl-propan-1-ol (8), 2-(3-methoxy-propyl)-naphthalen-1-ol (10) and 2-(3-methoxy-2,2-dimethyl-propyl)-naphthalen-1-ol (13). Compounds 4, 5 and 8 were prepared by methylation of compounds 2, 3 and 7, respectively while compounds 10 and 13 were prepared in good yield from naphthols 2 and 7, respectively. When tested for inhibitory activity, five compounds (2, 3, 7, 10 and 13) showed preferential inhibition of COX-2 over COX-1, while compounds 4, 5 and 8 lacked inhibitory effect on either the COX-1 or COX-2 isozyme. The structure-activity relationships of these naphthols analyzed by docking experiments, indicated that the presence of hydroxyl group at C-1 position on the naphthalene nucleus enhanced the anti-inflammatory activity towards COX-2 via hydrogen bonding to the COX-2 Val 523 side chain. When this hydroxyl group was replaced by methoxy group, there was no inhibition. C-2' Dimethyl substituents on the propyl chain also increased the inhibitory activity. All active compounds have the C-1 hydroxyl group aligned so as to form hydrogen bond with Val 523. The results provide a model for the binding of the naphthol derivatives to COX-2 and facilitate the design of more potent or selective analogs prior to synthesis.
authors.affiliation: Natural Products and Organic Synthesis Research Unit (NPOS), Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
authors.forename: Boonsong
authors.initials: B
authors.lastname: Kongkathip
authors.forename: Chak
authors.initials: C
authors.lastname: Sangma
authors.forename: Kanyawim
authors.initials: K
authors.lastname: Kirtikara
authors.forename: Suwaporn
authors.initials: S
authors.lastname: Luangkamin
authors.forename: Komkrit
authors.initials: K
authors.lastname: Hasitapan
authors.forename: Nipa
authors.initials: N
authors.lastname: Jongkon
authors.forename: Supa
authors.initials: S
authors.lastname: Hannongbua
authors.forename: Ngampong
authors.initials: N
authors.lastname: Kongkathip
mesh_terms: D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D004987:Ethers / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D020128:Inhibitory Concentration 50; D008565:Membrane Proteins; D051379:Mice; D008958:Models, Molecular; D015394:Molecular Structure; D009284:Naphthols / Q000737:chemistry* / Q000494:pharmacology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D004987:Ethers; D008565:Membrane Proteins; D009284:Naphthols; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; C496512:Ptgs1 protein, mouse