pubs.acs.org/jmc Published on Web 10/28/2009 r 2009 American Chemical Society 7220 J. Med. Chem. 2009, 52, 7220–7227 DOI: 10.1021/jm9003957 Losartan-Antioxidant Hybrids: Novel Molecules for the Prevention of Hypertension-Induced Cardiovascular Damage Gonzalo Garcı´a, † Manuel Rodrı´guez-Puyol, ‡ Ram on Alajarı´n, † Isabel Serrano, ‡ Patricia S anchez-Alonso, † Mercedes Griera, ‡ Juan J. Vaquero,* ,† Diego Rodrı´guez-Puyol, § Julio  Alvarez-Builla, † and Marı´a L. Dı´ez-Marqu es* ,‡ † Departamento de Quı´mica Org anica, ‡ Departamento de Fisiologı´a and § Hospital Prı´ncipe de Asturias, Universidad de Alcal  a, Campus Universitario, 28871-Alcal  a de Henares, Madrid, Spain Received March 27, 2009 We report the first examples of a new series of antioxidant-sartan hybrids (AO-sartans), which were made by adding an antioxidant fragment to the hydroxymethyl side chain of losartan. Experiments performed in cultured cells demonstrate that these new hybrids retain the ability to block the angiotensin II effect with increased antioxidant ability. In hypertensive rats, these compounds show properties that suggest they may be more useful than losartan for controlling hypertension and preventing hyperten- sion-induced cardiovascular damage. Introduction Although it is believed that lowering blood pressure is the main protective mechanism of antihypertensive treatments, other possibilities to explain the beneficial effects of these drugs have been proposed. It is a well-known fact that local changes that take place at the vascular level, such as the increased oxidative stress, may also be a relevant mechanism of cardiovascular disease progression in hypertensive patients. Thus, treatments that interfere with this oxidative stress could be useful tools for management of these individuals. Among antihypertensive agents, angiotensin converting enzyme (ACE a ) inhibitors have been widely used in the treatment of hypertension. However, in the past two decades, research focused on drugs that can replace ACE inhibitors in hypertension therapy, without their side effects (mainly coughing), has led to the discovery of sartans (Chart 1). 1 Drugs of this class are antagonists of angiotensin II at the AT1 receptor and block the action of angiotensin II in a potentially more complete and specific way than ACE inhibitors. Lowering blood pressure is not the only beneficial effect of angiotensin II blockade. Angiotensin II plays a significant role in the progression of tissue damage in cardiovascular dis- eases, 2 and the beneficial effects of these drugs in the preven- tion of cardiovascular morbidity and mortality cannot be solely explained by their antihypertensive action. In this context, some chemical interventions have been performed on sartan molecules in order to modify, where possible, their antihypertensive potency, but mainly to increase their ability to prevent tissue damage in the cardiovascular system. 3 Oxidative stress is a well-known mechanism that is respon- sible for the development of vascular damage. 4 Different pathogenic stimuli involved in cardiovascular diseases, such as activated macrophages, hyperglycaemia, oxidized low den- sity lipoprotein (LDL), and even angiotensin II, exert their harmful effects, at least partially, through an increased local synthesis of reactive oxygen species. 5-8 These active metabo- lites induce a significant endothelial dysfunction 9 and are able to modify the normal balance among proliferation, apoptosis, and extracellular matrix synthesis in heart and arterial walls. 10-12 Some beneficial effects of antihypertensive mole- cules have been attributed, at least partially, to their antiox- idant ability. 13-15 The above-mentioned considerations prompted us to devel- op a new class of sartan derivatives by adding an antioxidant fragment to these drugs. We hypothesized that the adminis- tration of these hybrid compounds would be a more specific or efficient means to target antihypertensive or antioxidant molecules to cardiovascular cells. Herein, we report our strategy of incorporating a variety of antioxidant moieties onto the primary alcohol group of losartan through an ester linkage to generate new losartan-antioxidant hybrids, which retain the ability to block the angiotensin II effect, with increased antioxidant ability. Chemistry Among the sartans shown in Chart 1, losartan 16 was chosen as the appropriate candidate for chemical manipulation on the basis of its high activity as an angiotensin II receptor blocker, along with the presence in its structure of a hydro- xymethyl moiety, which made it suitable for attaching the antioxidant fragment in a simple synthetic chemical process. Among the antioxidant candidates to be incorporated in the losartan structure, a series of phenols were selected as the best choices because of their well-known redox properties. *To whom correspondence should be addressed. Phone þ34-91- 8854761; fax þ34-91-8854686; e-mail juanjose.vaquero@uah.es. a Abbreviations: ABTS, 2,2 0 -azino-di-(3-ethyl benzothiazoline-6-sul- fonic acid); ACE, angiotensin converting enzyme; AO, antioxidant; Bn, benzyl; EDTA, ethylenediamine tetraacetic acid; DMEM, Dulbecco 0 s Modified Eagle Medium; HNE, 4-hydroxy-2-nonenal; HPLC-MS/MS, high-performance liquid chromatography-tandem mass spectrometry; LDH, lactate dehydrogenase; LDL, low density lipoprotein; L-NAME, Nω-Nitro-L-arginine methyl ester hydrochloride; PCSA, planar cell surface area; QqQ, triple-quadrupole; TBAF, tetra n-butyl ammonium fluoride; TBDMS, tert-butyldimethylsilane; THF, tetrahydrofuran; VSMC, vascular smooth muscle cells.