The biological activities [15] of the phenylpropanoids and their role as antimicrobial agents [16,17] is well recognised, as well as their properties as antiallergic and anti-inflammatory agents through lipoxygenase inhibition [18] and their antimutagenic actions [19,20].In this study we have examined the antioxidant properties of the hydroxycinnamic acids in terms of their abilities to increase the resistance of low density lipoproteins (LDL) to cholesterol oxidation, lipid peroxidation and oxidative modification of the apoprotein B,j 0. The results show that the sequence of the effectiveness against lipid peroxyl radicals generated in the lipophilic phase of LDL and in protecting LDL cholesterol from oxidation is: chlorogenic = caffeic > ferulic > p-coumaric acid.

Myocardial perfusion imaging with single-photon emission computed tomography has poor concordance with FFR and tends to underestimate or overestimate the functional importance of coronary stenosis seen at angiography in comparison with FFR in patients with multivessel disease. These findings might have important consequences in using MPI to determine the optimal revascularization strategy in patients with multivessel coronary disease.

Background-Nitric oxide (NO)-mediated local regulation of vascular tone is considered to involve endothelial NO synthase (eNOS). However, we recently reported that human forearm basal microvascular tone in vivo is tonically regulated by neuronal NO synthase (nNOS), in contrast to an acetylcholine-stimulated reduction in tone, which is eNOS dependent. Here, we investigated the in vivo effects of an nNOS-selective inhibitor, S-methyl-L-thiocitrulline (SMTC), on the human coronary circulation and on flow-mediated dilatation in the forearm. Methods and Results-In patients with angiographically normal coronary arteries, intracoronary infusion of SMTC (0.625 mol/min) reduced basal coronary blood flow by 34.1Ϯ5.2% (nϭ10; PϽ0.01) and epicardial coronary diameter by 3.6Ϯ1.2% (Pϭ0.02) but had no effect on increases in flow evoked by intracoronary substance P (20 pmol/min). The nonselective NOS inhibitor N G -monomethyl-L-arginine (25 mol/min) also reduced basal coronary flow (by 22.3Ϯ5.3%; nϭ8; PϽ0.01) but, in contrast to SMTC, inhibited substance P-induced increases in flow (PϽ0.01). In healthy volunteers, local infusion of SMTC (0.2 mol/min) reduced radial artery blood flow by 36.0Ϯ6.4% (nϭ10; Pϭ0.03) but did not affect flow-mediated dilatation (Pϭ0.55). In contrast, N G -monomethyl-L-arginine (2 mol/min) infusion reduced radial blood flow to a similar degree (by 39.7Ϯ11.8%; Pϭ0.02) but also inhibited flow-mediated dilatation by Ϸ80% (PϽ0.01). Conclusions-These data indicate that local nNOS-derived NO regulates basal blood flow in the human coronary vascular bed, whereas substance P-stimulated vasodilatation is eNOS mediated. Thus, nNOS and eNOS have distinct local roles in the physiological regulation of human coronary vascular tone in vivo.