The effects of defatted safflower seed extract and its phenolic constituents, serotonin derivatives, on atherosclerosis were studied. Ethanol-ethyl acetate extract of safflower seeds (SSE) inhibited low-density lipoprotein (LDL) oxidation induced in vitro by an azo-containing free-radical initiator V70 or copper ions. Two serotonin derivatives [N-(p-coumaroyl)serotonin, CS; N-feruloylserotonin, FS] and their glucosides were identified as the major phenolic constituents of the extract. The study with chemically synthesized materials revealed that a majority of the antioxidative activity of SSE was attributable to the aglycones of these two serotonin derivatives. Orally administered CS and FS suppressed CuSO(4)-induced plasma oxidation ex vivo. Long-term (15 week) dietary supplementation of SSE (1.0 wt %/wt) and synthetic serotonin derivatives (0.2-0.4%) significantly reduced the atherosclerotic lesion area in the aortic sinus of apolipoprotein E-deficient mice (29.2-79.7% reduction). The plasma level of both lipid peroxides and anti-oxidized LDL autoantibody titers decreased concomitantly with the reduction of lesion formation. Serotonin derivatives were detected as both intact and conjugated metabolites in the plasma of C57BL/6J mice fed on 1.0% SSE diet. These findings demonstrate that serotonin derivatives of SSE are absorbed into circulation and attenuate atherosclerotic lesion development possibly because of the inhibition of oxidized LDL formation through their strong antioxidative activity.

1 A murine anti-human vWF monoclonal antibody, AJvW-2, was developed that inhibited the interaction between platelet glycoprotein Ib (GPIb) and von Willebrand factor (vWF) during the ristocetin-(IC 50 =0.7+0.1 mg ml 71 ) and botrocetin-(IC 50 =1.8+0.3 mg ml 71 ) induced aggregation of human platelets. 2 AJvW-2 inhibited the high shear stress (10.8 N m 72 ) induced aggregation of human platelets dosedependently with an IC 50 =2.4+0.3 mg ml 71 , but had no e ect on low shear stress induced platelet aggregation (1.2 N m 72 ) up to 100 mg ml 71 . 3 AJvW-2 also inhibited the high shear stress (5.0 N m 72 ) induced adhesion of human platelets to collagen I with the same e cacy (IC 50 =2.4+0.3 mg ml 71 ), but had no e ect at low shear conditions (1.5 N m 72 ). 4 AJvW-2 inhibited the botrocetin-induced aggregation of platelets from guinea-pig, rat, rabbit, dog and pig at the same concentration range as human platelets; it likewise also inhibited the high shear stress induced aggregation and adhesion to collagen I of guinea-pig platelets. 5 AJvW-2 prevented arterial thrombus formation in guinea-pigs at a dose of 100 mg kg 71 without prolonging the template bleeding time, whereas the GPIIb/IIIa antagonist lami®ban mediated inhibition of thrombosis at 1000 mg kg 71 was accompanied by a signi®cant prolongation of the bleeding time. 6 These results suggest that AJvW-2 is a potent inhibitor of the GPIb-vWF interaction and a potential novel antithrombotic agent with lower bleeding risk than GPIIb/IIIa antagonists.

ABSTRACT. Supplementation with both cystine and glutamic acid increases the synthesis of glutathione (GSH), which has a marked effect on immune cell function, as compared with supplementation with either amino acid alone in human macrophages in vitro. As dietary glutamic acid is metabolized during intestinal transport, oral administration of L-theanine (γ-glutamylethylamide), which is metabolized to glutamic acid mainly in the liver, may act as a glutamic acid donor in vivo. The present study was performed to investigate the effects of oral administration of L-cystine and/or L-theanine on GSH levels and immune responses. Co-administration of L-cystine (200 mg/kg) and L-theanine (80 mg/kg) for 11 days before immunization significantly increased the levels of total GSH in the liver 6 hr after immunization as compared with the levels in control mice. To examine the effects of administration of L-cystine and/or L-theanine on the balance of T helper (Th) 1/Th2 cell responses, the serum ratios of the Th1 cytokine, interferon (IFN)-γ, and the Th2 cytokine, interleukin (IL)-10, were investigated. At 24 hr after immunization, co-administration significantly increased the IL-10/IFN-γ ratio compared with the ratios of the control and single-administration mice. Furthermore, co-administration before primary immunization significantly enhanced serum antigen-specific IgG levels. Taken together, these findings suggest that co-administration of L-cystine and L-theanine enhances antigen-specific IgG production partly through augmentation of GSH levels and Th2-mediated responses.

We previously demonstrated that safflower seed extract (SSE) and its major antioxidant constituents, serotonin hydroxycinnamic acid amides, suppressed LDL oxidation in vitro, decreased plasma autoantibody titres to oxidized LDL and attenuated atherosclerotic lesion formation in apoE-deficient mice. In this report, we examined whether SSE, rich in serotonin derivatives, could affect markers of oxidative stress, inflammation and aortic stiffness in healthy human subjects. Twenty Japanese male volunteers were studied at baseline, after 2·1 g SSE supplementation daily (providing 290 mg serotonin derivatives/d) for 4 weeks, and after a 4-week washout period. Significant reductions in circulating oxidized LDL, autoantibody titres to malondialdehyde-modified LDL, the soluble form of vascular cell adhesion molecule-1 (sVCAM-1), and urinary 8-isoprostane were observed after a 4-week intervention. Although there were no statistically significant differences in blood pressure or brachial-ankle pulse wave velocity (baPWV), an index of arterial stiffness, baPWV was lower than baseline in eleven of twenty subjects and was accompanied by a reduction in blood pressure. Statistically significant negative correlations were observed between the extent of initial cardiovascular risk markers (autoantibody titres, 8-isoprostane, sVCAM-1 and baPWV) and the effect of intervention. This suggested that individuals with elevated oxidative stress, inflammation, and/or arterial stiffness may receive more benefit from SSE supplementation.