Antithrombotic effects of YS-49 and YS-51--1-naphthylmethyl analogs of higenamine.

The antiplatelet and antithrombotic effects of YS-49 and YS-51--l-naphthylmethyl analogs of higenamine, which is a benzyl-tetrahydroisoquinoline alkaloid isolated from Aconitum japonicum (Ranunculaceae)--were investigated. YS-49 and YS-51 showed inhibitory activities to both human and rat platelet aggregation induced by ADP, collagen and epinephrine. They were more inhibitory to epinephrine-induced aggregation (IC(50); 3.4 and 1.7 microM of YS-49, and 6.0 and 6.3 microM of YS-51 to human and rat platelets, respectively) than ADP- or collagen-induced aggregation. The antithrombotic effects of YS-49 and YS-51 were also observed in both mouse acute thrombosis model and rat arterio-venous shunt (AV shunt) model. The oral administration of YS-49 and YS-51 (50 or 100 mg/kg) increased the recovery rates from the acute thrombotic challenge in mice and lowered the weight of thrombus formed inside the AV shunt tube in rats.

Anti-thrombotic effects of higenamine.

The anti-platelet and anti-thrombotic effects of higenamine, a benzyltetrahydroisoquinoline alkaloid of the roots of Aconitum japonicum (Ranunculaceae), were investigated. The degree of platelet aggregation was measured with platelet rich plasma (PRP). An acute thrombotic condition was induced in mice by the injection of the mixture of collagen and epinephrine. The thrombus formation was induced inside the arterio-venous shunt tube installed between an abdominal aorta and the renal vein of rats. Higenamine showed inhibitory activities to both human and rat platelet aggregation induced by ADP, collagen and epinephrine. It was more inhibitory to epinephrine induced aggregation (IC(50); 19 and 7.2 microM to human and rat platelets respectively) than ADP- or collagen-induced aggregation. The anti-thrombotic effects of higenamine were also observed in both mouse acute thrombosis model and rat arterio-venous shunt (AV-shunt) models. The oral administration of higenamine (50 or 100 mg/kg) increased the recovery rates from the acute thrombotic challenge in mice and lowered the weight of thrombus formed inside the AV-shunt tube in rats.

Influence of melatonin on immunotoxicity of lead.

The results suggested that immunotoxicity induced by lead [Pb, as Pb(NO(3))(2)] was significantly restored or prevented by melatonin (MLT). MLT (10 or 50 mg/kg) was orally administered to ICR mice daily for 28 days, and Pb was also administered at 35 mg/kg in the same way 2 h after the administration of MLT, and the normal mice were given vehicle. Within the Pb plus MLT-treated group, the body weight gains and the relative thymus weights were significantly increased when compared with the treatment of Pb alone. The relative spleen and liver weights were increased by the treatment of Pb alone, and then restored to normal value by MLT treatment. Hemagglutination (HA) titer, plaque-forming cell response to sheep red blood cell (SRBC), and secondary IgG antibody response to BSA were significantly enhanced in the Pb plus MLT-treated mice, as opposed to when compared with the treatment of Pb alone. The mitogenic response of splenic T cell to concanavalin A and that of B cells to lipopolysaccharide was remarkably increased by MLT treatment when compared with treatment of Pb alone. Splenic CD4(+)cells were significantly increased by MLT treatment when compared with treatment of Pb alone. In case of CD8(+) cells, the slight enhancement was observed in MLT treatment. Splenic T and B cells were significantly increased by MLT treatment when compared with the treatment of Pb alone. The natural killer cell, phagocytic activity and the number of peripheral leukocytes were significantly enhanced in Pb plus MLT-treated mice when compared with the treatment of Pb alone.

Epinephrine induced platelet aggregation in rat platelet-rich plasma.

Epinephrine at even high concentrations neither caused shape change nor aggregation of rat platelets. However, epinephrine induced aggregation in the presence of low (near-threshold) concentrations of collagen at which concentration only platelet shape change was induced without aggregation. The platelet aggregation was also induced by some other catecholamines and clonidine but not by beta-agonist isoproterenol. The aggregatory potencies of R-(-)-isomers, (-)-epinephrine and (-)-norepinephrine were higher than the corresponding desoxy derivatives, epinine and dopamine. In addition, the epinephrine-induced rat platelet aggregation was inhibited by alpha2-antagonists, yohimbine and phentolamine, but not by alpha1-antagonist prazosin or beta-antagonist propranolol. These results suggested that the epinephrine-induced rat platelet aggregation is occurring through alpha2-adrenergic receptors as is the case with human platelets.

Antiplatelet and antithrombotic effects of a combination of ticlopidine and ginkgo biloba ext (EGb 761).

The antiplatelet and antithrombotic effects of the oral combination treatment of ticlopidine and Ginkgo biloba extract (EGb 761) were studied in normal and thrombosis-induced rats. The ex vivo inhibitory effect on ADP-induced platelet aggregation of a small dose of ticlopidine (50 mg/kg/day) in combination with EGb 761 (40 mg/kg/day) was comparable to a larger dose of only ticlopidine (200 mg/kg/day). Bleeding time was also prolonged by 150%. Thrombus weight was also consistently decreased by a combination of ticlopidine and EGb 761 in an arterio-venous shunt model at two doses of ticlopidine (50 mg/kg) plus EGb 761 (20 mg/kg) and ticlopidine (50 mg/kg) plus EGb 761 (40 mg/kg). A combinatory treatment in acute thrombosis model in mice also showed a higher recovery than a single treatment.

Isolation of 3-O-(4'-hydroxybenzyl)-beta-sitosterol and 4-[4'-(4"-hydroxybenzyloxy)benzyloxy]benzyl methyl ether from fresh tubers of Gastrodia elata.

Two new 4-hydroxybenzyl alcohol derivatives (1 and 2) were isolated from the methanol extract obtained from fresh tubers of Gastrodia elata together with 4-hydroxybenzyl methyl ether, 4-hydroxybenzyl alcohol, bis(4-hydroxyphenyl)methane, 4-hydroxybenzaldehyde, beta-sitosterol and palmitic acid. 1 and 2 were identified as 3-O-(4'-hydroxybenzyl)-beta-sitosterol and 4-[4'-(4"-hydroxybenzyloxy)benzyloxy]benzyl methyl ether, respectively, according to the spectroscopic data.

Dose dependency of earthworm powder on antithrombotic and fibrinolytic effects.

The freeze-dried powder of Lumbricus rubellus earthworm was administered orally to rats and its fibrinolytic and antithrombotic effects were investigated. The fibrinolytic activity of plasma was determined by measuring the plasmin activity of the euglobulin fraction and was increased to two-folds of the control at a dose of 0.5 g/kg/day and five times with 1 g/kg/day after 4-day administration. The antithrombotic effect was studied in an arterio-venous shunt model of rats. The thrombus weight decreased significantly from 43.2 mg to 32.4 mg at a dose of 0.5 g/kg/day after 8-day treatment. The level of fibrinogen/fibrin degradation product (FDP) in serum was elevated in a dose-dependent manner during the treatment period. On the 8th day after administration, the FDP value was increased to 7.7 micrograms/ml compared with the control value of 3.3 micrograms/ml. These results support that earthworm powder is valuable for the prevention and/or treatment of thrombotic conditions.

Evaluation of thein vivo antithrombotic, anticoagulant and fibrinolytic activities ofLumbricus rubellus earthworm powder.

A saline suspension ofLumbricus rubellus earthworm powder (EWP) was administered to rats (1 g/kg/day) orally for 15 days to evaluate an oral effectiveness for thrombotic disorders. Blood was drawn at 2-day interval after the administration. Several parameters for antithrombotic, anticoagulant and fibrinolytic activities were measured, including platelet aggregation, clotting time, plasmin activity and the levels of FDP (fibrin/fibrinogen degradation products), D-dimer, and t-PA antigen. It did not affect platelet aggregation induced by ADP and collagen but anticoagulant activity (aPTT and TT) was gradually increased to two-folds for the first 5 days of administration and back to normal. Fibrinolytic acitivity of euglobulin fraction was highest on the 11th day after the administration. The level of FDP was elevated to be comparable to the positve control (5-10 mug/ml) after 9-day treatment. Oral administration of the EWP could also reduce the formation of venous thrombus induced with viper venom. Complete blood count (CBC) profiles were within normal ranges except for a slight increase in white blood cells after the oral administration for 15 days. These results suggested that the EWP may be valuable for the prevention and/or treatment of thrombotic diseases.

Isolation of 4,4'-dihydroxybenzyl sulfoxide fromGastrodia elata.

In the course of continous work on tubers ofGastrodia elata, a new constituent, 4,4'-dihydroxybenzyl sulfoxide was isolated from the ethyl acetate soluble fraction prepared from the methanol extract. The structure of the compound was identified from the elemental analytical and spectroscopic data in comparison with those of non-substituted benzyl sulfoxide.