The present paper was investigated in the inhibitory action of vegetable and seaweed water-soluble extracts on the formation of carcinogenic N-nitrosodimethylamine(NDMA). The vegetable and seaweed extracts obtained from garlic(Allium sativum), onion(Allium cepa), green onion(Allium fistuiosum), chinese pepper(Fagara mandshurica), green pepper (Capsicum annuum), red pepper(Capsicum annuum), ginger(Zingiber officinale), carrot (Daucus carota), laver(Porphyra tenera), sea lettuce(Entero compresa), sea mustard (Undaria pinnatifida) and sea staghorn(Codium fragile) were incubated with sodium nitrite-dimethylamine mixtures at 37 degree C under different pH conditions. The formation of NDMA was reduced to 10 apprx 40% and 25 apprx 50% by the addition of vegetable and seaweed extracts 30mg at pH 1.2, respectively. The inhibition degree by the extracts at pH 1.2 was similar to that at pH 4.2 and to that by ascorbic acid at pH 1.2. The inhibitory action of the extracts against NDMA formation was not decreased by heat treatment at 80 degree C for 10min, but decreased by the treatment of sodium borohydride. It is assumed that reducing powers of the extracts participated in their inhibitory actions.

Ali M Angelo-Khattar M Farid A Hassan RA Thulesius O

Aqueous extracts of garlic (Allium sativum) inhibit prostaglandin synthesis in the ovine ureter.

In: Prostaglandins Leukot Essent Fatty Acids (1993 Nov) 49(5):855-9

The prostaglandins (PGs) synthesized from C-14-arachidonic acid by the homogenized sheep ureter were identified as being prostacyclin (PGI-2), PGF-2 alpha and thromboxane B-2 (TXB-2). The radioimmunoassay (RIA) estimation of 6-keto-PGF-1 alpha, a stable metabolite of PGI-2, confirms that it was the major metabolite or arachidonic acid. Aqueous extracts of fresh garlic (5, 12.5, 25 and 50 mg/ml) were shown to inhibit the synthesis of the prostanoids in a dose dependent manner. Fresh garlic extracts (1, 2.5, 5 and 10 mg/ml) also dose dependently inhibited spontaneous rhythmic contractions of the isolated ureter. Boiled garlic (5, 12.5, 25 and 50 mg/ml) had no effect on either ureteral motility or the PG synthesizing capacity of the sheep ureter.

Ali M Mohammed SY: Selective suppression of platelet thromboxane formation with sparing of vascular prostacyclin synthesis by aqueous extract of garlic in rabbits.

PROSTAGLANDINS LEUKOTRIENES MED 1986 Dec; 25(2-3):139-46

It has been suggested that a drug which selectively inhibits platelet thromboxane synthesis, sparing vascular synthesis of prostacyclin, would be more effective as an anti-thrombotic agent. We studied the effect of an aqueous extract of garlic on the production of thromboxane and prostacyclin by rabbit whole blood and aorta in vitro and ex vivo. A dose-dependent inhibition of thromboxane production was observed during blood clotting. Synthesis of prostacyclin was not affected by any concentration of garlic extract used in the experiment. A slight but insignificant reduction in the vascular synthesis of prostacyclin was observed at the highest concentration of garlic used in in vitro experiments. The synthesis of thromboxane by aorta was completely suppressed at all the concentrations of garlic tested. A similar pattern of results was observed after intraperitoneal administration of garlic (1 ml/kg) for one week on the enzymatic synthesis of thromboxane and prostacyclin of these tissues ex-vivo. Aortic synthesis of prostacyclin was significantly increased in the garlic treated rabbits compared to the controls. The data obtained from these rabbit experiments suggested that it may be possible to achieve a selective suppression of thromboxane formation by platelets with sparing of vascular synthesis of prostacyclin by garlic treatment.