Effect of Rhubarb (Rhei rhizoma) Extract on Urea Nitrogen and Amino Acid Metabolism after the Administration

Abstract

The effect of i.p. administration of rhubarb [Rheum officinale] extract (5 mg/rat) on urea N and amino acid metabolism in rats was investigated. Urea N concentrations were decreased by 21% in the liver at 8 h and by 46-51% in the kidney at 4-8 h after treatment. The excretion of urea and ammonia in the urine was not different from the control values and ammonia N concentrations in peripheral blood, the portal vein, liver and kidney were not different. In rats treated with rhubarb extract, .alpha.-amino acid N concentration in serum was significantly decreased by 20-36% at 2-8 h. Seven amino acid concentrations in the plasma were decreased glutamine (31%), alanine (51%), glycine (29%), serine (26%), glutamic acid (31%), methionine (39%) and arginine (25%), and 3 amino acid concentrations in the liver were significantly decreased glutamine (31%), glutamic acid (42%) and asp (45%) at 2 h after the treatment. As to the net balance of plasma amino acids across various organs at 2 h after the administration, release of glutamine from the liver was decreased by 40% and the uptake of glutamine by non-hepatic visceral organs was decreased by 44%.