Abstract
To follow up quantitatively the metabolic fate of labino clover saponins ingested by herbivorous animals, the present experiment has been carried out using rabbits fed a synthetic diet containing the purified ladino clover saponins. Two male Japanese white rabbits weighing 3.1 and 3.3kg were placed individually in metabolic cages. For 18 days the rabbits received saponin-free diet (control diet) of 70g per day per head and during the last 6 days feces and urine were collected as control specimens. Following 6 days they were fed on control diet of 35g plus saponin-treated diet of 35g (saponin intake 525mg per day per head) and next 6 days on saponin-treated diet of 70g (saponin 1050mg per day per head). Through the period feces and urine were collected daily. Saponins and sapogenins excreted in feces were determined by densitometric thin-layer chromatography. Materials derived in urine were divided into three fractions, 1) ether-soluble and neutral fraction, 2) ether-soluble and acidic fraction, and 3) water-soluble fraction. Each fraction was determined by thin-layer chromatography and/or gas-liquid chromatography, and compared with each of control urine. The results obtained were as follows. 1) Quantitative determination of saponin in feces indicated that 86-90% of ingested ladino clover saponin disappered while passing through the digestive tract. 2) Sapogenins appeared 6-8mg in feces per day when received saponin 525mg and even its twice dose. 3) In the ether-soluble and neutral fraction of urine, ladino clover sapogenins were not detected. 4) In the ether-soluble and acidic fraction of urine of saponin-fed rabbits, four materials positive with Liebermann-Burchard reagent were detected. These materials, however, could not be detected by gas-chromatography. 5) The water-soluble fraction of urine was hydrolyzed by sulfuric acid. In the hydrolyzate, ladino clover sapogenins were not determined, but large amounts of unknown materials blackened by 50% sulfuric acid and heat were obviously detected.
