Comparison of bioavailability (I) between soyasaponins and soyasapogenols, and (II) between group A and B soyasaponins.
OBJECTIVE
The bioavailability and absorption of soyasaponins and soyasapogenols remain unclear; therefore, the aim of this study was to evaluate plasma soyasaponin and soyasapogenol concentrations and absorption characteristics.


METHODS
Sprague-Dawley rats were divided into three groups (n = 6), and each group was orally administered a single dose of each test sample. Blood was collected from the cervical vein and plasma soyasapogenol concentrations were measured. A Caco-2 cell monolayer absorption assay was performed in which both soyasapogenol A and B (10 μmol/L) were added to the apical side, and soyasapogenol concentrations on the apical and basolateral sides were determined. Permeability parameters also were calculated.


RESULTS
Absorption of soyasapogenol B was better than that of group B soyasaponins. The time needed to reach peak soyasapogenol B concentration in rats administered soyasapogenol B was 1 to 3 h, whereas that in rats administered group B soyasaponins was 8 h. The ratio of plasma soyasapogenol A to plasma soyasapogenol B was lower than the ratio in the test samples administered. The apical-to-basolateral absorption of soyasapogenol B in the Caco-2 human colon cancer monolayer cell model (apparent permeability coefficient [Papp], 5.5 × 10(-6) cm/sec) was higher than that of soyasapogenol A (Papp, 1.6 × 10(-6) cm/sec).


CONCLUSIONS
These results suggest that bioavailability of soyasapogenols is better than that of corresponding soyasaponins and that of group B soyasaponins is better than that of group A soyasaponins.
Fine Chemical Laboratory, J-OIL MILLS, Inc., 1746 Nakashinden, Fukuroi-city, Shizuoka, Japan. Electronic address: shuichi.kamo@j-oil.com.
Shuichi
S
Kamo
Fine Chemical Laboratory, J-OIL MILLS, Inc., 1746 Nakashinden, Fukuroi-city, Shizuoka, Japan.
Shunsuke
S
Suzuki
Fine Chemical Laboratory, J-OIL MILLS, Inc., 1746 Nakashinden, Fukuroi-city, Shizuoka, Japan.
Toshiro
T
Sato
D000818:Animals; D018938:Caco-2 Cells; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D009828:Oleanolic Acid / Q000031:analogs & derivatives / Q000097:blood / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012503:Saponins / Q000097:blood / Q000493:pharmacokinetics*
D012503:Saponins; C407096:soyasapogenol B; C116604:soyasapogenol A; D009828:Oleanolic Acid
Absorption; Bioavailability; LC-MS/MS; Soyasapogenols; Soyasaponins