Enhanced small intestinal absorption of beta-lactam antibiotics in rats in the presence of monodesmosides isolated from pericarps of Sapindus mukurossi (Enmei-hi).

Monodesmoside, saponin A, B and C, isolated from pericarps of Sapindus mukurossi (Enmei-hi) have been shown to promote absorption of poorly absorbed beta-lactam antibiotics by the small intestine using an in situ loop method. Monodesmosides were solubilized with ginseng crude saponin extract, a mixture of bisdesmosides, saponin X, Y1 and Y2 which were isolated also from Sapindus mukurossi. These solubilizing agents were demonstrated not to influence the absorption promoting effect of monodesmosides. Among the monodesmosides, saponin B showed the greatest effect. No influence of osmolarity of the administered solution on the absorption promoting action was observed. The promoting functions of the three monodesmosides for the small intestinal absorption of antibiotics were suppressed by Ca2+ ion coexisting in the administered solution.