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1. Pallidifloside D, a saponin glycoside constituent from the total saponins of Smilax riparia, had been proved to be very effective in hyperuricemic control. But it is poorly bioavailable after oral administration. Here, we determined the role of P-glycoprotein (P-gp) in the intestinal absorption of Pallidifloside D.2. We found that Pallidifloside D significantly stimulated P-gp ATPase activity in vitro ATPase assay with a small EC50 value of 0.46 µM.3. In the single-pass perfused mouse intestine model, the absorption of Pallidifloside D was not favored in the small intestine (duodenum, jejunum and ileum) with a P*w value of 0.35–0.78. By contrast, this compound was well absorbed in the colon with a P*w value of 1.23. The P-gp inhibitors cyclosporine significantly enhanced Pallidifloside D absorption in all four intestinal segments (duodenum, jejunum, ileum and colon) and the fold change ranged from 5.5 to 15.3. Pharmacokinetic study revealed that cyclosporine increased the systemic exposure of P...

A phytochemical study on the rhizomes of Smilax riparia led to the isolation of 16 saponin compounds, including nine furostanol steroidal saponins (1–4, 6, 7, 10, 12, 14), six spirostanol steroidal saponins (5, 8, 9, 11, 13, 15) and one 20-carboxylic acid γ-lactone steroidal saponin (16). The structures of these compounds were identified by spectroscopic methods and comparison of their data with those reported in the literature. This is the first report of compounds 1, 4, 5, 8, 9, 11–16 from the genus Smilax . The chemotaxonomic significance of the isolated compounds has also been summarized.

Allopurinol is a commonly used medication to treat hyperuricemia and its complications. Pallidifloside D, a saponin glycoside constituent from the total saponins of Smilax riparia, had been proved to enhanced hypouricemic effect of allopurinol based on uric acid metabolism enzyme XOD. In this study, we evaluated whether Pallidifloside D (5mg/kg) enhanced hypouricemic effect of allopurinol (5mg/kg) related to others uric acid metabolism enzymes such as PRPS, HGPRT and PRPPAT. We found that, compared with allopurinol alone, the combination of allopurinol and Pallidifloside D significantly up-regulated HGPRT mRNA expression and down-regulated the mRNA expression of PRPS and PRPPAT in PC12 cells (all P

Pallidifloside D, a saponin glycoside constituent from the total saponins of Smilax riparia, had been proved to be effective in hyperuricemic control. Allopurinol is a commonly used medication to treat hyperuricemia and its complications. In this study, we evaluated whether Pallidifloside D could enhance allopurinol's effects by decreasing the serum uric acid level in a hyperuricemic mouse model induced by potassium oxonate. We found that, compared with allopurinol alone, the combination of allopurinol and Pallidifloside D significantly decreased the serum uric acid level and increased the urine uric acid level (both P0.05), leading to the normalized serum and urine uric acid concentrations. Data on serum, urine creatinine and BUN supported these observations. Our results showed that the synergistic effects of allopurinol combined with Pallidifloside D were linked to the inhibition of both serum and hepatic xanthine oxidase (XOD), the down-regulation of renal mURAT1 and mGLUT9, and the up-regulation of mOAT1. Our data may have a potential value in clinical practice in the treatment of gout and other hyperuricemic conditions.

The suspension-cultured protocorms of Dendrobium candidum were transplanted on the solid culture medium for studying the factors influencing their differentiation and growth.The growth and differentiation of protocorms were detected when different base-media, plant phytohormones, carbohydrates and pH were applied.The diluted MS medium promotes the growth of protocorms but inhibit differentiation. The phytohormone NAA, IAA, IBA and GA are helpful to the growth and differentiation of protocorms, however, the low pH values and presence of autoclaved fungi have suppressive effects on protocorms. The fungi also induce morphological variation of protocorms.