Influence of Nutritional Status on the Absorption of Polyphyllin I, an Anticancer Candidate from Paris polyphylla in Rats.

BACKGROUND AND OBJECTIVES: Protein-calorie malnutrition (PCM) is one of the most suffered complications in cancer patients. Polyphyllin I (PPI), a saponin isolated from rhizome of Paris polyphylla, is a potential candidate in cancer therapy. In this study, the influence of nutritional status on the absorption of PPI in rats was explored after oral administration. METHODS: PCM rats, namely mal-nourished (MN) rats, were induced from well-nourished (WN) rats by caloric restriction protocol. Intestinal absorption of PPI in WN and MN rats was evaluated by pharmacokinetic and intestinal perfusion methods. The potential mechanisms between two groups were investigated on the basis of intestinal permeability, intestinal efflux and PPI's depletions in vivo. The intestinal permeability was analyzed by determining the concentration of paracellular marker transport in serum and the expression of junction proteins in intestine. The intestinal efflux was evaluated through comparing the protein level of P-glycoprotein (P-gp) in intestine, and the depletions of PPI and/or generation of its metabolites in liver and intestines were analyzed by liquid chromatography triple quadrupole mass spectrometry (LC-MS/MS) method. RESULTS: Compared to WN rats, the oral systemic exposure of PPI was significantly increased in MN rats, evidenced by significant enhancement of maximum plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC0-60h) by more than 2.51- and 3.71-folds as well as terminal elimination half-life (t1/2) prolonged from to 7.3 to 14.1 h. Further studies revealed that the potential mechanism might be associated with combined contribution of improved intestinal absorption and depressed deglycosylation of PPI in MN rats. Furthermore, enhanced intestinal absorption of PPI was benefited from increased intestinal permeability and decreased intestinal efflux in MN rats. Meanwhile, the former manifested as increased transport of paracellular marker and decreased junction proteins levels, while the later evidenced by reduced P-gp expression. CONCLUSIONS: The oral exposure of PPI was enhanced in MN rats, which suggested that nutritional status alters the absorption of PPI, and thus the dosage of PPI should be modified during the treatment of cancer patient with PCM.

A high-throughput screening strategy for accurate quantification of menaquinone based on fluorescence-activated cell sorting.

To enhance the screening efficiency and accuracy of a high-yield menaquinone (vitamin K2, MK) bacterial strain, a novel, quantitative method by fluorescence-activated cell sorting (FACS) was developed. The staining technique was optimized to maximize the differences in fluorescence signals between spontaneous and MK-accumulating cells. The fluorescence carrier rhodamine 123 (Rh123), with its ability to reflect membrane potential, proved to be an appropriate fluorescent dye to connect the MK content with fluorescence signal quantitatively. To promote adequate access of the fluorescent molecule to the target and maintain higher cell survival rates, staining and incubation conditions were optimized. The results showed that 10 % sucrose facilitated uptake of Rh123, while maintaining a certain level of cell viability. The pre-treatment of cells with MgCl2 before staining with Rh123 also improved cell viability. Using FACS, 50 thousands cells can easily be assayed in less than 1 h. The optimized staining protocol yielded a linear response for the mean fluorescence against high performance liquid chromatography-measured MK content. We have developed a novel and useful staining protocol in the high-throughput evaluation of Flavobacterium sp. mutant libraries, using FACS to identify mutants with increased MK-accumulating properties. This study also provides reference for the screening of other industrial microbial strains.