Calcium bioavailability of nanonized pearl powder for adults.

The present study was aimed to evaluate the calcium bioavailability of pearl powder for humans. Both the nanonized pearl powder (NPP) and the micronized pearl powder (MPP) prepared by a dry grinder were tested. A group of healthy adults free from hyperthyroidism, hypercalcemia, and hypocalcemia were recruited as the subjects for oral administration with the pearl powder. The bioavailability was evaluated by the serum total calcium increment, the serum intact parathyroid hormone (iPTH) reduction, and the urine calcium/creatinine ratio increment in 6 h after administration. The results show better absorption and retention of calcium from NPP, as reflected with the shorter time elapsed before the maximum concentration of calcium appeared in the serum, higher iPTH reduction, more calcium absorption, and higher maximum calcium concentration (C(max)) in serum after ingestion, than that from MPP. We conclude that pearl powder is a beneficial source of calcium for adults and that nanonization improves its calcium bioavailability.

Growth inhibition and induction of apoptosis in U937 cells by Coptis chinensis extract.

Dried Coptidis Rizoma was extracted with boiling water. Conditioned medium was prepared by stimulating human peripheral blood mononuclear cells with Coptidis Rizoma extract (CR). The conditioned medium was then added to human leukemic U937 cells suspension for investigating the antiproliferation effect and the induction of apoptosis. Apparent DNA fragmentation and morphological changes occurred in U937 cells after incubating for 48 h to 72 h with the conditioned medium that had been prepared with 400 microg CR solids/mL. Flow cytometric analysis revealed that the percentage of apoptotic U937 cells increased in a time- and concentration-dependent manner. The upregulation of Bax expression, the downregulation of Bcl-2 and procaspase-3 expression, and the release of cytochrome c from the mitochondria in U937 cells were all observed. Reverse transcription-polymerase chain reaction detected cytokine-related mRNA expressions in human mononuclear cells incubated with CR. An increase in the concentration of CR in culturing medium downregulated granulocyte macrophage colony-stimulatory factor mRNA expression while upregulated interleuken-2 mRNA expression. All the above-mentioned evidences suggest that CR induces the apoptosis of human leukemic U937 cells via the changes in cytokine profile and protein expressions in mitochondria pathway and that CR has the potential to be used in the therapy of leukemia due to its strong apoptosis-promoting effect.