[A new cucurbitane glycoside from Picrorhiza scrophulariiflora].

Chemical constituents from the ethanol extract of Picrorhiza scrophulariiflora were isolated and purified by column chromatography. Their structures were identified by HR-MS, 1D and 2D-NMR, and their cytotoxicity was assessed by CCK-8 assay. Four compounds were isolated and identified as follows: 2ß-D-glucosyloxy-3ß,16α,20ß-trihydroxy-9-methyl-19-norlanosterol-5,25-diene-22-one(1), 2ß-D-glucosyloxy-3ß,16α,20ß-trihydroxy-9-methyl-19-norlanosta-5,24-diene-22-one(2), 25-acetoxy-2ß-glucosyloxy-3ß,16α,20ß-trihydroxy-9-methyl-19-norlanosta-5-ene-22-one(3) and 25-acetoxy-2ß-glucosyloxy-3ß,16α,20ß-trihydroxy-9-methyl-19-norlanosta-5,23-(E)-diene-22-one(4). Compound 1 represents a new cucurbitane glycoside. The half inhibitory concentrations of the 4 compounds exceeded 100 µmol·L~(-1) against four tumor cell lines, indicating no significant cytotoxicity.

Activation of brain endothelium by Escherichia coli K1 virulence factor cglD promotes polymorphonuclear leukocyte transendothelial migration.

Escherichia coli K1 is the most common Gram-negative bacteria causing neonatal meningitis. Polymorphonuclear leukocyte (PMN) transmigration across the blood-brain barrier (BBB) is the hallmark of bacterial meningitis. Reportedly, the deletion of virulence factor cglD (E44:ΔcglD) from E44 is responsible for a less efficient PMN transendothelial migration ability. In the present study, we found that complementation of the cglD gene into E44:ΔcglD mutant strain might restore the PMN count and myeloperoxidase level in a neonatal mouse meningitis. Using human brain microvascular endothelial cells (HBMECs), the main model of the BBB in vitro, we found that E44:ΔcglD mutant strain induced a less efficient PMN adhesion to HBMECs and down-regulated chemokines CXCL1, CXCL6 and CXCL8 and adhesion molecule E-selectin, compared with the E44 strain. Complementation of cglD restored the PMN adhesion to HBMECs and the level of these proteins. E44:ΔcglD mutant strain also induced a less efficient NF-κB pathway activation in HBMECs and reduced the soluble p65 (sp65) level in the cerebral spinal fluid of newborn mice, compared with the E44 strain. Complementation of cglD restored the NF-κB pathway activation and increased the sp65 levels. This suggests that cglD in E44 contributes to NF-κB pathway activation in the brain endothelium to promote PMN adhesion to HBMECs and transendothelial migration. Our identified novel requirement of cglD for immune activation and subsequent PMN entry into the central nervous system suggests that therapies directed at neutralising this molecule will be beneficial in preventing bacterial meningitis progression.

Transport and uptake of clausenamide enantiomers in CYP3A4-transfected Caco-2 cells: An insight into the efflux-metabolism alliance.

The present study developed a CYP3A4-expressed Caco-2 monolayer model at which effects of the efflux-metabolism alliance on the transport and uptake of clausenamide (CLA) enantiomers as CYP3A4 substrates were investigated. The apparent permeability coefficients (Papp) of (-) and (+)CLA were higher in the absorptive direction than those in the secretory direction with efflux ratios (ER) of 0.709±0.411 and 0.867±0.250 (×10(-6)cm/s), respectively. Their bidirectional transports were significantly reduced by 75.6-87.5% after treatment with verapamil (a P-glycoprotein inhibitor) that increased the rate of metabolism by CYP3A4, whereas the CYP3A4 inhibitor ketoconazole treatment markedly enhanced the basolateral to apical flux of (-) and (+)CLA with ERs being 2.934±1.432 and 1.877±0.148(×10(-6)cm/s) respectively. These changes could be blocked by the duel CYP3A4/P-glycoprotein inhibitor cyclosporine A, consequently, Papp values for CLA enantiomers in both directions were significantly greater than those obtained by using verapamil or ketoconazole, and their ERs were similar to those following (-) or (+)-isomer treatment alone. Furthermore, the uptake of (-)CLA was more than that of (+)CLA in the transfected cells. Incubation with ketoconazole decreased the intracellular concentrations of the two enantiomers. This effect disappeared in the presence of a CYP3A4 inducer dexamethasone. These results indicated that CYP3A4 could influence P-gp efflux, transport and uptake of CLA enantiomers as CYP3A4 substrates and that a duel inhibition to CYP3A4/ P-glycoprotein could enhance their absorption and bioavailability, which provides new insight into the efflux-metabolism alliance and will benefit the clinical pharmacology of (-)CLA as a candidate drug for treatment of Alzheimer's disease.