The Lignan-containing Extract of Schisandra chinensis Berries Inhibits the Growth of Chlamydia pneumonia.

The purpose of this study was to investigate the effect and selectivity of an extract of Schisandra chinensis berries against Chlamydia pneumoniae and C. trachomatis. Among the ethnopharmacological uses of the extract from Schisandrae fructus are cough and pneumonia. Therefore we focused on respiratory pathogens. The extract completely inhibited the growth of C. pneumoniae strain CV6 at 250 µg/mL concentration. The inhibition of C. pneumoniae and C. trachomatis growth was dose dependent and established with three different strains. The extract inhibited C. pneumoniae production of infectious progeny in a dose dependent manner. Chlamydia selectivity was elucidated with growth inhibition measurements of three other respiratory bacterial species. A pure compound found in Schisandra chinensis berries, schisandrin B at 20.0 µg/mL concentration inhibited the growth of both C. pneumoniae and C. trachomatis. The extract was found to be non-toxic to the human host cells. These findings highlight the potential of the extract from Schisandra chinensis berries as a source for antichlamydial compounds.

Dibenzocyclooctadiene lignans from Schisandra spp. selectively inhibit the growth of the intracellular bacteria Chlamydia pneumoniae and Chlamydia trachomatis.

Lignans from Schisandra chinensis berries show various pharmacological activities, of which their antioxidative and cytoprotective properties are among the most studied ones. Here, the first report on antibacterial properties of six dibenzocyclooctadiene lignans found in Schisandra spp. is presented. The activity was shown on two related intracellular Gram-negative bacteria Chlamydia pneumoniae and Chlamydia trachomatis upon their infection in human epithelial cells. All six lignans inhibited C. pneumoniae inclusion formation and infectious progeny production. Schisandrin B inhibited C. pneumoniae inclusion formation even when administered 8 h post infection, indicating a target that occurs relatively late within the infection cycle. Upon infection, lignan-pretreated C. pneumoniae elementary bodies had impaired inclusion formation capacity. The presence and substitution pattern of methylenedioxy, methoxy and hydroxyl groups of the lignans had a profound impact on the antichlamydial activity. In addition our data suggest that the antichlamydial activity is not caused only by the antioxidative properties of the lignans. None of the compounds showed inhibition on seven other bacteria, suggesting a degree of selectivity of the antibacterial effect. Taken together, the data presented support a role of the studied lignans as interesting antichlamydial lead compounds.

Role of low voltage activated calcium channels in neuritogenesis and active migration of embryonic neural progenitor cells.

The central role of calcium influx and electrical activity in embryonic development raises important questions about the role and regulation of voltage-dependent calcium influx. Using cultured neural progenitor cell (NPC) preparations, we recorded barium currents through voltage-activated channels using the whole-cell configuration of the patch-clamp technique and monitored intracellular free calcium concentrations with Fura-2 digital imaging. We found that NPCs as well as expressing high-voltage-activated (HVA) calcium channels express functional low-threshold voltage-dependent calcium channels in the very early stages of differentiation (5 h to 1 day). The size of the currents recorded at -50 versus -20 mV after 1 day in differentiation was dependent on the nature of the charge carrier. Peak currents measured at -20 mV in the presence 10 mM Ca2+ instead of 10 mM Ba2+ had a tendency to be smaller, whereas the nature of the divalent species did not influence the amplitude measured at -50 mV. The T-type channel blockers mibefradil and NNC 55-0396 significantly reduced the calcium responses elicited by depolarizing with extracellular potassium, while the overall effect of the HVA calcium channel blockers was small at differentiation day 1. At differentiation day 20, the calcium responses were effectively blocked by nifedipine. Time-lapse imaging of differentiating neurospheres cultured in the presence of low-voltage-activated (LVA) blockers showed a significant decrease in the number of active migrating neuron-like cells and neurite extensions. Together, these data provide evidence that LVA calcium channels are involved in the physiology of differentiating and migrating NPCs.