In vitro effects on calcium oxalate crystallization kinetics and crystal morphology of an aqueous extract from Ceterach officinarum: Analysis of a potential antilithiatic mechanism.

Ceterach officinarum Willd is a plant widespread throughout Europe and used in southern Italy as a diuretic. Beliefs in the benefits of C. officinarum aqueous extract in the treatment of calcium oxalate kidney stones are widely held. Little is known, however, about the actual mechanism of its antilithiatic action. Our results in this in vitro study corroborate C. officinarum aqueous extract as a good source of antioxidants with a high antioxidant effects. Our results also demonstrate a major impact of C. officinarum aqueous extract on in vitro induced calcium oxalate crystallization kinetics and crystal morphology, showing its critical role in kidney stone formation and/or elimination. We show that progressively increasing doses of C. officinarum aqueous extract cause a sequence of effects. A powerful inhibitory action on calcium oxalate monohydrate (COM) growth and aggregation is first observed. C. officinarum aqueous extract also appears highly effective in stimulating nucleation increasing the number and reducing the size of COM crystals, which become progressively thinner, rounded and concave in a dose-dependent manner. These shape-modified COM crystals are known to be less adherent to renal tubular cells and more easily excreted through the urinary tract preventing kidney stone formation. Further, C. officinarum aqueous extract promotes the formation of calcium oxalate dihydrate (COD) rather than the monohydrate so that, at the highest concentrations used, only COD crystals are observed, in significant greater numbers with a clear reduction in their size, in a dose-dependent manner. Furthermore, AFM analyses allowed us to reveal the presence of C. officinarum component(s) on the surfaces of COD and modified COM crystals. The crystal surface adsorbed component(s) are shown to be similarly active as the total aqueous extract, suggesting a trigger factor which may direct crystal modification towards COD forms. In urolithiasis pathogenesis COD crystals are less dangerous than the COM forms due to their lower affinity for renal tubular cells. Our results are important in understanding the mechanisms which guide the modification induced by C. officinarum on the crystallization process. Based on these data, together with no adverse toxic effect being observed on the in vitro model of human intestinal enterocytes, C. officinarum aqueous extract could represent an attractive natural therapy for the treatment of urolithiasis.

Phospholipase C-dependent phosphoinositide breakdown induced by ELF-EMF in Peganum harmala calli.

With the aim of examining the response of plant cells to extremely low frequency (ELF) electromagnetic fields (EMF), we investigated the behaviour of the phosphatidylinositol 4,5 bisphosphate (PtdIns 4,5-P(2)) molecule (the precursor of the phosphoinositide signal transduction cascade) by exposing callus cells from Peganum harmala to 50 Hz, 1 gauss EMF for 10 min and by examining the level and the fatty acid composition of PtdIns 4,5-P(2) after the exposure. Our results evidenced a statistically significant decrease in PtdIns 4,5-P(2) concentrations and a different involvement of the constituting fatty acids in the induced breakdown. The manipulation of the lipid-based signalling pathway by phosphoinositide-phospholipase C (PI-PLC) inhibitors (i.e., neomycin, U-73122 and ET-18-OCH(3)) seems to support the hypothesis that, as in animals, also in plants, the cell membrane is the primary impact site of ELF electromagnetic stimulus and that this interaction could probably involve the activation of PI signal transduction pathway including a heterotrimeric G protein.

Morphological and biochemical modifications induced by a static magnetic field on Fusarium culmorum.

The effects of the exposure to a static magnetic field (sMF) of 0.3 +/- 0.03 T on the Fusarium culmorum were investigated in vitro. sMF inhibition of mycelia growth was accompanied by morphological and biochemical changes. Fungal conidia germination and cell viability were also reduced. We provide evidence of the influence of sMF on Ca(2+)-dependent signal transduction pathways involved in conidia germination. Perturbation of these pathways by adding different compounds (i.e. CaCl(2), phorbol 12-myristate 13-acetate, neomycin, EGTA, LiCl) to the medium, suggested that exposed conidia are unable to mobilise calcium from intracellular stores and that the hindered mechanism may be IP(3)-dependent.

Antibacterial effect of a magnetic field on Serratia marcescens and related virulence to Hordeum vulgare and Rubus fruticosus callus cells.

The exposure to a static magnetic field of 80+/-20 Gauss (8+/-2 mT) resulted in the inhibition of Serratia marcescens growth. Callus cell suspensions from Hordeum vulgare and Rubus fruticosus were also examined and only the former was found to be affected by the magnetic field, which induced a decreased viability. S. marcescens was shown to be virulent only toward H. vulgare and this virulence was reduced by the presence of the magnetic field. The modification of glutathione peroxidase activity under the different experimental conditions allowed us to speculate on the possibility of an oxidative-stress response of H. vulgare both to S. marcescens infection and magnetic field exposure. Since the control of microbial growth by physical agents is of interest for agriculture, medicine and food sciences, the investigation presented herein could serve as a starting point for future studies on the efficacy of static magnetic field as low-cost/easy-handling preservative agent.