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Calcium hydroxyl and fluoroapatite (CaHAp and CaFAp) were prepared in the presence of the 2-carboxyletylphosphonic acid (2-CEPA), by hydrothermal method. The incorporation of phosphonic acid within the apatite structure was confirmed by powder XRD, IR and MAS-NMR spectroscopies and SSA. The X-ray powder analysis showed that the cristallinity was not affected by the presence of organic moieties. IR spectroscopy showed new vibration modes related to phosphonate groups. 31P MAS-NMR spectra exhibit new signals, assigned to the presence of organic phosphorus. Specific surface area (SSA) increases with increasing of phosphonate amount, especially for CaHAp. According to these results, a mechanism is proposed for the formation of two types of ionic interaction (-C-O-Ca) and (Ca-O-Porg).

Background: Plants are an abundant natural source of potential chemical compounds; they have been widely used in various industries, such as pharmaceuticals, cosmetics, and food. This work aims to study two Saharan medicinal plants by evaluating the activity of plant extract against bacterial and fungal plant pathogens as well as against the model nematode Caenorhabditis (C.) elegans. Methods: The antimicrobial activity of plant extracts against plants pathogen was assessed in a 96- well plate assay by calculating the percentage of inhibition of bacteria. The antifungal activity against plant pathogenic fungi was evaluated by the agar diffusion method, and inhibition was calculated by measuring the diameter of the inhibition zone. Anthelmintic activity was evaluated by calculating the average movement of C. elegans worms. Preliminary phytochemical screening was realized with HPTLC. Results: Hexane and ethyl acetate extract of Pergularia tomentosa showed broad-spectrum antimicrobial activity. This plant has the potential to act as a broad-spectrum antibacterial biopesticide. Hexane extract of Forsskaolea tenacissima exhibited good activity against one fungus. The extracts of Pergularia tomentosa showed good activity against Caenorhabditis elegans, and the extracts of Forsskaolea tenacissima exhibited a low activity. Preliminary phytochemical screening with HPTLC shows that both plants are rich in steroids and flavonoids. Conclusion: Our study shows that the studied plants may possess a broad-spectrum antibacterial effect with narrow-spectrum antifungal properties which can offer more sustainable crop protection with a much safer environmental and human health impact. Plant extracts that inhibited C. elegans could provide a starting point for the development of new anthelmintic drugs.

Continuous solid solutions of barium/strontium fluoroapatites Ba(10−x)Srx(PO4)6F2 (Ba(10−x)SrxFAp; 0  x  10) were obtained in an aqueous medium. They were investigated by Rietveld structure-refinement methods using powder X-ray diffraction patterns and by chemical analysis, IR spectroscopy and 31P MAS NMR spectroscopy. Replacement of barium by strontium induces a regular decrease of the lattice constants a and c according to Vegard’s law. The results of the powder-fitting structure refinements indicate a clear preference of strontium for the S(1) site of the apatitic structure. A high-wavenumber shift of the IR absorption bands characteristic of PO4 internal modes is also observed, in agreement with the diminution of the ionic character of the M−O bonds. For increasing strontium content, a regular δiso increase is shown in the 31P MAS NMR spectra, from δ = 0.91 ppm for Ba10FAp to δ = 3.06 ppm for Sr10FAp. For all mixed Ba/Sr fluoroapatites, the low intensities of the spinning bands reflect the weak 31P chemical-shift anisotropy, in agreement with the low distortion of the PO4 tetrahedron, as shown by Rietveld refinement. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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