Biocompatible Periodic Mesoporous Ionosilica Nanoparticles with Ammonium Walls: Application to Drug Delivery.

Periodic mesoporous ionosilica nanoparticles with ammonium walls were synthesized exclusively from a trisilylated ammonium precursor. The nanoparticles display a uniform particle size, together with a high specific surface area and an ordered hexagonal pore architecture. Completely biocompatible in vitro and in vivo, the nanoparticles are efficiently endocytosed by RAW 264.7 macrophages and used as carrier vehicles for anionic drugs. Diclofenac-loaded ionosilica nanoparticles are very efficient in inhibiting lipopolysaccharides-induced inflammation.

Chemical Diversity of Podocarpaceae in New Caledonia: Essential Oils from Leaves of Dacrydium, Falcatifolium, and Acmopyle Species.

Plant secondary metabolites can be useful chemosystematic markers to distinguish species at different taxonomy levels. For example, sesquiterpenes and diterpenes show specific distribution patterns within conifers and so provide especially precious information about the diversity and evolutionary relationships of this group. The aim of the present study was to provide a first insight into the terpene diversity of endemic Podocarpaceae from New Caledonia. The leaf essential oils of Dacrydium araucarioides Brongn. & Gris, Dacrydium balansae Brongn. & Gris, Dacrydium guillauminii J.Buchholz, Dacrydium lycopodioides Brongn. & Gris, Falcatifolium taxoides (Brongn. & Gris) de Laub., and Acmopyle pancheri (Brongn. & Gris) Pilg. from New Caledonia were characterized by GC/FID and GC/MS analyses, and the chemotaxonomic relationships of these species were determined by comparison of their terpene compositions. Cluster analysis based on the biosynthetic origin of their volatile terpenes led to the description of three distinct groups of essential oils and showed close relationships between those of D. araucarioides and D. balansae as well as between those of A. pancheri and F. taxoides.

Acaricidal activity of essential oils from five endemic conifers of New Caledonia on the cattle tick Rhipicephalus (Boophilus) microplus.

The aim of the present study was to demonstrate acaricidal activity on the cattle tick Rhipicephalus (Boophilus) microplus of essential oils from endemic conifers of New Caledonia in the context of the development of natural alternatives. Acaricidal activity of essential oils extracted from resin and heartwood of five endemic conifers of New Caledonia (Araucaria columnaris, Agathis moorei, Agathis ovata, Callitris sulcata, and Neocallitropsis pancheri) was evaluated on 14- to 21-day-old Rhipicephalus microplus tick larvae using the Larval Packal Test bioassay. A first screening with 5% dilute solution was carried out and the oils with 100% of mortality at this rate were diluted until no activity was shown. The heartwood oils of the two Cupressaceae were the most active with LC50 value of 0.65% for C. sulcata and 0.55% for N. pancheri while resin oil of A. columnaris (LC50=1.62%) was the most active of the Araucariaceae family. Negative control (ethanol) was not toxic to the larvae. The chemical composition of essential oil from resin of A. columnaris was analyzed by gas chromatography-mass spectrometry. The essential oil was characterized by high level of sesquiterpene hydrocarbons and oxygenated sesquiterpenes and was composed mainly of aromadendrene (23.1%) and bicyclogermacrene (16.0%). In order to compare different plant resources in a sustainable program of natural acaricide, an "essential oil efficiency EOE" can be measured as the ratio between the yield of extraction and LC50 value. This study shows that A. columnaris (EOE=2.36) and N. pancheri (EOE=3.51) could provide valuable and effective natural acaricides for control of the cattle tick R. microplus.