Supercritical fluid extraction of Eucalyptus globulus bark: a promising approach for triterpenoid production

Eucalyptus bark contains significant amounts of triterpenoids with demonstrated bioactivity, namely triterpenic acids and their acetyl derivatives (ursolic, betulinic, oleanolic, betulonic, 3-acetylursolic, and 3-acetyloleanolic acids). In this work, the supercritical fluid extraction (SFE) of Eucalyptus globulus deciduous bark was carried out with pure and modified carbon dioxide to recover this fraction, and the results were compared with those obtained by Soxhlet extraction with dichloromethane. The effects of pressure (100-200 bar), co-solvent (ethanol) content (0, 5 and 8% wt), and multistep operation were studied in order to evaluate the applicability of SFE for their selective and efficient production. The individual extraction curves of the main families of compounds were measured, and the extracts analyzed by GC-MS. Results pointed out the influence of pressure and the important role played by the co-solvent. Ethanol can be used with advantage, since its effect is more important than increasing pressure by several tens of bar. At 160 bar and 40 degrees C, the introduction of 8% (wt) of ethanol greatly improves the yield of triterpenoids more than threefold

A Natural Combination Extract of Viscum album L. Containing Both Triterpene Acids and Lectins Is Highly Effective against AML In Vivo

Aqueous Viscum album L. extracts are widely used in complementary cancer medicine. Hydrophobic triterpene acids also possess anti-cancer properties, but due to their low solubility they do not occur in significant amounts in aqueous extracts. Using cyclodextrins we solubilised mistletoe triterpenes (mainly oleanolic acid) and investigated the effect of a mistletoe whole plant extract on human acute myeloid leukaemia cells in vitro, ex vivo and in vivo. Single Viscum album L. extracts containing only solubilised triterpene acids (TT) or lectins (viscum) inhibited cell proliferation and induced apoptosis in a dose-dependent manner in vitro and ex vivo. The combination of viscum and TT extracts (viscumTT) enhanced the induction of apoptosis synergistically. The experiments demonstrated that all three extracts are able to induce apoptosis via caspase-8 and -9 dependent pathways with down-regulation of members of the inhibitor of apoptosis and Bcl-2 families of proteins. Finally, the acute myeloid leukaemia mouse model experiment confirmed the therapeutic effectiveness of viscumTT-treatment resulting in significant tumour weight reduction, comparable to the effect in cytarabine-treated mice. These results suggest that the combination viscumTT may have a potential therapeutic value for the treatment AML

Silicon comb-drive X-Y microstage with frame-in-the-frame architecture for MOEMS applications

International audienceIn this paper we present the silicon comb-drive X-Y microstage with the frame-in-the-frame architecture intended to be monolithically integrated with a glass microlens as a MOEMS 2D scanner for the Miniaturized Confocal Microscope On-Chip. The microstage is characterized by relatively large travel range (± 35 μm in X-direction and ± 28 μm in Y-direction at 100 V) for a small number of driving electrodes, without noticeable mechanical X-Y crosstalk. We describe the design, ANSYS modeling, fabrication process and static characterization of the device

Flexible function block for industrial applications of active disturbance rejection controller

In this paper, the PLC-based (Programmable Logic Controller) industrial implementation in the form of the general-purpose function block for ADRC (Active Disturbance Rejection Controller) is presented. The details of practical aspects are discussed because their reliable implementation is not trivial for higher order ADRC. Additional important novelties discussed in the paper are the impact of the derivative backoff and the method that significantly simplifies tuning of higher order ADRC by avoiding the usual trial and error procedure. The results of the practical validation of the suggested concepts complete the paper and show the potential industrial applicability of ADRC