In vitro and in vivo immunologic potentiation of herb extracts on shrimp (Litopenaeus vannamei).

In vitro and in vivo effects of Astragalus polysaccharide (APS), chlorogenic acid (CGA) and berberine (BBR) on shrimp (Litopenaeus vannamei) were studied. In vitro test showed that the combination of APS and BBR and the combination of APS and CGA have strong immune enhancement effects and no lysosomal membrane damage on hemocyte. Then, feeding experiment was proceeded to optimize the concentrations of compound herbal extracts. Four diets containing G1-G4(0.5 g kg -1 APS + 0.5 g kg -1 BBR, 1.0 g kg -1 APS +1.0 g kg -1 BBR, 0.5 g kg -1 APS +0.5 g kg -1 CGA, 1.0 g kg -1 APS + 1.0 g kg -1 CGA) associated with the control group (common diet) were compared and determined their biomolecule damage to hepatopancreas including DNA damage, lipid peroxidation and protein carbonyl. The results indicated that G3 (0.5 g kg -1 APS +0.5 g kg -1 CGA) showed higher total hemocyte counts, phagocytic activities, antibacterial activities and bacteriolytic activities during 6 days feeding, and without biomolecule damages after 6 days post-withdrawal. Therefore, the appropriate immunostimulants formula in this study was the combination of 0.5 g kg -1 APS and 0.5 g kg-1 CGA, which was used for 6 days followed by 6 days post-withdrawal. Additionally, our study provides new support for screening composite immunostimulants formula by using primary shrimp hemocyte culture.

Direct Asymmetric Reductive Amination for the Synthesis of (S)-Rivastigmine.

In this article we demonstrate how asymmetric total synthesis of (S)-rivastigmine has been achieved using direct asymmetric reductive amination as the key transformation in four steps. The route started with readily available and cheap m-hydroxyacetophenone, through esterification, asymmetric reductive amination, N-diphenylmethyl deprotection and reductive amination, to provide the final (S)-rivastigmine in 82% overall yield and 96% enantioselectivity. In the asymmetric reductive amination, catalysed by the iridium⁻phosphoramidite ligand complex and helped by some additives, the readily prepared 3-acetylphenyl ethyl(methyl)carbamate directly reductively coupled with diphenylmethanamine to yield the chiral amine product in 96% ee and 93% yield.