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To appraise the effects and involved mechanism of Dendropanax morbifera leaves extract (DLE) on diabetes and retinal degeneration, in this study, male C57BLKS/J-m+/db and five groups of db/db mice were treated with 0.5% CMC or metformin or three doses of DLE for 6 weeks. Administration of DLE stimulated AMP-activated protein kinase in the liver, skeletal muscle and adipose tissue, leading to the improvement of gene and protein expression related with insulin resistance and glucose homeostasis in db/db mice. Morphological changes and insulin depletion of pancreatic islets were also attenuated by treatment of DLE. Moreover, DLE treatment prevented the deterioration of retina by regulating not only the gene expression related with apoptosis and neovascularization, but also the level of activator protein-1 in retina. Therefore, DLE improves diabetic phenotype and retinal degeneration, suggesting that DLE could be a prospective agent for preventing diabetes and related eye complication. [ABSTRACT FROM AUTHOR]

Dendropanax morbifera extracts were obtained from three different tissues: the heartwood, stem bark, and leaves. The 95% ethanol extract from leaf showed the strongest inhibitory activity (88% inhibition at 50 μg/mL with HepG2 cells) against triglyceride (TG) biosynthesis. Bioactivity-guided fractionation and metabolite investigation of the leaf extracts resulted in the separation and identification of three polyacetylene derivatives that inhibited newly synthesized TG in HepG2 cells. A method for the profile and contents analyses of the leaf extracts were measured using QTOF-MS with a charged aerosol detector (CAD), including (9 Z ,16 S)-16-hydroxy-9,17-octadecadiene-12,14-diynoic acid (1), which was decomposed during the temperature and storage studies. All metabolites decomposed at different temperatures, especially the polyacetylene, which was rapidly oxidized when the isolated form was exposed to air. However, it was fairly stable in the extract at low temperature <–20 °C. The aim of this study was to provide a way to protect the active ingredients in the process of developing and distributing functional foods containing D. morbifera. The application of this quality control/quality assurance step may improve the chemistry, manufacturing, and control for raw materials. [Display omitted] • Polyacetylene metabolites showed the greatest increase year after year. • Three polyacetylenes in D. morbifera leaves decreased with storage and temperature. • Three marker metabolites were isolated from D. morbifera leaves. • Polyacetylene metabolites 1 – 3 were dependent upon the quality and activity of leaf extracts. • The polyacetylenes in the leaf extracts were shown to be strong inhibitors of TG. [ABSTRACT FROM AUTHOR]