Search

A pair of new enantiomeric indolopyridoquinazoline-type alkaloids, (+)-1,7 S ,8 R - and (−)-1,7 R ,8 S -trihydroxyrutaecarpine (3a and 3b), and a new limonoid-tyrosamine hybrid, austrosinin (8), along with six known alkaloids and limonoids, were isolated from the stems with leaves of Tetradium austrosinense. Their structures were elucidated on the basis of analysis of MS, NMR, ECD and time-dependent density functional theory-based electronic circular dichroism (TDDFT-ECD) calculations, as well as proposed biosynthetic pathway. An anti-inflammatory bioassay in vitro showed 8 had significant immunosuppressive effect against the production of pro-inflammatory cytokine TNF-α in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. [Display omitted] • Six alkaloids and three limonoids were isolated from Tetradium austrosinense. • A pair of enantiomeric indolopyridoquinazoline-type alkaloids were isolated and resolved. • Austrosinin is the first example of limonoid-tyrosamine hybrid from the nature source. • Austrosinin displayed significant immunosuppressive effect. [ABSTRACT FROM AUTHOR]

3-O-[(E)-4-(4-cyanophenyl)-2-oxobut-3-en-1-yl] kaempferol is a novel lead compound to discover anti-diabetic and anti-obesity drugs. The present study reported the scaffold hopping of the lead compound to obtain a new isoxazole derivative, C45 , which has improved glucose consumption at the nanomolar level (EC 50 = 0.8 nM) in insulin resistant (IR) HepG2 cells. Western blotting showed that C45 markedly enhanced the phosphorylation of AMPK (AMP-activated protein kinase) and reduced the levels of the gluconeogenesis key enzymes PEPCK (phosphoenolpyruvate carboxykinase) and G6Pase (glucose 6-phosphatase) in HepG2 cells. The potential molecular mechanism of C45 may be activation of the AMPK/PEPCK/G6Pase pathways. We concluded that C45 might be a valuable candidate to discover anti-diabetic drugs. Unlabelled Image [ABSTRACT FROM AUTHOR]