A Triterpenoid Inhibited Hormone-Induced Adipocyte Differentiation and Alleviated Dexamethasone-Induced Insulin Resistance in 3T3-L1 adipocytes

6a-Hydroxylup-20(29)-en-3-on-28-oic acid(1),a natural triterpenoid,was found to possess the ability in a dose-dependent manner inhibiting hormone-induced adipocyte differentiation in 3T3-L1 preadipocytes,and restoring glucose consuming ability in dexamethasone(DXM)-induced insulin resistant 3T3-L1 adipocytes.Compound 1 was also found to ameliorate DXM-induced adipocyte dysfunction in lipolysis and adipokine secretion.Mechanistic studies revealed that 1 inhibited adipocyte differentiation in 3T3-L1 preadipocytes via down-regulating hormone-stimulated gene transcription of peroxisome proliferator-activated receptor c and CCAAT-enhancer-binding protein alpha which are key factors in lipogenesis,and restored DXM-impaired glucose consuming ability in differentiated 3T3-L1 adipocytes via repairing insulin signaling pathway and activating down-stream signaling transduction by phosphorylation of signaling molecules PI3K/p85,Akt2 and AS160,thus leading to increased translocation of glucose transporter type 4 and transportation of glucose.

Sterols and Terpenoids from Viburnum odoratissimum

A new stigmasterol type natural product,viburodorol A(1),along with eleven known sterols and terpenoids(2–12),were isolated from the aerial parts of Viburnum odoratissimum.The structure of 1 was elucidated on the basis of comprehensive spectroscopic analysis.It’s noteworthy that compound 2,the major constituent of this plant,can signifi-cantly stimulate glucose absorption in insulin resistant HepG2 cells without affecting cell viability.Furthermore,this compound can also restore the glucose absorption in DXMS-induced insulin resistant 3T3-L1 cells.