Abstract:The effects of Phyllanthus emblica L extract on mRNA expressions of GLUT-2 (glucose transporter type 2) and PPARγ (peroxisome proliferator-activated receptor-γ) and the activities of PPRE (peroxisome proliferator response element) and NF-κB in LO2 cells were studied to elucidate the hypoglycemic mechanism and the main active components of this extract. The methanol extracts of P. emblica L were first isolated using a D101 macroporous resin column to yield three fractions. Real-time polymerase chain reaction (PCR) and luciferase reporter gene methods were applied to study the effects of the extracts of P. emblica L and their active components on the mRNA expressions of GLUT-2 and PPARγ and the activities of PPRE and NF-κB. The extracts of P. emblica L significantly enhanced the mRNA expression of GLUT-2 and PPARγ and activity of the PPRE reporter gene (p<0.05), inhibited the lipopolysaccharide (LPS)-induced inflammation (p<0.05), and reduced the activity of the NF-κB reporter gene; the inhibitory effect was dose-dependent (p<0.05). The 30% ethanol-eluted fraction from the macroporous resin column was the active fraction. Sephadex LH-20, C18 (ODS), semi-preparative high performance liquid chromatography (HPLC) columns were used, and one main component was isolated and identified as gallic acid. P. emblica L might exert its hypoglycemic effect by increasing the expressions of GLUT-2 and PPARγ and inhibiting the inflammation-related pathway. Gallic acid may be the major active component.
