Ethanol extract from Gynostemma pentaphyllum ameliorates dopaminergic neuronal cell death in transgenic mice expressing mutant A53T human alpha-synuclein

Gynostemma(G.) pentaphyllum(Cucurbitaceae) contains various bioactive gypenosides. Ethanol extract from G. pentaphyllum(GP-EX) has been shown to have ameliorative effects on the death of dopaminergic neurons in animal models of Parkinson’s disease(PD) induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-and 6-hydroxydopamine. PD patients exhibit multiple symptoms, so PD-related research should combine neurotoxin models with genetic models. In the present study, we investigated the ameliorative effects of GP-EX, including gypenosides, on the cell death of dopaminergic neurons in the midbrain of A53 T α-synuclein transgenic mouse models of PD(A53 T). Both GP-EX and gypenosides at 50 mg/kg per day were orally administered to the A53 T mice for 20 weeks.α-Synuclein-immunopositive cells and α-synuclein phosphorylation were increased in the midbrain of A53 T mice, which was reduced following treatment with GP-EX. Treatment with GP-EX modulated the reduced phosphorylation of tyrosine hydroxylase, extracellular signal-regulated kinase(ERK1/2), Bcl-2-associated death promoter(Bad) at Ser112, and c-Jun N-terminal kinase(JNK1/2) due to α-synuclein overexpression. In the A53 T group, GP-EX treatment prolonged the latency of the step-through passive avoidance test and shortened the transfer latency of the elevated plus maze test. Gypenosides treatment exhibited the effects and efficacy similar to those of GP-EX. Taken together, GP-EX, including gypenosides, has ameliorative effects on dopaminergic neuronal cell death due to the overexpression of α-synuclein by modulating ERK1/2, Bad at Ser112, and JNK1/2 signaling in the midbrain of A53 T mouse model of PD. Further studies are needed to investigate GP-EX as a treatment for neurodegenerative synucleinopathies, including PD. This study was approved by the Animal Ethics Committee of Chungbuk National University(approval No. CBNUA-956-16-01) on September 21, 2016.

Improved photocatalytic activity of surface charge functionalized ZnO nanoparticles using aniline

Functionalization of aniline molecules on zinc oxide(ZnO)nanoparticles is reported using a simple impregnation technique.Functionalized ZnO samples were systematically characterized based on morphology,surface and optical properties,and photocatalytic performance towards methyl orange(MO).Aniline functionalization increased the surface charge of the modified ZnO.Compared to pristine ZnO,the aniline-functionalized ZnO yielded faster photodegradation of MO,degrading 98.29%of MO in 60 min and superoxide radicals were the major species during the MO photodegradation reaction.These results indicate that the improvement of photocatalytic degradation could be attributed to opposite charge-induced surface adsorption.Hence,protonated amine as a positively charged molecule was expected to increase the surface adsorption of MO(as an anionic dye)on ZnO nanoparticles surfaces,thereby increasing their photocatalytic degradation performance.