1,2,3,4,6-penta-O-galloyl-β-D-glucose Protects PC12 Cells from MPP^+-mediated Cell Death by Inducing Heme Oxygenase-1 in an ERK- and Akt-dependent Manner

This study examined the ability of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (β-PGG) to induce the expression of heme oxygenase-1 (HO-1) in the PC12 cells and its regulation in the PC12 cells.One week before treatment with the drug,nerve growth factor (NGF) was added to the cultures at a final concentration of 50 ng/mL to induce neuronal differentiation.After drug treatment,HO-1 gene transcription was analyzed by reverse transcription polymerase chain reaction (RT-PCR).Expression of HO-1 and NF-E2-related factor2 (Nrf2) and activation of extracellular signal-regulated kinase (ERK) and Akt were detected by Western blotting.The viability of the PC12 cells treated with different medicines was examined by MTT assay.The oxidative stress in the PC12 cells was evaluated qualitatively and quantitatively by DCFH-DA.The results showed that β-PGG up-regulated HO-1 expression and this increased expression provided neuroprotection against MPP+-induced oxidative injury.Moreover,β-PGG induced Nrf2 nuclear translocation,which was found to be upstream of β-PGG-induced HO-1 expression,and the activation of ERK and Akt,a pathway that is involved in β-PGG-induced Nrf2 nuclear translocation,HO-1 expression and neuroprotection.In conclusion,β-PGG up-regulates HO-1 expression by stimulating Nrf2 nuclear translocation in an ERK-and Akt-dependent manner,and HO-1 expression by β-PGG may provide the PC12 cells with an acquired antioxidant defense capacity to survive the oxidative stress.

Discovery of human pancreatic lipase inhibitors from root of Rhodiola crenulata via integrating bioactivity-guided fractionation,chemical profiling and biochemical assay

Although herbal medicines(HMs)are widely used in the prevention and treatment of obesity and obesity-associated disorders,the key constituents exhibiting anti-obesity activity and their molecular mechanisms are poorly understood.Recently,we assessed the inhibitory potentials of several HMs against human pancreatic lipase(hPL,a key therapeutic target for human obesity),among which the root-extract of Rhodiola crenulata(ERC)showed the most potent anti-hPL activity.In this study,we adopted an integrated strategy,involving bioactivity-guided fractionation techniques,chemical profiling,and biochemical assays,to identify the key anti-hPL constituents in ERC.Nine ERC fractions(retention time=12.5e35 min),obtained using reverse-phase liquid chromatography,showed strong anti-hPL activity,while the major constituents in these bioactive fractions were subsequently identified using liquid chromatography-quadrupole time-of-flight mass spectrometry(LC-Q-TOF-MS/MS).Among the identified ERC constituents,1,2,3,4,6-penta-O-galloyl-β-D-glucopyranose(PGG)and catechin gallate(CG)showed the most potent anti-hPL activity,with pIC50 values of 7.59±0.03 and 7.68±0.23,respectively.Further investigations revealed that PGG and CG potently inhibited hPL in a non-competitive manner,with inhibition constant(Ki)values of 0.012 and 0.082 mM,respectively.Collectively,our integrative analyses enabled us to efficiently identify and characterize the key anti-obesity constituents in ERC,as well as to elucidate their anti-hPL mechanisms.These findings provide convincing evidence in support of the anti-obesity and lipid-lowering properties of ERC.

Isolation of Antifungal Compound from Paeonia Suffruticosa and Its Antifungal Mechanism

Objective：To isolate antifungal compound from Paeonia suffruticosa,and to find the antifungal mechanisms by observing the ultrastructural modifications of yeasts in growth phase produced by 1,2,3,4,6-pentaO-galloyl-beta-D-glucose（PGG）.Methods：Peony（Paeonia suffruticosa） root bark（PRB） was separated by solvent extraction and purified by high performance liquid chromatography（HPLC） method using analytical and preparative reversed phase C18 column on the basis of bio-assay method.In order to investigate the antifungal mechanism of PGG,Yeasts were submitted to different concentrations[3×minimum inhibition concentration（MIC）,0.3×MIC]for 1 h under constant stirring at 30 ℃,and transmission electron microscopy was performed.Results：Based on the antifungal activity of PRB on Candida glabrata CBS138,the antifungal compound were isolated in ethyl acetate layer of PRB and identified as PGG by mass spectrometry,1H nuclear magnetic resonance（NMR） analyses,with molecular weight of 940 and molecular formular as C41H32O26.Transmission electron microscopy showed that PGG degraded the cell wall envelope.Conclusion：The results suggest that PGG may be responsible for the antifungal activity of PRB by disrupting the structure of cell wall directly.