Effect of AE on palmitate-induced activation of caspase 3.

<p>β cells were incubated for 24 h with or without palmitate and AE treatment, and then analyzed using Western blot. The protein levels of pro-caspase and active caspase were calculated as a percentage compared to that of the control group. Data are presented as means ± SD (n = 3) and analyzed using ANOVA. ###p < 0.001, compared to the controls. *p < 0.05, **p < 0.01, ***p < 0.001, compared to palmitate treatment.</p

Effect of AE on palmitate-induced signals of AMPK and mTOR.

<p>β cells were incubated for 24 h with or without palmitate and AE treatment, and then analyzed using Western blot. The phosphorylated or total protein levels of AMPK and mTOR were calculated as a percentage compared to the control group. Data are presented as means ± SD (n = 3) and analyzed using ANOVA. #p < 0.05, ##p < 0.01, compared to the controls. *p < 0.05, **p < 0.01, compared to palmitate treatment.</p

Active subfractions of <i>Abelmoschus esculentus</i> substantially prevent free fatty acid-induced β cell apoptosis <i>via</i> inhibiting dipeptidyl peptidase-4

<div><p>Lipotoxicity plays an important role in exacerbating type 2 diabetes mellitus (T2DM) and leads to apoptosis of β cells. Recently dipeptidyl peptidase-4 (DPP-4) inhibitors have emerged as a useful tool in the treatment of T2DM. DPP-4 degrades type 1 glucagon-like peptide (GLP-1), and GLP-1 receptor (GLP-1R) signaling has been shown to protect β cells by modulating AMPK/mTOR, PI3K, and Bax. The anti-hyperglycemic effect <i>of Abelmoschus esculentus</i> (AE) is well known, however its mucilage makes it difficult to further examine this effect. In our recent report, a sequence of extraction steps was used to obtain a series of subfractions from AE, each with its own composition and property. Among them F1 (rich in quercetin glucosides and pentacyclic triterpene ester) and F2 (containing large amounts of carbohydrates and polysaccharides) were found to be especially effective in attenuating DPP-4 signaling, and to have the potential to counter diabetic nephropathy. Hence, the aim of the present study was to investigate whether AE subfractions can prevent the palmitate-induced apoptosis of β cells, and the putative signals involved. We demonstrated that AE, and especially 1 μg/mL of F2, decreased palmitate-induced apoptosis analyzed by flow cytometry. The result of western blot revealed that palmitate-induced decrease in GLP-1R and increase in DPP-4 were restored by F1 and F2. The DPP-4 inhibitor linagliptin decreased the expression of caspase 3, suggesting that DPP-4 is critically involved in apoptotic signaling. Analysis of enzyme activity revealed that palmitate increased the activity of DPP4 nearly 2 folds, while F2 especially inhibited the activation. In addition, AMPK/mTOR, PI3K and mitochondrial pathways were regulated by AE, and this attenuated the palmitate-induced signaling cascades. In conclusion, AE is useful to prevent the exacerbation of β cell apoptosis, and it could potentially be used as adjuvant or nutraceutical therapy for diabetes.</p></div

Effect of AE on DPP-4-mediated apoptosis.

<p>β cells were incubated for 24 h with or without palmitate and AE. DPP-4 activity was analyzed and calculated as a percentage compared to the control group. Data are presented as means ± SD (n = 3) and analyzed using ANOVA. ###p < 0.001, compared to the controls. **p < 0.01, ***p < 0.001, compared to palmitate treatment.</p

Cytotoxicity test for palmitate and AE subfractions.

<p>β cells were incubated for 24 h with or without different concentrations of (A) palmitate, (B) F1 and F2. Cell viability was calculated as percentage compared to the control group. Data are presented as means ± SD (n = 3) and analyzed using ANOVA. *p < 0.05, **p < 0.01, ***p < 0.001, compared to the controls.</p

Effect of AE on palmitate-induced apoptosis.

<p>β cells were incubated for 24 h with or without palmitate and AE treatment, and then analyzed using flow cytometry. Top to bottom indicates the controls, palmitate, palmitate with 1 μg/mL of F1, and palmitate with 1 μg/mL of F2, respectively, with the percentage of cell distribution. The percentage of sub-G1 was calculated. Data are presented as means ± SD (n = 3) and analyzed using ANOVA. ###p < 0.001, compared to the controls. *p < 0.05, **p < 0.01, ***p < 0.001, compared to palmitate treatment.</p

Effect of AE on palmitate-induced signals of PI3K and Bax.

<p>β cells were incubated for 24 h with or without palmitate and AE treatment, and then analyzed using Western blot. The phosphorylated or total protein levels of PI3K and Bax were calculated as a percentage compared to the control group. Data are presented as means ± SD (n = 3) and analyzed using ANOVA. #p < 0.05, ##p < 0.01, compared to the controls. *p < 0.05, **p < 0.01, compared to palmitate treatment.</p

Procedures of extracting AE subfractions.

<p>Procedures of extracting AE subfractions.</p

Quercetin-3-O-β‑d‑glucuronide in the Nuciferine Leaf Polyphenol Extract Promotes Neurogenesis Involving the Upregulation of the Tropomyosin Receptor Kinase (Trk) Receptor and AKT/Phosphoinositide 3‑Kinase Signaling Pathway

Neurogenesis is crucial during the human lifespan for the maintenance of synaptic plasticity and normal function. The impairment of hippocampal neurogenesis in adults may lead to neurodegenerative disease, such as Alzheimer’s disease. Miquelianin (quercetin-3-O-β-d-glucuronide, Q3GA) is a constituent of the nuciferine leaf polyphenol extract (NLPE), and it has protective effects against neurodegeneration. In this study, we examined the effect of the NLPE on neurogenesis and the mechanisms underlying Q3GA on neurogenesis. We fed 24-week-old male C57BL/6 mice with 0.1 or 0.25% NLPE for 2 weeks. NLPE treatment increased small spindle-shaped stem cell numbers in the subgranular zone and the number of doublecortin (DCX)- and neuron-specific nuclear protein (NeuN)-expressing neurons. HT22, a hippocampal cell line, treated with Q3GA revealed significant neurite growth and upregulated TrkR and PI3K/Akt levels. The evidence from a model of retinoic acid-induced SH-SY5Y cell differentiation showed that Q3GA or NLPE increases neurite growth significantly. Taken together, the NLPE containing Q3GA to promote neurogenesis involving the upregulation of TrkR and the PI3K/Akt signaling pathway might be potentiated as an alternative strategy for the treatment of neurodegeneration

Additional file 1: of Radix Paeoniae Rubra stimulates osteoclast differentiation by activation of the NF-ÎşB and mitogen-activated protein kinase pathways

Figure S1. Representative base peak chromatograms of aqueous extract of RPR positive (A) and negative (B) ion modes obtained from Bruker HCT Ultra Ion Trap MS spectrometer. Detailed experimental conditions were shown in the text. (PDF 10 kb