Anti-α-glucosidase and Anti-dipeptidyl Peptidase-IV Activities of Extracts and Purified Compounds from Vitis thunbergii var. <i>taiwaniana</i>

Ethanol extracts (Et) from the stem (S) and leaf (L) of Vitis thunbergii var. <i>taiwaniana</i> (VTT) were used to investigate yeast α-glucosidase and porcine kidney dipeptidyl peptidase-IV (DPP-IV) inhibitory activities. Both VTT-Et showed complete α-glucosidase inhibition at 0.1 mg/mL; VTT-S-Et and VTT-L-Et showed 26 and 11% DPP-IV inhibition, respectively, at 0.5 mg/mL. The VTT-Et interventions (20 and 50 mg/kg) resulted in improvements in impaired glucose tolerance of diet-induced obese rats. (+)-Hopeaphenol, (+)-vitisin A, and (−)-vitisin B were isolated from the ethyl acetate fractions of S-Et and showed yeast α-glucosidase inhibition (IC₅₀ = 18.30, 1.22, and 1.02 μM) and porcine kidney DPP-IV inhibition (IC₅₀ = 401, 90.75, and 15.3 μM) compared to acarbose (6.39 mM) and sitagliptin (47.35 nM), respectively. Both (+)-vitisin A and (−)-vitisin B showed mixed noncompetitive inhibition against yeast α-glucosidase and porcine kidney DPP-IV, respectively. These results proposed that VTT extracts might through inhibitions against α-glucosidase and DPP-IV improve the impaired glucose tolerance in diet-induced obese rats

135-Day Interventions of Yam Dioscorin and the Dipeptide Asn-Trp (NW) To Reduce Weight Gains and Improve Impaired Glucose Tolerances in High-Fat Diet-Induced C57BL/6 Mice

The C57BL/6J mice were fed a 135-day normal diet or a high-fat diet (HFD) without, or concurrent with, a single yam dioscorin (80 mg/kg) or dipeptide NW (40 mg/kg) intervention every day. The final body weights (g) of mice were 26.1 ± 1.4, 34.97 ± 2.1, 31.75 ± 2.6, and 31.66 ± 3.1, respectively, for normal diet-fed, HFD-fed, dioscorin-intervened, and NW-intervened group. The mice in both intervened groups showed similar less weight gains and had significant differences (<i>P</i> < 0.05) compared to those in the HFD group under the same cumulative HFD intakes. The blood biochemical index of mice with dioscorin interventions showed significantly lower contents in total cholesterol and low-density lipoprotein, and NW interventions showed significantly lower total triglyceride contents compared to those of the HFD group (<i>P</i> < 0.05). Both intervened mice exhibited similar reductions in total visceral lipid contents and have significant differences compared to those of the HFD group (<i>P</i> < 0.05). The dioscorin intervention was better than NW interventions in lowering blood glucose levels by oral glucose tolerance tests and both showed significant differences (<i>P</i> < 0.05) compared to those in the HFD group. Yam dioscorin or dipeptide NW will potentially be used for preventive functional foods of less body weight gains and impaired glucose tolerance controls, which require further clinical trial investigations

Data_Sheet_1_Design of Diarylheptanoid Derivatives as Dual Inhibitors Against Class IIa Histone Deacetylase and β-amyloid Aggregation.PDF

<p>Alzheimer’s disease (AD) is a progressive neurodegenerative disorder with multiple etiologies. Beta-amyloid (Aβ) self-aggregation and overexpression of class IIa histone deacetylases (HDACs) are strongly implicated with AD pathogenesis. In this study, a series of novel diarylheptanoid derivatives were designed, synthesized and evaluated for use as dual Aβ self-aggregation and class IIa HDAC inhibitors. Among these compounds, 4j, 5c, and 5e displayed effective inhibitions for Aβ self-aggregation, HDAC5 activity and HDAC7 activity with IC₅₀ values of <10 μM. The compounds contain three common features: (1) a catechol or pyrogallol moiety, (2) a carbonyl linker and (3) an aromatic ring that can function as an HDAC cap and create hydrophobic interactions with Aβ_1-42. Furthermore, compounds 4j, 5c, and 5e showed no significant cytotoxicity to human neuroblastoma SH-SY5Y cells and also exhibited neuroprotective effect against H₂O₂-induced toxicity. Overall, these promising in vitro data highlighted compounds 4j, 5c, and 5e as lead compounds that are worthy for further investigation.</p