• Food Science and Preservation
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• v.20 no.6
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• pp.877-885
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• 2013

Wine extracts of four different berry fruits, such as mulberry, blueberry, strawberry, and raspberry, were investigated for antioxidant, anti-tyrosinase, and ${\alpha}$-glucosidase activities by using in vitro assays. Additionally, quantitative changes of ${\alpha}$-glucosidase inhibitor in mulberry wine were determined by HPLC according to mulberry cultivars and fermentation process. Among four berry wines examined, mulberry wine showed the most potent ${\alpha}$-glucosidase inhibitory activity with 69.37% at 0.23 mg/mL, while blueberry and strawberry wines exhibited the strongest inhibition against DPPH radical and tyrosinase activity, respectively. Four compounds were isolated and purified from mulberry wine by a series of isolation procedures, such as solvent fractionation, and Diaion HP-20, ODS-A, and Sephadex LH-20 column chromatographies. Among them, Comp. 4 exerted the strongest ${\alpha}$-glucosidase inhibitory activity ($I_C_{50}=31.57{\mu}M$), and its chemical structure was identified as quercetin by UV and NMR spectral analysis. Finally, the "Daeseongppong" (16.83 ppm) muberry wine had larger amount of quercetin than the "Iksuppong" (14.85 ppm) and "Cheongilppong" (8.92 ppm) mulberry wines, but their contents of three mulberry wines decreased considerably with aging process. These results suggest that mulberry wine containing quercetin acted as ${\alpha}$-glucosidase inhibitor may be useful as a potential functional wine for improving diabetic disorder.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.929-937
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• 2016

The purpose of this study was to investigate the effect of Acanthopanax senticosus extract (ASE) (ethanol : DW=1:1, v/v) on inhibition of type 2 diabetes using an OLETF rat model via regulation of HbA1c and AGEs levels. Supplementation with ASE 0.1% and 0.5% effectively lowered levels of glucose, insulin, oral glucose tolerance test, and Homa-insulin resistance, suggesting reduced insulin resistance. Blood levels of HbA1c and AGEs were significantly reduced in a dose-dependent manner. As oxidative stress plays a key role in accelerating production of HbA1c and AGEs, which worsen symptoms of type 2 diabetes, levels of malonaldehyde and pro-inflammatory cytokines were measured. Lipid peroxidation in both blood and liver tissues was significantly reduced, and induction of pro-inflammatory cytokines interleukin-${\beta}$ and tumor necrosis factor-${\alpha}$, which elevate production of HbA1c and AGEs, was inhibited (P<0.05). To evaluate the possible cellular events after AGEs receptor activation, genetic expression of protein kinase C (PKC)-${\delta}$ and transforming growth factor (TGF)-${\beta}$ was measured by real-time polymerase chain reaction. Supplementation with both ASE 0.1% and 0.5% significantly inhibited mRNA expression of PKC-${\delta}$ and TGF-${\beta}$, indicating that ASE may have beneficial effects on preventing insulin-resistant cells or tissues from progressing to diabetic complications. Taken together, ASE has potential to improve type 2 diabetes by inhibiting insulin resistance and protein glycosylation, including production of HbA1c and AGEs. Anti-oxidative activities of ASE are a main requisite for reducing production of HbA1c and AGEs and are also related to regulation of the PKC signaling pathway, resulting in suppression of TGF-${\beta}$, which increases synthesis of collagen, prostaglandin, and disease-related proteins.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.430-437
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• 2017

The protective effect of Pteridium aquilinum on high glucose-induced cytotoxicity was examined in vitro to investigate the relationship between diabetic condition and neuronal dysfunction. The ethyl acetate fraction of P. aquilinum (EFPA), with total phenolic content of 265.08 mg gallic acid equivalent/g, showed higher 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)/2,2-diphenyl-1-picrylhydrazyl radical scavenging activities and lipid peroxidation inhibitory effect than any other fraction. In addition, EFPA showed a significant reduction in the inhibitory effect on ${\alpha}$-glucosidase activity ($IC_{50}$ value=$205.26{\mu}g/mL$) compared to the acarbose positive control. The anti-oxidative effect in PC12 cells, protective effects on high glucose-induced oxidative stress in neuronal cells, and neurotoxicity were measured using 2',7'-dichlorofluorescin diacetate, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide, and lactate dehydrogenase assays, respectively. EFPA showed conspicuous inhibitory effect on cellular reactive oxygen species production and neuronal cell apoptosis. Finally, kaempferol-3-glucoside was identified as the main phenolic compound of EFPA using high performance liquid chromatography.