• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.973-979
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• 2016

Lentils (Lens culinaris) have been gaining increasing attention recently as a top five superfood, as they are high in protein and other essential nutrients, including folate, iron, potassium, and various antioxidants. In the present study, phenolic extracts from four different lentil cultivars (green, red, French, and beluga) were evaluated for their total phenolic contents and in vitro antioxidant activities. Total polyphenol and flavonoid contents of four different lentil extracts were 27.30~30.30 mg tannic acid equivalents (TAE)/g and 13.14~16.29 mg quercetin equivalents (QUE)/g, respectively. Beluga and red lentil extracts showed higher polyphenol contents than others (P<0.05), whereas there was no significant difference in flavonoid contents among the four lentil cultivars. $RC_{50}$ values of the lentil extracts for DPPH radical, ABTS radical, and $H_2O_2$ were $57.42{\sim}64.49{\mu}g/mL$, $66.11{\sim}75.69{\mu}g/mL$, and $59.72{\sim}72.86{\mu}g/mL$, respectively. Among the four lentil extracts, beluga lentil extract showed the most potent scavenging effect in all three reactive oxygen species (ROS) scavenging assays, and thus beluga extract was further tested for its inhibitory effect on early peroxidation of linoleic acid. The results showed that beluga lentil extract significantly inhibited linoleic acid peroxidation in a dose-dependent manner (concentration required for 50% reduction=$222.76{\m}g/mL$). In addition, beluga lentil extract showed a significant protective effect against alcohol-induced cytotoxicity in AML-12 cells (normal mouse hepatocyte cell line). Taken together, these results suggest that lentil extracts represent potential sources of natural antioxidants, and further studies will be necessary to determine their protective effects against oxidative stress in vivo.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.267-272
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• 2017

Piceatannol (PIC) is a natural hydroxylated analog of resveratrol (RSV), which is a polyphenol known to extend lifespan by stimulating sirtuins. The aim of this study was to investigate the effects of PIC and RSV on the toll-like receptor 4 (TLR4)-nuclear factor kappa B ($NF-{\kappa}B$) pathway in mouse hepatocytes and an obese/diabetic KK/HlJ mouse model. AML12 mouse hepatocytes in the absence or presence of palmitic acids (PA) were treated with PIC ($50{\mu}M$) or RSV ($50{\mu}M$). Male KK/HlJ mice at 20 weeks of age were divided into three subgroups as follows: 1) obese and diabetic control (KK), 2) KK_PIC, and 3) KK_RSV. PIC and RSV were administered orally at a dose of 10 mg/kg/d for 4 weeks. Four weeks of PIC and RSV treatment did not affect body weight or food intake in KK mice. Serum fasting blood glucose was significantly reduced in KK_PIC, and 2 h oral glucose tolerance test area under the curve was significantly reduced by PIC and RSV treatment in KK mice. PIC tended to improve homeostasis model assessment of the insulin resistance index (HOMA-IR) and HOMA beta-cells in diabetic KK mice. TLR4 and $NF-{\kappa}B$ were down-regulated by PIC and RSV treatments in hepatocytes in the absence or presence of PA. Insulin receptor, AMP-activated protein kinase, peroxisome proliferator-activated receptor gamma, nucleotide oligomerization domain-like receptor family pyrin domain-containing 3, interleukin-1, and $NF-{\kappa}B$ were altered in PIC-treated livers. Collectively, PIC and RSV inhibited the $TLR4-NF-{\kappa}B$ pathway, and PIC seems to be more effective than RSV in the regulation of analyzed targets, which are involved in insulin signaling and inflammation in vivo.