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Okada Y.,Aichi Prefectural University | Okada M.,Ageing and Nutrition Research
Journal of Pharmacy and Bioallied Sciences | Year: 2013

Aim: Alzheimer's disease (AD) is characterized by large deposits of amyloid β (Aβ) peptide. Aβ is known to increase reactive oxygen species (ROS) production in neurons, leading to cell death. In this study, we screened 15 plant seeds' aqueous extracts (PSAE) for inhibitory effects on Aβ (25-35)-induced cell death using hippocampus neurons (HIPN). Materials and Methods: Fifteen chosen plants were nine medical herbs (Japanese honeywort, luffa, rapeseed, Chinese colza, potherb mustard, Japanese radish, bitter melon, red shiso, corn, and kaiware radish) and six general commercial plants (common bean, komatsuna, Qing geng cai, bell pepper, kale, and lettuce). PSAE were measured for total phenolic content (TPC) with the Folin-Ciocalteu method, and the 2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging effect of each seed extract was measured. To find a protectant against Aβ-induced oxidative stress, we screened 15 PSAE using a 2', 7'-dichlorofluorescein diacetate assay. To further unravel the anti-inflammatory effects of PSAE on Aβ-induced inflammation, PSAE were added to HIPN. The neuroprotective effects of the PSAE were evaluated by Cell Counting Kit-8 assay, measuring the cell viability in Aβ-induced HIPN. Results: TPC of 15 PSAE was in the range of 0.024-1.96 mg of chlorogenic acid equivalents/gram. The aqueous extracts showed antioxidant activities. Furthermore, intracellular ROS accumulation resulting from Aβ treatment was reduced when cells were treated with some PSAE. Kale, bitter melon, kaiware radish, red shiso, and corn inhibited tumor necrosis factor-alpha secretion by the Aβ-stimulated neurons and all samples except Japanese honeywort showed enhancement of cell survival. Conclusion: From these results, we suggest that some plant seed extracts offer protection against Aβ-mediated cell death.

Okada M.,Ageing and Nutrition Research | Okada Y.,Aichi Prefectural University
Bio-Medical Materials and Engineering | Year: 2015

Advanced glycation end products' (AGEs) engagement of a cell-surface receptor for AGEs (RAGE) has been causally implicated in the pathogenesis of vascular complications in diabetic patients. Methanolic extracts from edible plants (MEEP) are naturally occurring phenolic compounds. The phenolic compounds have been reported to possess potent radical-scavenging properties. We investigated whether MEEP could inhibit high glucose-induced RAGE production through interference with reactive oxygen species generation in endothelial cells (ECs). ECs were incubated with 4.5 g/l of glucose in culture medium treated with 21 MEEP. Determination of RAGE production in the culture supernatants was performed by colorimetric ELISA. DNA damage was determined by using the 8-hydroxydeoxyguanosine ELISA kit. Because peroxynitrite radicals with stronger toxicity were produced by nitric oxide radical (NO), the NO scavenging activity of MEEP was assessed as nitrite generation. Peroxynitrite radical-dependent oxidation inhibition by MEEP was estimated by the Crow method. The results showed that four extracts reduced RAGE production. The extract from onion peel showed the highest RAGE production inhibition activity, followed by that of onion rhizome, cow pea and burdock. The results showed that RAGE production is correlated with the above-mentioned indicators. This study supports the utilization of four extracts for improved treatment of diabetic complications. © 2015 - IOS Press and the authors. All rights reserved.

Okada Y.,Aichi Prefectural University | Okada M.,Ageing and Nutrition Research
Journal of Pharmacy and Bioallied Sciences | Year: 2016

Introduction: Glycation process might contribute to both extensive protein cross-linking and oxidative stress in Alzheimer's disease (AD). The amyloid-like aggregation of glycated bovine serum albumin induces apoptosis in the neuronal cell. Dietary supplementation of antioxidants, vitamins, and polyphenols are beneficial to AD, and consumption of fruits and vegetables reduce the risk of AD. We conducted a screening of 14 aqueous extracts from plant seeds (PSAE) for inhibitory activity on amyloid beta (Aβ). Materials and Methods: To examine the effects of PSAE on the Aβ (1-42) concentration, PSAE were analyzed by Aβ (1-42) enzyme-linked immunosorbent assay. Furthermore, we carried out an antiglycation experiment of PSAE and an antiaggregation experiment of PSAE to confirm the modification mechanism of PSAE. PSAE were added to buffer containing D-ribose and albumins. The solutions were incubated at 37 °C for 10 days. After incubation, the products were assayed on a fluorophotometer. Results: PSAE associated differential reduction in the levels of Aβ (1-42) (lettuce; 98.7% ± 2.4%, bitter melon; 95.9% ± 2.6%, and corn; 93.9% ± 2.1%), demonstrating that treatment with lettuce seeds extracts (LSE) effectively decreases Aβ (1-42) concentration. Among the 14 PSAE, LSE exhibited the second greatest potential for antiglycation. Inhibition of aggregates was not recognized in LSE. Conclusion: These results suggest that LSE reduces the toxicity of Aβ by modifying Aβ. © 2016 Journal of Pharmacy And Bioallied Sciences | Published by Wolters Kluwer - Medknow 83.

Okada Y.,Aichi Prefectural University | Okada M.,Ageing and Nutrition Research | Sagesaka Y.,Nagoya University
Plant Foods for Human Nutrition | Year: 2010

To search for dried plant seeds with potent anti-diabetes activity, we conducted a large scale screening for inhibitory activity on tumor necrosis factor-alpha and facilitating activity on adiponectin production in vitro. These activities in 3T3-L1 adipocytes were screened from ethanol extracts of 20 kinds of dried plant seed marketed in Japan. komatsuna (Brassica rapa var. perviridis), common bean (Phaseolus vulgaris L.), qing geng cai (Brassica rapa var. chinensis), green soybean (Glycine max), spinach (Spinacia oleracea L.) and sugar snap pea (Pisum sativum L.) markedly enhanced adiponectin production (11. 3 ~ 12. 7 ng/ml) but Japanese radish (Raphanus sativus), edible burdock (Arctium lappa L.), bitter melon (Momordica charantia) and broccoli (Brassica oleracea var. italica) did not (0. 9 ~ 2. 7 ng/ml). All adiponectin-production-enhancing seeds except spinach (2. 7 pg/ml) and okra (Abelmoschus esculentus) (6. 6 pg/ml) effectively decreased tumor necrosis factor-alpha levels (0. 0 pg/ml). We further examined the effects on free radical scavenging activities in the dried seed extracts. Although scavenging activity correlated well with total phenolic content of samples, no correlation was observed with adiponectin production. These results point to the potential of dried seed extracts as a means to modify the activity of tumor necrosis factor-alpha for the adiponectin production. © 2010 Springer Science+Business Media, LLC.

Okada Y.,Aichi Prefectural University | Okada M.,Ageing and Nutrition Research
Journal of Pharmacy and Bioallied Sciences | Year: 2015

Background: In diabetic populations, endogenous secretory receptor for advanced glycation end products (esRAGE) levels may be related to the degree of diabetic complications or to the protection from diabetic complications. Objective: We investigated the impact of 29 methanolic extracts from edible plants on esRAGE production in human umbilical vein endothelial cells (HUVECs) cultured in high (4.5 g/L) glucose. Materials and Methods: Edible plants were minced, and extracts were obtained with methanol overnight. The methanolic extracts from 29 edible plants were evaporated in a vacuum. For screening study purposes, HUVECs were seeded in culture dishes (1.5 × 105 cells). Then, HUVECs were incubated with 1 g/L or 4.5 g/L of glucose in SFM CS-C medium treated with methanolic extracts from edible plants (MEEP) for 96 h. Determination of esRAGE production in the cell culture-derived supernatants was performed by colorimetric ELISA. The 8-hydroxydeoxyguanosine (8-OHdG) level was determined by using the 8-OHdG Check ELISA kit. Peroxynitrite-dependent oxidation of 2', 7'- dichlorodihydrofluorescein to 2', 7'-dichlorofluorescein was estimated based on the method described by Crow. Because MEEP were methanolic extracts, we measured their total phenolic content (TPC). TPC was measured with a modified version of the Folin-Ciocalteu method. Results: The results showed eight extracts increased esRAGE production. The extract from white radish sprouts showed the highest esRAGE production activity, and then eggplant, carrot peel, young sweet corn, Jew's marrow, broad bean, Japanese radish and cauliflower. In order to understand the mechanism of esRAGE production, the eight extracts were examined for DNA damage, peroxynitrite scavenging activity, and TPC in correlation with their esRAGE production. The results showed esRAGE production correlates with the peroxynitrite level and TPC. Conclusion: This study supports the utilization of these eight extracts in folk medicine for improved treatment of diabetic complications.

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