In vitro screening on amyloid beta modulation of aqueous extracts from plant seeds

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.