Effects of a Standardized Phenolic-Enriched Maple Syrup Extract on β-Amyloid Aggregation, Neuroinflammation in Microglial and Neuronal Cells, and β-Amyloid Induced Neurotoxicity in Caenorhabditis elegans

Authors

Hang Ma, University of Rhode Island
Nicholas A. DaSilva, University of Rhode Island
Weixi Liu, University of Rhode Island
Pragati P. Nahar, University of Rhode Island
Zhengxi Wei, University of Rhode Island
Yongqiang Liu, University of Rhode Island
Priscilla T. Pham
Rebecca Crews
Dhiraj A. Vattem
Angela L. Slitt, University of Rhode IslandFollow
Zahir A. Shaikh, University of Rhode IslandFollow
Navindra P. Seeram, University of Rhode IslandFollow

Document Type

Article

Date of Original Version

2016

Department

Biomedical and Pharmaceutical Sciences

Abstract

Published data supports the neuroprotective effects of several phenolic-containing natural products, including certain fruit, berries, spices, nuts, green tea, and olive oil. However, limited data are available for phenolic-containing plant-derived natural sweeteners including maple syrup. Herein, we investigated the neuroprotective effects of a chemically standardized phenolic-enriched maple syrup extract (MSX) using a combination of biophysical, in vitro, and in vivo studies. Based on biophysical data (Thioflavin T assay, transmission electron microscopy, circular dichroism, dynamic light scattering, and zeta potential), MSX reduced amyloid β₁₋₄₂ peptide (Aβ₁₋₄₂) fibrillation in a concentration-dependent manner (50–500 μg/mL) with similar effects as the neuroprotective polyphenol, resveratrol, at its highest test concentration (63.5 % at 500 μg/mL vs. 77.3 % at 50 μg/mL, respectively). MSX (100 μg/mL) decreased H₂O₂-induced oxidative stress (16.1 % decrease in ROS levels compared to control), and down-regulated the production of lipopolysaccharide (LPS)-stimulated inflammatory markers (22.1, 19.9, 74.8, and 87.6 % decrease in NOS, IL-6, PGE₂, and TNFα levels, respectively, compared to control) in murine BV-2 microglial cells. Moreover, in a non-contact co-culture cell model, differentiated human SH-SY5Y neuronal cells were exposed to conditioned media from BV-2 cells treated with MSX (100 μg/mL) and LPS or LPS alone. MSX-BV-2 media increased SH-SY5Y cell viability by 13.8 % compared to media collected from LPS-BV-2 treated cells. Also, MSX (10 μg/mL) showed protective effects against Aβ₁₋₄₂ induced neurotoxicity and paralysis in Caenorhabditis elegans in vivo. These data support the potential neuroprotective effects of MSX warranting further studies on this natural product.

Citation/Publisher Attribution

Ma, H., DaSilva, N.A., Liu, W. et al. Neurochem Res (2016) 41: 2836. https://doi.org/10.1007/s11064-016-1998-6

Available at: https://doi.org/10.1007/s11064-016-1998-6