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

• Published in: Neurochemical research Vol. 41; no. 11; p. 2836
• Main Authors: Ma, Hang, Dasilva, Nicholas A, Liu, Weixi, Nahar, Pragati P, Wei, Zhengxi, Liu, Yongqiang, Pham, Priscilla T, Crews, Rebecca, Vattem, Dhiraj A, Slitt, Angela L, Shaikh, Zahir A, Seeram, Navindra P
• Format: Journal Article
• Language: English
• Published: New York Springer Nature B.V 01.11.2016
• ISSN: 0364-3190; 1573-6903
• DOI: 10.1007/s11064-016-1998-6

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 [beta]1-42 peptide (A[beta]1-42) fibrillation in a concentration-dependent manner (50-500 [mu]g/mL) with similar effects as the neuroprotective polyphenol, resveratrol, at its highest test concentration (63.5% at 500 [mu]g/mL vs. 77.3% at 50 [mu]g/mL, respectively). MSX (100 [mu]g/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 TNF[alpha] 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 [mu]g/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 [mu]g/mL) showed protective effects against A[beta]1-42 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.