title: Anti-glycation and anti-oxidative effects of a phenolic-enriched maple syrup extract and its protective effects on normal human colon cells.
abstract: Oxidative stress and free radical generation accelerate the formation of advanced glycation endproducts (AGEs) which are linked to several chronic diseases. Published data suggest that phenolic-rich plant foods, show promise as natural anti-AGEs agents due to their anti-oxidation capacities. A phenolic-enriched maple syrup extract (MSX) has previously been reported to show anti-inflammatory and neuroprotective effects but its anti-AGE effects remain unknown. Therefore, herein, we investigated the anti-glycation and anti-oxidation effects of MSX using biochemical and biophysical methods. MSX (500 μg mL-1) reduced the formation of AGEs by 40% in the bovine serum albumin (BSA)-fructose assay and by 30% in the BSA-methylglyoxal (MGO) assay. MSX also inhibited the formation of crosslinks typically seen in the late stage of glycation. Circular dichroism and differential scanning calorimeter analyses demonstrated that MSX maintained the structure of BSA during glycation. In the anti-oxidant assays, MSX (61.7 μg mL-1) scavenged 50% of free radicals (DPPH assay) and reduced free radical generation by 20% during the glycation process (electron paramagnetic resonance time scan). In addition, the intracellular levels of hydrogen peroxide induced reactive oxygen species were reduced by 27-58% with MSX (50-200 μg mL-1) in normal/non-tumorigenic human colon CCD-18Co cells. Moreover, in AGEs and MGO challenged CCD-18Co cells, higher cellular viabilities and rapid extracellular signal-regulated kinase (ERK) phosphorylation were observed in MSX treated cells, indicating its protective effects against AGEs-induced cytotoxicity. Overall, this study supports the biological effects of MSX, and warrants further investigation of its potential as a dietary agent against diseases mediated by oxidative stress and inflammation.
authors.affiliation: Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA. nseeram@uri.edu and Department of Chemistry, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: Weixi
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: Zhengxi
authors.initials: Z
authors.lastname: Wei
authors.affiliation: Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA. nseeram@uri.edu.
authors.forename: Hang
authors.initials: H
authors.lastname: Ma
authors.affiliation: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: Ang
authors.initials: A
authors.lastname: Cai
authors.affiliation: Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA. nseeram@uri.edu.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: Jiadong
authors.initials: J
authors.lastname: Sun
authors.affiliation: Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA. nseeram@uri.edu.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: DaSilva
authors.affiliation: Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA. nseeram@uri.edu.
authors.forename: Shelby L
authors.initials: SL
authors.lastname: Johnson
authors.affiliation: Department of Chemistry, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Kirschenbaum
authors.affiliation: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: Bongsup P
authors.initials: BP
authors.lastname: Cho
authors.affiliation: Department of Chemistry, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: Joel A
authors.initials: JA
authors.lastname: Dain
authors.affiliation: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Rowley
authors.affiliation: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: Zahir A
authors.initials: ZA
authors.lastname: Shaikh
authors.affiliation: Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA. nseeram@uri.edu.
authors.forename: Navindra P
authors.identifier: http://orcid.org/0000-0001-7064-2904
authors.initials: NP
authors.lastname: Seeram
mesh_terms: D031002:Acer / Q000737:chemistry*; D000975:Antioxidants / Q000494:pharmacology*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D003106:Colon / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000378:metabolism; D006031:Glycosylation / Q000187:drug effects; D006801:Humans; D018384:Oxidative Stress / Q000187:drug effects*; D010636:Phenols / Q000032:analysis / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017127:Glycation End Products, Advanced; D010636:Phenols; D010936:Plant Extracts; D017382:Reactive Oxygen Species