title: Preparation of Methylated Products of A-type Procyanidin Trimers in Cinnamon Bark and Their Protective Effects on Pancreatic β-Cell.
abstract: Polyphenols are partial metabolized to methylated conjugations in vivo, and then could modify bioavailability and bioactivity related to the uptake of parent compounds. Our previous studies have found that the antidiabetic effects of cinnamon barks are mainly related to polyphenol components, particularly A-type procyanidin trimer cinnamtannin-1 (CT1). It is necessary to understand the antidiabetic activity of methylations of CT1, nevertheless, sufficient amounts of methylated CT1 are difficult to obtain from metabolites in vivo. In this study, O-methyl derivatives of CT1 were prepared through one-pot methyl iodide reaction and isolation via column chromatography and RP-HPLC semipreparation. The structures of O-methyl substituents were determined through NMR (Nuclear Magnetic Resonance) and HPLC-ESI-MS (High-performance liquid chromatography-electrospray ionization-mass spectrometry). Five purified O-methyl substituents and 2 isomers of CT1 were obtained. Their protective effects on a palmitic acid-induced pancreatic β-cell apoptosis model were then evaluated. Results showed that the protective effects on pancreatic β-cell of O-methyl substituents were weaker than those of CT1. The results suggested that the methylation of catechol groups could be a relevant factor contributing to the decline of protective effects on pancreatic β-cell of CT1 via obstructing quinone intermediate formation and affecting antioxidant abilities. The antidiabetic effects of O-methyl derivatives of CT1 should be further determined by other antidiabetic models.
authors.affiliation: School of Pharmacy, Shanghai Univ. of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, 201203, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Chen
authors.affiliation: School of Pharmacy, Shanghai Univ. of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, 201203, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Shanghai Inst. of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.affiliation: School of Pharmacy, Shanghai Univ. of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, 201203, China.
authors.forename: Pulong
authors.initials: P
authors.lastname: Yuan
authors.affiliation: School of Pharmacy, Shanghai Univ. of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, 201203, China.|Shanghai Inst. of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China.
authors.forename: Kaixian
authors.initials: K
authors.lastname: Chen
authors.affiliation: School of Pharmacy, Shanghai Univ. of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, 201203, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Jia
authors.affiliation: Shanghai Inst. of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China.
authors.forename: Heyao
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Pharmacy, Shanghai Univ. of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, 201203, China.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Li
mesh_terms: D000818:Animals; D000872:Anthocyanins / Q000032:analysis / Q000494:pharmacology; D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology; D017209:Apoptosis; D016227:Benzoquinones; D044946:Biflavonoids / Q000032:analysis / Q000494:pharmacology*; D002392:Catechin / Q000032:analysis / Q000494:pharmacology*; D002396:Catechols; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002935:Cinnamomum zeylanicum / Q000737:chemistry*; D007004:Hypoglycemic Agents / Q000032:analysis / Q000494:pharmacology*; D050417:Insulin-Secreting Cells / Q000187:drug effects*; D008745:Methylation; D015394:Molecular Structure; D019308:Palmitic Acid; D024301:Plant Bark / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D059808:Polyphenols / Q000032:analysis / Q000494:pharmacology*; D044945:Proanthocyanidins / Q000032:analysis / Q000494:pharmacology*; D020011:Protective Agents / Q000032:analysis / Q000494:pharmacology; D051381:Rats; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000872:Anthocyanins; D000975:Antioxidants; D016227:Benzoquinones; D044946:Biflavonoids; D002396:Catechols; D007004:Hypoglycemic Agents; D010936:Plant Extracts; D059808:Polyphenols; D044945:Proanthocyanidins; D020011:Protective Agents; D019308:Palmitic Acid; C004532:quinone; C017674:procyanidin; D002392:Catechin; C034221:catechol
keywords: A-type procyanidin trimer; antidiabetic effects; cinnamon; cinnamtannin-1; methylation