title: Protective Effects of Dihydromyricetin against •OH-Induced Mesenchymal Stem Cells Damage and Mechanistic Chemistry.
abstract: As a natural flavonoid in Ampelopsis grossedentata, dihydromyricetin (DHM, 2R,3R-3,5,7,3',4',5'-hexahydroxy-2,3-dihydroflavonol) was observed to increase the viability of •OH-treated mesenchymal stem cells using a MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl] assay and flow cytometry analysis. This protective effect indicates DHM may be a beneficial agent for cell transplantation therapy. Mechanistic chemistry studies indicated that compared with myricetin, DHM was less effective at ABTS⁺• (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radical) scavenging and reducing Cu(2+), and had higher •O₂(-) and DPPH• (1,1-diphenyl-2-picrylhydrazyl radical) scavenging activities. Additionally, DHM could also chelate Fe(2+) to give an absorption maximum at 589 nm. Hence, such protective effect of DHM may arise from its antioxidant activities which are thought to occur via direct radical-scavenging and Fe(2+)-chelation. Direct radical-scavenging involves an electron transfer (ET) pathway. The hydrogenation of the 2,3-double bond is hypothesized to reduce the ET process by blocking the formation of a larger π-π conjugative system. The glycosidation of the 3-OH in myricitrin is assumed to sterically hinder atom transfer in the •O₂(-) and DPPH• radical-scavenging processes. In DHM, the Fe(2+)-chelating effect can actually be attributed to the 5,3',4',5'-OH and 4-C=O groups, and the 3-OH group itself can neither scavenge radicals nor chelate metal.
authors.affiliation: School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China. lixican@126.com.
authors.forename: Xican
authors.initials: X
authors.lastname: Li
authors.affiliation: School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China. 15622829151@163.com.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Liu
authors.affiliation: School of Basic Medical Science, Guangzhou University of Chinese Medicine, Guangzhou 510006, China. linjianchn@outlook.com.
authors.forename: Jian
authors.initials: J
authors.lastname: Lin
authors.affiliation: School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China. wtttx0304@163.com.
authors.forename: Tingting
authors.initials: T
authors.lastname: Wang
authors.affiliation: School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China. jieyuan_huang@163.com.
authors.forename: Jieyuan
authors.initials: J
authors.lastname: Huang
authors.affiliation: School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China. yorkoran@foxmail.com.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Lin
authors.affiliation: School of Basic Medical Science, Guangzhou University of Chinese Medicine, Guangzhou 510006, China. cdf27212@21cn.com.
authors.forename: Dongfeng
authors.initials: D
authors.lastname: Chen
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D005419:Flavonoids / Q000494:pharmacology; D044948:Flavonols / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000009:adverse effects*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects; D051381:Rats
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D044948:Flavonols; D017665:Hydroxyl Radical; C008577:myricitrin; C472036:dihydromyricetin
keywords: 2,3-double bond; 3–OH group; Fe2+-chelation; antioxidant mechanisms; dihydromyricetin; electron transfer (ET) pathway; hydroxyl radical-induced; mesenchymal stem cells