title: Sarcandra glabra (Caoshanhu) protects mesenchymal stem cells from oxidative stress: a bioevaluation and mechanistic chemistry.
abstract: BACKGROUND
  Sarcandra glabra (Caoshanhu) is a traditional Chinese herbal medicine used for treating various oxidative-stressed diseases. The present work evaluated its protective effect on mesenchymal stem cells (MSCs) from oxidative stress and then discussed possible mechanisms underlying this observation.
  
  
  METHODS
  Ethanolic extract of S. glabra (ESG) was investigated by chemical methods for its content of total phenolics, rosmarinic acid, and astilbin. ESG, along with rosmarinic acid and astilbin, was investigated for the effect on the viability of Fenton-treated MSCs using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay. The observed cell protective effect was further explored by mechanistic chemistry using various antioxidant assays, including DNA protection, •OH-scavenging, •O2--scavenging, FRAP (ferric ion reducing antioxidant power), ABTS+•-scavenging, DPPH•-scavenging, and Fe2+-chelating assays.
  
  
  RESULTS
  Analysis of ESG revealed a content of 46.31 ± 0.56 mg quercetin/g total phenolics, 0.78 ± 0.01 % rosmarinic acid, and 3.37 ± 0.01 % astilbin. Results from the MTT assay revealed that three compounds (rosmarinic acid>astilbin>ESG) could effectively increase the survival of Fenton-treated MSCs. Similarly, in •O2--scavenging, DPPH•-scavenging, and Fe2+-chelating assays, rosmarinic acid exhibited more activity than astilbin; while in FRAP, ABTS+•-scavenging assays, astilbin was stronger than rosmarinic acid.
  
  
  CONCLUSIONS
  S. glabra can prevent MSCs from •OH-induced oxidative stress. Such protective effect can be attributed to its antioxidant ability and the presence of two kinds of phytophenols, i.e. caffeoyl derivatives and flavonoids. As the respective representatives of caffeoyl derivatives and flavonoids, rosmarinic acid and astilbin may exert the antioxidant action via direct ROS-scavenging and indirect ROS-scavenging (i.e. Fe2+-chelating). The direct ROS-scavenging ability involves hydrogen atom transfer (HAT) and/or electron transfer (ET) pathway. Astilbin engages the latter pathway more, which can be attributed to the larger planar conjugation in A/C fused rings. Rosmarinic acid, on the other hand, shows more HAT and Fe2+-chelating potential, which may be due to rosmarinic acid bearing one more catechol moiety whereas astilbin has steric-hindrance from 3-α-L-rhamnose and an H-bonding between 4,5 sites. The antioxidant features of rosmarinic acid can be generalized to other caffeoyl derivatives, while that of astilbin cannot be generalized to other flavonoids because of the difference in chemical structures.
authors: School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Waihuan East Road No.232, Guangzhou Higher Education Mega Center, 510006, Guangzhou, China.
authors: Jingjing
authors: J
authors: Liu
authors: School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Waihuan East Road No.232, Guangzhou Higher Education Mega Center, 510006, Guangzhou, China. lixican@126.com.
authors: Xican
authors: X
authors: Li
authors: School of Basic Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, China, 510006.
authors: Jian
authors: J
authors: Lin
authors: School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Waihuan East Road No.232, Guangzhou Higher Education Mega Center, 510006, Guangzhou, China.
authors: Yunrong
authors: Y
authors: Li
authors: School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Waihuan East Road No.232, Guangzhou Higher Education Mega Center, 510006, Guangzhou, China.
authors: Tingting
authors: T
authors: Wang
authors: School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Waihuan East Road No.232, Guangzhou Higher Education Mega Center, 510006, Guangzhou, China.
authors: Qian
authors: Q
authors: Jiang
authors: School of Basic Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, China, 510006. cdf27212@21cn.com.
authors: Dongfeng
authors: D
authors: Chen
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology; D002934:Cinnamates; D053630:Depsides; D005419:Flavonoids; D007501:Iron; D019684:Magnoliopsida / Q000737:chemistry*; D059630:Mesenchymal Stem Cells / Q000187:drug effects*; D018384:Oxidative Stress / Q000187:drug effects*; D010636:Phenols; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000097123:Rosmarinic Acid
chemical_list: D000975:Antioxidants; D002934:Cinnamates; D053630:Depsides; D005419:Flavonoids; D007501:Iron; D010636:Phenols; D010936:Plant Extracts; D000097123:Rosmarinic Acid
keywords: Antioxidant mechanism; Astilbin; Caoshanhu; Electron transfer; Fe-chelating; Hydrogen atom transfer; Mesenchymal stem cells; Rosmarinic acid; Sarcandra glabra