Folium Sennae protects against hydroxyl radical-induced DNA damage via antioxidant mechanism: an in vitro study

Jian Lin; Xican Li; Lu Han; Fei Li; Wenbiao Lu; Ye Bai; Dongfeng Chen

doi:10.1186/1999-3110-55-16

Folium Sennae protects against hydroxyl radical-induced DNA damage via antioxidant mechanism: an in vitro study

Bot Stud. 2014 Dec;55(1):16. doi: 10.1186/1999-3110-55-16. Epub 2014 Feb 2.

Authors

Jian Lin¹, Xican Li², Lu Han¹, Fei Li³, Wenbiao Lu¹, Ye Bai³, Dongfeng Chen⁴

Affiliations

¹ School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Waihuan East Road No.232, Guangzhou Higher Education Mega Center, 510006, Guangzhou, PR China.
² School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Waihuan East Road No.232, Guangzhou Higher Education Mega Center, 510006, Guangzhou, PR China. lixican@126.com.
³ School of Basic Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, PR China.
⁴ School of Basic Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, PR China. cdf27212@21cn.com.

Abstract

Background: In the study, Folium Sennae (FS) was firstly extracted by various solvents to obtain five FS extracts. Then, five FS extracts were evaluated for the protective effects against •OH-induced DNA damage, antioxidant abilities in vitro, and chemical contents using various methods. On this basis, the correlation graphs between the pharmacological effects and chemical contents were plotted to obtain the correlation coefficients (R values). Finally, in order to obtain biological evidence, ethyl acetate extract of FS (EAFS) was investigated for the protective effect against •OH-induced MSCs (mesenchymal stem cells) damage using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl) assay.

Results: The pharmacological assays indicated that five FS extracts could effectively protect against •OH-induced DNA damage. The correlation analysis suggested that the average R values of total phenolics, total anthraquinones, aloe-emodin, rhein, and emodin were respectively 0.843, 0.833, 0.753, 0.820, and 0.784, while those of total sugars and total saponins were respectively 0.103 and 0.0068. The mechanistic analysis revealed that five FS extracts could also scavenge •OH, •O₂^-, DPPH• & ABTS•⁺ radicals, and reduce Cu²⁺ to Cu⁺. MTT assay revealed that the viability of MSCs which were treated with •OH radicals has been effectively protected by EAFS (3 and 30 μg/mL).

Conclusion: On this basis, it can be concluded that: (i) Folium Sennae exhibits a protective effect against •OH-induced damages to DNA and MSCs; (ii ) The effects may be attributed to phytophenols (especially aloe-emodin, rhein, and emodin), not sugars or saponins; (iii) They exert the protective action via hydrogen atom transfer (HAT) and/or sequential electron proton transfer (SEPT) mechanisms which make phenolic -OH moiety be oxidized to stable semi-quinone form; (iv) The stability of semi-quinone form can ultimately be responsible for the protective or antioxidant effect of phytophenols.

Keywords: Anthraquinones; Antioxidant mechanism; DNA oxidative damage; Folium Sennae; Hydroxyl-induced; ROS scavenging.