Radical Scavenging Activity of Natural Anthraquinones: a Theoretical Insight

Nguyen Quang Trung; Nguyen Minh Thong; Dao Hung Cuong; Tran Duc Manh; Loc Phuoc Hoang; Nguyen Khoa Hien; Pham Cam Nam; Duong Tuan Quang; Adam Mechler; Quan V Vo

doi:10.1021/acsomega.1c01448

Radical Scavenging Activity of Natural Anthraquinones: a Theoretical Insight

ACS Omega. 2021 May 13;6(20):13391-13397. doi: 10.1021/acsomega.1c01448. eCollection 2021 May 25.

Authors

Affiliations

¹ The University of Danang-University of Science and Education, Da Nang 550000, Vietnam.
² Quality Assurance and Testing Center 2, Danang 550000, Vietnam.
³ The University of Danang, Campus in Kon Tum, 704 Phan Dinh Phung, Kon Tum, 580000, Vietnam.
⁴ Institute of Research and Development, Duy Tan University, Danang 550000, Vietnam.
⁵ Mientrung Institute for Scientific Research, Vietnam Academy of Science and Technology, Hue 530000, Vietnam.
⁶ Department of Chemical Engineering, The University of Danang-University of Science and Technology, Danang 550000, Vietnam.
⁷ Hue University, Hue 530000, Vietnam.
⁸ Department of Chemistry and Physics, La Trobe University, Bundoora, Victoria 3086, Australia.
⁹ Faculty of Chemical Technology-Environment, The University of Danang-University of Technology and Education, Da Nang 550000, Vietnam.

Abstract

Anthraquinones (ANQs) isolated from Paederia plants are known to have antidiarrheal, antitussive, anthelmintic, analgesic, anti-inflammatory, antihyperlipidemic, antihyperglycaemic, and antimicrobial activities. The antioxidant properties were also noted but not confirmed thus far. In this study, the superoxide and hydroperoxide radical scavenging activities of six ANQs were evaluated using a computational approach. The results suggest that the ANQs exhibit low HOO^• antiradical activity in all environments, including the gas phase (k < 10² M^-1 s^-1). In contrast, the ANQs might exert excellent O₂ ^•- radical scavenging activity, particularly in aqueous solution. The rate constants of the superoxide anion scavenging in water (at pH = 7.4) range from 3.42 × 10⁶ to 3.70 × 10⁸ M^-1 s^-1. Compared with typical antioxidants such as ascorbic acid and quercetin, the superoxide anion scavenging activity of ANQs is significantly higher. Thus, the ANQs are promising O₂ ^•- radical scavengers in polar media.