Anti-inflammatory and antiviral activities of flavone C-glycosides of Lophatherum gracile for COVID-19

Yu-Li Chen; Chun-Yu Chen; Kuei-Hung Lai; Yu-Chia Chang; Tsong-Long Hwang

doi:10.1016/j.jff.2023.105407

Anti-inflammatory and antiviral activities of flavone C-glycosides of Lophatherum gracile for COVID-19

J Funct Foods. 2023 Feb:101:105407. doi: 10.1016/j.jff.2023.105407. Epub 2023 Jan 5.

Authors

Yu-Li Chen^{1

2}, Chun-Yu Chen^{3

4

5}, Kuei-Hung Lai^{6

7

8}, Yu-Chia Chang^{1

2}, Tsong-Long Hwang^{1

2

3

4

9}

Affiliations

¹ Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 33303, Taiwan.
² Graduate Institute of Health Industry Technology, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 33303, Taiwan.
³ Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan.
⁴ Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan.
⁵ Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan.
⁶ PhD Program in Clinical Drug Development of Herbal Medicine, College of Pharmacy, Taipei Medical University, Taipei 11031, Taiwan.
⁷ Graduate Institute of Pharmacognosy, College of Pharmacy, Taipei Medical University, Taipei 11031, Taiwan.
⁸ Traditional Herbal Medicine Research Center, Taipei Medical University Hospital, Taipei 11031, Taiwan.
⁹ Department of Chemical Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan.

Abstract

Lophatherum gracile (L. gracile) has long been used as a functional food and herbal medicine. Previous studies have demonstrated that extracts of L. gracile attenuate inflammatory response and inhibit SARS-CoV-2 replication; however, the underlying active constituents have yet to be identified. This study investigated the bioactive components of L. gracile. Flavone C-glycosides of L. gracile were found to dominate both anti-inflammatory and antiviral effects. A simple chromatography-based method was developed to obtain flavone C-glycoside-enriched extract (FlavoLG) from L. gracile. FlavoLG and its major flavone C-glycoside isoorientin were shown to restrict respiratory bursts and the formation of neutrophil extracellular traps in activated human neutrophils. FlavoLG and isoorientin were also shown to inhibit SARS-CoV-2 pseudovirus infection by interfering with the binding of the SARS-CoV-2 spike on ACE2. These results provide scientific evidence indicating the efficacy of L. gracile as a potential supplement for treating neutrophil-associated COVID-19.

Keywords: ACE2, angiotensin-converting enzyme 2; CB, cytochalasin B; COVID-19; COVID-19, coronavirus disease 2019; DMSO, dimethyl sulfoxide; Flavone C-glycosides; HBSS, Hank’s balanced salt solution; HPLC, high-performance liquid chromatography; IC50, half-maximal inhibitory concentration; LDH, lactate dehydrogenase; LG, Lophatherum gracile; Lophatherum gracile; MRM, multiple reaction monitoring; NETs, neutrophil extracellular traps; Neutrophils; O2•−, superoxide; RBD, receptor-binding domain; ROS, reactive oxygen species; SARS-CoV-2; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; UPLC, ultra-performance liquid chromatography; fMLF, N-formyl-methionyl-leucyl-phenylalanine.