title: An extract from Taxodium distichum targets hemagglutinin- and neuraminidase-related activities of influenza virus in vitro.
abstract: Influenza virus remains an emerging virus and causes pandemics with high levels of fatality. After screening different plant extracts with potential anti-influenza activity, a water extract of Taxodium distichum stems (TDSWex) showed excellent activity against influenza viruses. The EC50of TDSWex was 0.051 ± 0.024 mg/mL against influenza virus A/WSN/33. TDSWex had excellent antiviral efficacy against various strains of human influenza A and B viruses, particularly oseltamivir-resistant clinical isolates and a swine-origin influenza strain. We observed that the synthesis of viral RNA and protein were inhibited in the presence of TDSWex. The results of the time-of-addition assay suggested that TDSWex inhibited viral entry and budding. In the hemagglutination inhibition assay, TDSWex inhibited the hemagglutination of red blood cells, implying that the extract targeted hemagglutin-related functions such as viral entry. In the attachment and penetration assay, TDSWex showed antiviral activity with EC50s of 0.045 ± 0.026 and 0.012 ± 0.003 mg/mL, respectively. In addition, TDSWex blocked neuraminidase activity. We conclude that TDSWex has bimodal activities against both hemagglutinin and neuraminidase during viral replication.
authors: Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors: Chung-Fan
authors: CF
authors: Hsieh
authors: Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors: Yu-Li
authors: YL
authors: Chen
authors: Department of Cosmetic Science, Chang Gung University of Science and Technology, Taoyuan, Taiwan.|Research Center for Industry of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan.
authors: Chwan-Fwu
authors: CF
authors: Lin
authors: Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors: Jin-Yuan
authors: JY
authors: Ho
authors: Department of Cosmetic Science, Chang Gung University of Science and Technology, Taoyuan, Taiwan.|Research Center for Industry of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan.
authors: Chun-Hsun
authors: CH
authors: Huang
authors: Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors: Cheng-Hsun
authors: CH
authors: Chiu
authors: Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.|Research Center for Industry of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan.|Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan, Taiwan.|Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
authors: Pei-Wen
authors: PW
authors: Hsieh
authors: Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.|Research Center for Industry of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan.|Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan.|Research Center for Emerging Viral Infections, Chang Gung University, Taoyuan, Taiwan.
authors: Jim-Tong
authors: JT
authors: Horng
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004285:Dogs; D006388:Hemagglutinins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D008856:Microscopy, Fluorescence; D009439:Neuraminidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009975:Orthomyxoviridae / Q000201:enzymology / Q000378:metabolism*; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D012367:RNA, Viral / Q000737:chemistry / Q000378:metabolism; D032489:Taxodium / Q000737:chemistry* / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism; D053586:Virus Internalization / Q000187:drug effects; D057074:Virus Release / Q000187:drug effects
chemical_list: D006388:Hemagglutinins; D010936:Plant Extracts; D012367:RNA, Viral; D014764:Viral Proteins; D009439:Neuraminidase