Monomeric catechin and dimeric procyanidin B2 against human norovirus surrogates and their physicochemical interactions

• Type of Material: Article
• Authors: Dan Liu, Xi'an Jiaotong University; Jianjun Deng, Northwest University; Snehal Joshi, University of Tennessee; Pengbo Liu, Emory University; Chao Zhang, Xi'an Jiaotong University; Yan Yu, Xi'an Jiaotong University; Ruijuan Zhang, Xi'an Jiaotong University; Daidi Fan, Northwest University; Haixia Yang, Xi'an Jiaotong University; Doris H. D'Souza, University of Tennessee
• Language: English
• Date: 2018-12-01
• Publisher: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
• Publication Version: Final Published Version
• Copyright Statement: © 2018
• Final Published Version (URL): http://dx.doi.org/10.1016/j.fm.2018.06.009
• Title of Journal or Parent Work: FOOD MICROBIOLOGY
• Volume: 76
• Start Page: 346
• End Page: 353
• Grant/Funding Information: This project was supported by the National Natural Science Foundation of China (21306146 and 21676212) and the UT Institute of Agriculture and the Multistate Project S-1056.
• Keywords: Procyanidin B2; GRAPE SEED EXTRACT; POLYPHENOLS; Science & Technology; HUMAN ENTERIC VIRUSES; CRANBERRY PROANTHOCYANIDINS; Food Science & Technology; BLUEBERRY PROANTHOCYANIDINS; BLOOD GROUP ANTIGENS; UNITED-STATES; Life Sciences & Biomedicine; P domain; FOODBORNE VIRAL SURROGATES; Microbiology; TANNIC-ACID; Norovirus; Interaction; IN-VITRO; Biotechnology & Applied Microbiology
• Research Categories: Biology, Virology; Biology, Microbiology; Health Sciences, Nutrition

Abstract

Plant polyphenols have shown antiviral activity against several human pathogens, but their physicochemical interactions are not well-understood. The objectives of this study were to compare the antiviral activity between monomeric catechin and dimeric procyanidin B2 (PB2) using cultivable human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)) and to understand their potential antiviral mechanism using virus-like particles (VLPs) and the P domain of human norovirus GII (HNoV GII.4). Surrogate viruses at 5 log PFU/mL were treated with 0.5–5 mg/mL monomeric catechin monohydrate, PB2 or phosphate buffered saline (PBS, pH 7.2; control) at 37 °C over 24 h. Infectivity was determined using plaque assays and data from triplicate experiments were statistically analyzed. PB2 at 0.5 mg/mL and 1 mg/mL reduced FCV-F9 to undetectable levels after 3 h and MNV-1 by 0.21 and 1.23 log PFU after 24 h, respectively. Monomeric catechins at 1 mg/mL reduced FCV-F9 to undetectable levels after 6 h and MNV-1 titers to undetectable levels after 24 h. In addition, PB2 was shown to directly bind the P domain, the main capsid structure of HNoVs in the ratio of 1:1 through spontaneous interactions. Electrostatic interactions played a dominant role between PB2 and the P domain. PB2 significantly altered tertiary but not secondary structures of VLPs. Transmission electron microscopy demonstrated that PB2 aggregated VLPs, further indicating interactions between them. These findings indicate that PB2 causes structural changes of the P domain of VLPs, mainly through direct interaction leading to HNoV inactivation.