title: Aqueous Extracts of Hibiscus sabdariffa Calyces Decrease Hepatitis A Virus and Human Norovirus Surrogate Titers.
abstract: Hibiscus sabdariffa extract is known to have antioxidant, anti-diabetic, and antimicrobial properties. However, their effects against foodborne viruses are currently unknown. The objective of this study was to determine the antiviral effects of aqueous extracts of H. sabdariffa against human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)) and hepatitis A virus (HAV) at 37 °C over 24 h. Individual viruses (~5 log PFU/ml) were incubated with 40 or 100 mg/ml of aqueous hibiscus extract (HE; pH 3.6), protocatechuic acid (PCA; 3 or 6 mg/ml, pH 3.6), ferulic acid (FA; 0.5 or 1 mg/ml; pH 4.0), malic acid (10 mM; pH 3.0), or phosphate buffered saline (pH 7.2 as control) at 37 °C over 24 h. Each treatment was replicated thrice and plaque assayed in duplicate. FCV-F9 titers were reduced to undetectable levels after 15 min with both 40 and 100 mg/ml HE. MNV-1 was reduced by 1.77 ± 0.10 and 1.88 ± 0.12 log PFU/ml after 6 h with 40 and 100 mg/ml HE, respectively, and to undetectable levels after 24 h by both concentrations. HAV was reduced to undetectable levels by both HE concentrations after 24 h. PCA at 3 mg/ml reduced FCV-F9 titers to undetectable levels after 6 h, MNV-1 by 0.53 ± 0.01 log PFU/ml after 6 h, and caused no significant change in HAV titers. FA reduced FCV-F9 to undetectable levels after 3 h and MNV-1 and HAV after 24 h. Transmission electron microscopy showed no conclusive results. The findings suggest that H. sabdariffa extracts have potential to prevent foodborne viral transmission.
authors.affiliation: Department of Food Science and Technology, University of Tennessee-Knoxville, Knoxville, TN, 37996, USA.
authors.forename: Snehal S
authors.initials: SS
authors.lastname: Joshi
authors.affiliation: Department of Food Science and Technology, University of Tennessee-Knoxville, Knoxville, TN, 37996, USA.
authors.forename: Lezlee
authors.initials: L
authors.lastname: Dice
authors.affiliation: Department of Food Science and Technology, University of Tennessee-Knoxville, Knoxville, TN, 37996, USA. ddsouza@utk.edu.
authors.forename: Doris H
authors.initials: DH
authors.lastname: D'Souza
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000378:metabolism*; D001628:Beverages; D017250:Caliciviridae Infections / Q000517:prevention & control / Q000821:virology; D017927:Calicivirus, Feline / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology* / Q000648:ultrastructure; D002460:Cell Line; D035264:Flowers / Q000737:chemistry; D005503:Food Additives / Q000737:chemistry / Q000378:metabolism*; D005517:Foodborne Diseases / Q000517:prevention & control / Q000821:virology; D055951:Functional Food; D005759:Gastroenteritis / Q000517:prevention & control / Q000821:virology; D006506:Hepatitis A / Q000517:prevention & control / Q000821:virology; D030041:Hepatitis A virus / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology / Q000648:ultrastructure; D031584:Hibiscus / Q000737:chemistry*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008954:Models, Biological; D029322:Norovirus / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology* / Q000648:ultrastructure; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism*; D018406:Virus Physiological Phenomena
chemical_list: D000998:Antiviral Agents; D005503:Food Additives; D010936:Plant Extracts
keywords: Feline calicivirus (FCV-F9); Hepatitis A virus (HAV); Hibiscus extracts; Murine norovirus (MNV-1); Reduction