ABSTRACT
Aichi virus (AiV) is an enteric virus that affects humans and is prevalent in sewage waters. Effective strategies to control its spread need to be explored. This study evaluated grape seed extract (GSE) for: a) antiviral potential towards AiV infectivity at 37 °C and room temperature (RT); b) antiviral behavior in model foods (apple juice (AJ) and 2% fat milk) and also simulated gastric environments; and c) potential application as a wash solution on stainless steel surfaces. GSE at 0.5 mg/mL decreased AiV suspensions containing ~4.75 log PFU/mL to titer levels that were not detected after 30 s at both 37 °C and RT. Infectious AiV titers were not detected after 5 min treatment with 1 mg/mL GSE at 37 °C in AJ. GSE at 2 mg/mL and 4 mg/mL in 2% fat milk decreased AiV after 24 h by 1.18 and 1.57 log PFU/mL (4.75 log PFU/mL to 2.86 and 3.25 log PFU/mL), respectively. As a surface wash, GSE at 1 mg/mL after 30 s decreased AiV to undetectable levels under clean conditions. With organic load (mimicking unclean conditions), 2 and 4 mg/mL GSE reduced AiV after 5 min by 1.13 and 1.71 log PFU/mL, respectively. Overall, GSE seems to be a promising antiviral agent against AiV at low concentrations and short contact times.
Subject(s)
Antiviral Agents/pharmacology , Grape Seed Extract/pharmacology , Kobuvirus/drug effects , Animals , Cattle , Equipment Contamination/prevention & control , Equipment Contamination/statistics & numerical data , Food Contamination/prevention & control , Food Contamination/statistics & numerical data , Food-Processing Industry/instrumentation , Fruit and Vegetable Juices/virology , Kobuvirus/growth & development , Milk/virology , Models, Biological , Stainless Steel/analysisABSTRACT
Blueberry polyphenols are known for their high antioxidant and antimicrobial potential. Aichi virus (AiV) is an emerging human enteric virus that causes gastroenteritis outbreaks worldwide. This study aimed to (1) determine the time- and dose-dependent effects of blueberry proanthocyanidins (B-PAC) against AiV over 24â¯hâ¯at 37⯰C; (2) gain insights on their mode of action using pre- and post-treatment of host cells and Transmission Electron Microscopy; and (3) determine their anti-AiV effects in model foods and under simulated gastric conditions. AiV at â¼5 log PFU/ml was incubated with equal volumes of commercial blueberry juice (BJ, pH 2.8), neutralized BJ (pH 7.0), B-PAC (2, 4, and 10 mg/ml) prepared either in 10% ethanol, apple juice (AJ), 2% milk, simulated gastric fluid (SGF, pH 1.5) or simulated intestinal fluid (SIF, pH 7.5), and controls (malic acid (pH 3.0), phosphate buffered saline (pH 7.2), apple juice (pH 3.6) and 2% milk) over 24â¯hâ¯at 37⯰C, followed by standard plaque assays. Each experiment was replicated thrice and data were statistically analyzed. Differences in AiV titers with 1â¯mg/ml B-PAC were 2.13⯱â¯0.06 log PFU/ml lower after 24â¯h and ≥3 log PFU/ml (undetectable levels) lower with 2 and 5 mg/ml B-PAC compared to AiV titers in PBS after 24 h and 3â¯h, respectively. BJ at 37⯰C resulted in titer differences (lower titers compared to PBS) of 0.17⯱â¯0.06, 1.27⯱â¯0.01, and 1.73⯱â¯0.23 log PFU/ml after 1, 3, and 6â¯h and ≥3 log PFU/ml after 24â¯h. Pre- and post-treatment of host cells with 0.5 mg/ml B-PAC caused titer decreases of 0.62⯱â¯0.33 and 0.30⯱â¯0.06 log PFU/ml, respectively suggesting a moderate effect on viral-host cell binding. B-PAC at 2 mg/ml in AJ caused titer differences of ≥3 log PFU/ml after 0.5â¯h, while differences of 0.84⯱â¯0.03 log PFU/ml with 5 mg/ml B-PAC in milk, and ≥3 log PFU/ml with B-PAC at 5 mg/ml in SIF after 30 min were obtained. This study shows the ability of BJ and B-PAC to decrease AiV titers to potentially prevent AiV-related illness and outbreaks.
Subject(s)
Antiviral Agents/pharmacology , Blueberry Plants/chemistry , Food Microbiology , Kobuvirus/drug effects , Proanthocyanidins/pharmacology , Animals , Chlorocebus aethiops , Foodborne Diseases/prevention & control , Fruit and Vegetable Juices/analysis , Fruit and Vegetable Juices/virology , Gastroenteritis/prevention & control , Milk/virology , Plant Extracts/chemistry , Plant Extracts/pharmacology , Temperature , Vero Cells , Virus Attachment/drug effects , Virus Replication/drug effectsABSTRACT
Blueberry and blueberry extracts are known for their health benefits and antimicrobial properties. Natural therapeutic or preventive options to decrease the incidences of foodborne viral illnesses are becoming popular and being researched. This study aimed to determine the antiviral effects of blueberry juice (BJ) and blueberry proanthocyanidins (BB-PAC, B-type PAC structurally different from A-type PAC found in cranberries) against the infectivity of hepatitis A virus (HAV) and human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)) at 37 °C over 24 h using standard plaque assays. Viruses at ~5 log PFU/ml were mixed with equal volumes of BJ (pH 2.8), neutralized BJ (pH 7.0), BB-PAC (1, 2, 4, and 10 mg/ml), malic acid (pH 3.0), or phosphate-buffered saline (pH 7.2) and incubated over 24 h at 37 °C. Each experiment was carried out in duplicate and replicated thrice. FCV-F9 titers were found to be reduced to undetectable levels with 1 and 2 mg/ml BB-PAC after 5 min, with 0.5 mg/ml BB-PAC after 1-h, and with BJ after 3-h. MNV-1 titers were reduced to undetectable levels after 3 h with 1, 2, and 5 mg/ml BB-PAC and after 6 h with BJ. HAV titers were reduced to undetectable levels after 30 min with 2 and 5 mg/ml BB-PAC, after 3 h with 1 mg/ml BB-PAC, and by ~2 log PFU/ml with BJ after 24-h. BB-PAC shows preventive potential against infection by the tested enteric viruses in a dose- and time-dependent manner, although further in vitro studies in model food systems and in vivo studies using animal models are warranted.
Subject(s)
Antiviral Agents/pharmacology , Blueberry Plants/chemistry , Caliciviridae Infections/virology , Fruit and Vegetable Juices/analysis , Hepatitis A virus/drug effects , Hepatitis A/virology , Norovirus/drug effects , Plant Extracts/pharmacology , Proanthocyanidins/pharmacology , Animals , Fruit/chemistry , Hepatitis A virus/physiology , Humans , Norovirus/physiologyABSTRACT
Grape seed extract (GSE) has antiviral activities against hepatitis A virus (HAV) and human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)). The objectives of this study were to determine (1) time and dose-dependence of GSE against FCV-F9, MNV-1, and HAV at room temperature (RT) and 37 °C over 24 h; and (2) GSE effects in model foods (apple juice (AJ) and 2% milk) and simulated gastric conditions at 37 °C. Viruses at â¼5 log PFU/ml were treated with 0.5-8 mg/ml GSE prepared in water, AJ, milk or gastric juices, or water over 24 h at RT or 37 °C. Infectivity of triplicate treatments was evaluated using plaque assays. GSE effects increased with time and concentration. GSE at 1 mg/ml in AJ reduced MNV-1 to undetectable levels after 1 h and by 1 log in milk after 24 h. GSE at 1 and 2 mg/ml in AJ reduced HAV to undetectable levels after 1 h, while 2 and 4 mg/ml GSE in milk caused â¼1 log reduction after 24 h. GSE at 2 mg/ml in intestinal fluid reduced FCV-F9, MNV-1 and HAV to undetectable levels after 6 h. GSE appears to be a suitable natural option for foodborne viral reduction.
Subject(s)
Antiviral Agents/pharmacology , Beverages/virology , Calicivirus, Feline/drug effects , Grape Seed Extract/pharmacology , Hepatitis A virus/drug effects , Milk/virology , Norovirus/drug effects , Animals , Caliciviridae Infections/virology , Calicivirus, Feline/physiology , Cats , Cell Line , Hepatitis A/virology , Hepatitis A virus/physiology , Humans , Mice , Norovirus/physiology , Virus Inactivation/drug effectsABSTRACT
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.
Subject(s)
Antiviral Agents/metabolism , Calicivirus, Feline/physiology , Food Additives/metabolism , Hibiscus/chemistry , Models, Biological , Norovirus/physiology , Plant Extracts/metabolism , Animals , Antiviral Agents/chemistry , Beverages , Caliciviridae Infections/prevention & control , Caliciviridae Infections/virology , Calicivirus, Feline/growth & development , Calicivirus, Feline/isolation & purification , Calicivirus, Feline/ultrastructure , Cell Line , Flowers/chemistry , Food Additives/chemistry , Foodborne Diseases/prevention & control , Foodborne Diseases/virology , Functional Food , Gastroenteritis/prevention & control , Gastroenteritis/virology , Hepatitis A/prevention & control , Hepatitis A/virology , Hepatitis A virus/growth & development , Hepatitis A virus/isolation & purification , Hepatitis A virus/physiology , Hepatitis A virus/ultrastructure , Humans , Microscopy, Electron, Transmission , Norovirus/growth & development , Norovirus/isolation & purification , Norovirus/ultrastructure , Plant Extracts/chemistry , Virus Physiological PhenomenaABSTRACT
Blueberry juice and blueberry polyphenols reportedly have antimicrobial properties against foodborne pathogens, without much currently known on their effects against Cronobacter sakazakii. This study evaluated the antimicrobial effects of blueberry proanthocyanidins (PAC) and commercial blueberry juice (BJ) against two strains of C. sakazakii, ATCC 29004 and 29544. BJ (pH 2.8), blueberry PAC (5 mg/ml) and controls (phosphate buffered saline (PBS), pH 7.2, and malic acid pH 3.0) were mixed with equal volumes of washed overnight cultures of C. sakazakii and incubated for 30 min, 1 h, 3 h and 6 h at 37°C. Reductions of â¼1 and 1.50 log CFU/ml were obtained for strains 29004 and 29544, respectively after 30 min with BJ or blueberry PAC. Both C. sakazakii strains 29004 and 29544 were reduced to undetectable levels from 8.25 ± 0.12 log CFU/ml and 8.48 ± 0.03 log CFU/ml, respectively with BJ (pH 2.8) or blueberry PAC after 1 h, while malic acid (pH 3.0) showed â¼1.3 log CFU/ml reduction for both strains. Scanning electron microscopy studies showed differences in cell membrane morphology with clumping and formation of blebs of the treated strains compared to untreated controls. These results warrant further in vivo studies with blueberry bioactives to determine potential for preventing and treating C. sakazakii infections.