Phenolic Compounds of Potato Peel Extracts: Their Antioxidant Activity and Protection against Human Enteric Viruses.

Potato peels (PP) contain several bioactive compounds. These compounds are known to provide human health benefits, including antioxidant and antimicrobial properties. In addition, these compounds could have effects on human enteric viruses that have not yet been reported. The objective of the present study was to evaluate the phenolic composition, antioxidant properties in the acidified ethanol extract (AEE) and water extract of PP, and the antiviral effects on the inhibition of Av-05 and MS2 bacteriophages, which were used as human enteric viral surrogates. The AEE showed the highest phenolic content and antioxidant activity. Chlorogenic and caffeic acids were the major phenolic acids. In vitro analysis indicated that PP had a strong antioxidant activity. A 3 h incubation with AEE at a concentration of 5 mg/ml was needed to reduce the PFU/ml (plaque-forming unit per unit volume) of Av-05 and MS2 by 2.8 and 3.9 log10, respectively, in a dose-dependent manner. Our data suggest that PP has potential to be a source of natural antioxidants against enteric viruses.

Chemical constitution and effect of extracts of tomato plants byproducts on the enteric viral surrogates.

Byproducts of tomato are known to include phenolic compounds but have not been studied in depth. In this study, the phenolic compositions of (stem, leaf, root, and whole plant) of two tomato cultivars, Pitenza and Floradade, were analyzed by HPLC-DAD. In parallel, the antiviral effects of crude extracts on viral surrogates, the bacteriophages MS2 and Av-05 were evaluated. The leaf extracts from the two varieties showed the highest concentration of phenolic compounds. The compounds identified were gallic acid, chlorogenic acid, ferulic acid, cafeic acid, rutin, and quercetin, and they represented 3174.3 and 1057.9 mg/100 g dried weight of the Pitenza and Floradade cultivars, respectively. MS2 and Av-05 titers at 5 mg/mL were reduced by 3.47 and 5.78 log10 PFU/mL and 3.78 and 4.93 log10 PFU/mL by Pitenza and Floradade cultivar leaf extract, respectively. These results show that tomato extracts are natural sources of bioactive substances with antiviral activity.

Antiviral effects of persimmon extract on human norovirus and its surrogate, bacteriophage MS2.

UNLABELLED: Human noroviruses (NoVs) are the leading cause of gastroenteritis and foodborne illnesses worldwide. In this study, we investigated the effects of persimmon extract (PE) on NoV GII.4 and bacteriophage MS2. We also examined the relationship between the tannin content of PE and its antiviral effects to identify the active ingredient in PE. Different persimmon tannin (PT) solutions were prepared by mixing PE with different concentrations of bovine serum albumin. The antiviral efficacy of these solutions against NoV was evaluated by quantifying the amount of residual noroviral genome using a quantitative reverse transcription PCR (qRT-PCR) assay. The antiviral efficacy of PE against MS2 was examined with an infectivity assay (plaque assay). Solutions containing ≥ 0.11 mg/mL PT reduced the noroviral genome by more than 70.0% and the infectivity of MS2 by more than 2.5 log PFU/mL. However, the effects of PT on both viruses decreased markedly at a concentration of 0.08 mg/mL and solutions containing negligible PT had no antiviral activity. These results suggest that the PT component of PE inactivates NoV and MS2. Our results indicate that PE is a nontoxic antiviral agent effective against enteric viruses. PRACTICAL APPLICATION: Persimmon extract showed antiviral effects against NoV and bacteriophage MS2. Persimmon extract is suitable for use as an antiviral agent.

The role of surface functionalization of colloidal alumina particles on their controlled interactions with viruses.

Materials that interact in a controlled manner with viruses attract increasing interest in biotechnology, medicine, and environmental technology. Here, we show that virus-material interactions can be guided by intrinsic material surface chemistries, introduced by tailored surface functionalizations. For this purpose, colloidal alumina particles are surface functionalized with amino, carboxyl, phosphate, chloropropyl, and sulfonate groups in different surface concentrations and characterized in terms of elemental composition, electrokinetic, hydrophobic properties, and morphology. The interaction of the functionalized particles with hepatitis A virus and phages MS2 and PhiX174 is assessed by virus titer reduction after incubation with particles, activity of viruses conjugated to particles, and imaged by electron microscopy. Type and surface density of particle functional groups control the virus titer reduction between 0 and 99.999% (5 log values). For instance, high sulfonate surface concentrations (4.7 groups/nm(2)) inhibit attractive virus-material interactions and lead to complete virus recovery. Low sulfonate surface concentrations (1.2 groups/nm(2)), native alumina, and chloropropyl-functionalized particles induce strong virus-particle adsorption. The virus conformation and capsid amino acid composition further influence the virus-material interaction. Fundamental interrelations between material properties, virus properties, and the complex virus-material interaction are discussed and a versatile pool of surface functionalization strategies controlling virus-material interactions is presented.