Antioxidant and anti-aging activities of mycelial polysaccharides from Lepista sordida.

The intracellular polysaccharides (CLSP) were extracted from Lepista sordida mycelium in submerged culture followed by concentration and ethanol precipitation. The antioxidant activities of CLSP were evaluated both in vitro and in vivo. In vitro antioxidant assay, CLSP had noticeable scavenging activities on superoxide anion, hydroxyl radical and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical. For antioxidant testing in vivo, different doses of CLSP were orally administrated over a period of 6 weeks in a D-galactose induced aged mice model. As results, CLSP significantly inhibited the formation of malondialdehyde (MDA) and raised the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in mice brains and serums in a dose-dependent manner. The results provide a reference for large-scale production of CLSP by submerged fermentation and suggested that CLSP had potent antioxidant activity and could be explored as a potential dietary supplement to retard aging and attenuate age-related diseases in humans.

Effects of a variety of food extracts and juices on the specific binding ability of norovirus GII.4 P particles.

The effects of 13 food extracts and juices, including shellfish, fruits, and vegetables, on the binding ability of human norovirus (NoV) were examined, using P particles of human NoV GII.4 as a research surrogate. The enhancements (positive values) or reductions (negative values) of NoV P particle detection (changes in optical density at 450 nm) in the presence of different food extracts and juices as compared with P particles diluted in phosphate-buffered saline were tested by saliva-binding, enzyme-linked immunosorbent assay in triplicate. In the presence of different food extracts and juices at different concentrations, an increase or decrease of the receptor-binding ability of the NoV P particles was observed. Due to a higher specific binding and thus a higher accumulation of the viral particles, oysters may be contaminated with human NoV more often than other shellfish species (mussel, hard clams, and razor clams). Cranberry and pomegranate juices were shown to reduce the specific binding ability of human NoV P particles. No such binding inhibition effects were observed for the other tested extracts of fresh produce (strawberry, blackberry, blueberry, cherry tomato, spinach, romaine lettuce) or, notably, for raspberry, which has been associated with human NoV outbreaks.

Effect of grape seed extract on human norovirus GII.4 and murine norovirus 1 in viral suspensions, on stainless steel discs, and in lettuce wash water.

The anti-norovirus (anti-NoV) effect of grape seed extract (GSE) was examined by plaque assay for murine norovirus 1 (MNV-1), cell-binding reverse transcription-PCR for human NoV GII.4, and saliva-binding enzyme-linked immunosorbent assay for human NoV GII.4 P particles, with or without the presence of interfering substances (dried milk and lettuce extract). GSE at 0.2 and 2 mg/ml was shown to reduce the infectivity of MNV-1 (>3-log PFU/ml) and the specific binding ability of NoV GII.4 to Caco-2 cells (>1-log genomic copies/ml), as well as of its P particles to salivary human histo-blood group antigen receptors (optical density at 450 nm of >0.8). These effects were decreased as increasing concentrations of dried milk (0.02 and 0.2%) or lettuce extract were added. Under an electron microscope, human NoV GII.4 virus-like particles showed inflation and deformation after treatment with GSE. Under conditions that simulated applications in the food industry, the anti-NoV effect of GSE using MNV-1 as a target organism was shown to be limited in surface disinfection (<1-log PFU/ml, analyzed in accordance with EN 13697:2001). However, a 1.5- to 2-log PFU/ml reduction in MNV-1 infectivity was noted when 2 mg of GSE/ml was used to sanitize water in the washing bath of fresh-cut lettuce, and this occurred regardless of the chemical oxygen demand (0 to 1,500 mg/ml) of the processing water.

Tannic acid inhibited norovirus binding to HBGA receptors, a study of 50 Chinese medicinal herbs.

Noroviruses (NoVs) are the leading cause of viral acute gastroenteritis affecting people of all ages worldwide. The disease is difficult to control due to its widespread nature and lack of an antiviral or vaccine. NoV infection relies on the interaction of the viruses with histo-blood group antigens (HBGAs) as host receptors. Here we investigated inhibition effects of Chinese medicinal herbs against NoVs binding to HBGAs for potential antivirals against NoVs. Blocking assays was performed using the NoV protrusion (P) protein as NoV surrogate and saliva as HBGAs. Among 50 clinically effective Chinese medicinal herbs against gastroenteritis diseases, two herbs were found highly effective. Chinese Gall blocked NoV P dimer binding to type A saliva at IC(50)=5.35 µg/ml and to B saliva at IC(50)=21.7 µg/ml. Similarly, Pomegranate blocked binding of NoV P dimer to type A saliva at IC(50)=15.59 µg/ml and B saliva at IC(50)=66.67 µg/ml. Literature data on preliminary biochemistry analysis showed that tannic acid is a common composition in the extracts of the two herbs, so we speculate that it might be the effective compound and further studies using commercially available, highly purified tannic acid confirmed the tannic acid as a strong inhibitor in the binding of NoV P protein to both A and B saliva (IC(50)≈0.1 µM). In addition, we tested different forms of hydrolysable tannins with different alkyl esters, including gallic acid, ethyl gallate, lauryl gallate, octyl gallate and propyl gallate. However, none of these tannins-derivatives revealed detectable inhibiting activities. Our data suggested that tannic acid is a promising candidate antiviral against NoVs.