Screening of some indigenous plants as repellents or antifeedants for stored grain insects

Seven plant species were tested for their repellent activity against Tribolium castaneum (Herbst) and antifeedant activity against Rhyzopertha dominica F. The best repellent activity was found in the rhizomes of Saussurea lappa (DC.) and antifeedant activity in the leaves of Chenopodium ambrosioides L. and in azadirachtin isolated from neem kernels.     

Properties and application of inulinase obtained by fermentation of costus (Saussurea lappa) root powder with Aspergillus niger

Acetone precipitated extracellular inulinase from Aspergillus niger van Tieghem UV 11 grown on costus (Kuth; Saussurea lappa) root powder/corn steep liquor medium was found to have a pH optimum of 5.5, temperature optimum of 50 °C and stability at 50 °C for 60 min. Substrate affinity was in the order of inulin > sucrose > raffinose. At 0.001 M concentrations, Mg²⁺ and Ca²⁺ were weak activators of inulinase while Fe³⁺, Cu²⁺, Zn²⁺, Co²⁺ and Mn²⁺ were found to be inhibitors of inulinase. Hydrolysis of inulin extracted and purified from costus root powder and standard inulin with inulinase under similar conditions yielded 70% fructose and 68% fructose, respectively.     

Effects of yogurt containing probiotics on respiratory virus infections: Influenza H1N1 and SARS-CoV-2

Respiratory virus infections are an escalating issue and have become common worldwide. Influenza and COVID-19 are typical infectious respiratory diseases, and they sometimes lead to various complications. In a situation in which no established drug or treatment exists, consumption of proper food might be beneficial in maintaining health against external infections. We studied the potential effects of mixtures of probiotic strains on various viral infections. The purpose of this study was to assess the ability of yogurt containing probiotics to reduce the risk of respiratory viruses such as influenza H1N1 and SARS-CoV-2 infection. First, we performed in vitro tests using infected Madin-Darby canine kidney (MDCK) and Vero E6 cells, to evaluate the potential effects of yogurt containing high-dose probiotics against influenza H1N1 and SARS-CoV-2 infection. The yogurt significantly reduced plaque formation in the virus-infected cells. We also performed in vivo tests using influenza H1N1-infected C57BL/6 mice and SARS-CoV-2-infected Syrian golden hamsters, to evaluate the potential effects of yogurt. Yogurt was administered orally once daily during the experimental period. Yogurt was also administered orally as pretreatment once daily for 3 wk before viral infection. Regarding influenza H1N1, it was found that yogurt caused an increase in the survival rate, body weight, and IFN-γ, IgG1, and IL-10 levels against viral infection and a decrease in the inflammatory cytokines TNF-α and IL-6. Although the SARS-CoV-2 copy number was not significantly reduced in the lungs of yogurt-treated SARS-CoV-2-infected hamsters, the body weights and histopathological findings of the lungs were improved in the yogurt-treated group. In conclusion, we suggest that consumption of yogurt containing probiotics can lead to beneficial effects to prevent respiratory viral infections.     

Antimicrobial activity of <Emphasis Type="Italic">Myagropsis myagroides</Emphasis> and interaction with food composition

Ethanol extract of Myagropsis myagroides (MMEE) has substantial antimicrobial activity against Gram-positive bacteria and some of the yeasts. The minimum inhibitory concentration (MIC) of MMEE ranged from 0.0625 to 0.125 mg/mL for Bacillus subtilis, Listeria monocytogenes, and Clostridium perfringens. Chloroform fraction obtained through liquid-liquid extraction possessed the strongest antimicrobial activity, and was separated by silica gel column chromatography. Among 22 of subfraction, CH4 showed the strongest activity (4–8 times MIC of the crude extract). The antimicrobial activity of CH4 to Staphylococcus aureus was reduced at high concentrations of starch, but the bactericidal effect of CH4 was maintained at 1 and 5% starch model media. The efficacy of CH4 against S. aureus diminished in the presence of >5% beef extract and >1% soybean oil. In acute toxicity test, no mortalities occurred in mice administered 5 g/kg body weight of MMEE over 2 weeks observation.     

Anti-influenza A virus effects of fructan from Welsh onion (Allium fistulosum L.)

A fructan that acts as an anti-influenza A virus substance was isolated from hot water extract of the green leafy part of a Welsh onion (Allium fistulosum L.). The structure of the fructan was characterised and elucidated by chemical and spectroscopic analyses. The fructan was composed of terminal (21.0%) and 2,1-linked β-d-Fruf residues (65.3%) with 1,6-linked β-d-Glcp residues (13.7%). The molecular weight of the polysaccharide and polydispersity was estimated to be 1.5 × 10³ and 1.18, respectively. Although the fructan did not show anti-influenza A virus activity in vitro, it demonstrated an inhibitory effect on virus replication in vivo when it was orally administered to mice. In addition, the polysaccharide enhanced the production of neutralising antibodies against influenza A virus. Therefore, the antiviral mechanism of the polysaccharide seemed to be dependent on the host immune system, i.e., enhancement of the host immune function was achieved by the administration of the polysaccharide. From our observations, the fructan from Welsh onions is suggested to be one of the active principles which exert an anti-influenza virus effect.     

ANTIMICROBIAL AND ANTIOXIDANT ACTIVITY OF EMBLICA EXTRACTS OBTAINED BY SUPERCRITICAL CARBON DIOXIDE EXTRACTION AND METHANOL EXTRACTION

ABSTRACT

This study is aimed to evaluate the antimicrobial and antioxidant activities of two extracts of emblica (Phyllanthus emblica L.) obtained by supercritical fluid extraction (SFE) and methanol extraction. The SFE extract showed strong antimicrobial activity against all microorganisms tested, whereas the methanolic extract showed low activity against Staphylococcus aureus and fungi. In contrast, the methanolic extract exhibited significantly higher antioxidant activity than the SFE extract. The SFE extract was analyzed by gas chromatography with mass spectrometric detector. Thirty compounds were tentatively identified, representing 99.67% of the volatile components. β‐Bourbonene, teracosane, palmitic acid, thymol, β‐caryophyllene and undecane were the major compounds. The methanolic extract was subjected to separation and purification using reverse‐phase high‐performance liquid chromatography. Kaempferol 3‐β‐D‐glucopyranoside (1), kaempferol (2), quercetin (3), isocorilagin (4) and geraniin (5) respectively, were identified by spectral methods, ¹H and ¹³C nuclear magnetic resonance spectroscopy, ultraviolet‐visible spectrophotometry and mass spectroscopy, and comparison with literatures.

PRACTICAL APPLICATIONS

The study can be considered as the first report on the in vitro antimicrobial and antioxidant properties of supercritical fluid extraction (SFE) and methanolic extracts prepared from Phyllanthus emblica. The results introduce a unique natural source that possesses strong antimicrobial and antioxidant substances. The SFE extract had a strong and broad spectrum of antimicrobial activity, and in some cases, even found to have similar activity to the antibiotics ampicillin and nystatin. On the other hand, the methanolic extract exhibited quite strong antioxidant activities, which were found to be similar, and in some cases even higher than the reference compound butylated hydroxytoluene (BHT). Hence, the extracts of P. emblica could be used as a natural preservative ingredient in food and/or pharmaceutical industry.     

Hypoglycemic effect of fermented soymilk added with bokbunja (Rubus coreanus Miquel) in diabetic mice

This study investigated the hypoglycemic effect of fermented soymilk extracts added with bokbunja (FSB) in streptozotocin (STZ)-induced diabetic mice. FSB was prepared via fermentation with Bacillus subtilis of soymilk added with bokbunja extract and its extraction with methanol. The FSB showed higher (p<0.05) inhibitory activities than fermented soymilk extracts (FS) against α-glucosidase. The IC₅₀ values of 5% FSB for α-glucosidase was 0.55 mg/mL, which was superior to that of FS (0.77 mg/mL). The increase of postprandial blood glucose levels were more significantly suppressed in the 5% FSB administered group than control or FS group in the streptozotocin induced diabetic mice. Moreover, the area under curve (AUC) was significantly reduced via 5% FSB administration in the diabetic mice as well as it delayed absorption of dietary carbohydrates. Results from this study suggest that FSB may help decrease the postprandial blood glucose level via inhibiting α-glucosidase.     

Short communication: Antiviral activity of subcritical water extract of Brassica juncea against influenza virus A/H1N1 in nonfat milk

Subcritical water extract (SWE) of Brassica juncea was studied for antiviral effects against influenza virus A/H1N1 and for the possibility of application as a nonfat milk supplement for use as an “antiviral food.” At maximum nontoxic concentrations, SWE had higher antiviral activity against influenza virus A/H1N1 than n-hexane, ethanol, or hot water (80°C) extracts. Addition of 0.5 mg/mL of B. juncea SWE to culture medium led to 50.35% cell viability (% antiviral activity) for Madin-Darby canine kidney cells infected with influenza virus A/H1N1. Nonfat milk supplemented with 0.28 mg/mL of B. juncea SWE showed 39.62% antiviral activity against influenza virus A/H1N1. Thus, the use of B. juncea SWE as a food supplement might aid in protection from influenza viral infection.     

ANTIBACTERIAL ACTIVITY OF EXTRACTS FROM FAMILY ZINGIBERACEAE AGAINST FOODBORNE PATHOGENS

Chloroformic extracts of selected Thai medicinal plants commonly employed to treat infections were investigated for their antibacterial activity against important foodborne pathogenic bacteria. These included Bacillus cereus, Staphylococcus aureus, methicillin‐resistant S. aureus (MRSA), Escherichia coli O157:H7, Salmonella Typhi and Shigella sp. Among 33 extracts tested, only chloroformic extracts of five plant species exhibited antibacterial properties. Alpinia galanga, Boesenbergia rotunda, Zingiber zerumbet and Piper betel were active against S. aureus. Barleria lupulina was active against B. cereus. Only the extract from P. betel leaves possessed activity against gram‐negative bacteria. As extracts from the three plant species belonging to family Zingiberaceae displayed strong activity against S. aureus, they were further tested against 17 clinical isolates. Minimum inhibitory concentration (MIC) values of B. rotunda, A. galanga and Z. zerumbet extracts against most clinical S. aureus isolates were 0.01, 0.19 and 0.79 mg/mL and the minimum bactericidal concentration (MBC) values were 0.19, 1.57 and >12.5 mg/mL, respectively. Significant growth inhibition of MRSA was observed in the cultures incubated in the presence of the B. rotunda extract, A. galanga and Z. zerumbet. B. rotunda exhibited the greatest activity among the three plant species against S. aureus at MIC, 2MIC and MBC within 2 h.     

Antidiabetic Potential of Green Seaweed Enteromorpha prolifera Flavonoids Regulating Insulin Signaling Pathway and Gut Microbiota in Type 2 Diabetic Mice

This study aimed to investigate the antidiabetic activity of water–ethanol extract of green macroalgae Enteromorpha prolifera (EPW) and its flavonoid‐rich fraction less than 3 kDa (EPW3) in type 2 diabetic mice induced by streptozotocin and a high‐sucrose/high‐fat diet. The major active compounds were identified using ultra‐performance liquid chromatography coupled with quadrupole‐time‐of‐flight‐tandem mass spectrometry. Quantitative gene expression analysis of the insulin signaling pathway was performed. The effects of EPW3 on gut microflora in diabetic mice were analyzed by high‐throughput 16S rRNA gene sequencing. The results showed EPW3 treatment decreased the fasting blood glucose, improved oral glucose tolerance, and protected against liver and kidney injury with reduced inflammation in diabetic mice. The active principle of EPW3 revealed hypoglycemic effect as indicated by activation of the IRS1/PI3K/AKT and inhibition of the JNK1/2 insulin pathway in liver. Furthermore, the treatment significantly enriched the abundance of Lachnospiraceae and Alisties, which were positive correlation of metabolic phenotypes. These findings indicated that EPW3 possessed great therapeutic potential as adjuvant therapy for type 2 diabetes.     

Antioxidant and gastroprotective actions of butanol fraction of Zingiber officinale against diclofenac sodium‐induced gastric damage in rats

This study was designed to investigate the antioxidant and antiulcer activities of flavonoid‐rich fractions of Zingiber officinale extract. The fractions, obtained by solvents of increasing polarities, were subjected to 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity. The fraction which possessed the highest antioxidant activity was used to assess gastroprotective action against diclofenac sodium induced gastric ulcer in rats. Chromatographic profiling was carried out using LC‐ESI‐MS analysis. The butanol fraction (BF) showed the strongest antioxidant potential and the results of the in vivo study revealed that BF at 100 mg/kg protected against gastric lesions. At the same dose, BF prevented diclofenac sodium‐induced increase in tumor necrosis factor alpha (TNF‐α) and malondialdehyde (MDA) levels, and depletion of catalase (CAT) activity as well as glutathione (GSH) and prostaglandin E2 (PGE2) contents. LC‐ESI‐MS analysis revealed the presence of 12 phenolic compounds. BF exerted antiulcer action which could be linked to the presence of phenolic compounds.

Practical applications

Zingiber officinale has been widely consumed as a spice and used in folk medicine for treatment of gastric disorders. This is the first report evaluating the pharmacological effects of the butanol extract of ginger for the prevention of gastric ulcer. The results showed that the extract affords better gastroprotective activity against diclofenac sodium‐induced gastric ulcer in rats by reducing oxidative stress. Information provided in this study will be beneficial for developing applications of ginger in food biotechnology as functional and nutraceutical ingredient.     

Dietary Mannan Oligosaccharides Modulate Gut Microbiota,Increase Fecal Bile Acid Excretion,and Decrease Plasma Cholesterol and Atherosclerosis Development

1 Scope

Mannan oligosaccharides (MOS) have proven effective at improving growth performance, while also reducing hyperlipidemia and inflammation. As atherosclerosis is accelerated both by hyperlipidemia and inflammation, we aim to determine the effect of dietary MOS on atherosclerosis development in hyperlipidemic ApoE*3‐Leiden.CETP (E3L.CETP) mice, a well‐established model for human‐like lipoprotein metabolism.

2 Methods and results

Female E3L.CETP mice were fed a high‐cholesterol diet, with or without 1% MOS for 14 weeks. MOS substantially decreased atherosclerotic lesions up to 54%, as assessed in the valve area of the aortic root. In blood, IL‐1RA, monocyte subtypes, lipids, and bile acids (BAs) were not affected by MOS. Gut microbiota composition was determined using 16S rRNA gene sequencing and MOS increased the abundance of cecal Bacteroides ovatus. MOS did not affect fecal excretion of cholesterol, but increased fecal BAs as well as butyrate in cecum as determined by gas chromatography mass spectrometry.

3 Conclusion

MOS decreased the onset of atherosclerosis development via lowering of plasma cholesterol levels. These effects were accompanied by increased cecal butyrate and fecal excretion of BAs, presumably mediated via interactions of MOS with the gut microbiota.     

Antiviral effect of multipurpose contact lens disinfecting solutions against coronavirus

PurposeTo evaluate the antiviral potential of five multipurpose disinfecting solutions against coronavirus (mouse hepatitis virus, a surrogate for SARS-CoV-2 human corona virus).MethodsTest solutions (Biotrue, renu Advanced [Bausch and Lomb], ACUVUE RevitaLens [Johnson and Johnson Vision], cleadew [Ophtecs corp.] or AOSept Plus [Alcon]) were mixed with the coronavirus mouse hepatitis virus at 10⁴ plaque forming units (PFU)/mL as the final concentration and incubated at room temperature for the specified disinfection time. Surviving virus from each sample was then quantified by standard plaque forming unit assay and the reduction of PFU for each disinfectant was compared to the phosphate buffer saline (PBS) treated negative control. A regimen test was also conducted using Biotrue.ResultsThe three multipurpose disinfecting solutions Biotrue (containing PHMB and polyquaternium-1), renu Advanced (PHMB, polyquaternium-1 and alexidine) and ACUVUE RevitaLens (polyquaternium-1 and alexidine) did not kill the coronavirus at the manufacturers recommended disinfection time in the stand alone test. After treatment, the virus’s titer (3.8 ± 0.2 log₁₀ for Biotrue, 3.7 ± 0.1 log₁₀ for renu and 3.7 ± 0.2 log₁₀ for RevitaLens) was similar to the negative control (3.7 ± 0.1 log₁₀; p ≥ 0.996). AOSept Plus (hydrogen peroxide) and cleadew (povidone iodine) significantly (p < 0.001) reduced the numbers of coronaviruses to below the detection limit (i.e. killed 3.7 ± 0.1 log₁₀ viruses compared to control). However, there was a significant reduction (p = 0.028) in numbers of coronaviruses attached to lenses when using the regimen test with Biotrue.ConclusionsThis study shows that oxidative contact lens disinfecting solutions (i.e. those containing povidone-iodine or hydrogen peroxide) provide superior antiviral activity against a coronavirus surrogate of SARS-CoV-2, unless the full regimen test (rub, rinse, disinfect) is used.     

Effects of γ-irradiation on the biological activity of burdock (Arctium lappa L.) extracts

Burdock (Arctium lappa L.) extracts were prepared with different extraction methods, ethanol (70%, RT) and hot water (85°C for 3 hr, HT), and their biological activities were investigated after γ-irradiation (10 and 20 kGy). Color of the burdock extracts became brighter after application of irradiation regardless of the extraction system. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of the burdock extracts with RT and HT were 54.56 and 59.21% at 500 ppm, respectively, and the lipid oxidation of oil emulsion was delayed by addition of the extracts. The HT29 cancer cell viability was inhibited by burdock extracts with RT up to 52.45 at a 250 ppm level. The anti-mutagenicitiy against 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole and 2-nitrofluorene were also found. Results indicate that burdock extract possesses biological activities and RT showed an increasing trend in antixodiative activity and inhibition of cancer cell viability. Brighter color of the burdock extract after irradiation may improve industrial applicability.     

Indigenous microorganisms from iceberg lettuce with adherence and antagonistic potential for use as protective culture

The antagonistic effect of the indigenous microflora on pathogens was investigated by using Salmonella Typhimurium, Staphylococcus aureus and Listeria innocua as challenge microorganisms. 18 strains strongly adherent to the leaves of iceberg lettuce were selected and their taxonomic status was determined with the aid of API NE20, BBL CRYSTAL™ E/NF systems and 16 S rDNA sequencing. In the majority of cases (15/19), the identification by biochemical testing did not agree with that of 16 S rDNA sequencing. Six strains exerted antagonistic effects on S. Typhimurium and L. innocua, when overnight cultures or cell free culture supernatants were investigated in the agar diffusion test. In vivo experiments showed that the inoculation of lettuce with P. putida LTH 5878 by dipping and pre-incubation decreased the numbers of S. Typhimurium, L. innocua and S. aureus below the level of detection (< 100 cfu/g) after storage for 7–8 d at 4 °C. The dependency of the antagonistic efficacy on the numbers of P. putida LTH 5878 was determined using point inoculation. The study of the effect of the pseudomonades/pathogen ratio on the reduction of pathogens showed that the antagonistic activity of Pseudomonas is stronger against S. Typhimurium than against L. innocua. A major reduction was achieved for the counts of L. innocua at ratios of greater than 100:1 whereas for S. Typhimurium a ratio of 0.1:1 was already effective. The sensory properties of the inoculated and stored lettuce were in general better than those of the untreated control.

Industrial relevance

The increasing importance of minimally processed ready-to-eat (RTE) vegetables has initiated many studies using surface treatments for microbial decontamination. However, most treatments such as the use of chlorine or ozone have not proven highly effective or desirable. This study is of high relevance because it evaluates the potential of endogenous microbial populations with high surface adherence properties as a competitive tool against pathogenic microorganisms. This is an intriguing concept which deserves further development because of its potential as an new biological food preservation process.     

Study of the efficacy of a Streptococcus uberis mastitis vaccine against an experimental intramammary infection with a heterologous strain in dairy cows

Streptococcus uberis is a worldwide pathogen that causes intramammary infections in dairy cattle. Nevertheless, commercial vaccines are currently not available and measures to control S. uberis mastitis are limited to the implementation of good management practices. The aim of the present study was to evaluate the efficacy of an S. uberis subunit vaccine against bovine mastitis (Laboratorios Hipra S.A., Amer, Spain) administered precalving against an experimental intramammary challenge with a heterologous S. uberis strain in dairy cows postcalving. With this objective, 25 gestating Holstein-Friesian heifers were randomly assigned to 1 of 2 groups: group 1 (n = 13), vaccinated by intramuscular route with the vaccine, and group 2 (n = 12), vaccinated by intramuscular route with phosphate-buffered saline as a control group. Both groups were immunized 60 and 21 d before the expected parturition date (75 and 36 d before challenge). Fourteen days after calving all cows were challenged by intramammary infusion of 100 colony-forming units of a heterologous S. uberis strain in 2 quarters per cow. Then, challenged quarters were monitored for clinical signs of mastitis, bacterial count, and somatic cell count for the following 21 d. Rectal temperature and daily milk yield per cow were also assessed. Results showed that all challenged quarters developed clinical mastitis. Nevertheless, vaccination significantly reduced the clinical signs of mastitis, bacterial count, rectal temperature, and daily milk yield losses after the intramammary infection and significantly increased the number of quarters with no bacterial isolation and somatic cell count <200,000 cells/mL at the end of the study (d 19, 20, and 21 after challenge). To confirm the efficacy of this vaccine, further studies under field conditions are needed.     

THE EFFECT OF pH ON THE EFFICIENCY OF VINIFICATION BY‐PRODUCT EXTRACTS TO INHIBIT LIPID PEROXIDATION IN A LECITHIN LIPOSOME MODEL MATRIX

ABSTRACT

A series of extracts from vinification by‐products, generated under specified, optimal conditions, were tested for their efficiency to inhibit lipid peroxidation in lecithin liposomes at various pH values. Lipid peroxidation was assessed by measuring the kinetics of CDV onset, which over a period of 6 days was found to obey zero‐order kinetics. As positive control samples the synthetic antioxidant, butylated hydroxytoluene and the natural quercetin were also considered. The results obtained showed that the most distinct inhibition as compared with control sample (no antioxidant added) was found upon addition of grape stem extract from the variety Vitis vinifera var. Moschofilero at pH 8, with the kinetics constant (k) being 6.6 × 10⁻² CDV/d. By contrast, seed extract from the same variety at pH 2 was prominently prooxidant, with k = 50.7 × 10⁻² CDV/d. Extracts from both stems and seeds exhibited large variations as a function of pH, with stem extracts being in general more efficient than seed extracts, but no consistent trend in response to pH was observed. This outcome clearly pointed to efficiency dependence upon both the composition of the extracts and pH.

PRACTICAL APPLICATIONS

Because the use of antioxidants in food industry is indispensable, the study of the efficiency of certain widely used plant extracts possessing antioxidant properties becomes imminent. This is because the deployment of natural antioxidants in food matrices has often been accompanied by major discrepancies concerning their efficiency to shield against rancidity. Thus, revealing details on the antioxidant behavior of natural extracts with regard to significant food characteristics, such as pH, is of undisputed importance in utilizing these extracts in a technologically rational way. The results from this study showed that extracts from vinification by‐products, and presumably other extracts from various plant sources, might have variable behavior with regard to inhibiting and/or promoting lipid peroxidation. As this might depend on the pH of the matrix used or other intrinsic factors, the antioxidant potency of a particular extract can be reliably assessed only by case experimentation.