An evaluation of the inhibitory effects against rotavirus infection of edible plant extracts

Pistacia vera L. as natural source against antimicrobial and antiviral resistance

Increased global research is focused on the development of novel therapeutics to combat antimicrobial and antiviral resistance. Pistachio nuts represent a good source of protein, fiber, monounsaturated fatty acids, minerals, vitamins, and phytochemicals (carotenoids, phenolic acids, flavonoids and anthocyanins). The phytochemicals found in pistachios are structurally diverse compounds with antimicrobial and antiviral potential, demonstrated as individual compounds, extracts and complexed into nanoparticles. Synergistic effects have also been reported in combination with existing drugs. Here we report an overview of the antimicrobial and antiviral potential of pistachio nuts: studies show that Gram-positive bacterial strains, such as Staphylococcus aureus, are the most susceptible amongst bacteria, whereas antiviral effect has been reported against herpes simplex virus 1 (HSV-1). Amongst the known pistachio compounds, zeaxanthin has been shown to affect both HSV-1 attachment penetration of human cells and viral DNA synthesis. These data suggest that pistachio extracts and derivatives could be used for the topical treatment of S. aureus skin infections and ocular herpes infections.

Beneficial Role of Vitexin in Parkinson's Disease

Today, Parkinson's disease (PD) is the foremost neurological disorder all across the globe. In the quest for a novel therapeutic agent for PD with a multimodal mechanism of action and relatively better safety profile, natural flavonoids are now receiving greater attention as a potential source of neuroprotection. Vitexin have been shown to exhibit diverse biological benefits in various disease conditions, including PD. It exerts its anti-oxidative property in PD patients by either directly scavenging reactive oxygen species (ROS) or by upregulating the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and enhancing the activities of antioxidant enzymes. Also, vitexin activates the ERK1/1 and phosphatidyl inositol-3 kinase/Akt (PI3K/Akt) pro-survival signalling pathway, which upregulates the release of anti-apoptotic proteins and downregulates the expression of pro-apoptotic proteins. It could be antagonistic to protein misfolding and aggregation. Studies have shown that it can also act as an inhibitor of monoamine oxidase B (MAO-B) enzyme, thereby increasing striatal dopamine levels, and hence, restoring the behavioural deficit in experimental PD models. Such promising pharmacological potential of vitexin could be a game-changer in devising novel therapeutic strategies against PD. This review discusses the chemistry, properties, sources, bioavailability and safety profile of vitexin. The possible molecular mechanisms underlying the neuroprotective action of vitexin in the pathogenesis of PD alongside its therapeutic potential is also discussed.

Ammi-visnaga extract; a novel phyto-antiviral agent against bovine rotavirus

The spread of bovine rotavirus has a great impact on animal productivity, milk products, and human public health. Thus, this study aimed to develop a novel, effective and accessible Phyto-antiviral treatment made from methanolic Ammi-visnaga seed extract against rotavirus infection. Rotaviruses were isolated from raw milk and cottage cheese samples randomly collected from Cairo and Qalubia governorates. They were all identified serologically, however, only three of them were both biologically and molecularly confirmed. The methanolic extract derived from Khella seeds (MKSE) was chemically analyzed with mass chromatography. The cellular toxicity of MKSE was tested on Caco-2 cells and its antiviral activity against one of the isolated bovine rotaviruses (BRVM1) was tested by both the cytopathic inhibition assay and the plaque reduction assay. Our results showed that 17.3% of the total collected 150 dairy samples were bovine rotavirus antigen positive. Three representatives of them were phylogenetically identified to be included in group A based on a 379 bp coat protein gene. Visnagin, Benzopyran, Khellin, and Benzenepropanoic acid were the major active components found in the MKSE. The maximum non-toxic concentration of MKSE was 5 µg/mL and the CC50 value was 417 µg/mL. The MKSE exhibited in-vitro antiviral activity against BRVM1 indicated by inhibition of the viral cytopathic effect (SI = 204.5, IP = 98%), causing a 1.5 log decrease in BVRM1 TCID50 and reducing the viral plaques count by the percentage of 93.14% at MNTC (5 ug/ml). In conclusion, our study showed that bovine rotavirus represents a severe health problem that needs attention in Egypt, and it supports using MKSE as a potential natural anti-rotavirus agent.

UHPLC-QTOF-MS-based untargeted metabolomics and mineral element analysis insight into the geographical differences of Chrysanthemum morifolium Ramat cv. "Hangbaiju" from different origins

Chrysanthemum morifolium Ramat cv. "Hangbaiju" (HBJ), known as one of the "eight flavors of Zhejiang", is commonly used as a classical tea material for both food and medicine over three thousand years in China. The quality of HBJ is closely related to its geographical origins. However, the mechanism underlying the geographical differences of HBJ remains to be elucidated. In this study, an untargeted metabolomic strategy based on UHPLC-QTOF-MS was established to discover the differential metabolites in HBJ samples from four different origins and explore the possible relationship with mineral elements in planting soils by chemometric analysis. Eight compounds were screened and identified as the key differential metabolites in HBJ samples from different origins. Among them, four important pharmacodynamic compounds including L-arginine, rutin, chlorogenic acid and apigenin-7-O-glucoside are the most abundant in HBJ samples from Tongxiang region, which suggests that HBJ planted in Tongxiang has higher medicinal values. Pearson correlation analysis revealed that the contents of soil mineral elements are positively correlated with those of chlorogenic acid, rutin, apigenin-7-O-glucoside in HBJ samples. Furthermore, an interrelationship model based on random forest algorithm was established to successfully predict the contents of differential metabolites in HBJ samples by soil mineral elements. All these results indicated that the contents of differential metabolites in HBJ samples seemed to be affected by soil mineral elements and therefore resulted in the geographical differences of HBJ.

Screening of potential bio-molecules from Moringa olifera against SARS-CoV-2 main protease using computational approaches

COVID-19 caused by SARS-CoV-2 is responsible for the deaths of millions of people worldwide. It is having devastating effects on the people of all countries. In this regard, the phytochemicals of medicinal plants could be explored to prevent this disease. M. oleifera is a miracle plant with antibacterial, antiviral, and antioxidant properties because of its high content of flavonoids, glucosides and glucosinolates. Therefore, we constructed a library of 294 phytochemicals of M. oleifera and filtered it through the FAF-Drugs4. Further, molecular docking studies of filtered phytochemicals were performed with Mpro enzyme to investigate the binding interactions. Drug likeness properties, ADMET prediction were analyzed to determine the therapeutic aspect of these compounds. Based on the binding energy score of the top 4 compounds, the results indicate that Vicenin-2 has the highest binding affinity (-8.6 kcal mol^-1) as compared to the reference molecule (-8.4 kcal mol^-1). ADMET result reveals that all top four compounds have minimal toxic effects and good absorption. Further, 500 ns molecular dynamics simulation of the top four compounds showed that Kaempferol-3-O-rutinoside and Vitexin have good stability with Mpro. These two compounds were then subjected for MMPBSA (last 50 ns) calculation to analyze the protein-ligand stability and dynamic behavior. Kaempferol-3-O-rutinoside and Vitexin showed very good binding free energy i.e. -40.136 kJ mol^-1 and -26.784 kJ mol^-1, respectively. Promising outcomes from MD simulations evidence the worth of these compounds for future drug development to combat coronavirus disease.Communicated by Ramaswamy H. Sarma.

Effects of Plant Metabolites on the Growth of COVID-19 (Coronavirus Disease-19) Including Omicron Strain

According to recent reports out of India, a new strain of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) B1.1.529 Omicron virus has emerged. In comparison to the Wuhan (WHU) strain and the delta variant, this variant showed a far stronger effect on the angiotensin converting enzyme2 (ACE2) receptor. There are several medicinal compounds in plant metabolites, and their diverse chemical structures make them ideal for the treatment of serious illnesses. It's possible that some of these could be useful alternative pharmaceuticals, as well as a starting point for the repurposing of existing medications and new chemical discoveries. SARS-CoV-2 infection triggered a worldwide epidemic of the severe acute respiratory syndrome (SARS). There have been trials for different therapies for SARS-CoV-2 and so also there are recent announcements of extensive research into the development of viable medicines for this global health calamity. After a thorough examination of plant-derived treatments for COVID-19, investigators in the current study decided to focus on plant-derived secondary metabolites (PSMs). According to some researchers, new MDR (Multi-Drug Resistant) antibiotics may one day be developed due to the adaptability of secondary metabolites. Identifying plant metabolites that can treat a wide range of viral infections was one of the study's aims. Many natural medications that could be recommended for the treatment of COVID-19 were discovered as a result of this research, including remedies from plant families, viral candidates that are susceptible, antiviral assays, and mechanisms of therapeutic action. The findings of this study will inspire further research and speed up the development of new antiviral plant-based medications.

Bioprospecting for Anti-COVID-19 Interventions From African Medicinal Plants: A Review

The emergence of the novel coronavirus (SARS-CoV-2) that emanated from Wuhan in China in 2019 has become a global concern. The current situation warrants ethnomedicinal drug discovery and development for delivery of phytomedicines with potential for the treatment of COVID-19. The aim of this review is to provide a detailed evaluation of available information on plant species used in African traditional medicines with antiviral, anti-inflammatory, immunomodulatory, and COVID-19 symptoms relieving effects. Literature from scientific databases such as Scopus, PubMed, Google scholar, African Journals OnLine (AJOL), Science Direct, and Web of Science were used for this review. A total of 35 of the 38 reviewed plants demonstrated a wide range of antiviral activities. Bryophyllum pinnatum, Aframomum melegueta, Garcinia kola, Sphenocentrum jollyanum, Adansonia digitata, Sutherlandia frutescens, Hibiscus sabdariffa, Moringa oleifera, and Nigella sativa possess a combination of antiviral, immunomodulatory, anti-inflammatory, and COVID-19 symptoms relieving activities. Nine, 13, and 10 of the plants representing 23.7%, 34.2%, and 26.3% of the plants studied had antiviral activity with 3 other activities, antiviral activity with 2 other activities, and antiviral with one pharmacological activity alone, respectively. The plants studied were reported to be relatively safe at the subchronic toxicity level, except for 2. The study provides baseline information on the pharmacological activities, toxicity, and chemical components of 9 African medicinal plants with antiviral, immunomodulatory, anti-inflammatory, and symptoms relieving activities, thereby making the plants candidates for further investigation for effectiveness against COVID-19.

In Vitro Liver Metabolism of Six Flavonoid C-Glycosides

Several medical plants belonging to the genera Passiflora, Viola, and Crataegus accumulate flavonoid C-glycosides, which likely contribute to their efficacy. Information regarding their phase I and II metabolism in the liver are lacking. Thus, in vitro liver metabolism of orientin, isoorientin, schaftoside, isoschaftoside, vitexin, and isovitexin, all of which accumulated in Passiflora incarnata L., was investigated by incubation in subcellular systems with human liver microsomes and human liver S9 fraction. All metabolite profiles were comprehensively characterized using HPLC-DAD and UHPLC–MS/MS analysis. Mono-glycosylic flavones of the luteolin-type orientin and isoorientin showed a broad range of mono-glucuronidated and mono-sulfated metabolites, whereas for mono-glycosylic flavones of the apigenin-type vitexin and isovitexin, only mono-glucuronidates could be detected. For di-glycosylic flavones of the apigenin-type schaftosid and isoschaftosid, no phase I or II metabolites were identified. The main metabolite of isoorientin was isolated using solid-phase extraction and prep. HPLC-DAD and identified as isoorientin-3′-O-α-glucuronide by NMR analysis. A second isolated glucuronide was assigned as isoorientin 4′-O-α-glucuronide. These findings indicate that vitexin and isovitexin are metabolized preferentially by uridine 5′-diphospho glucuronosyltransferases (UGTs) in the liver. As only orientin and isoorientin showed mono-sulfated and mono-glucuronidated metabolites, the dihydroxy group in 3′,4′-position may be essential for additional sulfation by sulfotransferases (SULTs) in the liver. The diglycosylic flavones schaftoside and isoschaftoside are likely not accepted as substrates of the used liver enzymes under the chosen conditions.

Effects of Iranian Polyherbal Syrup (Zufa syrup) on oxygen saturation and clinical symptoms in suspected patients with COVID-19: a triple-blinded, randomized, placebo-controlled trial

Coronavirus disease 2019 (COVID-19) pandemic has caused an urgent need for investigating potential treatments. Traditional medicine offers many potential remedies that have been historically used and have the advantage of bypassing the cultural obstacles in the practice of medicine. We aimed to investigate the efficacy of Zufa syrup in the treatment of suspected patients with mild to moderate symptoms of COVID-19. This triple-blind randomized controlled trial recruited patients with evidence of COVID-19 on chest computed tomography without an indication of hospital admission from March 2020 until April 2020. Participants were assessed by a physician and completed a pre-specified form to assess the duration and severity of symptoms. Patients were randomized to receive Zufa syrup (a combination of herbal medicines: Nepetabracteata, Ziziphus jujube, Glycyrrhizaglabra, Ficuscarica, Cordia myxa, Papaver somniferum, Fennel, Adiantumcapillusveneris, Viola, Viper‘s-buglosses, Lavender, Iris, and sugar) or identical-looking placebo syrup at a dose of 7.5 mL (one tablespoon) every 4 hours for 10 days. After applying the eligibility criteria, 116 patients (49.1% male) were randomized to trial arms with a mean age of 44.3. During the follow-up, Cough, dyspnea, headache, myalgia, anorexia, anxiety, and insomnia improved gradually in both groups, and showed no difference between Zufa syrup and placebo. Oxygen saturation and pulse rate had stable trends throughout the follow-up and were similar between study arms. No patient required hospital admission or supplemental oxygen therapy during the study period. To conclude, in patients with mild to moderate symptoms of COVID-19, Zufa syrup did not show any difference in symptomatology over a 10 days’ period when compared with placebo. Due to potential effects of medicinal plants in the treatment of respiratory infections, further studies are warranted to clarify their role in COVID-19. The study was approved by the Ethics Committee of the Qom University of Medical Science (Ethics committee reference number IR.MUQ.REC.1398.165) on March 10, 2020 and was registered in Iranian Clinical Trial Center (approval ID: IRCT20200404046934N1) on April 13, 2020.

In Vitro Metabolism of Six C-Glycosidic Flavonoids from Passiflora incarnata L

Several medical plants, such as Passiflora incarnata L., contain C-glycosylated flavonoids, which may contribute to their efficacy. Information regarding the bioavailability and metabolism of these compounds is essential, but not sufficiently available. Therefore, the metabolism of the C-glycosylated flavones orientin, isoorientin, schaftoside, isoschaftoside, vitexin, and isovitexin was investigated using the Caco-2 cell line as an in vitro intestinal and epithelial metabolism model. Isovitexin, orientin, and isoorientin showed broad ranges of phase I and II metabolites containing hydroxylated, methoxylated, and sulfated compounds, whereas schaftoside, isoschaftoside, and vitexin underwent poor metabolism. All metabolites were identified via UHPLC-MS or UHPLC-MS/MS using compound libraries containing all conceivable metabolites. Some structures were confirmed via UHPLC-MS experiments with reference compounds after a cleavage reaction using glucuronidase and sulfatase. Of particular interest is the observed cleavage of the C–C bonds between sugar and aglycone residues in isovitexin, orientin, and isoorientin, resulting in unexpected glucuronidated or sulfated luteolin and apigenin derivatives. These findings indicate that C-glycosidic flavones can be highly metabolized in the intestine. In particular, flavonoids with ortho-dihydroxy groups showed sulfated metabolites. The identified glucuronidated or sulfated aglycones demonstrate that enzymes expressed by Caco-2 cells are able to potentially cleave C–C bonds in vitro.

Shenling Baizhu Powder Inhibits RV-SA11-Induced Inflammation and Rotavirus Enteritis via TLR4/MyD88/NF-κB Signaling Pathway

Rotavirus enteritis (RVE) is a common acute intestinal infectious disease caused by rotavirus infection. It is an important cause of death in children younger than 5 years worldwide. Shenling baizhu powder (SBP), a classic traditional Chinese formulation, is one of the most popularly prescribed medicines for digestive diseases. Clinical studies have revealed the protective effects of SBP on RVE. However, the potential mechanism is still unclear. In this study, we aimed to evaluate the anti-rotavirus effect of SBP and its mechanism, focusing on the TLR4/MyD88/NF-κB signaling pathway. Our results demonstrated that, based on the inhibition of the virus-induced cytopathic effect in Caco-2 cells, the concentration for 50% of maximal effect (EC₅₀) and selectivity index (SI) of SBP for RV-SA11 in the serum were 5.911% and 11.63, respectively. A total of 219 active compounds with oral bioavailability ≥30% and drug-likeness ≥ 0.18 were selected from the 10 ingredients present in the formulation of SBP, which acted on 471 potential targets. A total of 226 target genes of RVE were obtained from the GeneCards database. The protein-protein interaction (PPI) network showed that there was a close interaction between 44 common targets of SBP and RVE. The results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that SBP acted on RVE through various inflammatory pathways and the intestinal immune network. Subsequently, we investigated the effect of SBP on TLR4/MyD88/NF-κB signaling pathway in vitro. After infection with RV- SA11, the expression of TLR4, MyD88, and NF-κB mRNA and protein increased significantly, which could be abolished by SBP treatment. In addition, the IL-1β, TNF-α, IL-6, and IFN-β levels increased markedly in Caco-2 cells infected with RV-SV11. Treatment with SBP partly reversed the changes of IL-1β, TNF-α, and IL-6, while further increased the level of IFN-β. In conclusion, our study revealed that SBP can significantly inhibit rotavirus replication and proliferation in vitro. The antiviral effect may be related to the regulation of the TLR4/MyD88/NF-κB signaling pathway, followed by the down regulation of inflammatory cytokines and up regulation of IFN-β induced by rotavirus.

Medicinal Plants, Phytochemicals, and Herbs to Combat Viral Pathogens Including SARS-CoV-2

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome corona virus-2 (SARS-CoV-2), is the most important health issue, internationally. With no specific and effective antiviral therapy for COVID-19, new or repurposed antiviral are urgently needed. Phytochemicals pose a ray of hope for human health during this pandemic, and a great deal of research is concentrated on it. Phytochemicals have been used as antiviral agents against several viruses since they could inhibit several viruses via different mechanisms of direct inhibition either at the viral entry point or the replication stages and via immunomodulation potentials. Recent evidence also suggests that some plants and its components have shown promising antiviral properties against SARS-CoV-2. This review summarizes certain phytochemical agents along with their mode of actions and potential antiviral activities against important viral pathogens. A special focus has been given on medicinal plants and their extracts as well as herbs which have shown promising results to combat SARS-CoV-2 infection and can be useful in treating patients with COVID-19 as alternatives for treatment under phytotherapy approaches during this devastating pandemic situation.

Structure-based virtual screening, molecular dynamics and binding affinity calculations of some potential phytocompounds against SARS-CoV-2

COVID-19 caused by a positive-sense single stranded RNA virus named as severe acute respiratory syndrome-Coronavirus-2 (SARS-CoV-2) triggered the global pandemic. This virus has infected about 10.37 Crores and taken lives of 2.24 Crores people of 213 countries to date. To cope-up this emergency clinical trials are undergoing with some existing drugs like remdesivir, flavipiravir, lopinavir-ritonavir, nafamostat, doxycycline, hydroxy-chloroquine, dexamethasone, etc., despite their severe toxicity and health hazards among diabetics, hypertensive, cardiac patients or normal individuals. The lack of safe and approved treatment for COVID-19 has forced the scientific community to find novel and safe compounds with potential efficacy. This study evaluates a few selective herbal compounds like glucoraphanin, vitexin, niazinin, etc., as a potential inhibitor of the spike protein and 3-chymotrypsin-like protease (3CLpro) or main protease (Mpro) of SARS-COV-2 through in-silico virtual studies such as molecular docking, target analysis, toxicity prediction and ADME prediction and supported by a Molecular-Dynamic simulation. Selective phytocompounds were docked successfully in the binding site of spike glycoprotein and 3CLpro (Mpro) of SARS-CoV-2. In-silico approaches also predict this molecule to have good solubility, pharmacodynamic property and target accuracy through MD simulation and ADME studies. These hit molecules niazinin, vitexin, glucoraphanin also obey Lipinski's rule along with their stable binding towards target protein of the virus, which makes them suitable for further biochemical and cell-based assays followed by clinical investigations to highlight their potential use in COVID-19 treatment.Communicated by Ramaswamy H. Sarma.

Medicinal plants: Treasure for antiviral drug discovery

The pandemic of viral diseases like novel coronavirus (2019-nCoV) prompted the scientific world to examine antiviral bioactive compounds rather than nucleic acid analogous, protease inhibitors, or other toxic synthetic molecules. The emerging viral infections significantly associated with 2019-nCoV have challenged humanity's survival. Further, there is a constant emergence of new resistant viral strains that demand novel antiviral agents with fewer side effects and cell toxicity. Despite significant progress made in immunization and regenerative medicine, numerous viruses still lack prophylactic vaccines and specific antiviral treatments that are so often influenced by the generation of viral escape mutants. Of importance, medicinal herbs offer a wide variety of therapeutic antiviral chemotypes that can inhibit viral replication by preventing viral adsorption, adhering to cell receptors, inhibiting virus penetration in the host cell, and competing for pathways of activation of intracellular signals. The present review will comprehensively summarize the promising antiviral activities of medicinal plants and their bioactive molecules. Furthermore, it will elucidate their mechanism of action and possible implications in the treatment/prevention of viral diseases even when their mechanism of action is not fully understood, which could serve as the base for the future development of novel or complementary antiviral treatments.

Metabolomics Analyses of Cotyledon and Plumule Showing the Potential Domestic Selection in Lotus Breeding

Lotus (Nelumbo nucifera) seeds are widely consumed as functional food or herbal medicine, of which cotyledon (CL) is the main edible part, and lotus plumule (LP) is commonly utilized in traditional Chinese medicine. However, few studies have been conducted to investigate the chemical components of CL and LP in dry lotus seeds, not to mention the comparison between wild and domesticated varieties. In this study, a widely targeted metabolomics approach based on Ultra Performance Liquid Chromatography-electrospray ionization-Tandem mass spectrometry (UPLC-ESI-MS/MS) was utilized to analyze the metabolites in CL and LP of China Antique (“CA”, a wild variety) and Jianxuan-17 (“JX”, a popular cultivar). A total of 402 metabolites were identified, which included flavonoids (23.08% to 27.84%), amino acids and derivatives (14.18–16.57%), phenolic acids (11.49–12.63%), and lipids (9.14–10.95%). These metabolites were classified into ten clusters based on their organ or cultivar-specific characters. Most of these metabolites were more abundant in LP than in CL for both varieties, except for metabolites belonging to organic acids and lipids. The analysis of differentially accumulated metabolites (DAMs) demonstrated that more than 25% of metabolites detected in our study were DAMs in CL and LP comparing “JX” with “CA”, most of which were less abundant in “JX”, including 35 flavonoids in LP, 23 amino acids and derivatives in CL, 7 alkaloids in CL, and 10 nucleotides and derivatives in LP, whereas all of 11 differentially accumulated lipids in LP were more abundant in “JX”. Together with the fact that the seed yield of “JX” is much higher than that of “CA”, these results indicated that abundant metabolites, especially the functional secondary metabolites (mainly flavonoids and alkaloids), were lost during the process of breeding selection.

Anti-Inflammatory Effects of Fermented Lotus Root and Linoleic Acid in Lipopolysaccharide-Induced RAW 264.7 Cells

Inflammation is a protective response of the innate immune system. However, aberrant inflammatory responses lead to various diseases. Lotus root, the edible rhizome of Nelumbo nucifera, is a popular traditional herbal medicine in East Asia. In a previous study, we reported that fermented lotus root (FLR) alleviated ethanol/HCl-induced gastric ulcers in rats by modulating inflammation-related genes. However, the mechanisms underlying the anti-inflammatory effects of FLR and its major constituent, linoleic acid (LA), are still largely unknown. In this study, we investigated the anti-inflammatory effects of FLR and LA on lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 murine macrophages. We found that FLR inhibited LPS-induced expression of inflammatory mediators through down-regulation of NF-κB activity. Similarly, LA also attenuated LPS-induced inflammatory responses and reduced LPS-induced phosphorylation of proteins associated with NF-κB signaling, such as ERK, JNK, and p38. Overall, our results suggested that FLR and LA may effectively ameliorate inflammatory diseases.

Antiviral Properties of Flavonoids and Delivery Strategies

This review summarizes the latest advancements in phytochemicals as functional antiviral agents. We focused on flavonoids, like apigenin, vitexin, quercetin, rutin and naringenin, which have shown a wide range of biological effects including antiviral activities. The molecular mechanisms of their antiviral effects mainly consist in the inhibition of viral neuraminidase, proteases and DNA/RNA polymerases, as well as in the modification of various viral proteins. Mixtures of different flavonoids or combination of flavonoids with antiviral synthetic drugs provide an enhancement of their antiviral effects. Recent strategies in drug delivery significantly contribute to overcoming the low bioavailability of flavonoids. Frequent viral infections worldwide have led to the need for new effective antiviral agents, which can be identified among the various phytochemicals. In this light, screening the antiviral activities of a cocktail of flavonoids would be advantageous in order to prevent viral infections and improve current antiviral therapies.

Plants Metabolites: Possibility of Natural Therapeutics Against the COVID-19 Pandemic

COVID-19, a disease induced by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2), has been the cause of a worldwide pandemic. Though extensive research works have been reported in recent days on the development of effective therapeutics against this global health crisis, there is still no approved therapy against SARS-CoV-2. In the present study, plant-synthesized secondary metabolites (PSMs) have been prioritized to make a review focusing on the efficacy of plant-originated therapeutics for the treatment of COVID-19. Plant metabolites are a source of countless medicinal compounds, while the diversity of multidimensional chemical structures has made them superior to treat serious diseases. Some have already been reported as promising alternative medicines and lead compounds for drug repurposing and discovery. The versatility of secondary metabolites may provide novel antibiotics to tackle MDR (Multi-Drug Resistant) microbes too. This review attempted to find out plant metabolites that have the therapeutic potential to treat a wide range of viral pathogens. The study includes the search of remedies belonging to plant families, susceptible viral candidates, antiviral assays, and the mode of therapeutic action; this attempt resulted in the collection of an enormous number of natural therapeutics that might be suggested for the treatment of COVID-19. About 219 plants from 83 families were found to have antiviral activity. Among them, 149 plants from 71 families were screened for the identification of the major plant secondary metabolites (PSMs) that might be effective for this pandemic. Our investigation revealed that the proposed plant metabolites can serve as potential anti- SARS-CoV-2 lead molecules for further optimization and drug development processes to combat COVID-19 and future pandemics caused by viruses. This review will stimulate further analysis by the scientific community and boost antiviral plant-based research followed by novel drug designing.

Potential Role of Plant Extracts and Phytochemicals Against Foodborne Pathogens

Foodborne diseases are one of the major causes of morbidity and mortality, especially in low-income countries with poor sanitation and inadequate healthcare facilities. The foremost bacterial pathogens responsible for global outbreaks include Salmonella species, Campylobacter jejuni, Escherichia coli, Shigella sp., Vibrio, Listeria monocytogenes and Clostridium botulinum. Among the viral and parasitic pathogens, norovirus, hepatitis A virus, Giardia lamblia, Trichinella spiralis, Toxoplasma and Entamoeba histolytica are commonly associated with foodborne diseases. The toxins produced by Staphylococcus aureus, Bacillus cereus and Clostridium perfringens also cause these infections. The currently available therapies for these infections are associated with various limited efficacy, high cost and side-effects. There is an urgent need for effective alternative therapies for the prevention and treatment of foodborne diseases. Several plant extracts and phytochemicals were found to be highly effective to control the growth of these pathogens causing foodborne infections in in vitro systems. The present review attempts to provide comprehensive scientific information on major foodborne pathogens and the potential role of phytochemicals in the prevention and treatment of these infections. Further detailed studies are necessary to evaluate the activities of these extracts and phytochemicals along with their mechanism of action using in vivo models.

Ethnomedicines of Indian origin for combating COVID-19 infection by hampering the viral replication: using structure-based drug discovery approach

In the present study, we have explored the interaction of the active components from 10 different medicinal plants of Indian origin that are commonly used for treating cold and respiratory-related disorders, through molecular docking analysis. In the current scenario, COVID-19 patients experience severe respiratory syndromes, hence it is envisaged from our study that these traditional medicines are very likely to provide a favourable effect on COVID-19 infections. The active ingredients identified from these natural products are previously reported for antiviral activities against large group of viruses. Totally 47 bioactives identified from the medicinal plants were investigated against the structural targets of SARS-CoV-2 (Mpro and spike protein) and human ACE2 receptor. The top leads were identified based on interaction energies, number of hydrogen bond and other parameters that explain their potency to inhibit SARS-CoV-2. The bioactive ligands such as Cucurbitacin E, Orientin, Bis-andrographolide, Cucurbitacin B, Isocucurbitacin B, Vitexin, Berberine, Bryonolic acid, Piperine and Magnoflorine targeted the hotspot residues of SARS-CoV-2 main protease. In fact, this protease enzyme has an essential role in mediating the viral replication and therefore compounds targeting this key enzyme are expected to block the viral replication and transcription. The top scoring conformations identified through docking analysis were further demonstrated with molecular dynamics simulation. Besides, the stability of the conformation was studied in detail by investigating the binding free energy using MM-PBSA method. Overall, the study emphasized that the proposed hit Cucurbitacin E and orientin could serve as a promising scaffold for developing anti-COVID-19 drug.

Communicated by Ramaswamy H. Sarma

Glycyrrhiza glabra L. (Fabaceae/Leguminosae)

Liquorice is a perennial, temperate-zone herb or subshrub, native of India, Pakistan and southern Europe; also cultivated in England, Belgium, France, Germany, Spain, Italy, Greece, Turkey, Russia, South Africa, Egypt, Syria and Iraq. It has also been grown experimentally in the United States. Ancient historical manuscripts from China, India and Greece mention its use for symptoms of viral respiratory tract infections and hepatitis. The plant has also been described by Theophrastus. Licorice from Egypt has been described to be the best, followed by from Iraq and Syria; the root should be decorticated before use. It concocts viscid humours in diseases of liver, bladder and lungs, and expectorates them. It has been used in Iranian herbal medicine for skin eruptions, including dermatitis, eczema, pruritus and cysts, and for treatment of stomach disorders including peptic ulcers. The herb extract inhibits gastric motility in vivo, which is regarded to be an important aspect for its antiulcer activity. Licorice possesses both anti-inflammatory and antiulcer activities; whereas most anti-inflammatory agents are ulcerogenic. Former German Commission E believed it to be effective in the treatment of atopic dermatitis. Licorice root has been used for years to regulate gastrointestinal function in TCM, has been used for generations as an antidote, demulcent, and elixir in folk medicine of China, and is the most commonly used crude drug in Kampo Medicines, the Japanese form of modified TCM, for the treatment of peptic ulcer. Roots contain glycyrrhizin, the main water-soluble constituent that is 50× sweeter than sugar, 2-β-glucuronosyl glucuronic acid, and isoliquiritigenin-4-glucoside. Glycyrrhizin is a nonhemolytic saponin with foaming property, and one of the most potent hydroxyl radical scavengers. No significant effect of deglycyrrhizinised liquorice was observed on gastric ulcer in an RCT of British patients. Treatment of healthy men with licorice for one-week decreased salivary testosterone values by 26% but no significant decrease in free testosterone, and nine healthy women treated with licorice daily for two cycles, had their mean total serum testosterone decreased by 37% at the end of 2nd month. This property could be useful as an adjunct therapy of hirsutism and PCOS.

Antiviral activity of seselin from Aegle marmelos against nuclear polyhedrosis virus infection in the larvae of silkworm, Bombyx mori

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Indian medicine has utilized Aeglemarmelos (L.) Corr. commonly called as bael in several indigenous systems against various diseases. Bioactive components isolated from various plant parts of A. marmelos were used in ethno-medicine. More precisely they are known for its antiviral property against various human and animal viruses.

AIM OF THE STUDY

The study was conducted to investigate the antiviral activity of A.marmelos against Bombyx mori nucleopolyhedrovirus (BmNPV).

MATERIALS AND METHODS

Among the various crude extracts tested, hexane extracts of leaves of A. marmelos with promising anti-BmNPV activity was subjected to bioactivity guided fractionation based on column chromatography. Out of 40 fractions obtained from the fractionation, fractions showing similar TLC profiles were pooled into 14 fractions. A fraction with potential activity was used to purify a molecule with anti-BmNPV activity. This molecule was characterized through structural and functional analyses.

RESULTS

The functionally and structurally characterized molecule in the fraction with prospective anti-BmNPV activity revealed a single crystal compound 'seselin' (8, 8-dimethyl pyrido oxazine-2-one).

CONCLUSION

It is therefore understood that this seselin compound could be used as a natural medicine for the management of NPV infection in the silkworm larvae under commercial conditions after suitable field evaluations.

A Mouse Model of Trichophyton Inflammation Based on Trichophytin-induced Contact Hypersensitivity

The prevalence of Trichophyton-induced superficial skin mycosis is very high among human patients. Dermatophytes generally infect the epidermis, especially the stratum corneum, forming scales, hyperkeratosis, and vesicles. The important roles played by the immune system in Trichophyton infection are detection of fungal invasion and elimination of fungi.These immune mechanisms are presumed to involve not only innate immunity but also acquired immunity. Therefore, there is a substantial need for studies on treatment methods based on new basic knowledge, and the elucidation of immunological mechanisms of Trichophyton-induced inflammatory reactions is especially important.However, since Trichophyton cannot colonize on the mouse skin, we tried to develop a model for Trichophyton inflammation induced by trichophytin extracted from Trichophyton mentagrophytes using a method based on contact hypersensitivity.Trichophytin is a crude extract that mainly contains fungal cell wall constituents including β-glucan and zymosan. In this model, TLR2, TLR4, and dectin-1 were highly expressed, and production of IL-17A and IL23 was observed. This indicates that we succeeded in inducing fungal-specific inflammation in the mice.In this review, we introduce a mouse Trichophyton inflammation model developed to investigate the immunological mechanisms of Trichophyton-induced inflammatory reactions. In addition, we report results of evaluation of anti-inflammatory and anti-itching effects of anti-fungal agents using the inflammation model.

Quinoa Secondary Metabolites and Their Biological Activities or Functions

Quinoa (Chenopodium quinoa Willd.) was known as the "golden grain" by the native Andean people in South America, and has been a source of valuable food over thousands of years. It can produce a variety of secondary metabolites with broad spectra of bioactivities. At least 193 secondary metabolites from quinoa have been identified in the past 40 years. They mainly include phenolic acids, flavonoids, terpenoids, steroids, and nitrogen-containing compounds. These metabolites exhibit many physiological functions, such as insecticidal, molluscicidal and antimicrobial activities, as well as various kinds of biological activities such as antioxidant, cytotoxic, anti-diabetic and anti-inflammatory properties. This review focuses on our knowledge of the structures, biological activities and functions of quinoa secondary metabolites. Biosynthesis, development and utilization of the secondary metabolites especially from quinoa bran were prospected.

Suppression of pyrimidine biosynthesis by targeting DHODH enzyme robustly inhibits rotavirus replication

Rotavirus infection remains a great health burden worldwide especially in some developing countries. It causes severe dehydrating diarrhea in infants, young children, as well as immunocompromised and organ transplanted patients. Viral replication heavily relies on the host to supply nucleosides. Thus, host enzymes involved in nucleotide biosynthesis represent potential targets for antiviral development. Dihydroorotate dehydrogenase (DHODH) is the rate-limiting enzyme in the de novo biosynthesis pathway of pyrimidines. In this study, we demonstrated that two specific DHODH enzyme inhibitors, brequinar (BQR) and leflunomide (LFM) robustly inhibited rotavirus replication in conventional human intestinal Caco2 cell line as well as in human primary intestinal organoids. The antiviral effect is conserved in both laboratory strain SA11 and rotavirus strain 2011K isolated from clinical sample. Mechanistic study indicated that BQR and LFM exerted their anti-rotavirus effect through targeting DHODH to deplete pyrimidine nucleotide pool. Therefore, targeting pyrimidine biosynthesis represents a potential approach for developing antiviral strategies against rotavirus.

Structural Basis of Nanobodies Targeting the Prototype Norovirus

The discovery of vulnerable regions on norovirus particles is instrumental in the development of effective inhibitors, particularly for GI noroviruses that are genetically diverse. Analysis of these GI.1-specific Nanobodies has shown that similar to GII norovirus particles, the GI particles have vulnerable regions. The only known cofactor region, the HBGA binding pocket, represents the main target for inhibition. With a combination treatment, i.e., the addition of Nano-7 or Nano-94 with 2′FL, the effect of inhibition was increased. Therefore, combination drug treatments might offer a better approach to combat norovirus infections, especially since the GI genotypes are highly diverse and are continually changing the capsid landscape, and few conserved epitopes have so far been identified.

Human norovirus infections are a major disease burden. In this study, we analyzed three new norovirus-specific Nanobodies that interacted with the prototype human norovirus (i.e., genogroup I genotype 1 [GI.1]). We showed that the Nanobodies bound on the side (Nano-7 and Nano-62) and top (Nano-94) of the capsid-protruding (P) domain using X-ray crystallography. Nano-7 and Nano-62 bound at a similar region on the P domain, but the orientations of these two Nanobodies clashed with the shell (S) domain and neighboring P domains on intact particles. This finding suggested that the P domains on the particles should shift in order for Nano-7 and Nano-62 to bind to intact particles. Interestingly, both Nano-7 and Nano-94 were capable of blocking norovirus virus-like particles (VLPs) from binding to histo-blood group antigens (HBGAs), which are important cofactors for norovirus infection. Previously, we showed that the GI.1 HBGA pocket could be blocked with the soluble human milk oligosaccharide 2-fucosyllactose (2′FL). In the current study, we showed that a combined treatment of Nano-7 or Nano-94 with 2′FL enhanced the blocking potential with an additive (Nano-7) or synergistic (Nano-94) effect. We also found that GII Nanobodies with 2′FL also enhanced inhibition. The Nanobody inhibition likely occurred by different mechanisms, including particle aggregation or particle disassembly, whereas 2′FL blocked the HBGA binding site. Overall, these new data showed that the positive effect of the addition of 2′FL was not limited to a single mode of action of Nanobodies or to a single norovirus genogroup.

IMPORTANCE The discovery of vulnerable regions on norovirus particles is instrumental in the development of effective inhibitors, particularly for GI noroviruses that are genetically diverse. Analysis of these GI.1-specific Nanobodies has shown that similar to GII norovirus particles, the GI particles have vulnerable regions. The only known cofactor region, the HBGA binding pocket, represents the main target for inhibition. With a combination treatment, i.e., the addition of Nano-7 or Nano-94 with 2′FL, the effect of inhibition was increased. Therefore, combination drug treatments might offer a better approach to combat norovirus infections, especially since the GI genotypes are highly diverse and are continually changing the capsid landscape, and few conserved epitopes have so far been identified.

Therapeutics and Immunoprophylaxis Against Noroviruses and Rotaviruses: The Past, Present, and Future

Background:

Noroviruses and rotaviruses are important viral etiologies of severe gastroenteritis. Noroviruses are the primary cause of nonbacterial diarrheal outbreaks in humans, whilst rotaviruses are a major cause of childhood diarrhea. Although both enteric pathogens substantially impact human health and economies, there are no approved drugs against noroviruses and rotaviruses so far. On the other hand, whilst the currently licensed rotavirus vaccines have been successfully implemented in over 100 countries, the most advanced norovirus vaccine has recently completed phase-I and II trials.

Methods:

We performed a structured search of bibliographic databases for peer-reviewed research litera-ture on advances in the fields of norovirus and rotavirus therapeutics and immunoprophylaxis.

Results:

Technological advances coupled with a proper understanding of viral morphology and replication over the past decade has facilitated pioneering research on therapeutics and immunoprophylaxis against noroviruses and rotaviruses, with promising outcomes in human clinical trials of some of the drugs and vaccines. This review focuses on the various developments in the fields of norovirus and rotavirus thera-peutics and immunoprophylaxis, such as potential antiviral drug molecules, passive immunotherapies (oral human immunoglobulins, egg yolk and bovine colostral antibodies, llama-derived nanobodies, and anti-bodies expressed in probiotics, plants, rice grains and insect larvae), immune system modulators, probiot-ics, phytochemicals and other biological substances such as bovine milk proteins, therapeutic nanoparti-cles, hydrogels and viscogens, conventional viral vaccines (live and inactivated whole virus vaccines), and genetically engineered viral vaccines (reassortant viral particles, virus-like particles (VLPs) and other sub-unit recombinant vaccines including multi-valent viral vaccines, edible plant vaccines, and encapsulated viral particles).

Conclusions:

This review provides important insights into the various approaches to therapeutics and im-munoprophylaxis against noroviruses and rotaviruses..

Spirodela polyrhiza and its Chemical Constituent Vitexin Exert Anti-Allergic Effect via ORAI1 Channel Inhibition

Intracellular calcium signaling cascades are integral to early and late allergic responses involving mast cell degranulation and type 2 helper T cell activation, respectively. Both the responses are accompanied by the movement of calcium through the calcium release-activated calcium (CRAC) channel, encoded by the ORAI1 gene. Spirodela polyrhiza (L.) Schleid (SP) has anti-inflammatory and anti-allergic effects, but its effect on calcium signaling has not been reported. This study investigated whether a 30% ethanolic SP extract (SP_EtOH) and its constituents can reduce CRAC currents ([Formula: see text]), and thus inhibit mast cell degranulation and T cell activation. In Jurkat T lymphocytes, we found that 3[Formula: see text]mg/mL SP_EtOH inhibited the [Formula: see text] by [Formula: see text]%, whereas one of its constituents vitexin (100[Formula: see text][Formula: see text]M) inhibited the [Formula: see text] by [Formula: see text]%. Furthermore, in the RBL-2H3 mast cell, the [Formula: see text] was inhibited by 3[Formula: see text]mg/mL SP_EtOH ([Formula: see text]%) and 100[Formula: see text][Formula: see text]M vitexin ([Formula: see text]%). Investigation of human primary T cell proliferation induced by co-stimulation with antibodies to cluster of differentiation 3 and 28, and of RBL-2H3 mast cell degranulation following IgE-antigen complex stimulation revealed that 100[Formula: see text][Formula: see text]M vitexin inhibited both T-cell proliferation (by [Formula: see text]%) and mast cell degranulation (by [Formula: see text]%). These effects were concentration-dependent, and no cytotoxicity was observed. Our findings suggest that vitexin is a promising candidate compound for the development of therapeutic agents to prevent and treat allergic diseases.

TNF-α exerts potent anti-rotavirus effects via the activation of classical NF-κB pathway

Active virus-host interactions determine the outcome of pathogen invasions. It has been shown that in isolated dendritic cells (DCs), rotavirus can induce the expression of tumor necrosis factor α (TNF-α), a vital cytokine mediating host immune responses. However, the role of TNF-α in rotavirus infection is unknown. In this study, we demonstrated that TNF-α has potent anti-rotavirus effects, independent of type I interferon production. Blocking of TNF-α by infliximab, a clinically available TNFα antibody, totally abrogated this effect. Mechanistic studies revealed that the anti-rotavirus effect of TNF-α was achieved by NFκB-regulated genes via the activation of classical nuclear factor κB (NF-κB) signaling. Our study reveals the pivotal role and the mechanism-of-actions of TNF-α in the host defense against rotavirus. Thus, this knowledge may contribute to the better understanding of the complexity of rotavirus-host interactions.

Basal interferon signaling and therapeutic use of interferons in controlling rotavirus infection in human intestinal cells and organoids

Rotavirus (RV) primarily infects enterocytes and results in severe diarrhea, particularly in children. It is known that the host immune responses determine the outcome of viral infections. Following infections, interferons (IFNs) are produced as the first and the main anti-viral cytokines to combat the virus. Here we showed that RV predominantly induced type III IFNs (IFN-λ1), and to a less extent, type I IFNs (IFN-α and IFN-β) in human intestinal cells. However, it did not produce detectable IFN proteins and thus, was not sufficient to inhibit RV replication. In contrast, we revealed the essential roles of the basal IFN signaling in limiting RV replication by silencing STAT1, STAT2 and IRF9 genes. In addition, exogenous IFN treatment demonstrated that RV replication was able to be inhibited by all types of IFNs, both in human intestinal Caco2 cell line and in primary intestinal organoids. In these models, IFNs significantly upregulated a panel of well-known anti-viral IFN-stimulated genes (ISGs). Importantly, inhibition of the JAK-STAT cascade abrogated ISG induction and the anti-RV effects of IFNs. Thus, our study shall contribute to better understanding of the complex RV-host interactions and provide rationale for therapeutic development of IFN-based treatment against RV infection.

Luteolin Ameliorates Experimental Chronic Pancreatitis Induced by Trinitrobenzenesulfonic Acid in Rats

OBJECTIVES

The purpose of this study is to assess the effect and possible mechanism of luteolin on chronic pancreatitis (CP).

METHODS

Trinitrobenzenesulfonic acid-induced CP was used as CP models in vivo. After the intervention of luteolin for 28 days, chronic pancreatic injury was assessed by serum hydroxyproline and pancreatic histology. α-Smooth muscle actin (α-SMA) expression was performed to detect the activation of pancreatic stellate cells (PSCs). Pancreatic stellate cells were also isolated and cultured in vitro, and the effect of luteolin on PSCs was evaluated. Transforming growth factor β (TGF-β1) signaling and its regulated mRNA expression was tested by Western blot and quantitative real-time polymerase chain reaction, respectively.

RESULTS

The protective role of luteolin on CP was confirmed by increased pancreas/body weight ratio, decreased pancreas hydroxyproline level, and reduced fibrosis. α-SMA expressions in PSCs were significantly decreased both in vitro and in vivo after the management of luteolin. Pancreas TGF-β1 expression was significantly decreased by luteolin. Luteolin inhibited the proliferation and activation of PSCs in a dose-dependent manner.

CONCLUSIONS

Luteolin played a protective role in CP in many aspects, partly by regulating release of inflammatory cytokines through TGF-β1 signaling pathway.

The Effects of Lemon balm on Menstrual Bleeding and the Systemic Manifestation of Dysmenorrhea

We conducted a double-blind randomized placebo controlled trial to evaluate the impact of Lemon balm (Melissa officinalis L.) on the bleeding and systemic manifestations of menstruation. A total of 90 students were randomly assigned to treatment or placebo group. Bleeding and systemic manifestations were evaluated with a menstrual pictogram and multidimensional verbal scale before and during 2 consecutive menstrual cycles, respectively. Statistical tests indicated that in both groups, the severity of the systemic symptoms associated with dysmenorrhea significantly decreased (P = 0.001). Among the systemic symptoms, the mean severity of fatigue, the lethargy, and nervous changes in the two groups decreased after the treatment, which was statistically significant. There was no significant difference between the two groups regarding fatigue in the three cycles, but there was a significant difference between the two groups regarding lethargy in the first cycle (P = 0.05) and the second cycle (P = 0.001) after the treatment. The present study demonstrated that Melissa officinalis decreases the severity of the systemic signs associated with menstruation. It showed that the herb does not increase the severity of bleeding and the duration of menstruation. However, it reduces the mean total score of the severity of all the systemic symptoms associated with dysmenorrhea.

Quantifying rotavirus kinetics in the REH tumor cell line using in vitro data

Globally, rotavirus is the most common cause of diarrhea in children younger than 5 years of age, however, a quantitative understanding of the infection dynamics is still lacking. In this paper, we present the first study to extract viral kinetic parameters for in vitro rotavirus infections in the REH cell tumor line. We use a mathematical model of viral kinetics to extract parameter values by fitting the model to data from rotavirus infection of REH cells. While accurate results for some of the parameters of the mathematical model were not achievable due to its global non-identifiability, we are able to quantify approximately the time course of the infection for the first time. We also find that the basic reproductive number of rotavirus, which gives the number of secondary infections from a single infected cell, is much greater than one. Quantifying the kinetics of rotavirus leads not only to a better understanding of the infection process, but also provides a method for quantitative comparison of kinetics of different strains or for quantifying the effectiveness of antiviral treatment.

Flavonoids: promising natural compounds against viral infections

Flavonoids are widely distributed as secondary metabolites produced by plants and play important roles in plant physiology, having a variety of potential biological benefits such as antioxidant, anti-inflammatory, anticancer, antibacterial, antifungal and antiviral activity. Different flavonoids have been investigated for their potential antiviral activities and several of them exhibited significant antiviral properties in in vitro and even in vivo studies. This review summarizes the evidence for antiviral activity of different flavonoids, highlighting, where investigated, the cellular and molecular mechanisms of action on viruses. We also present future perspectives on therapeutic applications of flavonoids against viral infections.

Antiviral Activity of Aspalathus linearis against Human Influenza Virus

Influenza A viruses are responsible for annual epidemics and occasional pandemics, which cause significant morbidity and mortality. The limited protection offered by influenza vaccination, and the emergence of drug-resistant influenza strains, highlight the urgent need for the development of novel anti-influenza drugs. However, the search for antiviral substances from the library of low molecular weight chemical compounds is limited. Thus, because of their natural diversity and accessibility, plants or plant-derived materials are rapidly becoming valuable sources for the discovery and development of new antiviral drugs. In this study, crude extracts of Aspalathus linearis, a plant reported to have anti-HIV activity, were evaluated in vitro for their activity against the influenza A virus. Of the extracts tested, an alkaline extract of Aspalathus linearis demonstrated the strongest inhibition against influenza A virus and could also inhibit different types of influenza viruses, including Oseltamivir-resistant influenza viruses A and B. Our time course of addition studies indicated that the alkaline extract of Aspalathus linearis exerts its antiviral effect predominantly during the late stages of the influenza virus replication process.

In vitro screening for antiviral activity of Turkish plants revealing methanolic extract of Rindera lanata var. lanata active against human rotavirus

Background

Human rotavirus (HRoV) is the leading cause of severe gastroenteritis in infants and children under the age of five years. No specific antiviral drug is available for HRoV infections and the treatment of viral diarrhea is mainly based on rehydration and zinc treatment. In this study, we explored medicinal plants endemic to Turkey flora as a source of anti-HRoV compunds.

Methods

We performed an antiviral screening on Ballota macrodonta, Salvia cryptantha and Rindera lanata extracts by focus reduction assay. The extract with the highest selectivity index (SI) was selected; its antiviral activity was further confirmed against other HRoV strains and by virus yield reduction assay. The step of viral replicative cycle putatively inhibited was investigated by in vitro assays.

Results

The methanolic extract of R. lanata (Boraginaceae) showed the most favourable selectivity index. This extract exhibited a dose-dependent inhibitory activity against three different HRoV strains (EC₅₀ values ranging from 5.8 μg/ml to 25.5 μg/ml), but was inactive or barely active against other RNA viruses, namely human rhinovirus and respiratory syncytial virus. The R. lanata extract targets the early steps of HRoV infection, likely by hampering virus penetration into the cells.

Conclusion

These results make the R. lanata methanolic extract a promising starting material for a bioguided-fractionation aimed at identifying anti-HRoV compounds. Further work is required to isolate the active principle and assess its clinical potential.

Medicinal plants and natural molecules with in vitro and in vivo activity against rotavirus: A systematic review

BACKGROUND

Rotaviruses can cause life-threatening health disorders, such as severe dehydrating gastroenteritis and diarrhea in children. Vaccination is the main preventive strategy to reduce rotavirus diarrhea and the severity of episodes, but vaccines are not fully effective and new episodes may occur, even in vaccinated children. The WHO recommends oral rehydration therapy and zinc supplementation for rotavirus-induced diarrhea management. There is little preclinical evidence to support the use of phytotherapeutics in the management of rotaviral infections.

PURPOSE

We aim to review the use of medicinal plants and natural molecules in the management of rotavirus infections in experimental studies.

METHODS

Articles, published in the English language between 1991 and 2016, were retrieved from PubMed, Scopus and Web of Science using relevant keywords. The scientific literature mainly focusing on plant natural products with therapeutic efficacies against experimental models of rotavirus, were identified and tabulated. In addition, an assessment of the reliability of animal experiments was determined under ``Risk of Bias'' criteria.

CHAPTERS

After an initial search and a revision of the inclusion criteria, 41 reports satisfied the objectives of the study. 36 articles were found concerning the anti-rotaviral potential in rotavirus infected cell lines. Among the active secondary metabolites screened for rotavirus inhibition, the polyphenols of flavonoid structure had acquired the highest number of studies in our survey, compared to phenolic acids, stilbenoids, tannins, pectins, terpenoids and flavonoid glycosides. Also, many phytochemicals reduced the efficacy of viral capsid proteins foremost to their elimination and improved the tendency of host-cell inhibiting virus absorption or by prevention of viral replication. Furthermore, five in vivo studies reported that herbs, as well its components, reduced the duration and severity of diarrhea in mice and piglets. The anti-rotavirus efficacy were highlighted based on improvements in reduction on liquid stool, fecal virus shedding, small intestinal histology, levels of inflammation related cytokines and signaling receptors. However, the quality of the experiments in animal studies contained certain types of bias in terms of how they were conducted and reported.

CONCLUSION

We identified and summarized studies on medicinal plants and natural molecules having anti-rotavirus activity in order to further future developments of cures for rotavirus gastroenteritis.

In vitro Antiviral Activity of Rubia cordifolia Aerial Part Extract against Rotavirus

The root of Rubia cordifolia has been used traditionally as a hemostatic agent, while the aerial part of the plant consisting of leaf and stem is known to exhibit anti-diarrheal properties and has been widely used as a remedy in many parts of China. As rotavirus is one of the most commonly associated diarrhea-causing pathogen, this study aims to investigate the anti-rotaviral effect of R. cordifolia aerial part (RCAP). The cytotoxicity of RCAP toward MA-104 cells was evaluated using the WST-8 assay. Colloidal gold method and real time polymerase chain reaction (qPCR) assay were used to confirm the findings of the antiviral assay. Then, 4',6-diamidino-2-phenylindole (DAPI) staining method was subsequently used to investigate the mode of death among the cells. And the representative components of aqueous extract were isolated and identified. It was shown that both the viability of MA-104 cells and the viral load were reduced with increasing concentration of the extract. DAPI staining showed that virus-induced apoptosis was the cause of the low cell viability and viral load, an effect which was accelerated with incubation in the aqueous herbal extract. The major compounds postulated to exhibit this activity were isolated from the aqueous herbal extract and identified to be compounds Xanthopurpurin and Vanillic Acid. This study showed that RCAP extract effectively inhibited rotavirus multiplication by promoting virus-induced apoptosis in MA-104 cells.

Mycophenolic acid potently inhibits rotavirus infection with a high barrier to resistance development

Rotavirus infection has emerged as an important cause of complications in organ transplantation recipients. Immunosuppressants used to prevent alloreactivity can also interfere with virus infection, but the direct effects of the specific type of immunosuppressants on rotavirus infection are still unclear. Here we profiled the effects of different immunosuppressants on rotavirus using a 2D culture model of Caco2 human intestinal cell line and a 3D model of human primary intestinal organoids inoculated with laboratory and patient-derived rotavirus strains. We found that the responsiveness of rotavirus to Cyclosporine A treatment was moderate and strictly regulated in an opposite direction by its cellular targets cyclophilin A and B. Treatment with mycophenolic acid (MPA) resulted in a 99% inhibition of viral RNA production at the clinically relevant concentration (10 μg/ml) in Caco2 cells. This effect was further confirmed in organoids. Importantly, continuous treatment with MPA for 30 passages did not attenuate its antiviral potency, indicating a high barrier to drug resistance development. Mechanistically, the antiviral effects of MPA act via inhibiting the IMPDH enzyme and resulting in guanosine nucleotide depletion. Thus for transplantation patients at risk for rotavirus infection, the choice of MPA as an immunosuppressive agent appears rational.

Medicinal plants--prophylactic and therapeutic options for gastrointestinal and respiratory diseases in calves and piglets? A systematic review

BACKGROUND

Gastrointestinal and respiratory diseases in calves and piglets lead to significant economic losses in livestock husbandry. A high morbidity has been reported for diarrhea (calves ≤ 35%; piglets ≤ 50%) and for respiratory diseases (calves ≤ 80%; piglets ≤ 40%). Despite a highly diverse etiology and pathophysiology of these diseases, treatment with antimicrobials is often the first-line therapy. Multi-antimicrobial resistance in pathogens results in international accordance to strengthen the research in novel treatment options. Medicinal plants bear a potential as alternative or additional treatment. Based on the versatile effects of their plant specific multi-component-compositions, medicinal plants can potentially act as 'multi-target drugs'. Regarding the plurality of medicinal plants, the aim of this systematic review was to identify potential medicinal plant species for prevention and treatment of gastrointestinal and respiratory diseases and for modulation of the immune system and inflammation in calves and piglets.

RESULTS

Based on nine initial sources including standard textbooks and European ethnoveterinary studies, a total of 223 medicinal plant species related to the treatment of gastrointestinal and respiratory diseases was identified. A defined search strategy was established using the PRISMA statement to evaluate 30 medicinal plant species starting from 20'000 peer-reviewed articles published in the last 20 years (1994-2014). This strategy led to 418 references (257 in vitro, 84 in vivo and 77 clinical trials, thereof 48 clinical trials in veterinary medicine) to evaluate effects of medicinal plants and their efficacy in detail. The findings indicate that the most promising candidates for gastrointestinal diseases are Allium sativum L., Mentha x piperita L. and Salvia officinalis L.; for diseases of the respiratory tract Echinacea purpurea (L.) MOENCH, Thymus vulgaris L. and Althea officinalis L. were found most promising, and Echinacea purpurea (L.) MOENCH, Camellia sinensis (L.) KUNTZE, Glycyrrhiza glabra L. and Origanum vulgare L. were identified as best candidates for modulation of the immune system and inflammation.

CONCLUSIONS

Several medicinal plants bear a potential for novel treatment strategies for young livestock. There is a need for further research focused on gastrointestinal and respiratory diseases in calves and piglets, and the findings of this review provide a basis on plant selection for future studies.

Glycyrrhetinic acid inhibits contact hypersensitivity induced by trichophytin via dectin-1

Trichophyton infection is highly prevalent and tends to be recurrent. Therefore, it is important to develop new therapeutic agents. Previously, we established a mouse model of Trichophyton-induced contact hypersensitivity (CHS) and demonstrated that dectin-1 was involved in inflammation induced by trichophytin, the Trichophyton antigen. Here, we used that model to investigate glycyrrhetinic acid (GA) from plants of the genus Glycyrrhiza as a potential anti-inflammatory agent against superficial mycoses. GA suppressed swelling and the expression of inflammatory cytokines, including macrophage inflammatory protein (MIP)-2, interleukin (IL)-6, tumor necrosis factor (TNF)-α and interferon (IFN)-γ mRNA. Anti-MIP-2 antibody suppressed trichophytin-induced inflammation, and antidectin-1 antibody suppressed zymosan-induced MIP-2 production in keratinocyte cells. These results suggest that MIP-2 is produced by dectin-1 activation and is involved in inflammation associated with CHS to trichophytin. GA also suppressed zymosan-induced MIP-2 and interleukin (IL)-8, production in mouse and human macrophages and keratinocytes. Furthermore, GA suppressed the phosphorylation of spleen tyrosine kinase (Syk) and inhibitor of nuclear factor-kappa B (IκBα) and the degradation of IκBα in zymosan-simulated RAW264.7 cells. The results of this study suggest that GA suppresses inflammation induced by trichophytin, partly by the downregulation of Syk phosphorylation.

Application of alkyl polyglycoside surfactant in ultrasonic-assisted extraction followed by macroporous resin enrichment for the separation of vitexin-2″-O-rhamnoside and vitexin from Crataegus pinnatifida leaves

An alkyl polyglycoside (APG) surfactant was used in ultrasonic-assisted extraction to effectively extract vitexin-2″-O-rhamnoside (VOR) and vitexin (VIT) from Crataegus pinnatifida leaves. APG0810 was selected as the surfactant. The extraction process was optimized for ultrasonic power, the APG concentration, ultrasonic time, soaking time, and liquid-solid ratio. The proposed approach showed good recovery (99.80-102.50% for VOR and 98.83-103.19% for VIT) and reproducibility (relative standard deviation, n=5; 3.7% for VOR and 4.2% for VIT) for both components. The proposed sample preparation method is both simple and effective. The use of APG for extraction of key herbal ingredients shows great potential. Ten widely used commercial macroporous resins were evaluated in a screening study to identify a suitable resin for the separation and purification of VOR and VIT. After comparing static and dynamic adsorption and desorption processes, HPD100B was selected as the most suitable resin. After column adsorption and desorption on this resin, the target compounds VOR and VIT can be effectively separated from the APG0810 extraction solution. Recoveries of VOR and VIT were 89.27%±0.42% and 85.29%±0.36%, respectively. The purity of VOR increased from 35.0% to 58.3% and the purity of VIT increased from 12.5% to 19.9%.

Glycyrrhiza glabra

Liquorice foliage

Comparison of nutritional properties of Stinging nettle (Urtica dioica) flour with wheat and barley flours

Stinging nettle (Urtica dioica. L) is a wild, unique herbaceous perennial flowering plant with Stinging hairs. It has a long history of use as a food sources as a soup or curries, and also used as a fiber as well as a medicinal herb. The current aim was to analyze the composition and bioactive compounds in Nepalese Stinging nettle. Chemical analysis showed the relatively higher level of crude protein (33.8%), crude fiber (9.1%), crude fat (3.6%), total ash (16.2%), carbohydrate (37.4%), and relatively lower energy value (307 kcal/100 g) as compared to wheat and barley flours. Analysis of nettle powder showed significantly higher level of bioactive compounds: phenolic compounds as 129 mg Gallic acid equivalent/g; carotenoid level 3497 μg/g; tannin 0.93 mg/100 g; anti-oxidant activity 66.3 DPPH inhibition (%), as compared to wheat and barley. This study further established that nettle plants as very good source of energy, proteins, high fiber, and a range of health benefitting bioactive compounds.