Antiviral activity of green silver nanoparticles produced using aqueous buds extract of Syzygium aromaticum.

In the present study, we synthesized silver (Ag) nanoparticles using aqueous extracts of clove (Syzygium aromaticum) (SAE). This synthesis of green silver nanoparticles (AgNP) was a novel and effectual tool against the Newcastle Viral Disease (NDV). Syzygium aromaticum extract was used as reducing and stabilizing agent for synthesis of silver nanoparticles. AgNP were characterized using diversity of biophysical methods inclusive of Fourier transform infrared spectroscopy (FTIR), UV-VIS spectroscopy and Transmission electron microscopy (TEM) for morphology and size. Furthermore, XRD analysis confirmed the crystalline nature of the particles. In current investigations, the antiviral activity of clove buds silver nanoparticles was inspected in-vitro and in-ovo. Embryonated chicken eggs were used to perform the cytotoxicity assay of the clove extract silver nanoparticles (CESN). CESN showed in vitro antiviral activity against NDV in embryonated eggs.

Polyalthia longifolia leaves methanolic extract targets entry and budding of viruses-an in vitro experimental study against paramyxoviruses.

ETHNOPHARMACOLOGICAL RELEVANCE: Synthetic antiviral drugs have several limitations including high cost. Thus research on antiviral property of medicinal plants is continuously gaining importance. Polyalthia longifolia possesses several medicinal properties and has been used in traditional ayurvedic medicine for treatment of dermatological ailments as kushta, visarpa/herpes virus infection and also to treat pyrexia of unknown origin as mentioned in Visarpa Chikitsa. AIM OF THE STUDY: Keeping in view the cytotoxic, anti-cancer activity and antiviral efficacy of Polyalthia longifolia against herpes, present study was undertaken to evaluate the in vitro antiviral activity of methanolic extract of Polyalthia longifolia leaves, if any, and to unravel the possible target(s)/mechanism of action. MATERIAL AND METHODS: Antiviral activity of Polyalthia longifolia methanolic extract was studied using Vero cell lines against paramyxoviruses, namely-peste des petits ruminants virus (PPRV) and Newcastle disease virus (NDV). Cytotoxicity of the test extract was evaluated employing MTT assay. Virucidal activity, and viral-attachment, virus entry and release assays were determined in Vero cells using standard experimental protocols. The viral RNA in the virus-infected cells was quantified by qRT-PCR. RESULTS: At non-cytotoxic concentration, methanolic extract of Polyalthia longifolia leaves was found to inhibit the replication of PPRV and NDV at viral entry and budding level, whereas other steps of viral life cycle such as attachment and RNA synthesis remained unaffected. CONCLUSIONS: Polyalthia longifolia leaves extract possesses promising antiviral activity against paramyxoviruses and acts by inhibiting the entry and budding of viruses; and this plant extract evidently possesses excellent and promising potential for development of effective herbal antiviral drug.

Inhibitory effect of grapefruit seed extract (GSE) on avian pathogens.

The inhibitory activities of grapefruit seed extract (GSE) on avian influenza virus (AIV), Newcastle disease virus (NDV), infectious bursal disease virus (IBDV), Salmonella Infantis (SI) and Escherichia coli (EC) were evaluated. Original GSE contained 0.24% benzalkonium chloride (BZC), however, 0.0025% BZC solution could not inactivate bacteria. The activity of diluted GSE (×100, ×500 and ×1,000 with redistilled water) against selected viruses and bacteria was evaluated in this study. The GSE solutions were incubated with the pathogens over a period of time after which the remaining viruses were titrated and the bacterial colonies were counted. In the presence of organic material-5% fetal bovine serum (FBS), the test solutions were sprayed at 1 cm and 30 cm distances to test the efficacy of GSE in a spray form. Furthermore, the efficacy of GSE against bacteria on clothes was tested using non-woven cloth. GSE×100 reduced the viral titer of both AIV and NDV even in 5% FBS condition. IBDV showed high resistance to GSE. GSE×1,000 inactivated both SI and EC within 5 sec, even in the presence of 5% FBS. The disinfectant was able to maintain its efficacy in the spray form at 30 cm distance. GSE was also effective against SI and EC inoculated on fabric. GSE is a potential novel disinfectant against viruses and bacteria, effective even within a short contact time.

Efficacy of CpG-ODN Administration Routes on Humoral Responses against Newcastle disease in Broilers.

Un-methylated cytosine-phosphate-guanosine oligodeoxynucleotides (CpG-ODN) has been considered as a powerful vaccine adjuvant and recognition of CpG-ODN by chicken leukocytes promotes their ability to fight against infections. In our study, efficacy of different routes of CpG-ODN application as an adjuvant on immune responses (antibody titer together with leukogram) following vaccination against Newcastle disease (ND) has been evaluated in broiler chickens (Ross-308). The results indicated that routes of CpG-ODN administration influence immune responses and comparison effectiveness of CpG-OND delivery routes showed that group vaccinated by eye-drop application had the highest antibody titer than that of the group injected intramuscularly (im) and the difference was significant (p = 0.04) on day 35 of age. Antibody titer of the group treated with Clone 30 plus CpG-ODN via eye-drop route was higher than that of the group vaccinated with clone 30 alone on days 28 and 35 of age and the difference was significant (p = 0.04). Co-administration of both vaccine and CpG improved outcome of leukogram of the chickens on days 21 to 42 of age and among the treated groups, WBC of the group received both vaccine and CpG by eye-drop route significantly (p < 0.05) differed from that of the group vaccinated with clone 30 alone on days 28 and 35 but not on day 42 of age. Average final body weight of the control group did not significantly differ from those of the treated groups at end of the experiment. In conclusion, co-administration of ND vaccine plus CpG-ODN via eye-drop route improves immune responses.

Explore the potential effect of natural herbals to resist Newcastle Disease Virus.

In this study, we examined the dose-dependent effects of the formula on Newcastle disease virus (NDV). In in-vitro test, the formula within safety concentration scope and NDV were added into cultured chick embryo fibroblast in 3 modes, and the cellular A570 values were determined by MTT (3-(4, 5-dimethyithiazol-2-yl)-2, 5-diphenyltetrazolium bromide) method. In in-vivo test, we examined the expression of interferon-induced transmembrane protein 3 (IFITM3) and Interferons (IFNs) in NDV-infected chickens. The results showed that the highest virus inhibitory rates of the formula at optimal concentration group were the highest (15.625 mg/mL) in post-adding and simultaneous-adding drug and virus modes, whereas medium concentration (7.813 mg/mL) showed the highest virus inhibitory rates in pre-adding drug mode. In vivo, the formula significantly upregulated the expression of IFITM3 in NDV-infected chickens at 3-D post-infection. However, the levels of IFNs were significantly downregulated. On days 5 and 7 post-infection, the levels of IFNs quickly upregulated. Moreover, the formula can significantly upregulate the antibody to resist the NDV compared with model control group on days 5 and 7 post-infection. In animals treated with the formula, the survival rate was nearly 37% higher at 7 d post-infection. We also found that the formula had a significantly stronger effect than a single herb on upregulating the expression of IFITM3. It confirmed that the formula could significantly inhibit the infectivity of NDV to chick embryo fibroblast. Also, the formula could significantly upregulated IFITM3 expression and inhibited virus replication in NDV-infected chickens. During the early stage of infection, IFNs were consumed to stimulate IFITM3 to inhibit virus replication, whereas during later stages of the infection, the formula upregulated the levels of IFNs and their antibodies to maintain a high level of immunity.

Vitamin E Supplementation Ameliorates Newcastle Disease Virus-Induced Oxidative Stress and Alleviates Tissue Damage in the Brains of Chickens.

Newcastle disease (ND), characterized by visceral, respiratory, and neurological pathologies, causes heavy economic loss in the poultry industry around the globe. While significant advances have been made in effective diagnosis and vaccine development, molecular mechanisms of ND virus (NDV)-induced neuropathologies remain elusive. In this study, we report the magnitude of oxidative stress and histopathological changes induced by the virulent NDV (ZJ1 strain) and assess the impact of vitamin E in alleviating these pathologies. Comparative profiling of plasma and brains from mock and NDV-infected chicken demonstrated alterations in several oxidative stress makers such as nitric oxide, glutathione, malondialdehyde, total antioxidant capacity, glutathione S-transferase, superoxide dismutase, and catalases. While decreased levels of glutathione and total antioxidant capacity and increased concentrations of malondialdehyde and nitric oxide were observed in NDV-challenged birds at all time points, these alterations were eminent at latter time points (5 days post infection). Additionally, significant decreases in the activities of glutathione S-transferase, superoxide dismutase, and catalase were observed in the plasma and brains collected from NDV-infected chickens. Intriguingly, we observed that supplementation of vitamin E can significantly reduce the alteration of oxidative stress parameters. Under NDV infection, extensive histopathological alterations were observed in chicken brain including neural inflammation, capillary hyperemia, necrosis, and loss of prominent axons, which were reduced with the treatment of vitamin E. Taken together, our findings highlight that neurotropic NDV induces extensive tissue damage in the brain and alters plasma oxidative stress profiles. These findings also demonstrate that supplementing vitamin E ameliorates these pathologies in chickens and proposes its supplementation for NDV-induced stresses.

Biosurfactants production potential of native strains of Bacillus cereus and their antimicrobial, cytotoxic and antioxidant activities.

Present study was designed to evaluate the biosurfactant production potential by native strains of Bacillus cereus as well as determine their antimicrobial and antioxidant activities. The strains isolated from garden soil were characterized as B. cereus MMIC 1, MMIC 2 and MMIC 3. Biosurfactants were extracted as grey white precipitates. Optimum conditions for biosurfactant production were 37°C, the 7th day of incubation, 0.5% NaCl, pH 7.0. Moreover, corn steep liquor was the best carbon source. Biuret test, Thin Layer Chromatography (TLC), agar double diffusion and Fourier Transform Infrared Spectroscopy (FTIR) characterized the biosurfactants as cationic lipopeptides. Biosurfactants exhibited significant antibacterial and antifungal activity against S. aureus, E. coli, P. aeruginosa, K. pneumoniae, A. niger and C. albicans at 30 mg/ml. Moreover, they also possessed antiviral activity against NDV at 10 mg/ml. Cytotoxicity assay in BHK-21 cell lines revealed 63% cell survival at 10 mg/ml of biosurfactants and thus considered as safe. They also showed very good antioxidant activity by ferric-reducing activity and DPPH scavenging activity at 2 mg/ml. Consequently, the study offers an insight for the exploration of new bioactive molecules from the soil. It was concluded that lipopeptide biosurfactants produced from native strains of B. cereus may be recommended as safe antimicrobial, emulsifier and antioxidant agent.

An evaluation of the impact of aloe vera and licorice extracts on the course of experimental pigeon paramyxovirus type 1 infection in pigeons.

The progressive decrease in the efficiency of synthetic drugs has prompted research into phytogenic feed additives with potentially immunomodulatory and anti-infective properties. Complex diseases with a mixed etiology, including viral, pose a growing problem in domestic pigeons. The aim of this study was to determine the effectiveness of various doses of aloe vera and licorice extracts on the course of experimental PPMV-1 infection in pigeons. The experiment was performed on pigeons divided into 5 groups, including one control group and 4 experimental groups, which were orally administered aloe vera or licorice extracts at 300 or 500 mg/kg BW for 7 d after experimental inoculation with PPMV-1. On d 4, 7, and 14 after inoculation, cloacal swabs and samples of organs were collected from 4 birds in each group. The samples were analyzed to determine the copy number of PPMV-1 RNA by TaqMan qPCR. The results indicate that licorice and aloe vera extracts inhibited PPMV-1 replication by decreasing viral RNA copy numbers in the examined organs. The most inhibitory effect was observed in pigeons receiving aloe vera extract at 300 mg/kg BW, for which PPMV-1 RNA copy numbers were approximately 7-fold lower (brain), 9-fold lower (kidneys), and 14-fold lower (liver) than in the control group. The results of this study point to the potentially antiviral effects of aloe vera and licorice extracts in pigeons infected with PPMV-1. To the best of our knowledge, this is the first study to investigate the antiviral properties of aloe vera and licorice extracts in domestic pigeons.

In vivo antiviral potential of Glycyrrhiza glabra extract against Newcastle disease virus.

Newcastle disease is highly infectious viral disease causing huge economic losses worldwide. These losses can be prevented by control of viral diseases. Medicinal plants have been traditionally used for treatment of different diseases since long. In this study the effect of extracts from Glycyrrhiza glabra leaves are investigated against Newcastle disease virus (NDV) by an in-vivo assay. Seven groups of nine-day-old embryonated chicken eggs were inoculated with various treatments of different plant extracts. All the groups except uninoculated negative control group were inoculated with velogenic NDV strain; five groups received different concentrations of the three extracts. Daily observe the rate of embryo survival. Allantoic fluid from treated eggs was collected for hem agglutination test. Results showed that embryo survival rate was higher 300µg/mL treated group as all the extracts showed antiviral activity. Similarly, the plant extracts effectively control virus as no viruses were identified in the allantoic fluids of all groups treated with low doses of plant. The current results have clearly verified that all the extracts especially that of methanol 300µg/mL from leaves of Glycyrrhiza glabra have strong antiviral activity against NDV in vivo.

Ethanol extract and chromatographic fractions of Tamarindus indica stem bark inhibits Newcastle disease virus replication.

CONTEXT: The plethora of ethnomedicinal applications of Tamarindus indica Linn. (Leguminosae), tamarind, includes treatment of human and livestock ailments; preparations are recognized antipyretics in fevers, laxatives and carminatives. African folklore has various applications of tamarind. However, in Nyasaland, domestic fowl are fed with preparations for prophylactic properties. OBJECTIVES: The objective of this study is to evaluate the antiviral properties of T. indica extract. MATERIALS AND METHODS: Tamarindus indica stem bark was extracted through ethanol maceration over 24 h, and the crude extract was fractionated by gravity-propelled column chromatography. Newcastle disease virus (NDV) inhibitory activity of extract and fractions were evaluated in vivo using 10-d-old embryonated chicken egg (ECE) as the medium for virus cultivation and antivirus assay. About 240 ECE were grouped into eight (three controls and five experimental) and, 200 µL of the extract and fractions respectively inoculated into NDV pre-infected eggs and incubated at 37 °C. Allantoic fluid was harvested 5 d post-virus infection and assayed for haemagglutination (HA). RESULTS: Anti-NDV assessment showed 62.5 mg/mL of crude extract and fractions: TiA, TiC and TiD to yield a HA titre of 1:128 each, while TiB showed 1:64 HA titre. At 125 mg/mL, a titre of 1:16 was recorded against TiB and TiD and, 1:8 against TiA. Similarly, crude extract and TiC, each recorded 1:4 HA titre. However, the minimum concentrations of extract and fraction for virus inactivation were 0.24 mg/mL and 0.49 mg/mL, respectively. CONCLUSION: The antiviral activity shown by T. indica portends novel antiviral drugs and, perhaps, as scaffold for new drugs.

The screening and evaluation of herbs and identification of herbal combinations with anti-viral effects on Newcastle disease virus.

A total of 25 "heat-clearing and detoxifying" herbs used in Chinese medicine were investigated for their cytopathic effects on the growth of Newcastle Disease virus (NDV) in a chicken fibroblast cell line. The 5 herbs with the highest virus inhibitory effects were Herba agastaches, Flos chrysanthemi indici, Rhizoma anemarrhenae, Astragalus root and Baikal skullcap root and these were used in herbal formulations. Anti-NDV activities of 4 formulations were tested on the growth of NDV in the DF-1 fibroblast cell line. Formulation II, containing Baikal skullcap root, Astragalus root, Anemarrhena rhizome (1:1:2) and formulation IV containing Anemarrhena rhizome, Astragalus root and Flos chrysanthemi indici (1:1:1), which had strong anti-NDV activity in vitro, were used to determine the in vivo inhibitory effects of NDV-infection in chickens. After treatment with the two formulations serum IgY titres against NDV were improved, and morbidity was reduced in the NDV-infected chickens. The results suggest that the components in formulations II and IV acted synergistically to improve resistance to Newcastle disease and provide a basis for the developing an anti-NDV herbal medicine.

Anti-NDV activity of baicalin from a traditional Chinese medicine in vitro.

The purpose of this study was to investigate the anti-Newcastle disease virus (NDV) activities of baicalin from Scutellaria baicalensis, a Traditional Chinese Medicine in vitro. Chicken embryo fibroblasts (CEFs) were infected with NDV, and quantitative analysis of apoptotic cells was performed using flow cytometry. Cytotoxicity and anti-viral activities of baicalin were studied using the MTT method. The results showed that the maximal safe concentrations of baicalin to CEFs was 1 × 2(-2) mg/ml. Baicalin could directly kill NDV, inhibit the infectivity of NDV to CEF and block intracellular NDV. It inhibited the apoptosis of NDV-infected CEFs and suppressed the spread of NDV. These results indicate that baicalin has strong anti-NDV activity and has the potential for use as components of an antiviral drug.

Epimedium koreanum Nakai displays broad spectrum of antiviral activity in vitro and in vivo by inducing cellular antiviral state.

Epimedium koreanum Nakai has been extensively used in traditional Korean and Chinese medicine to treat a variety of diseases. Despite the plant's known immune modulatory potential and chemical make-up, scientific information on its antiviral properties and mode of action have not been completely investigated. In this study, the broad antiviral spectrum and mode of action of an aqueous extract from Epimedium koreanum Nakai was evaluated in vitro, and moreover, the protective effect against divergent influenza A subtypes was determined in BALB/c mice. An effective dose of Epimedium koreanum Nakai markedly reduced the replication of Influenza A Virus (PR8), Vesicular Stomatitis Virus (VSV), Herpes Simplex Virus (HSV) and Newcastle Disease Virus (NDV) in RAW264.7 and HEK293T cells. Mechanically, we found that an aqueous extract from Epimedium koreanum Nakai induced the secretion of type I IFN and pro-inflammatory cytokines and the subsequent stimulation of the antiviral state in cells. Among various components present in the extract, quercetin was confirmed to have striking antiviral properties. The oral administration of Epimedium koreanum Nakai exhibited preventive effects on BALB/c mice against lethal doses of highly pathogenic influenza A subtypes (H1N1, H5N2, H7N3 and H9N2). Therefore, an extract of Epimedium koreanum Nakai and its components play roles as immunomodulators in the innate immune response, and may be potential candidates for prophylactic or therapeutic treatments against diverse viruses in animal and humans.

Sulphated polysaccharides from Ulva clathrata and Cladosiphon okamuranus seaweeds both inhibit viral attachment/entry and cell-cell fusion, in NDV infection.

Sulphated polysaccharides (SP) extracted from seaweeds have antiviral properties and are much less cytotoxic than conventional drugs, but little is known about their mode of action. Combination antiviral chemotherapy may offer advantages over single agent therapy, increasing efficiency, potency and delaying the emergence of resistant virus. The paramyxoviridae family includes pathogens causing morbidity and mortality worldwide in humans and animals, such as the Newcastle Disease Virus (NDV) in poultry. This study aims at determining the antiviral activity and mechanism of action in vitro of an ulvan (SP from the green seaweed Ulva clathrata), and of its mixture with a fucoidan (SP from Cladosiphon okamuranus), against La Sota NDV strain. The ulvan antiviral activity was tested using syncytia formation, exhibiting an IC50 of 0.1 µg/mL; ulvan had a better anti cell-cell spread effect than that previously shown for fucoidan, and inhibited cell-cell fusion via a direct effect on the F0 protein, but did not show any virucidal effect. The mixture of ulvan and fucoidan showed a greater anti-spread effect than SPs alone, but ulvan antagonizes the effect of fucoidan on the viral attachment/entry. Both SPs may be promising antivirals against paramyxovirus infection but their mixture has no clear synergistic advantage.

Antiviral effect of sulfated Chuanmingshen violaceum polysaccharide in chickens infected with virulent Newcastle disease virus.

Newcastle disease virus (NDV) belonging to the Paramyxovirinae subfamily is one of the most devastating pathogens in poultry. Although vaccines are widely applied to control the infection, outbreaks of Newcastle disease (ND) repeatedly happen. Currently, there are no alternative control measures available for ND. In the present study, we found that sulfated Chuanmingshen violaceum polysaccharide (sCVPS) were potent inhibitors of NDV in specific pathogen free chickens infected with a virulent strain. With sCVPS treatment, the survival rate increased by almost 20% and virus titers in test organs, including brain, lung, spleen and thymus, were significantly decreased. The sCVPS also exhibited the ability to prevent viral transmission by reducing the amount of virus shed in saliva and feces. Higher concentrations of interferon α and γ in serum were detected in chickens treated with sCVPS, indicating that one of the antiviral mechanisms may be attributed to the property of immunoenhancement. Histopathological examination showed that sCVPS could alleviate the tissue lesions caused by NDV infection. These results suggest that sCVPS are expected to be a new alternative control measure for NDV infection and further studies could be carried out to evaluate the antiviral activity of sCVPS against other paramyxoviruses.

Scutellaria polysaccharide inhibits the infectivity of Newcastle disease virus to chicken embryo fibroblast.

BACKGROUND: To select the antiviral active site of Scutellaria polysaccharide (SPS), safe concentrations of crude total Scutellaria polysaccharide (SPS(t)) and fractional polysaccharide SPS50, SPS60, SPS70 and SPS80 on chicken embryo fibroblast (CEF) were first compared using the MTT method. Then, SPS(t), SPS50, SPS60, SPS70, and SPS80 at five concentrations within the safe concentration, together with Newcastle disease virus (NDV), were added to the cultivating system of CEF in three models: pre-addition of polysaccharide, post-addition of polysaccharide, and simultaneous addition of polysaccharides and NDV after mixing. The effects of SPS on the cellular infectivity of NDV (A570 value and the highest viral inhibitory rate) were compared using the MTT method. RESULTS: At appropriate concentrations, the five polysaccharides could significantly inhibit the infectivity of NDV on CEF. Among the five polysaccharide groups, the SPS80 group exhibited the highest viral inhibitory rate in the three sample-addition modes. CONCLUSION: This finding indicates that SPS80 possesses the best efficacy as a component of antiviral polysaccharide drug.

Flavone ingredients can synergistically inhibit NDV infecting cell and improve ND vaccine's protective rate.

In order to screen better flavone prescriptions of anti-Newcastle disease virus (NDV), four flavone ingredients of epimedium flavones (EF), baikal skullcap root flavones (BSRF), wild dendranthema flower flavones (WDFF), and sanchi flavones (SF) screened in previous experiments and their prescriptions were added into chicken embryo fibroblast monolayer with three drug-adding modes respectively. The cellular A(570) values, the highest virus inhibitory rates and the score based on virus inhibitory rate were calculated to compare their antiviral activity. In immune protective test, the effects of three preparations (EF-BSRF, EF-SF-WDFF-BSRF and EF-WDFF-BSRF screened by the results in vitro experiment) on NDV infection were compared in chickens vaccinated with ND vaccine then challenged with NDV. Blood was regularly sampled for serum antibody titer determination. The pathogenic and dead statuses of chickens were clinically examined. The results indicated that the A(570) values of the nine prescriptions, especially the foresaid three prescriptions at almost all concentrations in three drug-adding modes were significantly higher than that of the virus control group. The foresaid three prescriptions presented at the top five of the highest virus inhibitory rate, and located at the highest three of the score rank. The antibody titers and protective rates of the three prescriptions groups were higher than that of VC group, especially EF-SF-WDFF-BSRF group showed significant difference. These results indicated that flavone prescriptions composed with suitable compatibility could possess synergistical action of antiviral effect, ES-SF-WDFF-BSRF prescription could inhibit the cellular infectivity of NDV, improve the protective effect of ND vaccine and would be expected to exploit into a new-type antiviral drug.

Antiviral activity of crude extracts from Commiphora swynnertonii against Newcastle disease virus in ovo.

Studies were carried out to investigate the effect of crude extracts from resin, leaves, stem barks and root barks of Commiphora swynnertonii against Newcastle disease virus (NDV) using an in ovo assay. Nine-day-old embryonated chicken eggs were divided into seven groups (n = 6) and received various treatments. Six groups were inoculated with velogenic NDV strain; five groups out of these were treated with different concentrations of the four extracts or a diluent, dimethylsulphoxide. The uninoculated and inoculated groups were left as negative and positive controls, respectively. Embryo survival was observed daily and embryo weights were measured day 5 post-inoculation; a few eggs from selected groups were left to hatch. Allantoic fluid from treated eggs and serum from hatched chicks were collected for hemagglutination and hemagglutination inhibition (HI) tests to detect NDV in the eggs and antibodies against NDV in the hatched chicks respectively. Results showed that embryo survival and mean embryo weight were significantly higher (p < 0.001) in those groups which were treated with the crude extracts from C. swynnertonii than the positive control group. Also the extracts significantly (p < 0.001) reduced virus titres, whereas no viruses were detected in the allantoic fluids of the resin-treated group at the highest concentration of 500 µg/mL. Furthermore, the HI test results showed very low levels of antibodies against NDV in chicks hatched from resin and root bark extract-treated eggs suggesting that these plant materials were capable of destroying the NDV before stimulating the developing chick's immunity. The current findings have clearly demonstrated that crude extracts especially that of resin from C. swynnertonii have strong antiviral activity against NDV in ovo. In vivo trials are needed to validate the use of resin from the tree in controlling Newcastle disease in chickens.

Epimedium polysaccharide and propolis flavone can synergistically inhibit the cellular infectivity of NDV and improve the curative effect of ND in chicken.

Four prescriptions, epimedium flavone plus propolis flavone (EF-PF), epimedium flavone plus propolis extracts (EF-PE), epimedium polysaccharide plus propolis flavone (EP-PF) and epimedium polysaccharide plus propolis extracts (EP-PE), were prepared and their antiviral effects were compared. In test in vitro, the four prescriptions within safety concentration scope and Newcastle disease virus (NDV) were added into cultured chick embryo fibroblast (CEF) in three modes, pre-, post-adding drug and simultaneous-adding drug and virus after being mixed, the cellular A(570) values were determined by MTT method and the highest virus inhibitory rates were calculated to compare the antiviral activity of four prescriptions. In test in vivo, three hundred 21-day-old chickens were randomly divided into 6 groups and challenged with NDV except for blank control group. After 24h the chickens in four prescription groups were injected with corresponding drugs respectively, in virus control and blank control groups, with physiological saline, once a day for three successive days. On days 3, 7 and 14 after challenge, the serum antibody titer was determined. On day 15 after challenge, the mortality, morbidity and cure rate in every group were counted. The results showed that the most of A(570) values in EP-PF group were numberly or significantly larger than those of the corresponding virus control group and the highest virus inhibitory rates of EP-PF at optimal concentration group were the highest among four prescription groups in three drug-adding modes, which confirmed that EP-PF could significantly inhibit the infectivity of NDV to CEF, its action was stronger than those of other three prescriptions; in EP-PF group, the antibody titers and cure rate were the highest and the mortality and morbidity were lowest presenting numberly or significantly differences in comparison with other three prescription groups. These results indicated that epimedium polysaccharide and propolis flavone possessed synergistical action, EP-PF prescription could significantly inhibit the cellular infectivity of NDV, improve the curative effect of ND in chicken and would be expected to exploit into a new-type antiviral drug.

Lycium barbarum polysaccharide inhibits the infectivity of Newcastle disease virus to chicken embryo fibroblast.

Lycium barbarum polysaccharide (LBPS) was extracted by water decoction and ethanol precipitation. After purification, four sulfated lycium barbarum polysaccharides (sLBPSs), sLBPS(0.7), sLBPS(1.1), sLBPS(1.5) and sLBPS(1.9), were prepared by chlorosulfonic acid-pyridine method respectively at four designed modification conditions. Four sLBPSs at 5 concentrations, within the safety concentration scope, and Newcastle disease virus (NDV) were added into cultivating system of chick embryo fibroblast (CEF) respectively in three modes, pre- and post-adding polysaccharide and simultaneous adding polysaccharide and virus after being mixed. The effects of sLBPSs on cellular infectivity of NDV were assayed by MTT method taking the non-modified LBPS as control. The results showed that sLBPS(1.5), sLBPS(1.9) and sLBPS(1.1) in three sample-adding modes, sLBPS(0.7) in simultaneous adding after being mixed could significantly inhibit the infectivity of NDV to CEF. The viral inhibitory rate of sLBPS(1.5) in pre- and simultaneous adding and sLBPS(1.9) in post-adding was the highest. Non-modified LBPS did not present significant effect in any sample-adding mode. These results indicated that sulfated modification could significantly enhance the antiviral activity of LBPS, which was correlated with the degree of sulfation (DS) of sLBPS. sLBPS(1.5) and sLBPS(1.9) possessed better activity and would be as the compositions of antiviral prescription.