Ethnomedicines and ethnomedicinal phytophores against herpesviruses

A Review of African Medicinal Plants and Functional Foods for the Management of Alzheimer's Disease-related Phenotypes, Treatment of HSV-1 Infection and/or Improvement of Gut Microbiota

Alzheimer's disease (AD), which is a progressive neurodegenerative disorder is the most common form of dementia globally. Several studies have suggested alteration in the gut microbiota and HSV-1 infection as contributing factors to the development of the disease. As at now, there are no AD attenuating agents and AD pharmacotherapy is focused on managing symptoms while plants used in ethnomedicine remain potential sources of drugs for the treatment of the condition. Here, we reviewed published databases for African ethnomedicinal plants and functional foods of African origin that are used in the management of AD-related phenotypes, treatment of herpes simplex virus −1 (HSV-1) and/or improvement of gut microbiota. A total of 101 unique plant species and 24 different types of traditionally prepared African functional foodstuff were identified. Of the 101 identified plant species, 50 species serve as functional foodstuffs. Twenty-three (23) of the ethnomedicinal plant families were successfully identified for the treatment and management of AD-related phenotypes and age-related dementia. Eighteen (18) African plant species from 15 families were also identified as potent remedies for HSV-1; while many African wild fruits (3 species), roots and tubers (7 species), leafy vegetables (14 species), and seaweeds (26 species) were functional foods for modifying AD-related phenotypes. It was concluded that African medicinal plants are potential sources of both AD attenuating agents and phytocompounds that may be used against HSV-1 infection and alteration of gut microbiota. Additionally, a number of African functional foods are important sources of prebiotics and probiotics.

Phytochemical Moieties From Indian Traditional Medicine for Targeting Dual Hotspots on SARS-CoV-2 Spike Protein: An Integrative in-silico Approach

SARS-CoV-2 infection across the world has led to immense turbulence in the treatment modality, thus demanding a swift drug discovery process. Spike protein of SARS-CoV-2 binds to ACE2 receptor of human to initiate host invasion. Plethora of studies demonstrate the inhibition of Spike-ACE2 interactions to impair infection. The ancient Indian traditional medicine has been of great interest of Virologists worldwide to decipher potential antivirals. Hence, in this study, phytochemicals (1,952 compounds) from eight potential medicinal plants used in Indian traditional medicine were meticulously collated, based on their usage in respiratory disorders, along with immunomodulatory and anti-viral potential from contemporary literature. Further, these compounds were virtually screened against Receptor Binding Domain (RBD) of Spike protein. The potential compounds from each plant were prioritized based on the binding affinity, key hotspot interactions at ACE2 binding region and glycosylation sites. Finally, the potential hits in complex with spike protein were subjected to Molecular Dynamics simulation (450 ns), to infer the stability of complex formation. Among the compounds screened, Tellimagrandin-II (binding energy of −8.2 kcal/mol and binding free energy of −32.08 kcal/mol) from Syzygium aromaticum L. and O-Demethyl-demethoxy-curcumin (binding energy of −8.0 kcal/mol and binding free energy of −12.48 kcal/mol) from Curcuma longa L. were found to be highly potential due to their higher binding affinity and significant binding free energy (MM-PBSA), along with favorable ADMET properties and stable intermolecular interactions with hotspots (including the ASN343 glycosylation site). The proposed hits are highly promising, as these are resultant of stringent in silico checkpoints, traditionally used, and are documented through contemporary literature. Hence, could serve as promising leads for subsequent experimental validations.

Treatment of genital herpes using olive leaf extract

Genital herpes is one of the sexually transmitted diseases that is reported with a greater incidence of primary and secondary recurrence. In this study, olive leaf extract was used for its antiviral properties to treat the infection. The randomized-clinical trials using such a therapeutic approach are required in this field.

Development of Provesicular Nanodelivery System of Curcumin as a Safe and Effective Antiviral Agent: Statistical Optimization, In Vitro Characterization, and Antiviral Effectiveness

Curcumin is a natural compound that has many medical applications. However, its low solubility and poor stability could impede its clinical applications. The present study aimed to formulate dry proniosomes to overcome these pitfalls and improve the therapeutic efficacy of Curcumin. Curcumin-loaded proniosomes were fabricated by the slurry method according to 32 factorial design using Design-Expert software to demonstrate the impact of different independent variables on entrapment efficiency (EE%) and % drug released after 12 h (Q12h). The optimized formula (F5) was selected according to the desirability criteria. F5 exhibited good flowability and appeared, after reconstitution, as spherical nanovesicles with EE% of 89.94 ± 2.31% and Q12h of 70.89 ± 1.62%. F5 demonstrated higher stability and a significant enhancement of Q12h than the corresponding niosomes. The docking study investigated the ability of Curcumin to bind effectively with the active site of DNA polymerase of Herpes simplex virus (HSV). The antiviral activity and the safety of F5 were significantly higher than Curcumin. F5 improved the safety of Acyclovir (ACV) and reduced its effective dose that produced a 100% reduction of viral plaques. Proniosomes could be promising stable carriers of Curcumin to be used as a safe and efficient antiviral agent.

Antiviral Evaluation of Herbal Drugs

The viral infection and resistance to the existing antiviral drugs are alarming, which is a serious public health concern. Medicinal plants are valuable resources for treatment of viral infections and can be used for the management of infections like herpes simplex virus (HSV), human immunodeficiency virus (HIV), influenza, etc. The antiviral screening of plant extracts should be highly selective, specific, and sensitive for bioactivity guided isolation of the active compounds from the plant extracts. The antiviral screening system should be validated for accuracy, reproducibility, simplicity, and cost effectiveness. This chapter highlights on various aspects for screening and evaluation of antiviral natural components including factors affecting antiviral in vivo studies, host cells, organisms, and culture media followed by different virus-specific assays for antiviral screening of natural products.

In vitro Cytotoxicity and Anti-herpes Simplex Virus Type 1 Activity of Hydroethanolic Extract, Fractions, and Isolated Compounds from Stem Bark of Schinus terebinthifolius Raddi

Background:

Herpes simplex virus type 1 (HSV-1) is associated with orofacial infections and is transmitted by direct contact with infected secretions. Several efforts have been expended in the search for drugs to the treatment for herpes. Schinus terebinthifolius is used in several illnesses and among them, for the topical treatment of skin wounds, especially wounds of mucous membranes, whether infected or not.

Objective:

To evaluate the cytotoxicity and anti-HSV-1 activity of the crude hydroethanolic extract (CHE) from the stem bark of S. terebinthifolius, as well as its fractions and isolated compounds.

Materials and Methods:

The CHE was subjected to bioguided fractionation. The anti-HSV-1 activity and the cytotoxicity of the CHE, its fractions, and isolated compounds were evaluated in vitro by SRB method. A preliminar investigation of the action of CHE in the virus–host interaction was conducted by the same assay.

Results:

CHE presented flavan-3-ols and showed anti-HSV-1 activity, better than its fractions and isolated compounds. The class of substances found in CHE can bind to proteins to form unstable complexes and enveloped viruses, as HSV-1 may be vulnerable to this action. Our results suggest that the CHE interfered with virion envelope structures, masking viral receptors that are necessary for adsorption or entry into host cells.

Conclusion:

The plant investigated exhibited potential for future development treatment against HSV-1, but further tests are necessary, especially to elucidate the mechanism of action of CHE, as well as preclinical and clinical studies to confirm its safety and efficacy.

SUMMARY

Crude hydroethanolic extract (CHE) presents promising activity against herpes simplex virus type 1 (HSV 1), with selectivity index (SI) = 22.50

CHE has flavan-3-ols in its composition, such as catechin and gallocatechin

The fractions and isolated compounds obtained from CHE by bioguided fractionation are less active than the CHE against HSV-1

CHE interferes with viral entry process in the host cell and acts directly on the viral particle.

Abbreviations used: HSV: Herpes simplex virus, CHE: Crude hydroethanolic extract, WF: Water fraction, AF: Ethyl-acetate fraction, MPLC: Medium-performance liquid chromatography, TLC: Thin-layer chromatography, NMR: Nuclear magnetic resonance, ESI-MS: Electrospray ionization mass spectrometry, SRB: Sulforhodamine B, CPE: Cytopathic effect, CC50: 50% cytotoxic concentration, EC50: 50% effective concentration, PBS: Phosphate-buffered saline.

Potent in vitro antiviral activity of Cistus incanus extract against HIV and Filoviruses targets viral envelope proteins

Novel therapeutic options are urgently needed to improve global treatment of virus infections. Herbal products with confirmed clinical safety features are attractive starting material for the identification of new antiviral activities. Here we demonstrate that Cistus incanus (Ci) herbal products inhibit human immunodeficiency virus (HIV) infections in vitro. Ci extract inhibited clinical HIV-1 and HIV-2 isolates, and, importantly, a virus isolate with multiple drug resistances, confirming broad anti-HIV activity. Antiviral activity was highly selective for virus particles, preventing primary attachment of the virus to the cell surface and viral envelope proteins from binding to heparin. Bioassay-guided fractionation indicated that Ci extract contains numerous antiviral compounds and therefore has favorably low propensity to induce virus resistance. Indeed, no resistant viruses emerged during 24 weeks of continuous propagation of the virus in the presence of Ci extracts. Finally, Ci extracts also inhibited infection by virus particles pseudotyped with Ebola and Marburg virus envelope proteins, indicating that antiviral activity of Ci extract extends to emerging viral pathogens. These results demonstrate that Ci extracts show potent and broad in vitro antiviral activity against viruses that cause life-threatening diseases in humans and are promising sources of agents that target virus particles.

Pedilanthus tithymaloides Inhibits HSV Infection by Modulating NF-κB Signaling

Pedilanthus tithymaloides (PT), a widely used ethnomedicinal plant, has been employed to treat a number of skin conditions. To extend its utility and to fully exploit its medicinal potential, we have evaluated the in vitro antiviral activity of a methanolic extract of PT leaves and its isolated compounds against Herpes Simplex Virus type 2 (HSV-2). Bioactivity-guided studies revealed that the extract and one of its constituents, luteolin, had potent antiviral activity against wild-type and clinical isolates of HSV-2 (EC₅₀ 48.5–52.6 and 22.4–27.5 μg/ml, respectively), with nearly complete inhibition at 86.5–101.8 and 40.2–49.6 μg/ml, respectively. The inhibitory effect was significant (p<0.001) when the drug was added 2 h prior to infection, and was effective up to 4 h post-infection. As viral replication requires NF-κB activation, we examined whether the observed extract-induced inhibition of HSV-2 was related to NF-κB inhibition. Interestingly, we observed that treatment of HSV-2-infected cells with extract or luteolin suppressed NF-κB activation. Although NF-κB, JNK and MAPK activation was compromised during HSV replication, neither the extract nor luteolin affected HSV-2-induced JNK1/2 and MAPK activation. Moreover, the PT leaf extract and luteolin potently down-regulated the expression of tumor necrosis factor (TNF)-α, Interleukin (IL)-1β, IL-6, NO and iNOS and the production of gamma interferon (IFN-γ), which are directly involved in controlling the NF-κB signaling pathway. Thus, our results indicate that both PT leaf extract and luteolin modulate the NF-κB signaling pathway, resulting in the inhibition of HSV-2 replication.

Validation of Antiviral Potential of Herbal Ethnomedicine

Natural products are the basis of treatment since the dawn of human civilization, and modern medicine has gradually developed, over the years, by scientific and observational efforts from traditional medicine. Today most of the synthetic drugs showed adverse and unacceptable side effects, however, impressive bioactivities with reduced toxicities were reported for many botanicals against several chronic or difficult-to-treat diseases. A whole range of viral diseases including human immunodeficiency virus/acquired immunodeficiency syndrome, severe acute respiratory syndrome, Rabies, Dengue, and Herpes need effective drugs. Considerable research has been carried out on the pharmacognosy, chemistry, pharmacology, and therapeutics of traditional medicines of diverse cultures, and many pharmaceutical companies have renewed their strategies for antiviral drug development where no effective drugs or vaccine exist. Thus, phytochemicals with antiviral potentials need to be studied in depth with standardization, chemical isolation, effectivity, molecular mechanism, along with in vivo toxicity and efficacy to reduce cost and time. This review will portray the scientific approaches and methodologies used for the development of antiviral leads from traditional medicines against selected genetically and functionally diverse viral infections.

Antiviral and cytotoxic evaluation of coumarins from Prangos ferulacea

CONTEXT

Prangos ferulacea (L.) Lindl. (Apiaceae) is a perennial plant found in the Middle-East, where it is commonly used as an antispasmodic and anti-inflammatory agent. It is a rich source of coumarins.

OBJECTIVE

To purify several coumarins from P. ferulacea and to screen their cytotoxicity and anti-herpes activity.

MATERIALS AND METHODS

Acetone extract of roots of P. ferulacea was subjected to several chromatographic separations to render pure coumarins (1-8). Anti-herpes virus effects of 1-7 were evaluated at concentration 2.5, 5, and 10 µgmL(-1), on a confluent monolayer of Vero cells infected with 25 PFU of HSV1. Cytotoxic effects of 1 and 2 were evaluated on an A2780S cell line using the MTT assay. The cells were exposed to a series of concentrations of coumarins (0.01-2.5 mM, 37°C, 72 h).

RESULTS

Compounds 1-8 were identified as osthole, isoimperatorin, oxypeucedanin, psoralen, oxypeucedanin hydrate, gosferol, oxypeucedanin methnolate, and pranferol. This is the first report of occurrence of 4 and 7 in this plant. Compound 1 showed a viability of 9.41% ± 2.4 at 2.5 mM on A2780S cells (IC50 = 0.38 mM). The cell survival of 2 at 2.5 mM was 46.86% ± 5.5 with IC50 equal to 1.1 mM.

DISCUSSION AND CONCLUSION

Compound 1 shows cytotoxic effects on the A2780S cell line. Compound 2 is a cyclooxygenase-2 inhibitor and the A2780S cell line does not express COX-2 which may interpret the non-toxic effect of the compound on this cell line. None of the tested compounds showed an anti-HSV effect at non-toxic concentrations.

Anti-inflammatory activity of Odina wodier Roxb, an Indian folk remedy, through inhibition of toll-like receptor 4 signaling pathway

Inflammation is part of self-limiting non-specific immune response, which occurs during bodily injury. In some disorders the inflammatory process becomes continuous, leading to the development of chronic inflammatory diseases including cardiovascular diseases, diabetes, cancer etc. Several Indian tribes used the bark of Odina wodier (OWB) for treating inflammatory disorders. Thus, we have evaluated the immunotherapeutic potential of OWB methanol extract and its major constituent chlorogenic acid (CA), using three popular in vivo antiinflammatory models: Carrageenan- and Dextran-induced paw edema, Cotton pellet granuloma, and Acetic acid-induced vascular permeability. To elucidate the possible anti-inflammatory mechanism of action we determine the level of major inflammatory mediators (NO, iNOS, COX-2-dependent prostaglandin E2 or PGE2), and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-12). Further, we determine the toll-like receptor 4 (TLR4), Myeloid differentiation primary response gene 88 (MyD88), c-Jun N-terminal kinases (JNK), nuclear factor kappa-B cells (NF-κB), and NF-kB inhibitor alpha (IK-Bα) by protein and mRNA expression, and Western blot analysis in drug treated LPS-induced murine macrophage model. Moreover, we determined the acute and sub-acute toxicity of OWB extract in BALB/c mice. Our study demonstrated a significant anti-inflammatory activity of OWB extract and CA along with the inhibition of TNF-α, IL-1β, IL-6 and IL-12 expressions. Further, the expression of TLR4, NF-κBp65, MyD88, iNOS and COX-2 molecules were reduced in drug-treated groups, but not in the LPS-stimulated untreated or control groups, Thus, our results collectively indicated that the OWB extract and CA can efficiently inhibit inflammation through the down regulation of TLR4/MyD88/NF-kB signaling pathway.

Evaluation of antiherpetic activity of crude extract and fractions of Avicenna marina, in vitro

AIM

This study was carried out to check antiherpetic substances of crude methanol leaf extract of Avicenna marina and its column chromatographic fractions.

BACKGROUND

Herpes simplex virus 2 (HSV-2) is a harmful pathogen especially in highly susceptible individuals.

MATERIALS AND METHODS

The antiherpetic activity of crude methanol extract and sub-fractions was performed in different concentrations (20, 2, 0.2, and 0.02μg/ml) by use of plaque-forming unit (PFU) assay and real time polymerase chain reaction (PCR) assay.

RESULTS

The most active fraction analyzed by NMR contained luteolin 7-O-methylether 3'-O-beta-d-glucoside (LMEG). The other active fraction was detected by HPLC as luteolin. The apparent effective concentrations for 50% plaque reduction (EC50) of crude methanol extract, LMEG, luteolin and ACV were 10, 5, 16.6 and 2.97μg/ml, respectively. The three extracts showed no cytotoxic effect on Vero cell line at concentrations of 32μg/ml or below. According to the consequences of time-of-addition studies, antiherpetic compound LMEG exerted an inhibitory effect on the early stage of HSV-2 infection during which it was added.

CONCLUSIONS

In conclusion, LMEG isolated from A. marina could probably inhibit HSV attachment to the cell membrane and its entry into the cell.

Anti-herpes virus activities of bioactive fraction and isolated pure constituent of Mallotus peltatus: an ethnomedicine from Andaman Islands

BACKGROUND

Viral infections, particularly the infections caused by herpes simplex virus (HSV), represent one of the most serious public health concerns globally because of their devastating impact. The aim of this study was to evaluate the antiviral potential of methanolic crude extract of an ethnomedicine Mallotus peltatus, its active fraction and pure compound, against HSV-1 F and HSV-2 G.

RESULT

The cytotoxicity (CC(50), the concentration of 50% cellular toxicity), antiviral effective concentration (EC(50), the concentration required to achieve 50% protection against virus-induced cytopathic effect), plaque reduction and the selectivity index (SI, the ratio of CC(50) and EC(50)) was determined. Results showed that the crude methanolic extract of M. peltatus possessed weak anti-HSV activity. In contrast, the active fraction A and isolated ursolic acid from fraction A exhibited potent antiherpesvirus activity against both HSV-1 (EC(50)= 7.8 and 5.5 μg/ml; SI = 22.3 and 20) and HSV-2 (EC(50)= 8.2 and 5.8 μg/ml, and SI = 21.2 and 18.97). The fraction A and isolated ursolic acid (10 μg/ml) inhibited plaque formation of HSV-1 and HSV-2 at more than 80% levels, with a dose dependent antiviral activity, compared to acyclovir. The time response study revealed that the anti-HSV activity of fraction A and isolated ursolic acid is highest at 2-5 h post-infection. Moreover, the time kinetics study by indirect immunofluorescence assay showed a characteristic pattern of small foci of single fluorescent cells in fraction A- treated virus infected cells at 2 h and 4 h post-infection, suggesting drug inhibited viral dissemination. Further, the PCR study with infected cell cultures treated with fraction A and isolated ursolic acid at various time intervals, failed to show amplification at 48-72 h, like acyclovir treated HSV-infected cells. Moreover, fraction A or isolated ursolic acid showed no interaction in combination with acyclovir.

CONCLUSION

This study revealed that bioactive fraction A and isolated ursolic acid of M. peltatus has good anti-HSV activity, probably by inhibiting the early stage of multiplication (post-infection of 0-5 h), with SI value of 20, suggesting its potential use as anti-HSV agents.

Inhibition of NO(2), PGE(2), TNF-α, and iNOS EXpression by Shorea robusta L.: An Ethnomedicine Used for Anti-Inflammatory and Analgesic Activity

This paper is an attempt to evaluate the anti-inflammatory and analgesic activities and the possible mechanism of action of tender leaf extracts of Shorea robusta, traditionally used in ailments related to inflammation. The acetic-acid-induced writhing and tail flick tests were carried out for analgesic activity, while the anti-inflammatory activity was evaluated in carrageenan-and dextran- induced paw edema and cotton-pellet-induced granuloma model. The acetic-acid-induced vascular permeability, erythrocyte membrane stabilization, release of proinflammatory mediators (nitric oxide and prostaglandin E₂), and cytokines (tumor necrosis factor-α, and interleukins-1β and -6) from lipopolysaccharide-stimulated human monocytic cell lines were assessed to understand the mechanism of action. The results revealed that both aqueous and methanol extract (400 mg/kg) caused significant reduction of writhing and tail flick, paw edema, granuloma tissue formation (P < 0.01), vascular permeability, and membrane stabilization. Interestingly, the aqueous extract at 40 μg/mL significantly inhibited the production of NO and release of PGE₂, TNF-α, IL-1β, and IL-6. Chemically the extract contains flavonoids and triterpenes and toxicity study showed that the extract is safe. Thus, our study validated the scientific rationale of ethnomedicinal use of S. robusta and unveils its mechanism of action. However, chronic toxicological studies with active constituents are needed before its use.

Antiviral activity of Bignoniaceae species occurring in the State of Minas Gerais (Brazil): part 1

AIMS

To evaluate the antiviral activity of Bignoniaceae species occurring in the state of Minas Gerais, Brazil.

METHODS AND RESULTS

Ethanol extracts of different anatomical parts of bignoniaceous plant species have been evaluated in vitro against human herpesvirus type 1 (HSV-1), vaccinia virus (VACV) and murine encephalomyocarditis virus (EMCV) by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. A total of 34 extracts from 18 plant species selected according to ethnopharmacological and taxonomic criteria were screened. Fifteen of the 34 extracts (44.1%) have disclosed antiviral activity against one or more of the viruses assayed with EC(50) values in the range of 23.2 ± 2.5-422.7 ± 10.9 μg ml(-1).

CONCLUSIONS

Twelve of the 34 extracts (35.3%) might be considered promising sources of antiviral natural products, as they have shown EC50 ≤ 100 μg ml(-1). The present screening discloses the high potential of the Bignoniaceae family as source of antiviral agents.

SIGNIFICANCE AND IMPACT OF THE STUDY

Active extracts were identified and deserve bioguided studies for the isolation of antiviral compounds and studies on mechanism of action.

Development of an Antiviral Screening Protocol: One-Stone-Two-Birds

As prophylactic therapies and vaccines against viral infections continue to improve, drug resistant strains are continuing to arise; therefore it is imperative to develop new therapeutics against these diseases. For highly pathogenic viruses, such as Ebola and H5N1 influenza virus, the need for antivirals is even more urgent due to limited therapeutics against these viruses. Furthermore, the high pathogenicity of such viruses often makes it difficult to work with such agents. In this report, we describe a protocol called "One-stone-two-birds" which provides a safe and efficient screening system to identify anti-flu (entry) and anti-HIV (replication) activities. Using plant extracts as an example, we demonstrate the utility of this protocol in antiviral screening.

In vitro antiherpes effects of a C-glycosylflavonoid-enriched fraction of Cecropia glaziovii Sneth

AIMS

To investigate the in vitro antiherpes effects of the crude aqueous extract obtained from Cecropia glaziovii leaves and their related fractions, the n-butanol fraction (n-BuOH) and the C-glycosylflavonoid-enriched fraction (MeOH(AMB)), and to determine the viral multiplication step(s) upon which this C-glycosylflavonoid-enriched fraction acts.

METHODS AND RESULTS

The antiviral activity was evaluated against human herpes virus types 1 and 2 (HHV-1, HHV-2) by plaque reduction assay. The mode of action of the most active fraction was investigated by a set of assays, and the results demonstrated that MeOH(AMB) fraction exerts anti-herpes action by the reduction of viral infectivity (only against HHV-2); by the inhibition of virus entry into cells; by the inhibition of cell-to-cell virus spread as well as by the impaired levels of envelope proteins of HHV-1. The high-performance liquid chromatography (HPLC)-photo-diode array (PDA) analysis showed that the C-glycosylflavonoids are the major constituents of this fraction.

CONCLUSIONS

These data showed that the MeOH(AMB) fraction has an antiviral activity against HHV types 1 and 2. The C-glycosylflavonoids are the major constituents of this fraction, which suggests that they could be one of the compounds responsible for the detected anti-herpes activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

The MeOH(AMB) fraction can be regarded as a phytopharmaceutical candidate for the treatment of herpetic infections.

Fundamentals and Health Benefits of Xanthohumol, a Natural Product Derived from Hops and Beer

In recent years, there has been a growing interest in phenolic compounds and their presumed role in the prevention of various degenerative diseases, such as cancer and cardiovascular diseases. Xanthohumol, a prenylated chalcone from hops and beer, is among the phenolic compounds which have received the most attention in recent years. This compound has a range of interesting biological properties that may have therapeutic utility. Based on the health-promoting properties of xanthohumol, the production of a beer enriched in this substance would be of huge interest to the brewing industry, for the benefits this could bring to consumer's health. This paper reviews recent and important data with respect to the health benefits or biological activities of xanthohumol and beer. In addition, an overview of the chemistry and biotechnological aspects of xanthohumol is presented.

Recent advancements for the evaluation of anti-viral activities of natural products

Significant progress has been achieved for the development of novel anti-viral drugs in the recent years. Large numbers of these newly developed drugs belong to three groups of compounds, nucleoside analogues, thymidine kinase-dependent nucleotide analogues and specific viral enzyme inhibitors. It has been found that the natural products, like plant extract, plant-derived compounds (phytochemicals) and so on, as well as traditional medicines, like Ayurvedic, traditional Chinese medicine (TCM), Chakma medicines and so on, are the potential sources for potential and novel anti-viral drugs based on different in vitro and in vivo approaches. In this chapter some of these important approaches utilised in the drug discovery process of potential candidate(s) for anti-viral agents are being discussed. The key conclusion is that natural products are one of the most important sources of novel anti-viral agents.