Inhibition of hepatitis B virus by an aqueous extract of Agrimonia eupatoria L

A phylogenetic perspective of antiviral species of the genus Artemisia (Asteraceae-Anthemideae): A proposal of anti SARS-CoV-2 (COVID-19) candidate taxa

Introduction

Different classes of disease-causing viruses are widely distributed universally. Plant-based medicines are anticipated to be effective cures for viral diseases including the COVID-19, instigated by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). This study displays the phylogenetic perspective of Artemisia and proposes some candidate taxa against different viral diseases, including SARS-CoV-2.

Methods

Data of Artemisia with antiviral activity were obtained from different published sources and electronic searches. A phylogenetic analysis of the nrDNA ITS sequences of reported antiviral Artemisia species, along with the reference species retrieved from the NCBI GenBank database, was performed using the maximum likelihood (ML) approach.

Results

In total, 23 Artemisia species have been documented so far with antiviral activity for 17 different types of viral diseases. 17 out of 23 antiviral Artemisia species were included in the ITS phylogeny, which presented the distribution of these antiviral Artemisia species in clades corresponding to different subgenera of the genus Artemisia. In the resultant ML tree, 10 antiviral Artemisia species appeared within the subgenus Artemisia clade, 2 species appeared within the subgenus Absinthium clade, 3 species appeared within the subgenus Dracunculus clade, and 2 species appeared within the subgenus Seriphidium clade.

Discussion

Artemisia species from different subgenera with antiviral activity are prevalent in the genus, with most antiviral species belonging to the subgenus Artemisia. A detailed analysis of taxa from all subgenera, particularly the subgenus Artemisia, is therefore proposed in order to discover compounds with potential anti-SARS-CoV-2 activity.

Agrimonia eupatoria L.: An integrative perspective on ethnomedicinal use, phenolic composition and pharmacological activity

ETHNOPHARMACOLOGICAL RELEVANCE

Agrimonia eupatoria L., a plant which belongs to the Rosaceae family, is widespread in temperate regions, particularly throughout the northern hemisphere. In folk medicine, this plant species has been used for its astringent, anti-inflammatory, analgesic and hypotensive properties as well as in gastrointestinal disorders. As these biological properties have been linked to its phenolic composition, this plant species could be an interesting source of bioactive compounds with therapeutic potential.

AIM OF THE STUDY

The aim of the present review is to provide a comprehensive overview of the scientific literature on A. eupatoria, particularly in regard to its ethnobotanics and ethnomedicinal uses, phenolic composition and biological and pharmacological activities.

MATERIAL AND METHODS

Literature was retrieved from several bibliographic sources, namely PubMed, ScienceDirect and Google Scholar, since the first report on A. eupatoria in 1993.

RESULTS

Regarding the phytochemical composition, A. eupatoria is rich in phenolic acids, flavonoids and tannins. The most commonly reported compounds are astragalin, cynaroside, hyperoside, isoquercitrin, isovitexin, rutin, catechin, procyanidin B3 and agrimoniin. In terms of bioactivity, extracts or fractions obtained from this plant species have shown antioxidant, antimicrobial, antidiabetic, antinociceptive and anti-inflammatory properties, among others. So far, two clinical studies with the infusion of A. eupatoria have shown hepatoprotective properties as well as a protective role in cardiovascular disease, metabolic disorders and diabetes.

CONCLUSIONS

In this review, an integrative perspective on ethnomedicinal use, phenolic composition and pharmacological activity of A. eupatoria has been provided. As can be seen, this plant species exhibits several potential applications, including those beyond its traditional ethnomedicinal uses, as the safety of its consumption has been shown clinically. There still is limited pharmacological evidence that corroborates the ethnomedicinal uses of this plant species as well as regarding the specific bioactive compounds.

Phytochemical and Pharmacological Research in Agrimonia eupatoria L. Herb Extract with Anti-Inflammatory and Hepatoprotective Properties

The most promising plant from the genus Agrimony (Agrimonia L.) of the Rosaceae family for use in medical practice is Agrimonia eupatoria L. Phytochemical and pharmacological research in Agrimonia eupatoria L. herb extract, obtained with using 40% ethanol solution as an extractant were carried out. A total of 11 free and 17 bound monosaccharides, 17 amino acids were found in the studied extract, 9 of which are essential. Gallic and ellagic acids, gallocatechin, epigallocatechin, catechin, epicatechin, and epicatechin gallate were identified in the extract of A. eupatoria by the HPLC method; as well as hydroxycinnamic acids: hydroxyphenylacetate, caffeic, syringic, p-coumaric, ferulic, sinapic, cinnamic and quinic acid; flavonoids: quercetin-3-D-glucoside (isoquercitrin), neohesperidin, naringenin, luteolin were found, and their quantitative content was determined, as well by spectrophotometric methods. The herb extract of A. eupatoria belongs to practically non-toxic substances and has pronounced anti-inflammatory (at a dose of 10.0 mg/kg anti-exudative activity reached a maximum in 5 h (88.17%)) and hepatoprotective activity (at a dose of 25 mg/kg it reduce AlAt level by 1.1 and 1.2 times, respectively; AsAt by 1.2 and 1.1 times, respectively), reduces the level of lipid peroxidation and stabilizes the membrane structures of liver cells. Thus, the herb extract of A. eupatoria is a promising substance for the creation of phytomedicines with anti-inflammatory and hepatoprotective activity.

New Properties and Mitochondrial Targets of Polyphenol Agrimoniin as a Natural Anticancer and Preventive Agent

Agrimoniin is a polyphenol from the group of tannins with antioxidant and anticancer activities. It is assumed that the anticancer action of agrimoniin is associated with the activation of mitochondria-dependent apoptosis, but its mitochondrial targets have not been estimated. We examined the direct influence of agrimoniin on different mitochondrial functions, including the induction of the mitochondrial permeability transition pore (MPTP) as the primary mechanism of mitochondria-dependent apoptosis. Agrimoniin was isolated from Agrimonia pilosa Ledeb by multistep purification. The content of agrimoniin in the resulting substance reached 80%, as determined by NMR spectroscopy. The cytotoxic effect of purified agrimoniin was confirmed on the cultures of K562 and HeLa cancer cells by the MTT assay. When tested on isolated rat liver mitochondria, agrimoniin at a low concentration (10 µM) induced the low-amplitude swelling, which was inhibited by the MPTP inhibitors ADP and cyclosporine A, activated the opening of MPTP by calcium ions and stimulated the respiration supported by succinate oxidation. Also, agrimoniin reduced the electron acceptor DCPIP in a concentration-dependent manner and chelated iron ions. Owing to all these properties, agrimoniin can stimulate apoptosis or activate mitochondrial functions, which can be helpful in the prevention and elimination of stagnant pathological states.

NS3/4A helicase inhibitory alkaloids from Aptenia cordifolia as HCV target

Chemical investigation of Aptenia cordifolia roots extract, using chromatographic and spectroscopic techniques, resulted in isolation and identification of eight known compounds. The basic ethyl acetate fraction (alkaloidal fraction) afforded O-methylsceletenone, epinine, 4-methoxy phenethylamine, and N-methyl tyramine while, the acidic ethyl acetate fraction (non-alkaloidal fraction) afforded only cis-N-coumaroyl tyramine. Moreover, the petroleum ether fraction afforded capric acid, tricosanol, and a mixture of β-sitosterol & stigma sterol. Upon screening of anti HCV activity of these three fractions, only the basic ethyl acetate fraction had high activity against HCV with an IC50 value equal to 2.4 μg mL-1 which provoked us to carry out structure based in silico virtual screening on the drug targets of HCV of isolated alkaloidal compounds as well as the previously dereplicated alkaloids through metabolomics from the antiviral active fraction. The tortuosamine compound exhibited the strongest binding to the active site of NS3/4A helicase with a binding affinity (-7.1 kcal mol-1) which is very close to the native ligand (-7.7 kcal mol-1).

A Brief Overview of Potential Treatments for Viral Diseases Using Natural Plant Compounds: The Case of SARS-Cov

The COVID-19 pandemic, as well as the more general global increase in viral diseases, has led researchers to look to the plant kingdom as a potential source for antiviral compounds. Since ancient times, herbal medicines have been extensively applied in the treatment and prevention of various infectious diseases in different traditional systems. The purpose of this review is to highlight the potential antiviral activity of plant compounds as effective and reliable agents against viral infections, especially by viruses from the coronavirus group. Various antiviral mechanisms shown by crude plant extracts and plant-derived bioactive compounds are discussed. The understanding of the action mechanisms of complex plant extract and isolated plant-derived compounds will help pave the way towards the combat of this life-threatening disease. Further, molecular docking studies, in silico analyses of extracted compounds, and future prospects are included. The in vitro production of antiviral chemical compounds from plants using molecular pharming is also considered. Notably, hairy root cultures represent a promising and sustainable way to obtain a range of biologically active compounds that may be applied in the development of novel antiviral agents.

In Silico Exploration of Phytoconstituents From Phyllanthus emblica and Aegle marmelos as Potential Therapeutics Against SARS-CoV-2 RdRp

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide has increased the importance of computational tools to design a drug or vaccine in reduced time with minimum risk. Earlier studies have emphasized the important role of RNA-dependent RNA polymerase (RdRp) in SARS-CoV-2 replication as a potential drug target. In our study, comprehensive computational approaches were applied to identify potential compounds targeting RdRp of SARS-CoV-2. To study the binding affinity and stability of the phytocompounds from Phyllanthus emblica and Aegel marmelos within the defined binding site of SARS-CoV-2 RdRp, they were subjected to molecular docking, 100 ns molecular dynamics (MD) simulation followed by post-simulation analysis. Furthermore, to assess the importance of features involved in the strong binding affinity, molecular field-based similarity analysis was performed. Based on comparative molecular docking and simulation studies of the selected phytocompounds with SARS-CoV-2 RdRp revealed that EBDGp possesses a stronger binding affinity (-23.32 kcal/mol) and stability than other phytocompounds and reference compound, Remdesivir (-19.36 kcal/mol). Molecular field-based similarity profiling has supported our study in the validation of the importance of the presence of hydroxyl groups in EBDGp, involved in increasing its binding affinity toward SARS-CoV-2 RdRp. Molecular docking and dynamic simulation results confirmed that EBDGp has better inhibitory potential than Remdesivir and can be an effective novel drug for SARS-CoV-2 RdRp. Furthermore, binding free energy calculations confirmed the higher stability of the SARS-CoV-2 RdRp-EBDGp complex. These results suggest that the EBDGp compound may emerge as a promising drug against SARS-CoV-2 and hence requires further experimental validation.

The therapeutic effects of Agrimonia eupatoria L

Agrimonia eupatoria L. is an herb of the Rosaceae family, widely used in traditional (folk) medicine for its beneficial effects. Its water extracts (infusions and decoctions) are used in the treatment of airway and urinary system diseases, digestive tract diseases, and chronic wounds. Phytochemical analyses of Agrimonia eupatoria L. identified a variety of bioactive compounds including tannins, flavonoids, phenolic acids, triterpenoids and volatile oils possessing antioxidant, immunomodulatory and antimicrobial activities. The authors review the available literature sources examining and discussing the therapeutic and pharmacological effects of Agrimonia eupatoria L. at the molecular level in vitro and in vivo.

Genomics approaches to synthesize plant-based biomolecules for therapeutic applications to combat SARS-CoV-2

COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is devastative to the humankind for which neither vaccines nor precise therapeutic molecules for treatment are identified. The search for new drugs and repurposing of existing drugs are being performed; however, at the same time, research on plants to identify novel therapeutic compounds or testing the existing ones is progressing at a slower phase. In this context, genomics and biotechnology offer various tools and strategies to manipulate plants for producing those complex biopharmaceutical products. This review enumerates the scope for research on plant-based molecules for their potential application in treating SARS-CoV-2 infection. Strategies to edit gene and genome, overexpression and silencing approaches, and molecular breeding for producing target biomolecules in the plant system are discussed in detail. Altogether, the present review provides a roadmap for expediting research on using plants as a novel source of active biomolecules having therapeutic applications.

Antibacterial effect of traditional food ingredients for healthcare on Helicobacter pylori

BACKGROUND

The development of antibacterial materials using various traditional food ingredients will be valuable to inhibit Helicobacter pylori in the future. The vegetables and herbs used in this study were food ingredients that normal people eat every day. This paper can be used as a resource for healthcare.

OBJECTIVE

This paper presents the design to investigate the antibacterial effect of 20 vegetables and herbs used as traditional food ingredients on H. pylori.

METHODS

The antibacterial effect on H. pylori was studied using the disk diffusion test on the activity of H. pylori. For the control group, 50 mg/ml of Metronidazol, a widely used antibiotic, was used. In particular, four herbs of Artemisia argyi, Scutellaria baicalensis, Annona muricata and Agrimonia pilosa were selected to measure the microbial viability assay, MTT assay, and antioxidant activity owing to the DPPH free radical elimination ability.

RESULTS

The measurement results showed that Annona muricata and Agrimonia pilosa had an antibacterial effect on H. pylori and all four herbs were safe in terms of cytotoxicity. The measurement results on the antioxidant activity showed that Scutellaria baicalensia was the best. Annona muricata and Agrimonia pilosa also had an antioxidant activity.

CONCLUSIONS

The study results on antibacterial effect of traditional food ingredients of vegetables and herbs on H. pylori showed that Scutellaria baicalensis, Annona muricata and Agrimonia pilosa can be considered as healthcare functional materials through the inhibition of H. Pylori.

Novel approach to combat antibiotic resistance: evaluation of some Armenian herb crude extracts for their antibiotic modulatory and antiviral properties

AIMS

One of the strategies to combat antibiotic resistance can be the use of plant materials in combination with antibiotics, taking into account that phytochemicals can act as antibiotic resistance-modifying agents. This can give a second life to the traditional antibiotics. The aim was to evaluate antibiotic modulatory effect of crude extracts from Agrimonia eupatoria, Hypericum alpestre, Rumex obtusifolius and Sanguisorba officinalis herbs towards several commercial antibiotics using some Gram-positive and Gram-negative bacteria.

METHODS

The antibiotic modulatory activity was tested by determining MICs of antibiotics in the absence and presence of plant crude extracts at subinhibitory concentrations. Antiviral potential of different extracts of tested plant materials was also explored by double overlay plaque assay.

RESULTS

The tested plant crude extracts exhibited high modulatory activity towards used antibiotics. Particularly, high modulatory activity was observed with extracts of H. alpestre and R. obtusifolius. Many plant-antibiotic combinations induced the decrease in MICs of antibiotics up to ~fourfold indicating synergy. Moreover, the similar change was observed at both subinhibitory concentrations (MIC/2 and MIC/4) of the same plant crude extract. High anti-phage activity of plants with the exception of Lilium armenum against T4 phage of Escherichia coli C-T4 was also shown.

CONCLUSIONS

Plant crude extract or commercial antibiotic combinations significantly increased the efficiency of antibiotics. Tested plant materials with exception of L. armenum have antiviral property.

SIGNIFICANCE AND IMPACT OF THE STUDY

For the first time, antibiotic modulatory activity of tested herb extracts was shown, which could have potential in practical applications. Tested plant materials with exception of L. armenum could have prospective, as a source of new antiviral compounds.

Prevalence and current therapy in chronic liver disorders

BACKGROUND

Herbal medicine plays an important role in health, particularly in remote parts of developing areas with few health facilities. According to WHO estimates, about three-quarters of the world's population currently use herbs or traditional medicines to treat various ailments, including liver diseases. Several studies have found that the use of medicinal plants was effective in the treatment of infectious and non-infectious diseases. Hepatitis and liver cirrhosis associated with many clinical manifestations can be treated with allopathic medicines, but reports of a number of side effects including immunosuppression, bone marrow suppression, and renal complications have motivated researchers to explore more natural herbal medicines with low or no side effects and with high efficacy in treating hepatic diseases.

METHODS

Databases including PubMed, Medline, and Google Scholar were searched for findings on the hepatoprotective effects of plants.

RESULTS

Various medicinal plants are used for the treatment of liver disorders. The range of alternative therapies is huge, and they are used worldwide, either as part of primary health care or in combination with conventional medicine. Hepatoprotective plants contain a variety of chemical constituents including flavonoids, alkaloids, glycosides, carotenoids, coumarins, phenols, essential oil, organic acids, monoterpenes, xanthenes, lignans, and lipids.

CONCLUSION

This review shows that numerous plants are found to contain hepatoprotective compounds. However, further studies are needed to determine their association with existing regimes of antiviral medicines and to develop evidence-based alternative medicine to cure different kinds of liver disease in humans.

Agrimonia eupatoria L. (Agrimony) Extract Alters Liver Health in Subjects with Elevated Alanine Transaminase Levels: A Controlled, Randomized, and Double-Blind Trial

Agrimonia eupatoria L. has been shown to protect against liver injury due to its lipid lowering and antioxidant activities. The aim of this research was to evaluate the effect of A. eupatoria L. aqueous extract (AEE) on 80 subjects with elevated alanine transaminase (ALT) levels in a randomized, double-blind, placebo-controlled, 8-week study. This trial was conducted between January 2013 and July 2013 at the Oriental Medical Hospital (Jecheon) of Semyung University. The trial included subjects aged 20 years or older who were diagnosed with mildly to moderately elevated ALT levels (between 45 and 135 IU/L). Subjects received two capsules of placebo or AEE twice a day for 8 weeks. Adverse events were recorded. Eighty subjects were randomized to placebo or AEE groups who had similar baseline characteristics. During the 8 weeks of treatment, 11 subjects were excluded from the analysis for protocol violation or consent withdrawal; efficacy of treatment was, therefore, evaluated in 69 subjects (placebo = 35, AEE = 34). The AEE group showed a significant reduction in ALT and serum triglyceride (TG) at 8 weeks compared with the placebo group (ALT P = .044, TG P = .020). Significant group and time interactions were found in ALT (P = .038), aspartate aminotransferase (P = .040), and TG (P = .010). Alkaline phosphatase, total bilirubin, and gamma-glutamyl transferase levels were not different between the two groups. There were no reported severe adverse events during this study, and total protein, albumin, blood urea nitrogen, creatine, and total cholesterol levels were normal in both groups. AEE consumption was safe and generally well tolerated without severe adverse events.

Extracts of Agrimonia eupatoria L. as sources of biologically active compounds and evaluation of their antioxidant, antimicrobial, and antibiofilm activities

In this study, we determined the concentration of total phenols, flavonoids, tannins, and proanthocyanidins in the water, diethyl ether, acetone, and ethanol extracts of Agrimonia eupatoria L. We also investigated the antioxidant activity of these extracts using two methods [2,2-diphenyl-1-picrylhydrazyl (DPPH) and reducing power] and their in vitro antimicrobial (antibacterial and antifungal) activity on some selected species of bacteria and fungi. In addition, the effects of the acetone and water extracts on the inhibition of biofilm formation of Proteus mirabilis and Pseudomonas aeruginosa were investigated using the crystal violet method. The concentration of total phenols was measured according to the Folin-Ciocalteu method and the values obtained ranged from 19.61 mgGA/g to 220.31 mgGA/g. The concentration of flavonoids was examined by the aluminum chloride method and the values obtained ranged from 20.58 mgRU/g to 97.06 mgRU/g. The total tannins concentration was measured by the polyvinylpolypyrrolidone method and the values obtained ranged from 3.06 mgGA/g to 207.27 mgGA/g. The concentration of proanthocyanidins was determined by the butanol-HCl method and the values obtained ranged from 4.15 CChE/g to 103.72 CChE/g. Among the various extracts studied, the acetone extract exhibited good antioxidant activity (97.13%, as determined by the DPPH method). The acetone extract was active in the absorbance value range from 2.2665 to 0.2495 (as determined by the reducing power method). The strongest antimicrobial activity was detected on G⁺ bacteria, especially on probiotic species, and the acetone extract demonstrated the highest activity. Biofilm inhibitory concentration required to reduce biofilm coverage by 50% values for acetone extract was 4315 μg/mL for P. mirabilis and 4469.5 μg/mL for P. aeruginosa. The results provide a basis for further research of this plant species.

Anticholinesterase, antioxidant activity and phytochemical investigation into aqueous extracts from five species of Agrimonia genus

Aqueous extracts of aerial flowering parts of five Agrimonia species (Rosaceae): Agrimonia coreana Nakai, Agrimonia japonica (Miq.) Koidz, Agrimonia procera Wallr., Agrimonia eupatoria L. and Agrimonia leucantha Kunze were investigated on their antioxidant activity, measured using five different methods; the best was the extract from A. procera with IC50 values from 6 to 29 μg/mL. All the extracts displayed inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) at the tested concentration of 100 μg/mL. We found the highest inhibition of cholinesterase in the extract of A. japonica with inhibition 70.4% for AChE and 79.8% for BuChE. These findings are statistically significant in comparison with those of other extracts (p < 0.001). The phytochemical analyses showed that the antioxidant activity of Agrimonia extracts can be affected especially by hexahydroxydiphenoyl (HHDP)-glucose and quercetin glycosides, and inhibition of cholinesterases by apigenin, luteolin and quercetin glycosides.

Agrimonia eupatoria tea consumption in relation to markers of inflammation, oxidative status and lipid metabolism in healthy subjects

Phytotherapy reports strong anti-oxidative and anti-inflammatory potential of agrimony (Agrimonia eupatoria L.). However the effects of agrimony tea consumption are not scientifically proven in humans. We investigated the effects of one month's consumption of agrimony tea in healthy volunteers. Significant elevation of plasma total antioxidant capacity was observed and interleukin 6 levels were significantly lowered at the end of the intervention. An improved lipid profile as estimated by increased high density lipoprotein (HDL) cholesterol was established upon agrimony tea supplementation and HDL cholesterol correlated with adiponectin levels. The results presented in this first human intervention study with agrimony tea indicate that the plant has potential in improving markers of lipid metabolism, oxidative status and inflammation in healthy adults.

Anti-HBV agents derived from botanical origin

There are 350,000 hepatitis B virus (HBV) carriers all over the world. Chronic HBV infection is at a high risk of developing liver cirrhosis and hepatocelluar carcinoma (HCC), and heavily threatened people's health. Two kinds of drugs approved by FDA for anti-HBV therapy are immunomodulators (interferon α, pegylated-interferon α) and nucleos(t)ide analogues (lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate). These drugs have been proved to be far from being satisfactory due to their low specificity, side effects, and high rate of drug resistance. There is an urgent need to discover and develop novel effective anti-HBV drugs. With vast resources, various structures, diverse biological activities and action mechanisms, as well as abundant clinical experiences, botanical agents become a promising source of finding new anti-HBV drugs. This review summarizes the recent research and development of anti-HBV agents derived from botanical origin on their sources and active components, inhibitory effects and possible toxicities, as well as action targets and mechanisms, and also addresses the advantages and the existing shortcomings in the development of botanical inhibitors. This information may not only broaden the knowledge of anti-HBV therapy, and offer possible alternative or substitutive drugs for CHB patients, but also provides considerable information for developing new safe and effective anti-HBV drugs.

Antiviral Properties of Phytochemicals

In recent years, significant progress has been achieved for the development of novel anti-viral drugs. 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-derived compounds (phytochemicals) as well as traditional medicines, like traditional Chinese medicines (TCM), Ayurvedic medicines and so on, are the important sources for potential and novel anti-viral drugs. In this chapter, the history of natural products as antiviral drugs, the approaches to discover potential lead compounds, and the anti-viral properties of phytochemicals with different action mechanisms are discussed. The key conclusion is that natural products are most important sources for novel anti-viral drugs.

Anti-Viral Activity of Indian Plants

Plants continue to be a major source for new chemical entities to develop novel therapeutic agents. Large number of plants has been shown to be active in vitro against a variety of human pathogenic viruses or their near congeners. In several cases the active compounds have been isolated and characterized. Very few of them, however, have been investigated in detail in vivo or taken to the clinic. Pure compounds like andrographolide, curcumin and glycyrrhizic acid as well as extracts of Azadirachta indica have shown activity against several viruses and should be investigated further for their therapeutic potential. An analysis of available data from several hundred species indicates that antiviral activity is more likely to be found in plants belonging to certain families. It is necessary to screen more plants of these families which are available in India to obtain further leads.

Antiviral potentials of medicinal plants

Medicinal plants have been widely used to treat a variety of infectious and non-infectious ailments. According to one estimate, 25% of the commonly used medicines contain compounds isolated from plants. Several plants could offer a rich reserve for drug discovery of infectious diseases, particularly in an era when the latest separation techniques are available on one hand, and the human population is challenged by a number of emerging infectious diseases on the other hand. Among several other ailments, viral infections, particularly infections associated with human immunodeficiency virus type 1 (HIV-1) and 2 (HIV-2), and newly emerging infectious viruses have challenged mankind survival. Of importance, a variety of medicinal plants have shown promise to treat a number of viral infections, and some of them possess broad-spectrum antiviral activity. In the past, exploration into the antiviral activity of various promising medicinal plants was limited due to: (a) highly infectious nature of viruses and (b) lack of appropriate separation techniques for the identification of antiviral components from plants. Development of vector-based strategies, in which non-infectious molecular clone of a virus could be used for antiviral screening purposes, and advancement in separation technologies offers promise for medicinal plants usage in modern drug discovery. This article describes potential antiviral properties of medicinal plants against a diverse group of viruses, and suggests screening the potential of plants possessing broad-spectrum antiviral effects against emerging viral infections.

The activity of an extract and fraction of Agrimonia eupatoria L. against reactive species

Agrimonia eupatoria L. (agrimony) is a medicinal plant largely used in traditional medicine. Recently, phytochemical studies on an agrimony hydro-alcoholic extract and a polyphenol-enriched fraction obtained from it were carried out. The fraction was found to possess a high concentration of flavan-3-ols, flavonols, flavones and phenolic acids. So, the main purpose of this study was to search out, the extract and fraction antioxidant potential and scavenging activity against the reactive species formed during inflammation and to establish a relationship between such activity and the phenolic composition. Results showed that both the extract and the fraction promptly reacted with DPPH denoting a general radical scavenger activity and a potential antioxidant capacity. They also reacted with superoxide anion, peroxyl and hydroxyl radicals as well as with the oxidant species, hydrogen peroxide, hypochlorous acid and peroxynitrite, strengthening their radical scavenger and antioxidant activities. In most assays, the polyphenol-enriched fraction was more efficient, pointing to a significant contribution of the polyphenols content to those activities. Our data suggest that the significant scavenging capacity of reactive species by polyphenols from Agrimonia eupatoria L., could be a mechanism of its anti-inflammatory activity.