Indole alkaloids from the roots of Isatis ingigotica and their antiherpes simplex virus type 2 (HSV-2) activity in vitro

Quinazolinone nitriles and related metabolites from the deep-sea-derived fungus Penicillium viridicatum MCCC 3A00265

Two new quinazolinone nitriles (1 and 2) and one new indole alkaloid (3), together with 13 known compounds, were isolated from the deep-sea-derived Penicillium viridicatum MCCC 3A00265. Their structures were determined by extensive spectroscopic analysis, with the absolute configurations established by comparing experimental and calculated electronic circular dichroism (ECD) and optical rotation (OR) data as well as biogenetic considerations. Viricyanoamides A and B (1 and 2) are the sole representatives of quinazolinones featuring a nitrile group, while solitumidine F (3) incorporates a rare pyrrolidinedione unit as an indole terpenoid. In particular, compounds 2 and 10 exhibit significant activity in reactivating mutant p53 at 10 μM, indicating their potential for application in cancer therapy.

Antiproliferative metabolites against glioma cells from the marine-associated actinomycete Streptomyces sp. ZZ735

Metabolites produced by the genus Streptomyces are the most important resource for discovering bioactive compounds. In this study, chemical investigation on the metabolites produced by the marine-derived Streptomyces sp. ZZ735 in rice solid medium led to the isolation of eighteen compounds (1-18). Chemical structures of the isolated compounds were determined based on their HRESIMS data and the extensive NMR spectral analyses. Streptonaphthothiazines A (1), B (2), 2-(2-hydroxy-2-methylpropanoylamino)-benzoic acid (7), and streptomycinoic acids A (17), B (18) are characterized as five previously undescribed compounds. The structural backbones of streptonaphthothiazines A (1), B (2) and streptomycinoic acids A (17), B (18) are found from a natural resource for the first time. It is also the first report of 2-(2-methylpropanoylamino)-benzoic acid (3), 2-(2-methylpropanoylamino)-benzamide (4), methyl 2-(3-hydroxypropanoylamino)-benzoate (5), 2-propionylaminobenzamide (6), and (2E)-3-(3-hydroxy-4,5-dimethoxyphenyl)-2-propenoic acid (15) as natural products. Streptonaphthothiazines A (1), B (2) and streptomycinoic acids A (17), B (18) have antiproliferative activity against human glioma U87MG or U251 cells with IC50 values ranging from 31.8 to 37.9 μM.

Chemical constituents from the heterotrophic marine microalgae Aurantiochytrium sp. SC145 and their antimicrobial activities

One new indol, N-methoxymethyltryptophol (1), one new phenolic, (2 R)-2-(4-hydroxyphenyl)ethyl 2-hydroxy-3-phenylpropanoate (2) and fifteen known compounds (3-17) were isolated from the methanol extract of the fermentation of marine microalgae Aurantiochytrium sp. SC145. Their structures were elucidated by 1D-, 2D-NMR spectroscopic analysis, HR-ESI-MS, quantum chemical calculation methods and by comparing their NMR data with those reported in the literature. All compounds were evaluated for their antimicrobial activities against microorganisms. Compounds 2, 3 and 11 significantly exhibited antimicrobial activities on all tested Gram-(+), Gram-(-) bacteria and the yeast C. albicans with MIC values ranging from 32 to 256 µg/mL.

Characterization and Bioactive Potential of Secondary Metabolites Isolated from Piper sarmentosum Roxb

Piper sarmentosum Roxb. (Piperaceae) is a traditional medicinal plant in South-East Asian countries. The chemical investigation of leaves from this species resulted in the isolation of three previously not described compounds, namely 4″-(3-hydroxy-3-methylglutaroyl)-2″-β-D-glucopyranosyl vitexin (1), kadukoside (2), and 6-O-trans-p-coumaroyl-D-glucono-1,4-lactone (3), together with 31 known compounds. Of these known compounds, 21 compounds were isolated for the first time from P. sarmentosum. The structures were established by 1D and 2D NMR techniques and HR-ESI-MS analyses. The compounds were evaluated for their anthelmintic (Caenorhabditis elegans), antifungal (Botrytis cinerea, Septoria tritici and Phytophthora infestans), antibacterial (Aliivibrio fischeri) and cytotoxic (PC-3 and HT-29 human cancer cells lines) activities. Methyl-3-(4-methoxyphenyl)propionate (8), isoasarone (12), and trans-asarone (15) demonstrated anthelmintic activity with IC₅₀ values between 0.9 and 2.04 mM. Kadukoside (2) was most active against S. tritici with IC₅₀ at 5.0 µM and also induced 94% inhibition of P. infestans growth at 125 µM. Trans-asarone (15), piperolactam A (23), and dehydroformouregine (24) displayed a dose-dependent effect against B. cinerea from 1.5 to 125 µM up to more than 80% inhibition. Paprazine (19), cepharadione A (21) and piperolactam A (23) inhibited bacterial growth by more than 85% at 100 µM. Only mild cytotoxic effects were observed.

Determination of Free Amino Acids in Banlangen Granule and its Fractions by Solid Phase Extraction Combined with Ion-pair Hig-h Perfor mance Liquid Chromatography using a Corona-charged Aerosol Detector (SPE-HPLC-CAD)

Background:

Banlangen granules are broad-spectrum effective antiviral drugs, and have a large clinical demand in China. Free amino acid is one of the main antiviral active ingredients of Banlangen granules. The pre-processing of samples by the existing pre-column derivatization reversed- HPLC method is complicated. Therefore, the determination of free amino acids (AAs) by underivatized ion-pair HPLC-CAD is advantageous for simplifying the preparation process and improving sensitivity.

Objective:

To better optimize AAs analysis methods, here a sensitive SPE-HPLC-CAD method with a better resolution was established for the determination of underivatized AAs in Banlangen Granule for the first time.

Method:

The analytes were separated only by HPLC using a Hypercarb column with gradient elution of solvent A (20 mM nonafluorovaleric Acid in water) and solvent B (0.3% trifluoroacetic acid in acetonitrile-0.3% trifluoroacetic acid in water (1:9, v/v)) at a flow rate of 0.15 mL/min. N2 gas pressure and evaporation temperature of CAD were held at a constant 58.6 psi and 60 ℃, respectively.

Results:

This method was linear over the respective concentration range of six amino acids. The precision, accuracy, stability and recovery were satisfactory in all samples examined. And the method was successfully applied to determination of free amino acids in Banlangen granules and its fractions. The total contents of six amino acids in 28 batches of Banlangen Granule were between 1.36 mg/g-11.62 mg/g.

Conclusion:

The proposed method could be a simple, accurate and sensitive alternative approach for the determination of free AAs in Banlangen Granule.

Alkaloids as Potential Phytochemicals against SARS-CoV-2: Approaches to the Associated Pivotal Mechanisms

Since its inception, the coronavirus disease 2019 (COVID-19) pandemic has infected millions of people around the world. Therefore, it is necessary to find effective treatments against Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), as it is the viral source of COVID-19. Alkaloids are one of the most widespread plant-derived natural compounds with prominent antiviral effects. Accordingly, these phytochemicals have been promising candidates towards discovering effective treatments for COVID-19. Alkaloids have shown potential anti-SARS-CoV activities via inhibiting pathogenesis-associated targets of the Coronaviridae family that are required for the virus life cycle. In the current study, the chemistry, plant sources, and antiviral effects of alkaloids, as well as their anti-SARS-CoV-2 effect with related mechanisms, are reviewed towards discovering an effective treatment against COVID-19.

Acremolin D, a new acremolin alkaloid from the deep-sea sediment derived Aspergillus sydowii fungus

Chemical investigation of the deep-sea-derived fungus Aspergillus sydowii MCCC 3A00324 led to the isolation of one new acremolin type alkaloid (acremolin D, 1) and five known alkaloids (2‒6). The planar structure of 1 was established by the extensive analyses of the NMR and HRESIMS data, while its absolute configuration was assigned by the comparison of the experimental and calculated ECD data. Acremolin D (1) represented the second analogue of acremolin found in nature. All compounds were evaluated for their cytotoxic activities against six human cancer cell lines (A549, Hela-S3, MCF-7, HepG2, K562, and SF-268). As a result, compounds 1 and 2 exhibited a certain inhibitory effects against the proliferation of the A549, Hela-S3, HepG2, and K562 cell lines at the concentration of 20 µM.

In Search of Herbal Anti-SARS-Cov2 Compounds

On March 11, 2020, the World Health Organization (WHO) announced that the spread of the new coronavirus had reached the stage of a pandemic. To date (23.10.2020), there are more than 40 million confirmed cases of the disease in the world, at the same time there is still no effective treatment for the disease. For management and treatment of SARS-Cov2, the development of an antiviral drug is needed. Since the representatives of all human cultures have used medicinal plants to treat viral diseases throughout their history, plants can be considered as sources of new antiviral drug compounds against emerging viruses. The huge metabolic potential of plants allows us to expect discovery of plant compounds for the prevention and treatment of coronavirus infection. This idea is supported by number of papers on the anti-SARS-Cov2 activity of plant extracts and specific compounds in the experiments in silico, in vitro, and in vivo. Here, we summarize information on methods and approaches aimed to search for anti-SARS-Cov2 compounds including cheminformatics, bioinformatics, genetic engineering of viral targets, interacting with drugs, biochemical approaches etc. Our mini-review may be useful for better planning future experiments (including rapid methods for screening compounds for antiviral activity, the initial assessment of the antiviral potential of various plant species in relation to certain pathogens, etc.) and giving a hand to those who are making first steps in this field.

Indole alkaloid glycosides with a 1'-(phenyl)ethyl unit from Isatis indigotica leaves

Seven indole alkaloid glycosides containing a 1′-(4″-hydroxy-3″,5″-dimethoxyphenyl)ethyl unit (1–7) were isolated from an aqueous extract of Isatis indigotica leaves (da qing ye). Their structures were determined by spectroscopic data analysis combined with enzymatic hydrolysis as well as comparison of their experimental CD (circular dichroism) and calculated ECD (electrostatic circular dichroism) spectra. Based on analysis of [α]D20 and/or Cotton effect (CE) data of 1–7, two simple roles to assign location and/or configuration of β-glycopyranosyloxy and 1′-(phenyl)ethyl units in the indole alkaloid glycosides are proposed. Stereoselectivity in plausible biosynthetic pathways of 1–7 is discussed. Compounds 3 and 4 and their mixture in a 3:2 ratio showed activity against KCNQ2 in CHO cells. The mixture of 5 and 6 (3:2) exhibited antiviral activity against influenza virus H1N1 PR8 with IC₅₀ 64.7 μmol/L (ribavirin, IC₅₀ 54.3 μmol/L), however, the individual 5 or 6 was inactive. Preliminary structure–activity relationships were observed.

Targeted Isolation of Indole Alkaloids from Streptomyces sp. CT37

Four compounds (1-4) were isolated from the extracts of Streptomyces sp. CT37 using bioassay in conjunction with mass spectrometric molecular networking (MN) driven isolation. Their complete structures were established by high-resolution electrospray ionization mass spectrometry (HR-ESIMS), and 1D and 2D nuclear magnetic resonance (NMR) data. Legonimide 1 was identified as a new alkaloid containing a rare linear imide motif in its structure, while compounds 2-4 were already known and their structures were elucidated as 1H-indole-3-carbaldehyde, actinopolymorphol B, (2R,3R)-1-phenylbutane-2,3-diol, respectively. The biosynthetic pathways of 1-4 were proposed based on the reported biogenesis of indole alkaloids in literature. Bioactivity tests for 1 and 2 revealed moderate growth inhibition activity against Candida albicans ATCC 10231 with MIC95 values of 21.54 µg/mL and 11.47 µg/mL, respectively.

A chromosome-scale genome assembly of Isatis indigotica, an important medicinal plant used in traditional Chinese medicine: An Isatis genome

Isatis indigotica (2n = 14) is an important medicinal plant in China. Its dried leaves and roots (called Isatidis Folium and Isatidis Radix, respectively) are broadly used in traditional Chinese medicine for curing diseases caused by bacteria and viruses such as influenza and viral pneumonia. Various classes of compounds isolated from this species have been identified as effective ingredients. Previous studies based on transcriptomes revealed only a few candidate genes for the biosynthesis of these active compounds in this medicinal plant. Here, we report a high-quality chromosome-scale genome assembly of I. indigotica with a total size of 293.88 Mb and scaffold N50 = 36.16 Mb using single-molecule real-time long reads and high-throughput chromosome conformation capture techniques. We annotated 30,323 high-confidence protein-coding genes. Based on homolog searching and functional annotations, we identified many candidate genes involved in the biosynthesis of main active components such as indoles, terpenoids, and phenylpropanoids. In addition, we found that some key enzyme-coding gene families related to the biosynthesis of these components were expanded due to tandem duplications, which likely drove the production of these major active compounds and explained why I. indigotica has excellent antibacterial and antiviral activities. Our results highlighted the importance of genome sequencing in identifying candidate genes for metabolite synthesis in medicinal plants.

N-containing compounds from Periplaneta americana and their activities against wound healing

Three new compounds, periplanamides A (1) and B (2), periplanpyrazine A (3), a new naturally occurring compound salicyluric acid methyl ester (6), and seventeen known compounds were isolated from the medicinal insect Periplaneta americana. The structures of the new compounds were elucidated on the basis of spectroscopic methods. The absolute configurations of 2 were assigned by computational methods. Biological activities of these isolates except 1, 9, 11, and 13 toward nitric oxide (NO) production, cell proliferation in HDFs, cell migration and angiogenesis in HUVECs were evaluated.

Sulfur-enriched alkaloids from the root of Isatis indigotica

Five new sulfur-enriched alkaloids isatithioetherins A-E (1-5), and two pairs of scalemic enantiomers (+)- and (-)-isatithiopyrin B (6a and 6b) and isoepigoitrin and isogoitrin (7a and 7b), along with the known scalemic enantiomers epigoitrin and goitrin (8a and 8b), were isolated and characterized from an aqueous extract of the Isatis indigotica roots. Their structures were determined by extensive spectroscopic data analysis, including 2D NMR and theoretical calculations of electronic circular dichroism (ECD) spectra based on the quantum-mechanical time-dependent density functional theory (TDDFT). Compounds 1-5 represent a novel group of sulfur-enriched alkaloids, biogenetically originating from stereoselective assemblies of epigoitrin-derived units. Isolation and structure characterization of 6a and 6b support the postulated biosynthetic pathways for the diastereomers 9a and 9b via a rare thio-Diels-Alder reaction. Compounds 2 and 4 showed antiviral activity against the influenza virus A/Hanfang/359/95 (H3N2, IC50 0.60 and 1.92 μmol/L) and the herpes simplex virus 1 (HSV-1, IC50 3.70 and 2.87 μmol/L), and 2 also inhibited Coxsackie virus B3 (IC50 0.71 μmol/L).

Preferentially enhancing anti-cancer isothiocyanates over glucosinolates in broccoli sprouts: How NaCl and salicylic acid affect their formation

Broccoli (Brassica oleracea L. var. italica) sprouts contain glucosinolates (GLs) that when hydrolysed yield health promoting isothiocyanates such as sulforaphane (SF). SF content can be increased by salt (NaCl) stress, although high salt concentrations negatively impact plant growth. Salicylic acid (SA) treatments can attenuate the negative effects of salt on growth. To test whether sprout isothiocyanate content could be elevated without sprout growth being compromised, broccoli seed were germinated and grown for seven days in salt (0, 80 and 160 mM) alone and in combination with 100 μM SA. Increasing concentrations of salt lowered transcript accumulation of GL biosynthetic genes which was reflected in lowered content of Gluconapin, 4-methoxyglucobrassicin and neoglucobrassicin glucosinolates. Other glucosinolates such as glucoraphanin did not alter significantly. Salt (160 mM) increased transcript abundance of the GL hydrolytic gene MYROSINASE (BoMYO) and its cofactor EPITHIOSPECIFIER MODIFIER1 (BoESM1) whose encoded product directs MYROSINASE to produce isothiocyanate rather than nitrile forms. SF content was increased 6-fold by the 160 mM salt treatment, but the salt treatment reduced percentage seed germination, slowed seed germination, and reduced sprout hypocotyl elongation. This growth inhibition was prevented if 100 μM SA was included with the salt treatment. These findings suggest that the increase in SF production by salt occurs in part because of increased transcript abundance of genes in the hydrolytic pathway, which occurs independently of the negative impact of salt on sprout growth.

Anti-neuroinflammatory activities of indole alkaloids from kanjang (Korean fermented soy source) in lipopolysaccharide-induced BV2 microglial cells

Kanjang (Korean soy sauce) is a byproduct of the production of the Korean fermented soybean. In the present study, seven indole alkaloid derivatives were isolated from methanol extract of kanjang. Their structures were identified as 1-propyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (1), 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (2), 1-methyl-1,2,3,4-tetrahydro-β-carboline-1-carboxylic acid (3), 3-indoleacetic acid (4), Nb-acetyltryptamine (5), 1-methyl-3,4-dihydro-β-carboline (6), and flazine (7) by NMR and MS analyses. Preliminary screening for anti-neuroinflammatory effects of isolated indole alkaloids in lipopolysaccharide (LPS)-stimulated BV2 cells revealed that these compounds inhibited the production of nitric oxide and prostaglandin E2. For the subsequent investigation of anti-neuroinflammatory action of these metabolites, compounds 4 and 7 were selected, and the results revealed that these inhibitory effects correlated with the suppressive effect of 4 and 7 on inducible nitric oxide synthase and cyclooxygenase-2 expression in LPS-stimulated BV2 cells. In regards to the mechanism of the anti-inflammatory effect, 4 and 7 significantly inhibited the nuclear factor-kappa B pathway.

Antiherpetic Plants: A Review of Active Extracts, Isolated Compounds, and Bioassays

Herpes simplex is a disease that is widely distributed throughout the world. It is caused by herpes simplex virus type 1 (HSV-1) and simplex virus type 2 (HSV-2). The drugs of choice for treatment are acyclovir (ACV), Penciclovir (PCV) and other guanine analogues, which have the same mechanism of action. However, due to the constant increase of ACV-resistant strains in immunocompromised patients, it is necessary to find new treatment alternatives. It has been shown that natural products are a good alternative for the treatment of these diseases as well as being an excellent source of compounds with anti-herpetic activity, which may be useful for the development of new drugs and act through a mechanism of action different from ACV and PCV. This paper compiles reports on extracts and compounds isolated from plants that have anti-herpetic activity. We present an analysis of the solvents most widely used for extraction from plants as well as cells and commonly used methods for evaluating cytotoxic and anti-herpetic activity. Families that have a higher number of plants with anti-herpetic activity are evaluated, and we also highlight the importance of studies of mechanisms of action of extracts and compounds with anti-herpetic activity.

Antiviral effects against EV71 of pimprinine and its derivatives isolated from Streptomyces sp

Background

The pimprinine family of compounds represent very important and promising microbial metabolites for drug discovery. However, their ability in inhibiting viral infections has not yet been tested.

Methods

The antiviral activity of the pimprinine family of compounds was evaluated by determining the cytopathic effect (CPE), cell viability or plaque-forming unit (PFU), and virus yield. The mechanism of action against EV71 was determined from the virucidal activity, and effective stage and time-of-addition assays. The effects on EV71 replication were evaluated further by determining viral RNA synthesis, protein expression and cells apoptosis using the SYBR Green assays, immunofluorescence assays and flow cytometric assays, respectively.

Results

Pimprinethine, WS-30581 A and WS-30581 B inhibited EV71-induced CPE, reduced progeny EV71 yields, as well as prevented EV71-induced apoptosis in human rhabdomyosarcoma (RD) cells. These compounds were found to target the early stages of the EV71 replication in cells including viral RNA replication and protein synthesis. They also showed antiviral activity against ADV-7, and were slightly active against CVB3, HSV-1 and H1N1 with a few exceptions. Pimprinine was slightly active or inactive against all the viruses tested. The mechanisms by which these compounds act against the viruses tested may be similar to that demonstrated for EV71.

Conclusion

The data described herein demonstrate that the pimprinine family of compounds are inhibitors effective against the replication of EV71 and ADV-7, so they might be feasible therapeutic agents for the treatment of viral infections.

High-throughput sequencing and De Novo assembly of the Isatis indigotica transcriptome

Background

Isatis indigotica, the source of the traditional Chinese medicine Radix isatidis (Ban-Lan-Gen), is an extremely important economical crop in China. To facilitate biological, biochemical and molecular research on the medicinal chemicals in I. indigotica, here we report the first I. indigotica transcriptome generated by RNA sequencing (RNA-seq).

Results

RNA-seq library was created using RNA extracted from a mixed sample including leaf and root. A total of 33,238 unigenes were assembled from more than 28 million of high quality short reads. The quality of the assembly was experimentally examined by cDNA sequencing of seven randomly selected unigenes. Based on blast search 28,184 unigenes had a hit in at least one of the protein and nucleotide databases used in this study, and 8 unigenes were found to be associated with biosynthesis of indole and its derivatives. According to Gene Ontology classification, 22,365 unigenes were categorized into 48 functional groups. Furthermore, Clusters of Orthologous Group and Swiss-Port annotation were assigned for 7,707 and 18,679 unigenes, respectively. Analysis of repeat motifs identified 6,400 simple sequence repeat markers in 4,509 unigenes.

Conclusion

Our data provide a comprehensive sequence resource for molecular study of I. indigotica. Our results will facilitate studies on the functions of genes involved in the indole alkaloid biosynthesis pathway and on metabolism of nitrogen and indole alkaloids in I. indigotica and its related species.

Research progress of Chinese herbal medicine Radix isatidis (banlangen)

Radix isatidis (R. isatidis) (Banlangen) is a traditional Chinese medicine (TCM) famous for its broad antiviral activity. Its clinical medical history spans several thousands of years in China. Many scientists and scholars have conducted systematic research on this herb from its pharmacognosy to pharmaceuticals, especially in China. Through our research and literature reports, we inferred that the antiviral activity of R. isatidis mostly depended on the water-soluble part, including amino acids, IRPS, nucleosides, and sulfur-containing alkaloids. By playing a role in directly killing pathogenic viruses or regulating the immune system to enhance anti-virus ability, R. isatidis's biological activities mostly depend on the synergistic effect of its multiple components. This article aims to expand understanding of R. isatidis in the following aspects including medicinal resources, chemical constituents, pharmacological activities, clinical applications, and separation and analytical technologies.

A novel compound with antioxidant activity produced by Serratia ureilytica TKU013

The secondary metabolites from the cultured supernatant of Serratia ureilytica TKU013 with squid pen as the sole carbon/nitrogen source were isolated and ascertained the mechanism of biological activity. The EtOAc layer, which has high DPPH scavenging activity, was applied to silica gel column chromatography with a gradient of CH(2)Cl(2)/MeOH solvent system, to yield A-H and MeOH fractions. The DPPH scavenging activity and cytotoxic activities against Doay and HEp-2 cell lines of these fractions were examined. The active fractions were further applied to purification by RP-HPLC, to obtain seven compounds, including a novel compound, serlyticin-A (1), together with six known compounds, serranticin (2), serratamolide A (3), thymine (4), (4-hydroxyphenyl)acetic acid (5), methyl p-hydroxybenzoate (6), and uracil (7). Their structures were determined by physical and extensive spectral analyses such as 1D and 2D NMR data, as well as comparison with literature values. Furthermore, the major secondary metabolites of EtOAc extract of the cultured supernatant were examined by the fingerprinting data of the HPLC system.

Alkaloids from the root of Isatis indigotica

Seventeen new alkaloids (1-17) and 14 known analogues have been isolated from an aqueous extract of the root of Isatis indigotica. The structures and absolute configurations of these compounds were determined by extensive spectroscopic data analysis, including 2D NMR, single-crystal X-ray crystallography using anomalous scattering of Cu Kα radiation, and electronic circular dichroism spectra calculations based on the quantum-mechanical time-dependent density functional theory. Compounds 1, 2, and 3 are the first examples of natural products with unique linkages between a molecule of 2-(4-methoxy-1H-indol-3-yl)acetonitrile and 2-(1H-indol-3-yl)acetonitrile, 2-(4-methoxy-1H-indol-3-yl)acetonitrile, and 4-hydroxyphenylethane, respectively. Compounds (-)-4 and (+)-4 represent the first natural products with the pyrrolo[2,3-b]indolo[5,5a,6-b,a]quinazoline skeleton. Some structural assignments for the new alkaloids suggest that the assignments made for certain previously reported alkaloids require revision. Compounds 1-3 and arvelexin (18) show antiviral activity against the influenza virus A/Hanfang/359/95 (H3N2), with IC(50) values of 3.70-12.35 μM, and 17 inhibits Coxsackie virus B3 replication with an IC(50) of 6.87 μM.