Virucidal Effect of Guggulsterone Isolated from Commiphora gileadensis

Commiphora gileadensis, locally known as becham, is a plant used in traditional Arabian medicine for treating headache, constipation, stomach, joint pain, and inflammatory disorders. Several studies have reported its antibacterial properties; however, no study has demonstrated its antiviral activity. This study aimed to evaluate the antiviral activity of C. gileadensis as well as to isolate its active compound and investigate its mode of action. This activity was evaluated using 4 viruses, herpes simplex virus type 2 (HSV-2), respiratory syncytial virus type B (RSV‑B), coxsackie virus B type 3, and adenovirus type 5 by performing the plaque reduction assay and the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays for enveloped and nonenveloped viruses, respectively. The methanol extract of C. gileadensis leaves only showed antiviral activity against enveloped viruses with a selectivity index of 11.19 and 10.25 for HSV-2 and RSV‑B, respectively. The study of the mechanism underlying antiviral activity demonstrated a virucidal effect by direct contact with these target viruses. The active compound, isolated using bio-guided assays involving TLC, was identified as guggulsterone by HPLC-diode array detection coupled with electrospray ionization mass spectrometry. Guggulsterone is an antagonist of the bile acid receptor and a modulator of cholesterol metabolism; however, its antimicrobial properties have been reported for the first time in this study

Identification of an antiviral compound isolated from Pistacia lentiscus

This study screened mastic gum (Pistacia lentiscus L.) for antiviral activity against herpes simplex virus type 2 (HSV-2), coxsackievirus type B3, and adenovirus type 5. The organs of this plant (leaves, stem, and seed) were macerated sequentially using solvents of increasing polarity (hexane, dichloromethane, ethyl acetate, and methanol). Only the methanol extract of stem exhibited significant activity against HSV-2. This extract showed anti-HSV-2 activity with a selectivity index of 51 (50% cytotoxic concentration = 186 µg/mL; 50% inhibitory concentration = 3.63 µg/mL), and demonstrated direct inhibition against this virus with a virucidal selectivity index of 620 (50% virucidal concentration = 0.30 µg/mL). A bio-guided assay involving thin-layer chromatography led to the isolation of two active compounds, which have been identified as dammaradienone and dammaradienol using high-performance liquid chromatography-diode array detection coupled with electrospray ionization mass spectrometry. P. lentiscus has been widely studied for other biological activities. However, to our knowledge, this is the first report of P. lentiscus L. exhibiting antiviral activity

Phylogenetic Analysis of Echovirus 11 in the 3′ End of the VP1

International audienceObjective: Echovirus 11 is one of the most frequently isolated enterovirus serotypes, causing a wide range of clinical diseases. We studied the genetic diversity in the 3' end of the VP1 gene of strains from different geographical origin in the world. Methods: The sequences in the 3' end of the VP1 of 11 Tunisian isolates were determined and aligned with the published sequences to establish a phylogenetic profile. Results: The grouping of the sequences was similar to what was previously reported by analyzing the whole VP1 gene with 4 genogroups, designated A-D, and 5 lineages in genogroup D. All Tunisian strains belonged to genogroup D, together with other sequences mainly from the USA and Europe. Contrary to the sequences from the USA isolated during the last 3 decades, which mostly belonged to the D4 lineage, those from Tunisia belonged to different lineages within genogroup D according to their isolation date: isolates from the early 1990s belonged to D3, those of the mid 1990s to D4 and the most recent ones to D5. Conclusion: Our findings further widen the interest of partial sequencing in the VP1 to study the molecular epidemiology of echovirus 11 and indicate that the genetic evolution of circulating strains may differ from one country to another according to the region's epidemiological specificities. Copyright (c) 2007 S. Karger AG, Basel

Isolation and identification of an antibacterial compound from Diplotaxis harra (Forssk.) Boiss

The emergence of the antibiotic resistance is an ongoing problem in public health, and therefore the search for new natural molecules represents an alternative to synthetic drugs. The aim of this study was to test the antibacterial activity of ten Mediterranean plants (Diplotaxis harra, Ecballium elaterium, Pergularia tomentosa, Myrtus communis, Solanum villosum, Solanum sodomaeum, Peganum harmala, Lepidium sativum, Pistacia lentiscus, and Calendula arvensis) against seven pathogenic bacteria (Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Klebsiella sp., Salmonella enteritidis, and Bacillus cereus) using the disk diffusion method, in order to isolate and identify the active compound(s). Dichloromethane extract of D. harra flower showed the best activity against S. aureus and L. monocytogenes (MIQ = 30 μg/disk and 15 μg/disk, respectively). This extract was submitted to a bio-guided purification using Thin Layer Chromatography (TLC)-bioautography, and an antibacterial fraction (MIQ = 2 μg/disk) was isolated. The active fraction was characterized by RP-HPLC-DAD-ESI-MSn and GC–MS. Sulforaphane, an isothiocyanate known for its anti-cancer, antioxidant, and anti-inflammatory properties, was identified as antibacterial agent in D. harra for the first time. Due to its high antibacterial activity, sulforaphane could be considered a good candidate for the selection of new natural antibacterial molecules

Antioxidant, antibacterial, and antileishmanial potential of Micromeria nervosa extracts and molecular mechanism of action of the bioactive compound

Aims: This study aimed to determine the antibacterial and antileishmanial potential of Micromeria nervosa extracts. The identification of the antileishmanial compound and the study of its molecular mechanism of action have also been undertaken. Methods and results: Ethanol extract showed high polyphenol content and diethyl ether extract exhibited high DPPH scavenging and low beta-carotene bleaching activity (IC50 = 13.04 ± 0.99 and 200.18 ± 3.32 μg mL−1 , respectively). However, diethyl ether extract displayed high antibacterial activity against Gram-positive strains including methicillin-resistant Staphylococcus aureus (MIC = 31.25 μg mL−1 ), Staph. aureus ATCC6538 (MIC = 62.5 μg mL−1 ), and Listeria monocytogenes ATCC 19115 (MIC = 125 μg mL−1 ), as well as high antileishmanial activity against the promastigote forms of L. infantum and L. major (IC50 = 11.45 and 14.53 μg mL−1 , respectively). The active compound was purified using bioassay-guided fractionation and thin layer chromatography, and identified as ursolic acid using high-performance liquid chromatography coupled with a photodiode array and mass spectrometry. The purified compound was strongly inhibitory against the promastigote and amastigote forms of L. infantum and L. major (IC50 = 5.87 and 6.95 μg mL−1 versus 9.56 and 10. 68 μg mL−1 , respectively) without overt cytotoxicity against Raw 264.7 macrophage cells (SI = 13.53 and 11.43, respectively). The commercial compound (ursolic acid) showed similar activity against amastigotes and promastigotes forms of L. infantum and L. major. Moreover, its molecular mode of action against leishmaniasis seems to involve the expression of the ODC and SPS genes involved in thiol pathway. Conclusion: Extracts of M. nervosa can be considered as a potential alternative to antimicrobial and antileishmanial drugs

Natural Recombination Event within the Capsid Genomic Region Leading to a Chimeric Strain of Human Enterovirus B▿

Recombination between two strains is a known phenomenon for enteroviruses replicating within a single cell. We describe a recombinant strain recovered from human stools, typed as coxsackievirus B4 (CV-B4) and CV-B3 after partial sequencing of the VP1 and VP2 coding regions, respectively. The strain was neutralized by a polyclonal CV-B3-specific antiserum but not by a CV-B4-specific antiserum. The nucleotide sequence analysis of the whole structural genomic region showed the occurrence of a recombination event at position 1950 within the VP3 capsid gene, in a region coding for the 2b antigenic site previously described for CV-B3. This observation evidences for the first time the occurrence of an interserotypic recombination within the VP2-VP3-VP1 capsid region between two nonpoliovirus enterovirus strains. The neutralization pattern suggests that the major antigenic site is located within the VP2 protein

Phytochemical analysis, antimicrobial and antioxidant activities of Allium roseum var. odoratissimum (Desf.) Coss extracts

Polyphenolic extracts from fresh aerial parts (stalk, leaf, and flower) and bulbs of Allium roseum var. odoratissimum (Rosy garlic) harvested from Tunisian sandy soil were analyzed by high performance liquid chromatography (HPLC)-diode array detector (DAD) coupled with tandem mass spectrometry (MS), and tested for their antioxidant, antimicrobial, cytotoxic and antiviral activities. Leaves, stalks and flowers showed the highest total antioxidant capacity, scavenger activity against stable DPPH radical, and β-carotene bleaching capacity, with leaves and flowers extracts showing the highest total polyphenolic (84.39 mg gallic acid equivalents/g plant organs dry residue) and total flavonoid [5.88 mg (+)-catechin equivalents/g plant organs dry residue] contents, respectively. The metabolic profiles registered for the polyphenolic extracts revealed the presence of one hydroxycinnamic acid derivative, three flavones, and ten flavonols never detected before, with the only exception of kaempferol-3-O-glucuronide. Overall, all the tested polyphenolic extracts possessed high activity against Gram positive and Gram negative bacteria, and Candida spp. Strains, generally recognized as the most important pathogens affecting food dishes. Conversely, no toxicity on VERO cells line and no antiviral activity against Coxsakievirus B-3 and Herpes Simplex Virus type 2 were registered. This study gives a better insight into the potential healthy effects of Rosy garlic and the possibility of using it in food dishes to prevent contamination by the most common bacteria

Typing of Human Enterovirus by Partial Sequencing of VP2▿

The sequencing of the VP1 hypervariable region of the human enterovirus (HEV) genome has become the reference test for typing field isolates. This study describes a new strategy for typing HEV at the serotype level that uses a reverse transcription-PCR assay targeting the central part of the VP2 capsid protein. Two pairs of primers were used to amplify a fragment of 584 bp (with reference to the PV-1 sequence) or a part of it (368 bp) for typing. For a few strains not amplified by the first PCR, seminested primers enhanced the sensitivity (which was found to be approximately 10−1 and 10−4 50% tissue culture infective dose per reaction tube for the first and seminested assay, respectively). The typing method was then applied to 116 clinical and environmental strains of HEV. Sixty-one typeable isolates were correctly identified at the serotype level by comparison to seroneutralization. Forty-eight of 55 “untypeable” strains (87.3%) exhibited the same serotype using VP1 and VP2 sequencing methods. For six strains (four identified as EV-71, one as E-9, and one as E-30 by the VP2 method), no amplification was obtained by the VP1 method. The last strain, typed as CV-B4 by VP1 and CV-B3 by VP2 and monovalent antiserum, could exhibit recombination within the capsid region. Although the VP2 method was tested on only 36 of the 68 HEV serotypes, it appears to be a promising strategy for typing HEV strains isolated on a routine basis. The good sensitivity of the seminested technique could avoid cell culture and allow HEV typing directly from PCR products