Advances on antiviral activity of Morus spp. plant extracts: Human coronavirus and virus-related respiratory tract infections in the spotlight

(1) Background: Viral respiratory infections cause life-threatening diseases in millions of people worldwide every year. Human coronavirus and several picornaviruses are responsible for worldwide epidemic outbreaks, thus representing a heavy burden to their hosts. In the absence of specific treatments for human viral infections, natural products offer an alternative in terms of innovative drug therapies. (2) Methods: We analyzed the antiviral properties of the leaves and stem bark of the mulberry tree (Morus spp.). We compared the antiviral activity of Morus spp. on enveloped and nonenveloped viral pathogens, such as human coronavirus (HCoV 229E) and different members of the Picornaviridae family—human poliovirus 1, human parechovirus 1 and 3, and human echovirus 11. The antiviral activity of 12 water and water–alcohol plant extracts of the leaves and stem bark of three different species of mulberry—Morus alba var. alba, Morus alba var. rosa, and Morus rubra—were evaluated. We also evaluated the antiviral activities of kuwanon G against HCoV-229E. (3) Results: Our results showed that several extracts reduced the viral titer and cytopathogenic effects (CPE). Leaves’ water-alcohol extracts exhibited maximum antiviral activity on human coronavirus, while stem bark and leaves’ water and water-alcohol extracts were the most effective on picornaviruses. (4) Conclusions: The analysis of the antiviral activities of Morus spp. offer promising applications in antiviral strategies

Troubles érectiles, prise en charge et thérapeutique

LILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF

Bio-Inspired Casein-Derived Antioxidant Peptides Exhibiting a Dual Direct/Indirect Mode of Action

International audienceAntioxidant compounds are chemicals of primary importance, especially for their applications in nutrition and healthcare, thanks to their abilities to prevent oxidation processes and to limit and/or rebalance the oxidative stress, well-known for its impact on a wide variety of diseases. While several biomolecules are well-known for their antioxidant properties (e.g., ascorbic acid, carotenoids, phenolic derivatives), bio-sourced antioxidants have drawn considerable attention in the last decades, especially bioactive peptides, mainly obtained by the hydrolysis process. Antioxidant peptide sequences are mainly identified a posteriori, thanks to fastidious and time-consuming approaches and techniques, limiting the discovery of new efficient peptides. In this context and taking inspiration from nature, we report herein on a new series of three bio-inspired antioxidant peptides derived from the milk protein casein. These phosphopeptides, designed to chelate the redox-active iron(III) and forming highly soluble complexes up to pH 9, act both as indirect (i.e., inhibition of the metal redox activity) and direct (i.e., radical scavenging) antioxidant

Stimulating effect of both 4’- O -methylnorbelladine feeding and temporary immersion conditions on galanthamine and lycorine production by Leucojum aestivum L. bulblets

International audienceBulb cultures of Leucojum aestivum and L. aestivum ‘Gravety Giant’ were subcultured in medium containing the precursor 4’‐O‐methylnorbelladine (MN) at various concentrations [0 (control), 0.15 and 0.3 g/L]. The cultures were conducted in bioreactor RITA® and lasted for 15, 30, 40 and 50 days. The growth rate and the alkaloid accumulation in bulblets were studied. For this latter purpose, a purification method was developed. It comprised a highly selective solid phase extraction using on the one hand, UPTI‐CLEAN SI and SCX cartridges for plant extracts and on the other hand, 2H cartridges for culture media. Pure alkaloidal fractions were, thus, analyzed by LC‐ESI‐MS allowing the quantitative evaluation of galanthamine and lycorine from culture extracts. Precursor feeding along with temporary immersion conditions was found to significantly improve the accumulation of both galanthamine and lycorine. The maximal concentrations of galanthamine (0.81 mg/g DW) and lycorine (0.54 mg/g DW) in L. aestivum bulblets were reached, respectively, after 40 days of culture with 0.15 g/L of precursor and after 30 days of culture with 0.3 g/L of precursor. In L. aestivum ‘Gravety Giant’ bulb cultures, 0.3 g/L of precursor was the best condition for both galanthamine (0.6 mg/g DW after 50 days) and lycorine (1.13 mg/g DW after 30 days)

New method for the study of Amaryllidaceae alkaloid biosynthesis using biotransformation of deuterium-labeled precursor in tissue cultures.

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Identification of Amaryllidaceae alkaloids in bulbs and in vitro cultures in various species of Narcissus using GC-MS and LC-MS

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Structural Organizations of Qβ and MS2 Phages Affect Capsid Protein Modifications by Oxidants Hypochlorous Acid and Peroxynitrite

International audiencePathogenic enteric viruses and bacteriophages such as Qβ and MS2 are transmitted through the fecal-oral route. However, oxidants such as peroxynitrite (ONOOH) and hypochlorous acid (HClO) can prevent new infection by inactivating infectious viruses. Their virucidal effect is well recognized, and yet predicting the effects of oxidants on viruses is currently impossible because the detailed mechanisms of viral inactivation remain unclear. Our data show that ONOOH and HClO cross-linked the capsid proteins and RNA genomes of Qβ and MS2 phages. Consistently, the capsids appeared intact by transmission electron microscopy (TEM) even when 99% of the phages were inactivated by oxidation. Moreover, a precise molecular study of the capsid proteins shows that ONOOH and HClO preferentially targeted capsid protein regions containing the oxidant-sensitive amino acid C, Y, or W. Interestingly, the interaction of these amino acids was a crucial parameter defining whether they would be modified by the addition of O, Cl, or NO2 or whether it induced the loss of the protein region detected by mass spectrometry, together suggesting potential sites for cross-link formation. Together, these data show that HClO and ONOOH consistently target oxidant-sensitive amino acids regardless of the structural organization of Qβ and MS2, even though the phenotypes change as a function of the interaction with adjacent proteins/RNA. These data also indicate a potential novel mechanism of viral inactivation in which cross-linking may impair infectivity

Quantitative Determination of Lycorine and Galanthamine in Different in Vitro Tissues of Narcissus tazetta by GC-MS

International audienceNarcissus spp. are of great importance to pharmaceutical industries because of biosynthesis of Amaryllidaceae alkaloids. N. tazetta with several varieties is a widespread species, native to the Mediterranean region with considerable distribution in Iran. In the present study, calli, roots and bulblets were regenerated from N. tazetta var. Meskin. In order to report alkaloid profile and quantify galanthamine and lycorine, methanolic extract of different in vitro tissues were subjected to alkaloid purification by SPE (solid phase extraction) method, followed by GC-MS analysis. In general, galanthamine and lycorine were detected in all in vitro tissues, while demethylmaritidine was only identified in bulblets. Bulblet was identified as the best source of main Amaryllidaceae alkaloids regarding the highest quantities of galanthamine and lycorine with 15 and 731 µg/g dry weight (DW) respectively