Samuela Laconi

Chemical and biological comparisons on supercritical extracts of Tanacetum cinerariifolium (Trevir) Sch. Bip. with three related species of chrysanthemums of Sardinia (Italy)

In this manuscript, the authors compare the chemical composition and the biological effects of extracts of some Sardinian plant species: Glebionis coronaria (L.) Spach [=Chrysanthemum coronarium L.], locally known as ‘caragantzu’, Glebionis segetum (L.) Fourr. [=Chrysanthemum segetum L.], known as ‘caragantzu masedu’, and Sardinian endemic species Plagius flosculosus (L.) Alavi and Heywood [=Chrysanthemum flosculosus L.], known as ‘caragantzu burdu’. In addition, the authors compare the pyrethrins contained in these species with an extract of Tanacetum cinerariifolium (Trevir.) Sch. Bip. [=Chrysanthemum cinerariifolium (Trevir.) Vis.], a commercial species rich in pyrethrins. The volatile fractions from chrysanthemum flowers were obtained by supercritical fluid extraction (SFE) with CO2 at 90 bar and 50°C and by hydrodistillation. Pyrethrins were extracted, together with other high molecular mass compounds, by SFE at high pressure, 300 bar and 40°C. The composition of the volatile oils is determined by GC–MS analysis and the amount of pyrethrins by HPLC analysis. Moreover, the antibacterial and antimycotic activities of volatile fractions were investigated in order to compare to their traditional uses.

Antiviral Properties of Glycyrrhizic Acid and its Semisynthetic Derivatives

Some natural triterpenes exert a definite antiviral activity on several human viruses. New synthetic derivatives of glycyrrhizic acid (GL) are even more active than the parental molecule. GL can alter the expression of viral genes involved in cell transformation, thus opening a new window for speculating on viral cancerogenesis.

Study of the biological activity of novel synthetic compounds with antiviral properties against human rhinoviruses.

Picornaviridae represent a very large family of small RNA viruses, some of which are the cause of important human and animal diseases. Since no specific therapy against any of these viruses currently exists, palliative symptomatic treatments are employed. The early steps of the picornavirus replicative cycle seem to be privileged targets for some antiviral compounds like disoxaril and pirodavir. Pirodavir’s main weakness is its cytotoxicity on cell cultures at relatively low doses. In this work some original synthetic compounds were tested, in order to find less toxic compounds with an improved protection index (PI) on infected cells. Using an amino group to substitute the oxygen atom in the central chain, such as that in the control molecule pirodavir, resulted in decreased activity against Rhinoviruses and Polioviruses. The presence of an -ethoxy-propoxy- group in the central chain (as in compound I-6602) resulted in decreased cell toxicity and in improved anti-Rhinovirus activity. This compound actually showed a PI >700 on HRV14, while pirodavir had a PI of 250. These results demonstrate that modification of pirodavir’s central hydrocarbon chain can lead to the production of novel derivatives with low cytotoxicity and improved PI against some strains of Rhinoviruses.

In vitro characterisation of a pleconaril/pirodavir-like compound with potent activity against rhinoviruses

BackgroundRhinovirus infections do not only cause common colds, but may also trigger severe exacerbations of asthma and chronic obstructive pulmonary disease (COPD). Even though rhinoviruses have been the focus of extensive drug development efforts in the past, an anti-rhinoviral drug still has to make it to the market. In the past, the viral capsid protein VP1 has been shown to be an important target for the development of antiviral molecules. Furthermore, many different chemical scaffolds appear to possess the properties that are required to inhibit virus replication by this mechanism of action. I-6602, an analogue of the rhinovirus inhibitor pirodavir, was previously identified as a potent inhibitor of rhinovirus infection. Here, we describe the antiviral activity of its analogue ca603, a molecule with a modified linker structure, and corroborate its mechanism of action as a capsid binder.FindingsThe molecule ca603 shows antiviral activity against a panel of rhino-and enteroviruses. Cross-resistance is observed against viruses with mutations that render them resistant to the inhibitory effect of the capsid binder pleconaril and thermostability assays demonstrate that the compound binds and stabilizes the viral capsid. Binding of the molecule to the VP1 protein is corroborated by in silico modeling.ConclusionsIt is confirmed that ca603 inhibits rhinovirus replication by interaction with the VP1 protein and, by this, allows to further expand the chemical diversity of capsid-binding molecules.

Autophagy activation and antiviral activity by a licorice triterpene

The triterpene glycyrrhizic acid (GRA), the main product from the Glycyrrhiza glabra medicinal plant, is known for its antiinflammatory and antimicrobial activity. In this work, GRA was studied for its ability to induce the autophagic process activator Beclin 1 in epithelial cells and to observe how this property could influence its antiviral activity. After 24 h of treatment, GRA induced a Beclin 1 production that was more than twofold higher than that produced by rapamycin, used as a reference compound. When the compounds were added to HeLa cells together with the viruses, GRA demonstrated a strong antiherpes simplex virus type 1 (HSV1) activity, whereas rapamycin had no activity. However, if the compounds were added to the cells 24 h before the viruses, GRA induced the production of an even higher amount of Beclin 1 and showed an improved antiviral effect; under these conditions, rapamycin was also able to exert a significant anti‐HSV1 activity. In conclusion, GRA is a strong inducer of the autophagy activator Beclin 1, which establishes a resistance state to HSV1 replication. Copyright