No abstract

The use of ozonized vegetable oils as drugs or cosmetics requires having data on their stability over the time. In this study, ozonized sunflower oil was stored under different temperatures for up to 1 year. Peroxide index, acidity value, gas chromatography profile, infrared profile and antibacterial activity (against Streptococcus uberis) of this ozonized oil were followed. The results highlight the fact that the better way to preserve the initial composition of ozonized oil is to keep it at low temperature. However, the antibacterial activity is not diminished by the changes occurring to the composition.

Botanicals represent a promising source of metabolites in the search for new biofungicides. In this context, this study aimed at evaluating the in vitro anti-oomycete activity of hop (Humulus lupulus L.) extracts and metabolites against Phytophthora infestans, an oomycete causing late blight disease in Solanaceae. Crude hydro-ethanolic extracts and dichloromethane sub-extracts of different parts (cones, leaves, stems and rhizomes) were characterized by UHPLC-UV–MS and some cone specialized metabolites were purified by CPC and preparative HPLC. A commercial hop cone essential oil was also analyzed by GC–MS. All extracts succeeded in inhibiting mycelial growth and spore germination with morphological alteration of the mycelium. Extracts of leaves showed a significant anti-oomycete activity compared to the extracts of cones, stems, and rhizomes. Moreover, no difference was noticed between the crude hydro-ethanolic extract and the dichloromethane sub-extract activity, except for leaves, with the apolar sub-extract being more active than the crude one. The extracts of cones succeeded in inhibiting more P. infestans than the essential oil, which appeared to be the less active evaluated modality. Some purified prenylated phenolic compounds also inhibited P. infestans although copper sulfate, a mineral fungicide control, was still more active. This study highlights the potential use of hop by-products as biofungicides to manage P. infestans.

No abstract

Millions of people are still infected with hepatitis C virus (HCV) nowadays. Although recent antivirals targeting HCV proteins are very efficient, they are not affordable for many people infected with this virus. Therefore, new and more accessible treatments are needed. Several Ivorian medicinal plants are traditionally used to treat “yellow malaria”, a nosological category including illness characterized by symptomatic jaundice such as hepatitis. Therefore, some of these plants might be active against HCV. An ethnobotanical survey in Côte d’Ivoire allowed us to select such medicinal plants. Those were first extracted with methanol and tested for their anti-HCV activity. The most active ones were further studied to specify their IC50 and to evaluate their toxicity in vitro. Greener solvents were tested to obtain extracts with similar activities. Following a phytochemical screening, tannins of the most active plants were removed before re-testing on HCV. Some of these tannins were identified by UPLC-MS and pure molecules were tested against HCV. Out of the fifteen Ivorian medicinal plants selected for their putative antiviral activities, Carapa procera DC. and Pericopsis laxiflora (Benth. ex Baker) Meeuwen were the most active against HCV (IC50: 0.71 and 0.23 μg/ml respectively) and not toxic for hepatic cells. Their crude extracts were rich in polyphenols, including tannins such as procyanidins A2 which is active against HCV. The same extracts without tannin lost their anti-HCV activity. Replacing methanol by hydro-ethanolic solvent led to tannins-rich extracts with similar antiviral activities, and higher than that of aqueous extracts.

No abstract

Hop cones are well-known for their antimicrobial properties, attributed to their specialized metabolites. Thus, this study aimed to determine the in vitro antifungal activity of different hop parts, including by-products such as leaves and stems, and some metabolites against Venturia inaequalis, the causal agent of apple scab. For each plant part, two types of extracts, a crude hydro-ethanolic extract and a dichloromethane sub-extract, were tested on spore germination of two strains with different sensitivities to triazole fungicides. Both extracts of cones, leaves and stems were able to inhibit the two strains, whereas rhizomes did not show activity. The apolar sub-extract of leaves appeared as the most active modality tested with half maximal inhibitory concentrations (IC50) of 5 and 10.5 mg·L−1 on the sensitive strain and the strain with reduced sensitivity, respectively. Differences in activity level between strains were noticed for all active modalities tested. Sub-extracts of leaves were then separated into seven fractions by preparative HPLC and tested on V. inaequalis. One fraction, containing xanthohumol, was especially active on both strains. This prenylated chalcone was then purified by preparative HPLC and showed significant activity against both strains, with IC50 of 1.6 and 5.1 mg·L−1. Therefore, xanthohumol seems to be a promising compound to control V. inaequalis.

The COVID-19 pandemic, caused by SARS-CoV-2, addressed the lack of specific antiviral drugs against coronaviruses. In this study, bioguided fractionation performed on both ethyl acetate and aqueous sub-extracts of Juncus acutus stems led to identifying luteolin as a highly active antiviral molecule against human coronavirus HCoV-229E. The apolar sub-extract (CH2Cl2) containing phenanthrene derivatives did not show antiviral activity against this coronavirus. Infection tests on Huh-7 cells, expressing or not the cellular protease TMPRSS2, using luciferase reporter virus HCoV-229E-Luc showed that luteolin exhibited a dose-dependent inhibition of infection. Respective IC50 values of 1.77 µM and 1.95 µM were determined. Under its glycosylated form (luteolin-7-O-glucoside), luteolin was inactive against HCoV-229E. Time of addition assay showed that utmost anti-HCoV-229E activity of luteolin was achieved when added at the post-inoculation step, indicating that luteolin acts as an inhibitor of the replication step of HCoV-229E. Unfortunately, no obvious antiviral activity for luteolin was found against SARS-CoV-2 and MERS-CoV in this study. In conclusion, luteolin isolated from Juncus acutus is a new inhibitor of alphacoronavirus HCoV-229E.