Chemical profile and antifungal potential of essential oils from leaves and flowers of Salvia algeriensis (Desf.): A comparative study

Salvia is a plant genus widely used in folk medicine in the Mediterranean area since antiquity. A large number of Salvia essential oils have been reported against diverse microorganisms. In the current study, chemical composition of essential oils from leaves and flowers of Salvia algeriensis (Desf.) was determined using gas chromatography-electron impact mass spectrometry (GC-EIMS) as well as their antifungal activity against phytopathogenic fungi Alternaria solani and Fusarium oxysporum exploring disk method. The GC-EIMS analysis identified 59 compounds (84.8%) in the essential oil obtained from leaves of S. algeriensis. Its major constituents were benzaldehyde (9.7%), eugenol (8.7%) and phenylethyl alcohol (8.4%). In flowers oil, 34 compounds (92.8%) were detected. The main ones were viridiflorol (71.1%) and globulol (8.6%). The essential oil obtained from leaves exhibited the highest antifungal activity, where the effective dose inhibiting 50% of mycelial fungal (ED50) against A. solani was 0.90 μL mL-1 with minimum inhibitory concentration (MIC) equal to 2 μL mL-1, whereas the ED50 and MIC in F. oxysporum culture was 1.84 μL mL-1 and 3 μL mL-1 respectively. The mycelial inhibition by flowers oil varies from 1.77 μL mL-1 (ED50) with A. solani culture (MIC 6.5 μL mL-1) to the lowest effect recorded (ED50 3.00 μL mL-1 and MIC 9.33 μL mL-1) against F. oxysporum. To our best knowledge, this is the first report on S. algeriensis, their leaves oil can constitute an alternative biocontrol against phytopathogenic fungi commonly controlled by chemical fungicides.

Selection of polyvalent bacteriophages infecting Salmonella enterica serovar Choleraesuis

Background: Ideally, bacteriophages of pathogenic bacterial hosts should be polyvalent to be able to replicate in an alternative nonpathogenic bacterium. Thus, accidental infection by the original host can be avoided when bacteriophage lysates are used in biocontrol protocols. Results: From 15 wastewater samples, collected at different sites in the V Region in Chile, we selected three bacteriophages (FC, FP, and FQ) capable of productively infecting Salmonella enterica serovar Choleraesuis. By transmission electron microscopy (TEM) observation, the bacteriophages were found to belong to the order Caudoviridae. Molecular analyses indicated that FC, FP, and FQ contained double-stranded DNA genomes, of sizes similar to bacteriophage P22, and distinct recognition sites for the restriction endonucleases HaeIII and HindIII. Assays of host range revealed that the bacteriophages were polyvalent and thus capable of infecting different strains of Escherichia coli and other serovars of Salmonella . Conclusion: We have isolated newbacteriophages of the serovar Choleraesuiswith various potential applications in relation to this pathogenic bacterium.