ABSTRACT
The aim of this work was to study the antimicrobial activity of essential oils obtained from Thymus vulgaris (thyme) and Origanum vulgare (oregano) on phytopathogenic Pseudomonas species isolated from soybean. Strains with characteristics of P. syringae were isolated from leaves of soybean plants with blight symptoms. Ten of these could be identified in Group Ia of LOPAT as P. syringae. Six of these were confirmed as P. syringae using 16S rRNA, indicating the presence of these phytopathogenic bacteria in east and central Argentina. All the phytopathogenic bacteria were re-isolated and identified from the infected plants. MIC values for thyme were 11.5 and 5.7 mg·ml(-1) on P. syringae strains, while oregano showed variability in the inhibitory activity. Both essential oils inhibited all P. syringae strains, with better inhibitory activity than the antibiotic streptomycin. The oils were not bactericidal for all pseudomonads. Both oils contained high carvacrol (29.5% and 19.7%, respectively) and low thymol (1.5%). Natural products obtained from aromatic plants represent potential sources of molecules with biological activity that could be used as new alternatives for the treatment of phytopathogenic bacteria infections.
Subject(s)
Anti-Infective Agents/pharmacology , Glycine max/microbiology , Oils, Volatile/pharmacology , Origanum/chemistry , Plant Diseases/microbiology , Pseudomonas syringae/drug effects , Thymus Plant/chemistry , Anti-Infective Agents/analysis , Argentina , Base Sequence , Cymenes , Microbial Sensitivity Tests , Molecular Sequence Data , Monoterpenes/analysis , Monoterpenes/pharmacology , Oils, Volatile/chemistry , Plant Extracts/chemistry , Plant Extracts/pharmacology , Plant Leaves/microbiology , Pseudomonas syringae/genetics , Pseudomonas syringae/isolation & purification , RNA, Bacterial/analysis , RNA, Ribosomal, 16S/analysis , Thymol/analysis , Thymol/pharmacologyABSTRACT
AIMS: The antifungal effect of Pimpinella anisum (anise), Pëumus boldus (boldus), Mentha piperita (peppermint), Origanum vulgare (oregano) and Minthosthachys verticillata (peperina) essential oils against Aspergillus section Flavi (two isolates of Aspergillus parasiticus and two isolates of Aspergillus flavus) was evaluated in maize meal extract agar at 0.982 and 0.955 water activities, at 25 degrees C. METHODS AND RESULTS: The percentage of germination, germ-tube elongation rate, growth rate and aflatoxin B(1) (AFB(1)) accumulation at different essential oils concentrations were evaluated. Anise and boldus essential oils were the most inhibitory at 500 mg kg(-1) to all growth parameters of the fungus. These essential oils inhibited the percentage of germination, germ-tube elongation rate and fungal growth. AFB(1) accumulation was completely inhibited by anise, boldus and oregano essential oils. Peperina and peppermint essential oils inhibited AFB(1) production by 85-90% in all concentrations assayed. CONCLUSIONS: Anise and boldus essential oils could be considered as effective fungitoxicans for Aspergillus section flavi. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results suggest that these phytochemical compounds could be used alone or in conjunction with other substances to control the presence of aflatoxigenic fungi in stored maize.
Subject(s)
Aflatoxins/metabolism , Aspergillus flavus/growth & development , Food Microbiology , Fungicides, Industrial/pharmacology , Oils, Volatile/pharmacology , Plant Oils/pharmacology , Aspergillus flavus/drug effects , Dose-Response Relationship, Drug , Germination/drug effects , Mentha piperita , Origanum , Peumus , Pimpinella , Spores, Fungal/drug effects , Zea mays/microbiologyABSTRACT
The in vitro antiviral activity of the essential oil from Minthostachys verticillata was investigated against herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PrV). The viral inhibition was assayed employing viral plaque reduction assay. The antiviral activity of the essential oil specifically affects PrV and HSV-1 multiplication, since it was found that non toxic effects on cells were observed at the concentrations assayed. The therapeutic index values were 10.0 and 9.5 for HSV-1 and PrV, respectively. The antibacterial activity was studied using a diffusion assay and the broth tube dilution method. Gram-positive bacteria were more sensitive to inhibition by plant essential oil than the gram-negative bacteria. The essential oil of M. verticillata was analyzed by gas chromatography (GC) technique. Of the six components identified in the volatile oil, pulegone (44.56%) and menthone (39.51%) were the major constituents. The antimicrobial activity can be explained to some extent by the presence of pulegone. Results suggest that further investigations concerning the isolation of the substance responsible for the antimicrobial activity and an effort to define the mechanisms of action are warranted.
Subject(s)
Anti-Bacterial Agents/pharmacology , Antiviral Agents/pharmacology , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Herpesvirus 1, Suid/drug effects , Monoterpenes , Plant Oils/pharmacology , Plants, Medicinal/chemistry , Simplexvirus/drug effects , Bacillus cereus/drug effects , Chromatography, Gas , Cyclohexane Monoterpenes , Escherichia coli/drug effects , Herpesvirus 1, Suid/physiology , Menthol/analogs & derivatives , Menthol/isolation & purification , Menthol/pharmacology , Microbial Sensitivity Tests , Plant Oils/chemistry , Proteus mirabilis/drug effects , Pseudomonas aeruginosa/drug effects , Simplexvirus/physiology , Staphylococcus aureus/drug effects , Terpenes/isolation & purification , Terpenes/pharmacology , Viral Plaque Assay , Virus Replication/drug effectsABSTRACT
The in vitro antiviral activity of the essential oil from Minthostachys verticillata was investigated against herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PrV). The viral inhibition was assayed employing viral plaque reduction assay. The antiviral activity of the essential oil specifically affects PrV and HSV-1 multiplication, since it was found that non toxic effects on cells were observed at the concentrations assayed. The therapeutic index values were 10.0 and 9.5 for HSV-1 and PrV, respectively. The antibacterial activity was studied using a diffusion assay and the broth tube dilution method. Gram-positive bacteria were more sensitive to inhibition by plant essential oil than the gram-negative bacteria. The essential oil of M. verticillata was analyzed by gas chromatography (GC) technique. Of the six components identified in the volatile oil, pulegone (44.56) and menthone (39.51) were the major constituents. The antimicrobial activity can be explained to some extent by the presence of pulegone. Results suggest that further investigations concerning the isolation of the substance responsible for the antimicrobial activity and an effort to define the mechanisms of action are warranted.
Subject(s)
Anti-Bacterial Agents/pharmacology , Antiviral Agents , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Herpesvirus 1, Suid , Plant Oils/pharmacology , Plants, Medicinal , Simplexvirus , Bacillus cereus , Chromatography, Gas , Escherichia coli , Herpesvirus 1, Suid , Menthol , Microbial Sensitivity Tests , Plant Oils/chemistry , Proteus mirabilis , Pseudomonas aeruginosa , Virus Replication/drug effects , Simplexvirus , Staphylococcus aureus , Terpenes , Viral Plaque AssayABSTRACT
The in vitro antiviral activity of the essential oil from Minthostachys verticillata was investigated against herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PrV). The viral inhibition was assayed employing viral plaque reduction assay. The antiviral activity of the essential oil specifically affects PrV and HSV-1 multiplication, since it was found that non toxic effects on cells were observed at the concentrations assayed. The therapeutic index values were 10.0 and 9.5 for HSV-1 and PrV, respectively. The antibacterial activity was studied using a diffusion assay and the broth tube dilution method. Gram-positive bacteria were more sensitive to inhibition by plant essential oil than the gram-negative bacteria. The essential oil of M. verticillata was analyzed by gas chromatography (GC) technique. Of the six components identified in the volatile oil, pulegone (44.56) and menthone (39.51) were the major constituents. The antimicrobial activity can be explained to some extent by the presence of pulegone. Results suggest that further investigations concerning the isolation of the substance responsible for the antimicrobial activity and an effort to define the mechanisms of action are warranted.(AU)
Subject(s)
Anti-Bacterial Agents/pharmacology , Antiviral Agents/pharmacology , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Herpesvirus 1, Suid/drug effects , Plant Oils/pharmacology , Plants, Medicinal/chemistry , Simplexvirus/drug effects , Bacillus cereus/drug effects , Chromatography, Gas , Escherichia coli/drug effects , Herpesvirus 1, Suid/physiology , Menthol/analogs & derivatives , Menthol/isolation & purification , Menthol/pharmacology , Microbial Sensitivity Tests , Plant Oils/chemistry , Viral Plaque Assay , Proteus mirabilis/drug effects , Pseudomonas aeruginosa/drug effects , Simplexvirus/physiology , Staphylococcus aureus/drug effects , Terpenes/isolation & purification , Terpenes/pharmacology , Virus Replication/drug effectsABSTRACT
The in vitro antiviral activity of the essential oil from Minthostachys verticillata was investigated against herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PrV). The viral inhibition was assayed employing viral plaque reduction assay. The antiviral activity of the essential oil specifically affects PrV and HSV-1 multiplication, since it was found that non toxic effects on cells were observed at the concentrations assayed. The therapeutic index values were 10.0 and 9.5 for HSV-1 and PrV, respectively. The antibacterial activity was studied using a diffusion assay and the broth tube dilution method. Gram-positive bacteria were more sensitive to inhibition by plant essential oil than the gram-negative bacteria. The essential oil of M. verticillata was analyzed by gas chromatography (GC) technique. Of the six components identified in the volatile oil, pulegone (44.56
) and menthone (39.51
) were the major constituents. The antimicrobial activity can be explained to some extent by the presence of pulegone. Results suggest that further investigations concerning the isolation of the substance responsible for the antimicrobial activity and an effort to define the mechanisms of action are warranted.
