The Essential Oil of Ocimum americanum from Senegal and Gambia as a Source of Methyleugenol for the Control of Bactrocera dorsalis, Fruit Fly

The fruit fly, Bactrocera dorsalis (Diptera: Tephritidae) is one of the most important pests in all mango-producing areas, particularly in West Africa. In Senegal, O. americanum leaves have been used for several years to control this fly. However, to our knowledge, no chemical studies have been carried out. Thus, the aim of this study is to determine the chemical composition of the essential oil of O. americanum leaves collected in Senegal and Gambia. The essential oil obtained by hydrodistillation of these leaves is analyzed by GC/FID and GC/MS. Yields of essential oils from O. americanum leaves are 3.84% and 2.13%, respectively. Analysis of these essential oils by GC/FID and GC/MS allowed the identification of 23 compounds representing almost 100% of the total compositions. These essential oils are mainly dominated by methyleugenol (72.0% and 75.8%, respectively). Other components in significant percent are trans-β-caryophyllene (13.9% and 13.0%, respectively), germacrene D (4.1% and 3.7%, respectively), β-elemene (3.3% and 0.9%, respectively). Due to the high methyleugenol content, this study explains the attractive potential of O. americanum towards B. dorsalis. In perspective, we plan to evaluate the attractive effect of the essential oil and leaf powder of O. americanum against B. dorsalis, a real pest of mango orchards in Senegal.

Chemical Variability and Antibacterial Activity of Eucalyptus camaldulensis Essential Oils from Senegal

1,8-cineole, also known as eucalyptol, is the main constituent and the most important of the leaf oils of many species of the genus Eucalyptus. In present study, the essential oils isolated by hydrodistillation from the leaves of Eucalyptus camaldulensis from six different locations were analyzed by GC-FID and GC-MS. Essential oil yields ranged from 0.33% to 4.35%. In total, 34 constituents were identified, accounting for 94.0% to 99.8% of the total compositions. 1,8-cineole (46.4% - 84.4%) was the main constituent of all the essential oil samples, except for one sample collected in the Fatick region, which had p-cymene (46.4%) and 1,8-cineole (26.0%) as major compounds. The essential oil showed excellent activity against S. aureus, E. coli and E. faecalis (IZ = 25.3 ± 1.2 mm;18.7 ± 0.6 mm;17.8 ± 0.3 mm, respectively) and moderate activity against P. aeruginosa (IZ = 10.8 ± 0.8 mm). They may have potential applications in food and pharmaceutical products.

Composition and antimicrobial activity of Cistus munbyi essential oil: an endemic plant from Algeria

The chemical composition and antimicrobial potential of Cistus munbyi essential oil were studied for the first time. GC and GC–MS analysis revealed 48 compounds representing 96.98% of the oil. Terpinen-4-ol(23.75%), meta-Cymene(17.30%), and Sabinene(12.38%)were the major constituents. Antimicrobial activity was evaluated against nine pathogens using the disc diffusion and broth micro-dilution methods. Results show that C.munbyi essential oil possesses strong antimicrobial activity against all strains, regardless if Gram-positive or Gramnegative bacteria, or yeast, with MICs values not exceeding10(mg/ml). In addition to its efficacy, C. munbyi essential oil has an unusual antimicrobial potency which is attributed to its specific chemical composition. Thus, findings presented here suggest that endemic C. munbyi contains a very interesting essential oil that may be valuable in several areas.

Antimicrobial activity of some essential oils against oral multidrugresistant Enterococcus faecalis in both planktonic and biofilm state

Objective:To evaluate some essential oils in treatment of intractable oral infections,principally caused by hiofilm of multidrug-resistant Enterococcus faecalit(E.faecalis),such as persistent endodontic infections in which their treatment exhibits a real challenge for dentists.Methods:Ten chemically analyzed essential oils by gas chromatography-mass spectrometry were evaluated for antimicrobial activity against sensitive and resistant clinical strains of E.faecalit in both planktonic and hiofilm state using two methods,disk diffusion and broth microdilution.Results:Studied essential oils showed a good antimicrobial activity and high ability in E.faecalit biofilm eradication,whether for sensitive or multidrug-resistant strains,especially those of Origanum glandulosum and Thymbra capitata with interesting minimum inhibitory concentration,biofilm inhibitory concentration,and biofilm eradication concent ration values which doesn't exceed 0.063%,0.75%,and 1.5%,respectively.Conclusions:Findings of this study indicate that essential oils extracted from aromatic plants can be used in treatment of intractable oral infections,especially caused by biofilm of multidrugresistant E.faecalis.

Antimicrobial activity of Rosmarinus eriocalyx essential oil and polyphenols:An endemic medicinal plant from Algeria

Objective:To evaluate the antimicrobial potency of Rosmarinus eriocalyx(R.eriocalyx)essential oil and total polyphenols against pathogenic microorganisms.Methods:Antimicrobial activity of R.eriocalyx extracts was assessed by disc diffusion method and minimum inhibitory concentrations determination.Essential oil obtained from endemic rosemary by hydrodistillation was analysed by gas chromatograph/retention index and gas chromatograph-mass spectrometer.Results:An interesting antimicrobial activity was shown by R.eriocalyx extracts.Polyphenols,constituted mainly by flavonoids,were the most effective extract with very low minimum inhibitory concentrations values,ranged between 0.06 and 8.00 mg/mL,while essential oil was less efficient.It should be noted that antimicrobial activities of both R.eriocalyx extracts were more directed against fungi and Gram-positive bacteria than Gram-negative ones,in which Staphylococcus aureus,Enterococcus faecalis,and Candida albicans were the most sensitive strains.Concerning chemical composition of R.eriocalyx essential oil,camphor(37.8%),1,8-cineole(17.4%),camphene(13.3%),and α-pinene(10.9%)were the major compounds.Conclusions:The findings of the present study indicate that R.eriocalyx extracts possess significant bactericidal and fungicidal activities.Because of its richness in essential oil,and especially flavonoids,R.eriocalyx may be a source for effective and safe antimicrobial agents.