The Biological Activity of Monarda didyma L. Essential Oil and Its Effect as a Diet Supplement in Mice and Broiler Chicken.

The use of growth-promoting antibiotics in livestock faces increasing scrutiny and opposition due to concerns about the increased occurrence of antibiotic-resistant bacteria. Alternative solutions are being sought, and plants of Lamiaceae may provide an alternative to synthetic antibiotics in animal nutrition. In this study, we extracted essential oil from Monarda didyma, a member of the Lamiaceae family. We examined the chemical composition of the essential oil and then evaluated the antibacterial, antioxidant, and anti-inflammatory activities of M. didyma essential oil and its main compounds in vitro. We then evaluated the effectiveness of M. didyma essential oil in regard to growth performance, feed efficiency, and mortality in both mice and broilers. Carvacrol (49.03%) was the dominant compound in the essential oil extracts. M. didyma essential oil demonstrated antibacterial properties against Escherichia coli (MIC = 87 µg·mL-1), Staphylococcus aureus (MIC = 47 µg·mL-1), and Clostridium perfringens (MIC = 35 µg·mL-1). Supplementing the diet of mice with essential oil at a concentration of 0.1% significantly increased body weight (+5.4%) and feed efficiency (+18.85%). In broilers, M. didyma essential oil significantly improved body weight gain (2.64%). Our results suggest that adding M. didyma essential oil to the diet of broilers offers a potential substitute for antibiotic growth promoters.

Pili Tree (Canarium ovatum) Resin's Antibacterial Essential Oil and Hydrosol as Rich Sources of (S)-Phellandrenes Derivatives.

Five batches of resin from the Pili tree (Canarium ovatum Engl.) were distilled, and their essential oils and hydrosols were analyzed by gas chromatography. The oils, obtained in yields of 13.4-19.7 % v/m, featured α-phellandrene in high proportions (50-65 %), alongside limonene, ß-phellandrene and para-cymene. Chiral GC analysis confirmed that both phellandrenes were in fact >95 % (S)-(+) enantiomers, while the other monoterpenes featured less pronounced enantiomeric excesses. The hydrosols were rich in α-phellandrene oxidation products including cis-α-phellandrene epoxide and a series of para-menth-5-ene-1,2-diol isomers. Both essential oils and hydrosols were tested for their antibacterial activity against Escherichia coli and Staphylococcus aureus and exhibited MIC90 of less than 5 and 0.5 mg/mL of total volatiles, respectively. The essential oil features some potential as a source of readily available natural (S)-(+)-α-phellandrene.

Chemical composition and antibacterial activity of Tussilago farfara (L.) essential oil from Quebec, Canada.

The chemical composition of Tussilago farfara L. essential oil from the Saguenay-Lac-St-Jean region of Quebec, Canada was analyzed by gas chromatography-flame ionisation detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS), and the antibacterial activity of the oil was tested against Escherichia coli and Staphylococcus aureus. Forty-five (45) compounds were identified from the GC profile. The main components were 1-nonene (40.1%), α-phellandrene (26.0%) and ρ-cymene (6.6%). The essential oil demonstrated antibacterial activity against E. coli (MIC50 = 468 µg·mL-1; MIC90 = 6869 µg·mL-1) and S. aureus (MIC50 = 368 µg·mL-1; MIC90 = 773 µg·mL-1). Dodecanoic acid was found to be active against both bacteria having a MIC50 and MIC90 of 16.4 µg·mL-1 and 95 µg·mL-1, respectively for E. coli and a MIC50 and MIC90 of 9.8 µg·mL-1 and 27.3 µg·mL-1, respectively for S. aureus. In addition, 1-decene and (E)-cyclodecene were also found to be active against E. coli.

Balsacone C, a New Antibiotic Targeting Bacterial Cell Membranes, Inhibits Clinical Isolates of Methicillin-Resistant Staphylococcus aureus (MRSA) Without Inducing Resistance.

New options are urgently needed for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. Balsacone C is a new dihydrochalcone extracted from Populus balsamifera that has been reported previously as being active against Staphylococcus aureus. Here, we evaluate the antibacterial activity of balsacone C against MRSA. Thirty-four (34) MRSA isolates were obtained from hospitalized patients; these isolates were then characterized for their resistance. Most of these MRSA (>85%) were resistant to penicillin, amoxicillin/clavulanic acid, ciprofloxacin, moxifloxacin, levofloxacin, clindamycin, erythromycin, and cefoxitin as well as being sensitive to linezolid, trimethoprim/sulfamethoxazole, rifampicin, and gentamicin. When tested against all MRSA isolates and various gram-positive bacteria, the antibacterial activity of balsacone C produced a MIC of 3-11.6 mg/mL. We observed no resistant isolates of MRSA (against balsacone C) even after 30 passages. Microscopy fluorescence showed that bacteria cell membrane integrity was compromised by low concentrations of balsacone C. Scanning electron microscope (SEM) confirmed balsacone C-provoked changes in the bacterial cell membrane and we find a dose-dependent release of DNA and proteins. This loss of cellular integrity leads to cell death and suggests a low potential for the development of spontaneous resistance.

Anti-Inflammatory, Antioxidant, Antibiotic, and Cytotoxic Activities of Tanacetum vulgare L. Essential Oil and Its Constituents.

Background:Tanacetum vulgare L. (Asteraceae) is a perennial herb that has been used to treat multiple ailments. Regional variability of the chemical composition of T. vulgare essential oils is well-known. Despite these regional chemotypes, most relevant studies did not analyze the complete chemical composition of the T. vulgare essential oil and its constituents in relation to their biological activities. Here, we assess the anti-inflammatory, antioxidant, antibacterial, and cytotoxic activities of T. vulgare collected from northern Quebec (Saguenay-Lac-St-Jean), Canada. Methods: Essential oil was extracted from plants by steam distillation and analyzed using GC-FID. Biological activities of essential oil and its main constituents were evaluated in vitro. Results: We identified the major compounds as camphor, borneol, and 1,8-cineole. The oil possesses anti-inflammatory activity inhibiting NO production. It also inhibits intracellular DCFH oxidation induced by tert-butylhydroperoxide. Anti-inflammatory activity of essential oil appears driven mainly by α-humulene while antioxidant activity is provided by α-pinene and caryophyllene oxide. Essential oil from T vulgare was active against both Escherichia coli and Staphylococcus aureus with camphor and caryophyllene oxide responsible for antibacterial activity. Finally, T. vulgare essential oil was slightly cytotoxic against the human healthy cell line WS1 while α-humulene and caryophyllene oxide were moderately cytotoxic against A-549, DLD-1, and WS1. Conclusion: We report, for the first time, links between the specific compounds found in T. vulgare essential oil and anti-inflammatory, antioxidant, antibacterial, and cytotoxic activities. T. vulgare essential oil possesses interesting biological properties.

New antibacterial hydrophobic assay reveals Abies balsamea oleoresin activity against Staphylococcus aureus and MRSA.

ETHNOPHARMACOLOGICAL RELEVANCE: Oleoresin of Abies balsamea (L.) Mill. was used by Native Americans of the boreal forest of Canada and French Canadians to treat various infections, suggesting that oleoresin has antibacterial properties. AIM OF THE STUDY: In this study, the antibacterial activity of whole oleoresin from A. balsamea was investigated against E. coli, S. aureus and two methicillin-resistant S. aureus (MRSA) strains using a new sensitive assay developed to evaluate hydrophobic matrix and compounds. MATERIALS AND METHODS: Antibacterial activity of oleoresin was first investigated using dilution and disk diffusion methods against E. coli and S. aureus, and compared to a new sensitive assay for hydrophobic matrix. Moreover, whole oleoresin was analyzed by GC-MS to characterize the composition and to identify the compounds responsible of the antibacterial activity. RESULTS: The results showed that whole oleoresin was inactive against Gram-negative E. coli (MIC90 >90µg/ml) but active against Gram-positive S. aureus and MRSA with MIC90 ranging from 18.2 to 30µg/ml. The oleoresin is mainly composed of monoterpene (28%), sesquiterpenes (2%), and diterpenes (45%). Resin acids were found, in part, responsible for the antibacterial activity of whole oleoresin. Isopimaric acid and levopimaric acid are the most active with a MIC90 of respectively 9.7µg/ml and 10µg/ml. CONCLUSION: This study supports the use of oleoresin of A. balsamea by the Native Americans and French Canadians to treat bacterial infections due to S. aureus.

Genetic structure and rabies spread potential in raccoons: the role of landscape barriers and sex-biased dispersal.

Identifying natural barriers to movements of hosts associated with infectious diseases is essential for developing effective control strategies. Raccoon rabies variant (RRV) is a zoonosis of concern for humans because its main vector, the raccoon (Procyon lotor), is found near residential areas. In Québec, Canada, all cases of RRV found in raccoons since 2006 were detected on the eastern side of the Richelieu River, suggesting that this river acts as a barrier to gene flow and thus the potential for RRV to spread. The objectives of this study were to characterize the genetic structure of raccoon populations and assess the effect of the Richelieu River on the population structure in southern Québec, Canada. We also evaluated whether RRV spread potential differed between sex and at a larger spatial scale. Our analyses revealed a weak signal of genetic differentiation among individuals located on each side of the Richelieu River. At a larger spatial scale, genetic structuring was weak. Our results suggest that rivers might not always efficiently restrain raccoon movements and spread of RRV. We suggest that the difference in genetic structure found between sexes can be partly explained by male movements during the breeding season in winter, when ice bridges allow passage over most rivers in Québec.