Chemical profile and antimicrobial activity of Boldo (Peumus boldus Molina) extracts obtained by compressed carbon dioxide extraction

Chemical Composition and Antiplasmodial Activity of the Essential Oil of Rhododendron subarcticum Leaves from Nunavik, Québec, Canada

Dwarf Labrador tea, Rhododendron subarcticum Harmaja, is a popular medicinal plant in use by First Nations of Northern Canada, but its phytochemistry has remained largely unexplored. We have isolated and characterized the essential oil from a population of this species harvested near the treeline in Nunavik, Québec. Analyses by gas chromatography-mass spectrometry (GC-MS) and gas chromatography/flame-ionization detection (GC/FID) led to the identification of 53 compounds; the main secondary metabolites were ascaridole (64.7% of the total FID area) and p-cymene (21.1%). Such a composition resembles a chemotype observed for R. tomentosum, a close relative found mainly in Europe and Asia, but has never been attributed to R. subarcticum. Growth inhibition assays against different strains of Plasmodium falciparum (3D7, Dd2), the parasite responsible for the most severe form of malaria, were conducted with either the R. subarcticum's essential oil or the isolated ascaridole. Our results show that the essential oil's biological activity can be attributed to ascaridole as its IC₅₀ is more than twice that of ascaridole [ascaridole's IC₅₀ values are 147.3 nM (3D7) and 104.9 nM (Dd2)].

Supercritical fluid extraction of four aromatic herbs and assessment of the volatile compositions, bioactive compounds, antibacterial, and anti-biofilm activity

Artemisia arborescens, Artemisia abyssinica, Pulicaria jaubertii, and Pulicaria petiolaris are fragrant herbs traditionally used in medication and as a food seasoning. To date, there are no studies on the use of supercritical fluids extraction with carbon dioxide (SFE-CO₂) on these plants. This study evaluates and compares total phenolic content (TPC), antioxidant activity by DPPH^• and ABTS^•+, antibacterial, and anti-biofilm activities of SFE-CO₂ extracts. Extraction was done by SFE-CO₂ with 10% ethanol as a co-solvent. A. abyssinica extract had the highest extraction yield (8.9% ± 0.41). The GC/MS analysis of volatile compounds identified 307, 265, 213, and 201compounds in A. abyssinica, A. arborescens, P. jaubertii, and P. petiolaris, respectively. The P. jaubertii extract had the highest TPC (662.46 ± 50.93 mg gallic acid equivalent/g dry extract), antioxidant activity (58.98% ± 0.20), and antioxidant capacity (71.78 ± 1.84 mg Trolox equivalent/g dry extract). The A. abyssinica and P. jaubertii extracts had significantly higher antimicrobial activity and were more effective against Gram-positive bacteria. B. subtilis was the most sensitive bacterium. P. aeruginosa was the most resistant bacterium. P. jaubertii extract had the optimum MIC and MBC (0.4 mg/ml) against B. subtilis. All SFE-CO₂ extracts were effective as an anti-biofilm formation for all tested bacteria at 1/2 MIC. Meanwhile, P. jaubertii and P. petiolaris extracts were effective anti-biofilm for most tested bacteria at 1/16 MIC. Overall, the results indicated that the SFE-CO₂ extracts of these plants are good sources of TPC, antioxidants, and antibacterial, and they have promising applications in the industrial fields.

The effect of Seidlitzia rosmarinus (eshnan) on the prevention of recurrent cystitis in women of reproductive age: A randomized, controlled, clinical trial

The World Health Organization has recommended herbal medicine for treatment and control of recurrent cystitis. This study was conducted to determine effect of eshnan on the prevention of recurrent cystitis. The present triple-blind clinical trial was conducted on 126 women (63 women per group) with recurrent cystitis. The participants were assigned to the intervention and control groups. Three 500-mg eshnan or placebo tablets were taken orally with a glass full of water by the participants half an hour after each meal for 2 months. The study subjects were clinically and paraclinically evaluated by the end of the second, fourth, and sixth months after the intervention and every time they showed clinical symptoms of cystitis. The present findings showed that the incidence rate of cystitis and symptoms of cystitis was significantly lower in the eshnan group compared with the placebo group 2, 4, and 6 months after the intervention (p < .05). The incidence of recurrent was also significantly lower in the intervention group compared with the control group (p < .001). No side effects were observed in the intervention and control groups. The consumption of eshnan can improve the symptoms of cystitis and prevent the incidence of recurrent cystitis in women of reproductive age.

High pressure extraction of olive leaves (Olea europaea): bioactive compounds, bioactivity and kinetic modelling

In this study, the extraction yield, the mathematical modeling of pressurized liquid extraction (PLE) kinetics with sub- and supercritical carbon dioxide (SC-CO2) of olive leaves (Olea europaea) and the biological activity of the extracts were evaluated. The extraction with PLE was conducted isobarically (10.3 MPa), varying the temperature (20, 40 and 60 °C) and the solvent (ethyl acetate, acetone, ethanol, ethanol:water-80:20, v:v), solvent flow (2 mL min-1) and time (110 min) and the extractions with SC-CO2, varying the temperature between 20 and 60 °C and the pressure between 8 and 25 MPa, keeping the time constant (210 min) and the CO2 flow of 2 mL min-1. In the extracts, antioxidant activity, total phenolic and flavonoid contents and oleuropein were evaluated. The highest total extract yield in the PLE was 30.91% at 60 °C, 10.3 MPa using ethanol:water (80:20, v:v). The yield obtained using the supercritical fluid was 0.68% at 60 °C and 25 MPa. The PLE extract obtained with ethanol at 60 °C presented the highest concentration of total phenolic content (386.42 mg GAE g-1 extract), total flavonoids content (33.43 mg CAT g-1 extract), oleuropein (73.65 mg g-1 extract) and antioxidant activity (82.87%). The overall extraction curves were modeled using the well-established Sovová model and kinetic extraction model based on the Brunauer-Emmett-Teller theory of adsorption. Both kinetic models used were able to correlate well with the experimental data with slightly better results obtained by the former. The alternative PLE extraction technique investigated in this work was found to be suitable for the extraction of olive leaves after short times of extraction obtaining an extract with high biological activities.

Antioxidant and antimicrobial properties of ethanolic extracts of guarana, boldo, rosemary and cinnamon

Abstract In this investigation, the ethanolic extracts of two less known plants, little reported in the literature (guarana and boldo leaves) were studied in comparison with the ethanolic extracts of two well studied plants (cinnamon and rosemary), regarding their colour, GC-MS profile, phenolic content and their antioxidant and antimicrobial properties. The rosemary (59.20 ± 0.28) and guarana (56.63 ± 0.54) extracts showed the highest values for luminosity (L*) and the UV-Vis absorption increased when L* decreased. GC-MS identified a limited number of compounds in the cinnamon and guarana extracts. The cinnamon extract showed the highest value for the total phenolic content (172 mg GA/g extract) as compared to the other extracts. The highest antioxidant capacity was observed for the boldo leaves extract in the TEAC (6.66 ± 0.17 mM) assay and for the rosemary extract in the DPPH (0.80 ± 0.14 mg/L) test. In addition, all the extracts showed antimicrobial activity against the S. aureus strain, indicating that all the extracts studied could be used by food industries to develop new active food packaging materials.

Supercritical CO2 extraction, chemical characterisation and antioxidant potential of Brassica oleracea var capitata against HO·, O2(·-) and ROO·

In this work were extracted bioactive compounds from Brassica oleracea var capitata using supercritical CO2 and evaluated the antioxidant potential of the extracts. Five extractions were accomplished to investigate the influence of pressure (10-25 MPa) and temperature (20-60 °C) in the extraction yield, chemical composition and antioxidant potential towards peroxyl, superoxide and hydroxyl radicals. The highest extraction yield was obtained at 60 °C and 25 MPa, which was 0.47 wt% (run 2). In the characterisation of the extracts obtained was possible the identification of sulforaphane and iberin nitrile that present known biological properties. The extracts of all runs presented antioxidant activities towards the three radicals, but the highest activities for all radicals were using the extracts obtained in the run 2. The use of supercritical CO2 extraction to obtain bioactive compounds of B. oleracea var capitata showed to be a promising alternative to conventional extraction methods, since allowed the extraction of compounds with scientific and industrial interest.

Antibacterial activity of the essential oils from the leaves of Eucalyptus globulus against Escherichia coli and Staphylococcus aureus

OBJECTIVE

To examine the in vitro antimicrobial activities of essential oil of the leaves of Eucalyptus globulus (E. globulus).

METHODS

The essential oils of this plant were obtained by the hydrodistillation method. The inhibitory effects of this essential oil were tested against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by using agar disc diffusion and dilution broth methods.

RESULTS

The results obtained showed that essential oil of the leaves of E. globulus has antimicrobial activity against gram negative bacteria (E. coli) as well as gram positive bacteria (S. aureus).

CONCLUSION

The encouraging results indicate the essential oil of E. globulus leaves might be exploited as natural antibiotic for the treatment of several infectious diseases caused by these two germs, and could be useful in understanding the relations between traditional cures and current medicines.