Lynda Lamari

New Dithiolopyrrolone Antibiotics from Saccharothrix sp. SA 233

Three new natural dithiopyrrolone antibiotics, 3-methyl-2-butenoylpyrrothine (1), tigloylpyrrothine (2), and n-butyropyrrothine (3) were isolated along with the known isobutyropyrrothine (4) and thiolutin (5) from the fermentation broth of Saccharothrix sp. SA 233. The structures of the novel compounds were established on the basis on their spectral data.

Inhibitory effect on corrosion of carbon steel in acidic media, antioxidant, antimicrobial, anti-5-lipooxygenase and anti-xanthine oxidase activities of essential oil from Tetraclinis articulata (Vahl) Masters leaves

Abstract The leaves essential oil of Tetraclinis articulata (Vahl) Masters was analyzed by GC and GC-MS, and then tested as corrosion inhibitor of carbon steel in 0.1 N of HCl, H2SO4 and HNO3, using electrochemical polarization method. It was also screened for possible biological activities especially antioxidant, antimicrobial, anti-5-lipooxygenase and anti-xanthine oxidase activities. Thirty-five components were identified, accounting for 96.6% of the total essential oil. The major components were α-pinene (29.0%), bornyl acetate (25.5%), camphor (16.6%) and limonene (6.7%). The corrosion rate of carbon steel decreased in the presence of the essential oil giving increased inhibition efficiency with increasing essential oil concentration. Polarization curves showed that this essential oil behave as mixed-type inhibitor with dominated cathodic character in the studied acidic media. The investigated essential oil showed substantial antimicrobial activity, which S. aureus was found to be the most sensitive bacteria. Also, this essential oil showed substantial antiradical and reduction activities. In addition, the 5-lipooxygenase and xanthine oxidase were efficiently inhibited by the tested essential oil. According to these finding, this essential oil may be suggested as new green inhibitor agent against corrosion in acidic media and could be considered as a potential natural antioxidant alternative for use in food industry.

Chemical composition, antimicrobial and antioxidant activities of essential oil of Salvia chudaei Batt. et Trab. endemic plant from Algeria

The essential oil composition and in vitro antioxidant and antimicrobial activities of the essential oil from Salvia chudaei Batt. et Trab. were investigated in this research for the first time. Gas chromatography (GC) and GC/mass spectrometry (GC/MS) analysis of the plant essential oil resulted in the identification of fifty compounds representing 90.8% of the oil. The principal constituents were identified as bornyl acetate (20.5%), β-eudesmol (13.6%), β-caryophyllene (10.6%), valencene (9.3%), τ-cadinol (9.3%), α-pinene (6.9%) and γ-cadinene (5.8%). The antimicrobial activity of the essential oil was evaluated using disk diffusion and agar dilution methods. A great potential antimicrobial activity was observed against Staphylococcus epidermidis and Candida albicans, followed by Bacillus subtilis, Staphylococcus aureus and Listeria monocytogenes, with their respective zones of inhibition of 13.33 ± 1.52 to 40.5 ± 2.12 mm and minimal inhibition concentration (MIC) values of 0.062–1 mg/mL. The plant essential oil was also subjected to screenings for the evaluation of their antioxidant activities using 2.2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene–linoleic acid tests, and weak activities were found for this essential oil.

Chemical Composition and Antimicrobial Activity of the Essential Oil of Thymus lanceolatus Desf., an endemic Thyme from Algeria

Abstract The aim of this study is to investigate the chemical composition and antimicrobial activities of essential oil of Thymus lanceolatus Desf. (T. Lanceolatus) endemic thyme from Tiaret (province of Algeria). The chemical composition of hydrodistilled essential oil from flowering aerial parts has been analyzed by GC-FID and GC-MS techniques, the antimicrobial activity was realised by agar disc diffusion method and MIC was determined in solid medium by direct contact. Essential oil of T. lanceolataus has been yielded of 2.336 (w/w) based on dry weight, the analyses cited above, led to the identiûcation of 29 components, which accounted for 97.34 % of the total oil. Oxygenated monoterpenes was the main fraction (88.31 %) dominated by thymol (80.2 %) as major component of this oil followed by carvacrol (6.25 %). The oil was found effective against all tested strains especially fungus, except Pseudomonas aeruginosa were low activity observed. In addition Gram (+) bacteria found to be more sensitive to the essential oil than Gram (-) bacteria. This activity was ranging from12±2.65 mm to 60.00±0.00 mm, with the lowest MIC value of under 0.06 mg/ml to 12.53 mg/ml. This results provided the evidence that the studied plant might indeed be potential sources of natural antimicrobial agents.

Essential Oil Variability of Tetraclinis articulata (Vahl) Mast. Parts During Its Phenological Cycle and Incidence on the Antioxidant and Antimicrobial Activities.

The impact of phenological stages (vegetative, flowering and fruiting stages) on chemical composition, antioxidant, and antimicrobial activities of Tetraclinis articulata (Vahl) Mast. parts essential oils were investigated for the first time. GC and GC/MS analyses pointed to a quantitative variability of components; terpene hydrocarbons derivatives, represented by α‐pinene (16.38 ± 0.19 – 31.78 ± 0.35%) and limonene (3.41 ± 0.07 – 9.49 ± 0.14%) as major components, predominate at the vegetative stage, whereas oxygenated derivatives, represented by camphor (16.11 ± 0.23 – 26.17 ± 0.29%) and bornyl acetate (15.21 ± 0.21 – 27.33 ± 0.33%) as major components, predominate at the fruiting stage. Furthermore, our findings showed that the plant parts collected at the fruiting stage possess the highest antioxidant activity and the best antimicrobial activity against the tested microorganisms, than plant parts collected at the vegetative and flowering stages. This highlighted variability reflects the high impact of phenological cycle on chemical composition and biological activities, which led to conclude that we should select essential oils to be investigated carefully depending on phenological stage, in order to have the highest effectiveness of essential oil in terms of biological activities for human health purposes.