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.

Nocardiopsis and Saccharothrix genera in Saharan soils in Algeria: isolation, biological activities and partial characterization of antibiotics.

Twenty-five soil samples were collected in the Algerian Sahara and analyzed to isolate rare actinomycetes. Eighty-six isolates with the same Nocardiopsis or Saccharothrix morphology were isolated on humic-vitamin B agar medium using dilution techniques and several antibiotics as selective agents. Certain of these antibiotics seemed to be very selective for some phenotypes. Morphological and chemotaxonomic characteristics led to identifying 54 isolates belonging to the Nocardiopsis genus and 32 isolates belonging to the Saccharothrix genus. An assessment of the antimicrobial properties of the isolates showed activities against Gram-positive bacteria, fungi and yeasts. Saccharothrix isolates possessed better antifungal activity than Nocardiopsis. One of them, labeled SA 103, was therefore selected for identification of its antifungal antibiotic activities. Production of overall antifungal and antibacterial activities was checked on the complex medium ISP2 and a synthetic medium (SM) that contains glucose or starch as carbon source, and ammonium or nitrate as nitrogen source. The SM medium containing ammonium sulfate (0.2%), supplemented with starch (0.5%) and yeast extract (0.3%), was retained for production of antibiotics. Active substances were purified by a G25-80 Sephadex column and reverse phase HPLC. Two pure substances were obtained and named ZA01 and ZA02; they were characterized on the basis of combined data resulting from chemical tests, UV visibile and IR spectra and mass spectrometry. The two antibiotics were found to be related and were partially characterized as nucleotidic or nucleosidic antibiotics. Their structures consisted of a chain of three sugar units linked to an aromatic base containing a phosphate residue.

New dithiolopyrrolone antibiotics from Saccharothrix sp. SA 233. I. Taxonomy, fermentation, isolation and biological activities.

Three new natural antibacterial and antifungal dithiolopyrrolone antibiotics were isolated along with the known iso-butyropyrrothine and thiolutine from the fermentation broth of an actinomycete strain which was isolated from a saharian palm grove soil collected at Adrar, south Algeria. The strain was identified as Saccharothrix sp. The three new antibiotics exhibited broad antimicrobial activity against gram-positive bacteria, yeasts and fungi in vitro.

New dithiolopyrrolone antibiotics from Saccharothrix sp. SA 233. II. Physicochemical properties and structure elucidation.

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.