Martina Wurster

Bio: Martina Wurster is an academic researcher from University of Greifswald. The author has contributed to research in topics: Antimicrobial & Essential oil. The author has an hindex of 13, co-authored 35 publications receiving 715 citations.

Chemical Composition and Biological Activities of Essential Oils from the Oleogum Resins of Three Endemic Soqotraen Boswellia Species

Abstract: The chemical composition, antioxidant and anticholinesterase activity of three essential oils (EOs) obtained from the oleogum resin of three endemic Sqotraen Boswellia species, Boswellia socotrana Balf. f , Boswellia ameero Balf. f, and Boswellia elongata Balf. f were determined. GC-MS technique was used for the analysis of the oils. Oils of B. socotrana and B. ameero were characterized by a high content of monoterpenes. The main constituens of B. socotrana and B. ameero were (E)-2,3-epoxycarene (51.8%), 1,5-isopropyl-2- methylbicyclo(3.1.0)hex-3-en-2-ol (31.3%), and α-cymene (7.1%); (3E,5E)-2,6-dimethyl-1,3,5,7-octatetraene (34.9%), 1-(2,4-Dimethylphenyl)ethanol (20.3%), 3,4-dimethylstyrene (17.3%), α-campholenal (13.4%) and α- terpineol (12.4%) respectively. The composition of B. elongata oil was dominated by the diterpene verticiol (52.4%), the sesquiterpene caryophellene (39.1%) and methylcycloundecanecarboxylate (7.8%). The oils were screened for their antioxidant activity by using the DPPH free radical scavenger assay and their anticholinesterase activity on acetylcholinesterase enzyme by using in vitro Ellman method. The antioxidant activity of EOs from B. socotrana (IC 50 =121.4 µg/mL) appeared to be more potent than that of B. elongata (IC 50 =211.2 µg/mL) and B. ameero (IC 50 =175.2 µg/mL). EO of B. socotrana showed the higher AChE inhibitory activity with 59.3% at concentration of 200 µg/mL in comparison to EOs of B. elongata and B. ameero (29.6, 41.6 enzyme inhibition) respectively.

Novel β-Lactam Antibiotics Synthesized by Amination of Catechols Using Fungal Laccase

Abstract: Novel cephalosporins, penicillins, and carbacephems were synthesized by amination of catechols with amino-beta-lactams like cefadroxil, amoxicillin, ampicillin and the structurally related carbacephem loracarbef using laccase from Trametes sp. All isolated monoaminated products inhibited the growth of several Gram positive bacterial strains in the agar diffusion assay, among them methicillin-resistant Staphylococcus aureus strains and vancomycin-resistant Enterococci. Observed differences in the cytotoxicity and in vivo activity in a "Staphylococcus-infected, immune suppressed mouse" model are discussed.

Extracellular degradation of phenol by the cyanobacterium Synechococcus PCC 7002

Abstract: Investigations of the unicellular marine cyanobacterium Synechococcus PCC 7002 revealed its ability to metabolize phenol under non-photosynthetic conditions up to 100 mg L−1. Under continuous light, photoautotrophic growth was reduced only slightly in the presence of this phenol concentration, but no transformation was observed. However neither under photoautotrophic nor heterotrophic conditions were the cells able to use phenol for growth. During the degradation of phenol in the dark cis,cis-muconic acid was produced as the major product, which was identified by gas chromatography/mass spectrometry. This result was confirmed by an identical absorption spectrum and an identical retention time in high performance liquid chromatographic analysis with authentic muconic acid as standard. This provides the first record for an ortho-fission of a phenolic substance by cyanobacteria. Further investigations of the breakdown mechanism of phenol have shown that the transformation is an extracellular process inhibited by heat, proteases and metal ions and is probably catalyzed by a protein.