A bryozoan species may offer novel antioxidants with anti-carbon-dioxide anion radical activity

<div><p>The antiradical activity of the freshwater bryozoan <i>Hyalinella punctata</i> water extracts (two samples, seasonal collection) was evaluated by using electron paramagnetic resonance spectroscopy against hydroxyl (√OH), superoxide anion (√O₂⁻), methoxy (√CH₂OH), carbon-dioxide anion (√CO₂⁻), nitric-oxide (√NO) and 2,2-diphenyl-1-picrylhydrazyl (√DPPH) radicals. The extracts reduced the production of all tested radicals but to a varying degree. The better activity was observed against √CO₂⁻ and √CH₂OH radicals (54 ± 5% and 44 ± 4%, and 58 ± 6% and 22 ± 2%, respectively) than towards √DPPH, √NO, √OH and √O₂⁻ radicals (59 ± 6% and 1.0 ± 0.1%, 46 ± 5% and 14 ± 1%, 7.0 ± 0.5% and 34 ± 3%, and 33 ± 3% and 0%, respectively). FTIR spectra of the both extracts indicate the presence of cyclic peptides and polypeptides which might be responsible for the observed activity. According to the experimental data obtained, <i>H. punctata</i> water extract may be considered as a novel promising resource of natural products with anti √CO₂⁻ radical activity.</p></div

<i>In vitro</i> antibiofilm activity of the freshwater bryozoan <i>Hyalinella punctata</i>: a case study of <i>Pseudomonas aeruginosa</i> PAO1

<p>The antibiofilm and possible antiquorum sensing effects against the strain <i>Pseudomonas aeruginosa</i> PAO1 of five crude extracts of the freshwater bryozoan <i>Hyalinella punctata</i> (Hancock, 1850) were evaluated <i>in vitro</i> for the first time. <i>H. punctata</i> ethyl acetate extract (HpEtAc) exhibited the highest antibiofilm activity reducing the biofilm formation of <i>P. aeruginosa</i> PAO1 in the range of 80.63–88.13%. While all tested extracts reduced the twitching motility of the aforementioned bacterial strain, HpEtAc showed to be the most effective. Finally, at a concentration of 0.5 MIC, the same extract mostly inhibited the production of pyocyanin by <i>P. aeruginosa</i> PAO1 (71.53%). In comparison both with the positive controls used (streptomycin and ampicillin, 67.13 and 69.77%, respectively), HpEtAc was found to inhibit pyocyanin in a higher extent. An extensive chemical characterisation of this particular extract may result in isolation and identification of novel lead compounds targeting <i>P. aeruginosa</i>, an opportunistic human pathogen.</p

An insight into antimicrobial activity of the freshwater bryozoan <i>Pectinatella magnifica</i>

<p>The antimicrobial activity of five crude extracts of the freshwater bryozoan <i>Pectinatella magnifica</i> (Leidy, 1851) was evaluated <i>in vitro</i> for the first time. <i>P. magnifica</i> acetone extract exhibited the highest antibacterial activity (minimum inhibitory concentrations (MIC) 0.004–0.350 mg/mL and MBC 0.007–0.500 mg/mL), while its methanol extract showed the most promising antifungal activity (MIC 0.03–0.12 mg/mL and MFC 0.06–0.25 mg/mL). Furthermore, at a concentration of 0.25 MIC, the methanol extract reduced biofilm formation of the bacterial strain <i>Pseudomonas aeruginosa</i> PAO1 in a considerable extent (59.14%). FTIR spectra of the most active extracts indicate the presence of carbonyl compounds, long-chain alcohols and/or sterols. According to the experimental data obtained, <i>P. magnifica</i> methanol extract may be considered as a good resource of novel natural products with potent antibiofilm activity against the bacterium well known for its resistance.</p