| dc.description.abstract | The main objectives of this study were to chemically characterize the melanin
pigments extracted from potential species of fungi and slime mold and investigate
their antibacterial and antibiofilm activities against Cutibacterium acnes (the main
pathogenic bacterium causing inflammatory acne vulgaris). The melanin pigment
samples were extracted using alkaline solution, then UV-Vis spectroscopy and Fourier
transform infrared (FTIR) techniques were used to confirm and initially characterize
the melanin nature of the isolated pigments. Antibacterial activities of the samples
were evaluated using microdilution method (from these data, minimum inhibitory
concentrations [MIC] were calculated) and accompanied with minimum bactericidal
concentration (MBC) for confirmation; the antibiofilm activity was evaluated via
minimum biofilm eradication assay. Data on UV-Vis and FTIR spectra analysis
suggested the extracted pigments were melanin because they had similar features
compared with those of previously reported melanins. Besides, the melanins
extracted from different samples in this study were quite similar in chemical
compositions. In terms of antibacterial activity, among the tested samples, Xylaria sp
melanin was found to be the most potential. Melanin from this fungus could inhibit
the growth of C. acnes with MIC50 value was smaller than 500ug/ml and MIC90 was
about 2000ug/ml, MBC at 2000ug/ml and MBEC50 at 2000 ± 1.7269ug/ml. At the
concentration of 2000ug/ml, Xylaria sp displayed a comparable growth inhibition
against C. acnes as erythromycin (positive control), whereas, its antibiofilm activity
was much lower.
This project generated the first set of data on antibacterial activities and initial
characteristics of melanin from slime molds and puffballs. The obtained results
suggest that melanin from Xylaria sp is worth further investigation for cosmetic
applications or acnes treatment. | en_US |
