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Advisor(s)
Abstract(s)
Bark residual side streams from industries (Eucalyptus globulus—Eg and Picea
abies—Pa) or from control of invasive species in Mediterranean countries (Acacia
melanoxylon—Am and Acacia dealbata—Ad) are burned for energy production,
although their high content of extractable compounds points to a possible valorization as sources of phytochemicals with antioxidant and antimicrobial activities.
Non-polar and polar extracts were obtained, and their phenolic contents, antioxidant
activity, antiquorum sensing and antimicrobial potential against several human pathogenic microbes (nine bacteria and two yeasts) were determined. Extraction yield
ranged from 0.5 to 37% of barks dry weight varying with species and solvent used,
and both water and ethanol extracts presented strong or very strong scavenging antioxidant ability. Eg and Pa non-polar extracts showed the lowest minimum inhibitory concentration for gram-positive bacteria (0.04–1.25 mg/mL), while Ad presented the best results among polar extracts regarding bacteria (0.16 mg/mL for K.
pneumoniae) and yeast strains (0.02–0.04 mg/mL). Non-polar extracts showed great
response against both Candida species (MIC=0.04–0.63 mg/mL). Each extract had
diferent antimicrobial activity showing that species and solvents can be used to tailor compounds to target specifc pathogens. Information regarding these bioactive
extracts from residual forest side streams can provide possible utilization routes for
natural compounds recovery prior to combustion.
Description
Keywords
Antioxidant Antimicrobial