Antimicrobial activity of ethanolic extracts from algae against Penicillium expansum Link (Trichocomaceae, Ascomycota)

Penicillium expansum is a cosmopolitan, highly aggressive pathogen that causes blue mold, a disease of great importance that leads to losses in quality and quantity of harvested fruits. The application of chemicals is traditionally used as a control method. However, algae bioprospecting has revealed many antifungal compounds that can be used to control pathogens. Thus, the objective of this study was to evaluate the effects of ethanolic extracts from seven microalgae and five macroalgae against P. expansum. The antifungal potential was evaluated by analyzing germination percentage, the size of the germ tube, minimum inhibitory concentration (MIC), and the median effective concentration (EC50). The spectrophotometric profile was determined for extracts that showed an inhibitory effect. Among the investigated algae, the Chlorella sp. and H. pluvialis extracts, which had final concentrations of 18.8 and 125.95mg.mL-1, inhibited 100% and 91% germination, respectively. The EC50 was 2.93 and 61.20 mg.mL-1 for Chlorella sp. and H. pluvialis, respectively. Chlorella sp. showed absorption peaks in the range of chlorophyll-a and H. pluvialis presented a peak in the range of phenolic compounds. Although further studies are required to characterize the extracts, Chlorella sp. and H. pluvialis showed promising antifungal effects on the control of P. expansum