Tumisi Beiri Jeremiah Molelekoa, Wilma Augustyn, Thierry Regnier, Laura Suzanne da Silva
Concerns associated with the use of synthetic colourants backs the demand for natural colourants. Thus, the current study aimed at characterizing crude fungal pigments produced by Penicillium multicolour, P. canescens, Talaromyces verruculosus, Fusarium solani and P. herquie. This included their antioxidant and antimicrobial properties together with acute toxicity evaluation on zebrafish embryos. The identification of pigment compounds was achieved through MS and IR data. The study demonstrated a substantial radical scavenging activity of extracts ranging from 65.49 to 74.46%, close to that of ascorbic acid (89.21%). Penicillium canescens and F. solani exhibited a strong antimicrobial activity against Escherichia coli and Enterococcus aerogenes and Salmonella typhi, Staphylococcus aureus and Bacillus cereus at MIC values ranging from 1.5 to 2.5 mg/mL. However, some levels of toxicity were observed for all extracts at a concentration range of 3-5 mg/mL. Pigment by P. multicolour, T. verruculosus and F. solani were tentatively identified through IR and MS data as sclerotiorin (yellow), rubropunctamine (red) and bostrycoidin (red). In conclusion, the study demonstrates a market potential of filamentous fungi pigments due to their antioxidant, antimicrobial activities, and prominent colours. Although there are some toxicity concerns, further tests must be done using molecular docking, albino mice and cell linings.
