Phytotoxic, cytotoxic and antimicrobial effect of the organic extract of Aspergillus niger

Biological screening of Aspergillus niger culture extract was carried out on antimicrobial, cytotoxic and phytotoxic activities with the aim to identify bioactive natural products in the extract as new drug candidates. The investigation was carried out using disc diffusion (antibacterial), agar diffusion (antifungal), brine shrimps lethality (cytoxicity) and Lemna minor (herbicidal) bioassays. The crude extract subjected to the bioassays exhibited no antibacterial property at concentration up to 200 µg. mL -1 . The extract showed antifungal potential against tested fungal pathogens. Growth of Fusarium oxyosproum and Alternaria alternata was inhibited up to 36% and 64% when compared to negative reference. The phytopathogen A. alternata was found highly sensitive to the antifungal effect of the extract among the tested fungal species. Potent activity in brine shrimp bioassays was shown by the extract and mortality up to 96.7% was observed at concentration of 200 µg. mL-1 after 48 hrs. LC50 of the extract against brine shrimp was calculated as 9.25µg. mL -1 . Plant inhibitory effect was observed at all concentrations. Mortality up to 83% of Lemna minor frond with reference to negative control was observed at 200 µg. mL-1. FI50 against Lemna minor was determined as 15.4 µg. mL-1. The observed high toxicity against Lemna minor and brine shrimps larvae make the fungal extract worthy of further exploration for isolation and