Inhibitory effect of various aqueous medicinal plant extracts on citrinin production and fungal biomass by Penicillium notatum and Aspergillus niger

Citrinin is a nephrotoxic mycotoxin produced by several species of the genus Aspergillus, Penicillium and Monascus. Citrinin is generally formed after harvest and occurs mainly in stored grains. The efficacy of different concentrations of aqueous leaf extracts of Aervalanata, Nerium oleander, Rhazya stricta Decne and Cleome amblyocarpa (5 to 10 mg/mL) on growth and citrinin production in two fungal strains Penicillium notatum and Aspergillus niger was investigated. Mycotoxin production and fungal biomass by the isolates was suppressed, depending on the concentration of the plant extract added to culture media at the time of spore inoculation. Citrinin production in fungal mycelia grown for 15 days in culture media containing 5 ? 10 mg/mL of the aqueous extracts of A. lanata, N. oleander, R. stricta Decne and C. amblyocarpa showed inhibition of approximately 14.2 to 91.8 % in Penicillium notatum and 13.4 to 90.3% in Aspergillus niger. Among the all four extracts, Rhazya stricta Decne was more efficient than other tested plant extracts in inhibiting the citrinin production ranging from 22.4 to 91.8% in P. notatum and 32.6 to 93.2% in A. niger.