Controlling aflatoxins production in maize by new formulation of neem seed extract

Mycotoxins are naturally occurring secondary metabolites of several toxigenic fungi that contaminate the whole food chain from agricultural products such as nuts like peanuts, fruits and dried fruits which ultimately are consumed by the human. Neem is an adaptable medicinal plant that has been in use since ancient. Neem seed extract is source of various types of compounds specially azadirachtins, with diverse chemical structure which many of them have pesticide activity. There is scanty information available in the literature on the effect of neem oil on growth, sporulation level and aflatoxins production by A. flavus in submerged cultures. Thus, current study aims to determine the effectiveness of the new formulation of neem seed extract (FNSE) on the AFB1 and AFB2 production by A. flavus on liquid medium and maize. Neem seed were collected from sites in Bandar Abbas in Hormozgan province (IRAN) from August to September 2017. The extraction from De-hulled neem seeds was carried out in a sequential manner with Ethyl acetate, water and hexane. After drying, the powdered extract was formulated with Tween 85 and sunflower oil. Evaluation of aflatoxin production of A. flavus (6 log CFU/mL) on liquid medium (Potatoes Dextrose Broth (PDB)) and maize that contain 0.3 uL/ml of FNSE was conducted after 9 days incubation at 28 °C. The findings revealed that more than 60% of AFB1 and 41% of AFB2 in liquid medium and 54% of AFB1 and 33% of AFB2 in maize were reduced in comparison to controls (P < 0.05). This activity was attributed to the tetranortritepenoids such as azadirachtin A that was measured by HPLC.