Solvent-Dependent Bioactive Composition and Antifungal Potential of Neem (Azadirachta indica) Seed Extracts Against Mycotoxigenic Aspergillus Species.

This study investigated the bioactive composition and antifungal efficacy of neem seed extracts (NSE) prepared using acetone, ethyl acetate, chloroform, methanol, and ethanol against Aspergillus parasiticus and Aspergillus flavus. Gas chromatography-mass spectrometry (GC-MS) analysis revealed solvent-specific compounds profiles: ethanol extract contained 35 bioactive compounds (mainly esters and fatty acids), dominated by n-hexadecanoic acid (28.65%); methanol extract had 29 diketopiperazines, with 3,6-bis(2-methylpropyl)-2,5-piperazinedione (45.45%) as major; chloroform, ethyl acetate, and acetone extracts featured long-chain esters, hydrocarbons, and 2-heptadecanone (33.15%), respectively. All extracts inhibited fungal growth at 500 mg/mL, whereas ethanol was most effective at 31.25 mg/mL, reducing mycelial biomass by 45%. Methanol and ethanol extracts (250 mg/mL) suppressed aflatoxin (AF) (AFB1, AFB2) production by >90%. Six-month feed trials confirmed neem seed powder (NSP) as a potent biopreservative, achieving complete AF inhibition at 30% concentration. These findings highlight neem's potential as a natural antifungal and anti-aflatoxigenic agent.