Abstract
Active components of neem leaves and seeds were extracted with different methods in order to study the effect of different extract concentrations on the inhibition of some pathogenic fungi. High-performance liquid chromatography (HPLC) was used to identify the active components of neem extract. Highest inhibition percentage of ethanolic neem leaf extract was recorded with Rhizoctonia solani, while the lowest was recorded with Alternaria solani. A complete inhibition percentage was recorded with 40% ethanolic neem leaf extract of R. solani and Fusarium oxysporum. The highest inhibition percentages were recorded with F. oxysporum (10, 20, 30 and 40%) concentrations of hexane neem leaf extract, while the lowest was recorded with A. solani. The highest inhibition percentages were recorded with R. solani (10, 20 and 30%) concentrations of methanolic neem leaf extract, while the lowest was recorded with the same mentioned concentration of Sclerotinia sclerotiorum. A complete inhibition percentage was recorded with 40% methanolic neem leaf extract of F. oxysporum and R. solani, while the lowest was recorded with S. sclerotiorum. The highest inhibition percentage was recorded with R. solani (10 and 20%) concentrations of ethanolic neem leaf extract and the lowest was recorded with A. solani. The highest inhibition percentage was recorded with (10, 20, 30 and 40%) hexane neem seed extract of F. oxysporum. The lowest inhibition percentages with the same mentioned concentrations were recorded with A. solani. The highest inhibition percentage was recorded with (10 and 20%) methanolic neem seed extract of R. solani. The lowest inhibition percentage was recorded with S. sclerotiorum. The inhibition percentage of tested fungi increased by increasing neem leaf and seed extract by different rates. Also, neem seed organic extracts had higher inhibition percentage than that of neem leaf organic extracts. HPLC chromatogram of neem organic extract showed that nimonol (82%) is the major active component of neem organic extract.