Evaluation of Black Cumin Oils under Various Nitrogen Treatments

Essential oil (EO) and fixed oil (FO) isolated from the seeds of Nigella sativa L. (N. sativa) used in various aspects of traditional medicine and different food prducts. The bilogical activities such as antimicrobial of N. sativa oils were reported by previous investigators. There are tow major nitrogen (N) sources i.e Urea (UR) and ammonium sulfate (AS). The UR and AS contain 46 and 21% of N respectively. In addition, AS also contains about 24% of sulfur (S). Nutrition with more N content are preferred over low-N nutrition because of the lower cost of transport and application. The objective of this study was to evaluate effect of AS and UR on EO and FO composition of Black cumin. Experimental areas were divided into 3 main groups. The first group was subjected to no rate of N (control). The second group was subjected to different doses of N (50, 100 and 150 kg N ha⁻¹) as AS (20.5 % N). The third group was subjected to the same treatments of N but UR (46 % N) was added. The EO and FO were isolated from black cumin seeds of all treatments and analyzed by GC- MS. Data were statistically analyzed using 1-way analysis of variance (ANOVA-1). Significant rates were identified according to P values (P 0.05 = significant, P 0.01 = moderate significant and P 0.001 = highly significant). The highest amounts of EO contents were recorded under at 100 kg N ha⁻¹) rate (as UR) with the values of 0.4 - 0.5%; 11.6 -14.5 g (100 plant)⁻¹. Greatest amounts of main components were produced from 100 kg N ha⁻¹ (as AS) with the values of 51.7% (p-cymene) and 15.9 (α-thujene). Treatment 50 kg N ha⁻¹ (as UR) produced the highest contents of FO which recoded 31.8 and 33.6%; 699.6 and 739.2 g (100 plant)⁻¹. Greatest amounts of major FA were obtained from the treatment of 150 kg N ha⁻¹ (as AS) with the values of 22.9% (oleic) and 74.7% (linoleic). Different nitrogen sources caused significant changes (P 0.05) in EO, FO, main compounds of EO and major FA.