Effects of different nitrogen doses on thymoquinone and fatty acid composition in seed oil of black cumin (Nigella sativa L.)

Abstract

Black cumin,Nigella sativaL. belonging to Ranunculaceae, is a valuablemedicinal plant because of the curative effects of seed and oil. Despite studieson black cumin, there are few studies on the effects of nitrogen on fatty acidcomposition, no records on thymoquinone yield, and the thymoquinone contentof the seed oil. In this study, the effects of different nitrogen doses on the seedoil yield, thymoquinone ratio/yield, and fatty acid compositions were investi-gated. Field studies with nitrogen doses (0, 40, 60, 80, and 100 kg/ha) werestudied using the randomized plot design. As a result of the research, nitrogendoses significantly affected the oil and thymoquinone yields while insignificanton the thymoquinone ratio. The highest oil yield with 501.6 kg/ha was obtainedfrom 80 kg/ha of the nitrogen doses, while the highest thymoquinone yield with10.24 kg/ha was obtained from the control plots. Thymoquinone yields were inthe same statistical group with other nitrogen doses, except for means of100 kg/ha nitrogen doses. Linoleic, oleic, and palmitic acids were major fattyacids of black cumin, and their variations were insignificant in nitrogen applica-tions. The values of butyric, capric, and linolenic acids varied significantly in dif-ferent nitrogen doses. As a result of the study, it was determined that thehighest oil yield was obtained from 80 kg/ha nitrogen application. It has beendetermined that nitrogen doses above 60–80 kg/ha should be avoided for theseed oil and thymoquinone yields in black cumin.