Chemical composition of seed essential oils from Algerian Nigella sativa extracted by microwave and hydrodistillation

Extraction of essential oil from Nigella sativa seed collected at two locations in the Sahara desert, Timimoun (T) and Adrar (A), has been conducted by hydrodistillation (HD) and a microwave distillation process (MD). The composition of the volatile oil was investigated by capillary gas chromatography and gas chromatography–mass spectrometry. Using the hydrodistillation, active compounds such as p‐cymene (8.9 and 7.2% in T and A, respectively), 4‐terpineol (0.6–8.9%), thymohydroquinone (6.1–12.2%), thymoquinone (1.6–21.8%), carvacrol (12.9–12.9%), carvone (4.4–0.3%) and thymol (1.5–0.7%) were the major components, representing more than 36% (T) and 64% (A) of the oils. For the microwave distillation, p‐cymene (28.1% and 32.0% in T and A, respectively), 4‐terpineol (3.4–2.0%), thymohydroquinone (0.7–1.1%), thymoquinone (10.8–24.6%), carvacrol (3.0–6.0%), and thymol (0.3–0.3%) represent respectively 46.1% and 66.0% of the T and A oils.