Forty-eight compounds have been identi¼ed in the essential oil from Nigella sativa (black cumin) seeds, 14 of which are volatiles that have never been isolated from black cumin before. This is the ¼rst time to show two monoterpenoids: cis-and trans-4-methoxythujane, occur naturally in plants, speci¼cally in the essential oil from N. sativa seeds in 0.3% and 4%, respectively. The structures of the 4-methoxythujanes were established by both spectroscopic and chemical methods.SEED ESSENTIAL OIL OF NIGELLA SATIVA L. 127 tr, trace (<0.05%); RI exp , experimental retention index given for CP-Sil5 column; RI lit , literature retention index given for CP-Sil5 column. 18 * New compounds for essential oil of N. sativa. 130 A. WAJS ET AL. 5 32.1 (d) 1 . 1 8 ( dd, 1H, J = 3.8/8.5 Hz) 32.8 (d ) 1 . 0 0 ( dd, 1H, J = 3.8/7.9 Hz) 34.4 (d) 1 . 0 6 ( dd, 1H, J = 3.5/8.2 Hz) 33.6 (d) 1 . 0 4 ( dd, 1H, J = 3.7/7.9 Hz) 6 12.1 (t) 0 . 1 5 ( dd, 1H endo , J = 3.8 Hz J gem = 4.9 Hz) 11.7 (t) 0 . 3 3 ( dd, 1H exo , J gem = 5.0 Hz, J = 7.9 Hz) 13.2 (t) 0 . 2 2 ( dd, 1H endo , J = 3.5 Hz, J gem = 5.1 Hz) 11.1 (t) 0 . 3 2 ( dd, 1H exo , J gem = 5.0 Hz, J = 7.9 Hz) 0.38 (dd, 1H exo , J gem = 4.9 Hz, J = 8.5 Hz) 0.64 (dd, 1H endo , J = 3.8 Hz, J gem = 5.0 Hz) 0.40 (dd, 1H exo , J gem = 5.1 Hz, J = 8.2 Hz) 0.64 (dd, 1H endo , J = 3.7 Hz, J gem = 5.0 Hz) 7 30.8 (d) 1 . 5 2 ( sp, 1H, J = 6.8 Hz) 29.9 (d ) Scheme 1. Synthesis of cis-and trans-4-methoxythujanes from sabinene and from appropriate thujan-4-ols