A fast, inexpensive, and ecological method based on liquid-liquid extraction principle has been developed for preparation of extract with high content of Nigella sativa (N. sativa) quinones. The gas chromatography-mass spectrometry (GC-MS) analysis showed that oil extraction using 70% ethanol for 6 h yielded extract containing 50% of thymoquinone (TQ) and 13% of thymohydroquinone (THQ).
Keywords:
Nigella sativa; quinones; crude oil; liquid-liquid extraction
| No. | Compound | Retention index | Oil (peak area) / % | Extract (peak area) / % | Identificationc c identification method: MS: mass spectrum was identical to that of National Institute of Standards and Technology Library (ver. 2.0.f), RI: the retention index was consistent with that of the literature database, Std.: constituent identity confirmed by co-injection of authentic standards; | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Observeda a Retention indices calculated from retention times on a DB-5 column and based on C9-C29 alkanes; | Publishedb b data taken from literature;15,28 | A | B | C | A | B | C | |||||
| 1 | α -thujene | 938 | 931 | 4.91 | 10.49 | 8.85 | 2.78 | 1.36 | 1.42 | MS, RI | ||
| 2 | α -pinene | 944 | 939 | 1.16 | 2.90 | 1.58 | 0.82 | 0.25 | 0.49 | MS, RI, Std. | ||
| 3 | sabinene | 977 | 973 | 0.48 | 1.19 | 0.96 | -d d compound not determined in the sample; | - | - | MS, RI, Std. | ||
| 4 | β -pinene | 981 | 980 | 1.12 | 2.78 | 2.06 | - | - | - | MS, RI, Std. | ||
| 5 | p-cymene | 1022 | 1026 | 11.55 | 17.97 | 27.74 | 7.28 | 3.50 | 7.59 | MS, RI, Std. | ||
| 6 | limonene | 1028 | 1031 | 0.72 | 1.81 | 1.27 | - | - | - | MS, RI, Std. | ||
| 7 | γ -terpinene | 1056 | 1062 | 0.37 | 1.76 | 0.52 | - | - | - | MS, RI, Std. | ||
| 8 | cis-4-methoxythujane | 1092 | 1088 | 0.36 | 0.97 | 0.58 | 0.99 | 0.46 | 0.63 | MS, RI | ||
| 9 | trans-4-methoxythujane | 1117/1116 | 1110 | 1.79 | 4.01 | 3.55 | 6.55 | 3.71 | 4.81 | MS, RI | ||
| 10 | 4-terpineol | 1180/1178 | 1189 | 0.16 | 0.59 | 0.28 | 1.37 | 0.86 | 1.25 | MS, RI, Std. | ||
| 11 | dihydrocarvone | 1196 | 1193 | 0.06 | 0.80 | 0.49 | 0.86 | 0.57 | 0.79 | MS, RI, Std. | ||
| 12 | thymoquinone | 1247 | 1249 | 9.37 | 32.95 | 39.73 | 29.83 | 47.39 | 50.62 | MS, RI, Std. | ||
| 13 | (E)-dec-2-enal | 1260 | 1261 | 0.17 | 0.22 | 0.02 | - | - | - | MS, RI, Std. | ||
| 14 | thymol | 1294/1293 | 1290 | 0.59 | 0.41 | 0.95 | 2.76 | 1.59 | 4.82 | MS, RI, Std. | ||
| 15 | (E, E)-deca-2,4-dienal | 1314 | 1314 | 0.64 | 0.55 | 0.16 | - | - | - | MS, RI, Std. | ||
| 16 | tetradecane | 1400 | 1400 | 0.18 | 0.50 | 0.07 | - | - | - | MS, RI, Std. | ||
| 17 | longifolene | 1403 | 1402 | 0.30 | 2.53 | 1.35 | - | - | - | MS, RI | ||
| 18 | thymohydroquinone | 1551/1552 | 1559 | 0.77 | 0.61 | 0.55 | 13.65 | 10.80 | 13.12 | MS, RI, Std. | ||
| 19 | 2,4-diethoxybenzoic acid | 1724/1726 | n.a.e e literature data not available; | 0.21 | 0.20 | 0.05 | 5.61 | 1.66 | 1.24 | MS, Std. | ||
| 20 | 3,7-dimethyloctanal | 1729 | n.a.e e literature data not available; | - | - | - | 4.13 | 3.79 | 0.33 | MS, Std. | ||
| 21 | hexadecanoic acid | 1960/1958 | 1970 | 8.92 | 0.91 | 1.42 | 1.68 | 0.58 | 0.26 | MS, RI, Std. | ||
| 22 | sesquiterpene esterf f tentatively identified compound. Data on quinone compounds are indicated in bold. | 2128/2130 | n.a.e e literature data not available; | 1.68 | 6.03 | 0.07 | 6.36 | 2.22 | 5.31 | MS | ||
| 23 | octadecadienoic acid | 2153/2159 | 2150 | 32.86 | 5.5 | 4.55 | 6.64 | 5.44 | 1.50 | MS, RI, Std. | ||
| 24 | octadecenoic acid | 2163 | 2161 | 21.63 | 4.32 | 3.2 | 4.03 | 3.55 | 1.97 | MS, RI, Std. | ||
| 25 | β -monolinolein | - | n.a.e e literature data not available; | - | - | - | 4.66 | 12.27 | 3.85 | MS | ||
