Table 1.

Chemical constituents of essential oils (EOs) of the aboveground parts of Calotropis procera collected from Saudi Arabia and Egypt.

No	Rt.	KI		Compound Name	Conc. (%)		Identification
		Exp	Lit		Saudi Arabia	Egypt
Oxygenated Monoterpenes
1	7.06	1030	1031	Eucalyptol	0.37 ± 0.03	0.21 ± 0.01	a & b
2	11.12	1123	1122	α-Cyclocitral	0.15 ± 0.02	---	a & b
3	11.45	1139	1137	trans-Pinocarveol	0.88 ± 0.03	---	a & b
4	12.00	1143	1143	Camphor	1.50 ± 0.06	---	a & b
5	12.75	1146	1145	Verbenol	0.33 ± 0.02	---	a & b
6	13.48	1189	1189	4-Terpineol	0.16 ± 0.02	---	a & b
7	13.61	1201	1202	Safranal	0.35 ± 0.02	---	a & b
8	15.74	1235	1234	trans-Chrysanthenyl acetate	12.33 ± 0.09	1.09 ± 0.04	a & b
9	16.95	1336	1338	α-Terpinyl propionate	0.41 ± 0.02	---	a & b
10	25.03	1453	1455	Neryl acetone	---	0.61 ± 0.03	a & b
Oxygenated Sesquiterpenes
11	24.10	1499	1501	β-Himachalene	0.30 ± 0.01	---	a & b
12	24.32	1439	1440	α-Guaiene	0.17 ± 0.01	---	a & b
13	24.40	1511	1512	Germacrene D-4-ol	0.24 ± 0.02	---	a & b
14	24.90	1517	1516	6-Epishyobunol	0.28 ± 0.01	---	a & b
15	25.53	1535	1533	Nerolidol	0.64 ± 0.03	---	a & b
16	26.80	1551	1554	Diepicedrene-1-oxide	1.95 ± 0.06	---	a & b
17	27.14	1558	1557	Dihydro-α-agarofuran	0.86 ± 0.04	---	a & b
18	27.73	1563	1561	Hexahydrofarnesol	0.23 ± 0.02	---	a & b
19	27.95	1564	1562	Epiglobulol	0.28 ± 0.01	---	a & b
20	28.29	1567	1568	Palustrol	0.40 ± 0.03	---	a & b
21	28.52	1575	1580	Caryophyllene oxide	---	0.41 ± 0.02	a & b
22	28.77	1578	1579	Spathulenol	0.46 ± 0.02	---	a & b
23	28.94	1586	1584	Viridiflorol	2.47 ± 0.07	---	a & b
24	29.58	1588	1588	Calarene epoxide	0.21 ± 0.01	---	a & b
25	29.66	1594	1594	Isoaromadendrene epoxide	0.27 ± 0.01	---	a & b
26	29.85	1596	1597	α-Cedrol	0.56 ± 0.03	---	a & b
27	30.73	1604	1606	Cedrenol	0.59 ± 0.02	---	a & b
28	30.94	1619	1622	Humulane-1,6-dien-3-ol	0.78 ± 0.01	---	a & b
29	31.09	1625	1625	Aromadendrene oxide (1)	0.45 ± 0.02	---	a & b
30	31.39	1627	1628	4-epi-cubedol	1.82 ± 0.06	---	a & b
31	31.81	1632	1631	1,4-trans-1,7-cis-Acorenone	7.62 ± 0.05	---	a & b
32	32.21	1638	1638	Hinesol	13.50 ± 0.08	---	a & b
33	32.48	1649	1651	β-Eudesmol	0.60 ± 0.02	---	a & b
34	33.24	1657	1656	α-Acorenol	1.95 ± 0.05	0.35 ± 0.02	a & b
35	33.76	1669	1671	Cedr-8-en-15-ol	0.36 ± 0.02	---	a & b
36	34.23	1689	1687	Cedr-8-en-13-ol	0.78 ± 0.03	0.45 ± 0.01	a & b
37	36.89	1691	1692	Juniper camphor	0.18 ± 0.01	0.40 ± 0.02	a & b
38	38.66	1885	1885	(8S,14)-Cedrandiol	0.43 ± 0.02	1.38 ± 0.04	a & b
39	45.69	1922	1925	(E,E)-Farnesyl acetone	0.16 ± 0.01	---	a & b
40	40.79	2045	2005	Isochiapin B	0.56 ± 0.02	1.03 ± 0.05	a & b
Sesquiterpenes Hydrocarbons
41	19.26	1351	1351	α-Cubebene	2.19 ± 0.06	---	a & b
42	20.48	1376	1378	α-Copaene	0.84 ± 0.02	---	a & b
43	21.26	1409	1409	α-Cedrene	0.44 ± 0.03	---	a & b
44	21.71	1410	1412	α-Gurjunene	0.32 ± 0.01	---	a & b
45	22.29	1418	1418	trans-Caryophyllene	1.44 ± 0.07	3.07 ± 0.06	a & b
46	22.78	1429	1429	cis-Thujopsene	0.61 ± 0.03	0.83 ± 0.02	a & b
47	22.96	1462	1460	α-Humulene	0.26 ± 0.02	---	a & b
48	23.55	1480	1483	α-Muurolene	0.15 ± 0.01	---	a & b
49	23.81	1484	1486	Germacrene-D	0.19 ± 0.01	---	a & b
50	23.95	1496	1489	Aromadendrene	0.43 ± 0.02	---	a & b
51	24.64	1493	1496	β-Muurolene	0.56 ± 0.02	---	a & b
52	25.16	1500	1502	Bicyclogermacrene	---	4.37 ± 0.08	a & b
53	25.22	1517	1515	α-Selinene	0.95 ± 0.04	---	a & b
54	25.63	1521	1524	cis-Calamenene	0.74 ± 0.03	---	a & b
55	26.22	1532	1533	γ-Cadinene	1.86 ± 0.07	---	a & b
56	26.39	1537	1537	α-Cadinene	3.31 ± 0.06	---	a & b
57	26.56	1555	1557	Junipene	0.52 ± 0.03	---	a & b
58	27.45	1548	1546	α-Calacorene	0.16 ± 0.01	---	a & b
Oxygenated Diterpenes
59	44.31	1942	1944	Isophytol	0.25 ± 0.01	2.66 ± 0.08	a & b
60	46.99	1949	1950	Phytol	8.73 ± 0.09	38.02 ± 0.13	a & b
61	47.95	2201	2203	trans-Geranyl geraniol	0.80 ± 0.02	3.24 ± 0.08	a & b
Diterpenes Hydrocarbons
62	44.81	2064	2062	Kaur-16-ene	0.39 ± 0.03	0.90 ± 0.02	a & b
Oxygenated Hydrocarbons
63	35.57	1635	1636	1-Heptatriacontanol	0.47 ± 0.03	---	a & b
64	41.35	1754	1756	Hexyl cinnamic aldehyde	0.91 ± 0.04	---	a & b
65	46.78	1927	1927	Methyl palmitate	2.86 ± 0.07	2.70 ± 0.05	a & b
66	47.23	2108	2109	Linoleic acid, methyl ester	---	0.72 ± 0.03	a & b
67	47.69	2128	2128	Methyl stearate	---	0.98 ± 0.04	a & b
68	47.78	2144	2145	Z-7-Hexadecenal	0.49 ± 0.03	2.10 ± 0.06	a & b
69	48.57	2152	2152	Linoleic acid	0.15 ± 0.01	6.36 ± 0.07	a & b
70	54.87	2161	2161	Oleic Acid	0.59 ± 0.02	3.51 ± 0.09	a & b
Non-oxygenated Hydrocarbons
71	32.55	1900	1901	n-Nonadecane	---	0.45 ± 0.01	a & b
72	39.99	2000	2000	n-Eicosane	---	0.67 ± 0.02	a & b
73	43.24	2100	2101	n-Heneicosane	---	1.30 ± 0.05	a & b
74	49.33	2200	2200	n-Docosane	---	6.86 ± 0.11	a & b
75	52.45	2300	2303	n-Tricosane	0.84 ± 0.03	---	a & b
76	57.85	2500	2502	n-Pentacosane	0.76 ± 0.02	6.31 ± 0.07	a & b
Aromatics
77	19.93	1355	1353	1,1,6-Trimethyl-1,2-dihydronaphthalene	0.37 ± 0.02	---	a & b
78	36.99	1438	1436	Bolandiol	0.17 ± 0.01	0.15 ± 0.01	a
79	38.42	1845	1843	Myristicin	6.13 ± 0.08	2.09 ± 0.05	a & b
80	40.73	1457	1457	Myristic acid	0.50 ± 0.02	---	a & b
81	44.51	2277	2478	Ethyl iso-allocholate	---	1.58 ± 0.06	a
Carotenoid-derived compounds
82	17.41	1284	1283	Dihydroedulan II	0.16 ± 0.01	---	a & b
83	20.94	1351	1354	α-Damascenone	1.42 ± 0.03	0.71 ± 0.01	a & b
84	23.67	1426	1426	trans-α-Ionone	2.00 ± 0.05	2.91 ± 0.04	a & b
85	32.07	1473	1472	α-Iso methyl ionone	0.38 ± 0.03	0.38 ± 0.02	a & b
86	33.01	1518	1519	Methyl-α-ionone	0.19 ± 0.02	---	a & b
Total identified					99.11	98.80

Rt: Retention time; KI_exp: experimental Kovats retention index; KI_Lit: Kovats retention index on DB-5 column with reference to n-alkanes; values are average ± SD. The identification of essential oil (EO) components was performed based on the (a) mass spectral data of compounds (MS) and (b) Kovats indices with those of Wiley spectral library collection and NIST (National Institute of Standards and Technology) library database.