Table 1.

Chemical composition (%) of P. burchardii Hutch. essential oil (PBB).

No.	Compound a	LRI b	LRI c	Area (%) d
1	Hexanal	805	801	0.04
2	Methyl β-methylvalerate	861	866	0.02
3	α-Pinene	932	934	2.24
4	Camphene	955	954	0.02
5	β-Pinene	1034	1039	0.14
6	Benzacetaldehyde	1024	1025	0.05
7	Eucalyptol	1031	1037	13.87
8	Nonanal	1102	1105	0.09
9	Camphenol	1109	1110	0.03
10	trans-Pinocarveol	1134	1139	0.08
11	cis-Verbenol	1148	1144	0.06
12	Myrtenol	1195	1198	0.35
13	Verbenyl acetate	1291	1294	0.42
14	Myrtenyl acetate	1318	1322	0.16
15	2,3-Dihydro-1,1,5,6-tetramethyl-1H-indene	1320	1325	0.07
16	Dihydro-β-ionone	1416	1414	0.06
17	Humulene	1449	1456	0.86
18	γ-Muurolene	1472	1477	0.13
19	Germacrene D	1478	1480	0.26
20	β-Himachalene	1493	1498	0.31
21	β-Curcumene	1511	1513	0.15
22	δ-Cadinene	1521	1525	0.31
23	Caryophyllene oxide	1593	1594	1.91
24	τ-Cadinol	1637	1642	4.21
25	β-Eudesmol	1649	1648	1.35
26	1-Oxo-bisabolone	1747	1750	65.09
27	Ethyl palmitate	1971	1975	0.09
	Monoterpene hydrocarbons			2.40
	Oxygenated monoterpenes			15.03
	Sesquiterpene hydrocarbons			2.02
	Oxygenated sesquiterpenes			72.59
	Other compounds			0.36
	Total composition			92.37

^a Compounds are classified in order of linear retention time on the non-polar column (DB-5MS); ^b Experimental LRIs on a DB-5MS non-polar column; ^c LRIs on DB-5 MS column reported in the literature; ^d Area is the peak volume percentage of the compound in the essential oil sample.