Seasonal Variation in Essential Oils Composition and the Biological and Pharmaceutical Protective Effects of Mentha longifolia Leaves Grown in Tunisia

Table 2

Seasonal variation in content and chemical composition of essential oils from leaves of M. longifolia.

Component^A	Rt (min)	KI^C	Area
			Spring	Winter
Monoterpene hydrocarbons
α-pinene	8.557	941	0.12±0.008	0.93±0.02
camphene	9.764	953	0.18±0.03	0.41±0.008
β-pinene	9.827	978	0.24±0.02	1.22±0.05
Oxygenated monoterpenes
1,8 cineole	11.492	1030	2.37±0.16	21.3±0.24
L-menthone	15.206	1152	4.68±0.2	10.66±0.1
Iso-menthone	15.429	1163	0.16±0.008	8.69±0.12
Borneol	15.503	1166	2.6±0.02	1.87±0.04
Menthol	15.801	1171	4.29±0.2	0
Cis-isopulegone	17.960	1175	0	0.86±0.04
Pulegone	18.349	1237	38.2±0.28	26.92±0.53
Piperitone	19.539	1251	0	0.82±0.1
Piperitenone	21.324	1340	1.18±0.12	9.62±0.2
cis-Jasmone	22.406	1400	0	0.45±0.02
Sesquiterpene hydrocarbons
trans-Caryophyllene	22.949	1419	0.87±0.04	2.7±0.1
D-germacrene	24.046	1482	0.34±0.008	0
gamma.-Cadinene	25.106	1514	0	0.52±0.08
d-Cadinene	27.607	1523	0.4±0.006	0
delta.-Selinene	27.857	1578	0	0.30±0
Oxygenated sesquiterpenes
alpha.-Humulene	23.659	1454	0	0.2±0
alpha.-Cadinol	28.196	1654	0	2.81±0.05
Esters
Geranyl tiglate	29.260	1685	0	0.24±0.008
Fatty Acids
Palmitic acid	34.729	1927	15.26±0.2	0
Oleic acid	38.002	2128	23.79±0.5	0
Linoleic acid	38.317	2173	3.27±0.01	0
Total compound			97.95	89.91

Compounds listed in order of elution from a HP-5 MS column.
Retention time (as minutes).
K.I. Kovats Index on HP-5MS column in reference to n-alkanes.
Values in the same line with different subscript (a > b) are significantly different within season (P < 0.05).