Antioxidant activity and chemical composition of essential oils of three aromatic plants from La Rioja province

Figures & data

Table 1. Main components of the essential oils from L. turbinata, C. gilliesii, and L. integrifolia.

Compound	KI^a	L. turbinata (%)	Compound	KI^a	C. gilliesii (%)	Compound	KI^a	L. integrifolia (%)
Monoterpenes		7.2	Monoterpenes		0.5	Monoterpenes		7.0
Limonene	1024	7.2	Limonene	1024	0.5	Sabinene	969	1.7
Oxygenated monoterpenoids		71.4	Oxygenated monoterpenoids		74.0	p-Cymene	1020	3.5
cis-Verbenol	1137	1.0	β-Ocimene	1041	1.2	Limonene	1024	1.8
Carvone	1239	1.1	β-Linalool	1086	1.8	Oxygenated monoterpenoids		18.3
cis-Piperitone oxide	1250	2.4	Menthone	1136	9.7	cis-Sabinene hydrate	1065	6.9
Bornylacetate	1287	1.2	Isomenthone	1146	6.2	trans-Verbenol + camphor	1140/1141	2.7
Piperitenone	1340	1.6	Isopulegone	1148	12.0	Terpinen-4-ol	1174	8.7
Piperitenone oxide	1366	63.0	Pulegone	1215	19.2	Sesquiterpenes		23.5
Methyleugenol	1403	1.1	cis-Carvone oxide	1268	9.2	β-Caryophyllene	1417	15.3
Sesquiterpenes		2.4	Piperitenone oxide	1366	14.7	Bicyclogermacrene	1500	3.3
β-Caryophyllene	1417	2.4	Sesquiterpenes		2.8	β-Bisabolene	1505	4.9
Oxygenated sesquiterpenoids		5.6	β-Caryophyllene	1417	1.2	Oxygenated sesquiterpenoids		19.6
Caryophyllene oxide	1582	5.6	Bicyclogermacrene	1494	1.6	Muurol-5-en-4a-ol	1559	1.7
			Oxygenated sesquiterpenoids		0.7	trans-Davanone	1564	4.9
			1,6-Germacradien-5-ol	1585	0.7	Spathulenol	1577	6.5
						Caryophyllene oxide	1582	6.5
Total		86.6			78.0			68.4

^aKI, Kovat's index; relative retention index.

Figure 1. Free radical scavenging activity of essential oils from L. turbinata, C. gilliesii, and L. integrifolia. The activity was measured by the scavenging of ABTS (A) and DPPH (B) radicals. Values are means ± SD, n = 3.

Table 2. Antioxidant activity of L. turbinata, C. gilliesii, and L. integrifolia essential oils.

	Free radical scavenging		ROS scavenging		Inhibition of lipid peroxidation
EO^a	ABTS	DPPH	H2O2		β-Carotene–linoleic acid
	SC50^b		SC25^b	SC50^b	IC25^c	IC50^c
L. turbinata	0.40 ± 0.14^a	0.74 ± 0.08^a	1.87 ± 0.31^a,b	^e	0.15 ± 0.04^a	0.99 ± 0.18^a
C. gilliesii	2.42 ± 0.30^b	5.80 ± 0.14^b	1.52 ± 0.27^a	^e	0.73 ± 0.15^b	1.56 ± 0.22^b
L. integrifolia	3.60 ± 0.20^c	^e	2.21 ± 0.29^b	4.56 ± 0.46	1.32 ± 0.14^c	^e
Quercetin^d	0.0067 ± 0.0010	0.0105 ± 0.0015	–	–	0.0035 ± 0.0005	0.0069 ± 0.0009

Values are means ± SD. Means in a column without a common letter differ (p < 0.05), a <b < c.

^aEO, essential oil.

^bSC, concentration required to scavenge 25 or 50% ABTS, DPPH radicals, or H₂O₂.

^cIC, concentration required to inhibit 25 or 50% β-carotene bleaching.

^dPositive control (mg mL⁻¹).

^eIn the range of concentrations tested, we were unable to determine SC₅₀ and IC₅₀ values. Results are expressed in mg mL⁻¹.

Figure 2. β-Carotene bleaching assay of L. turbinata, C. gilliesii, and L. integrifolia essential oils. The β-carotene oxidation induced by heat was monitored for 120 min. The maximum concentrations used were 1.13 mg mL⁻¹ for L. turbinata, 1.79 mg mL⁻¹ for C. gilliesii, and 1.38 mg mL⁻¹ for L. Integrifolia.