Pharmacological evaluation of the anxiolytic-like effects of Lippia graveolens and bioactive compounds

Figures & data

Table 1. Constituents of L. graveolens leaf hexane extract analyzed by GC-MS.

LRI	Compound	Relativeabundance (%)	Method ofidentification
1113	Linalool	5.17	MS
1166	Borneol	4.05	MS, RI
1178	m-Cymen-8-ol	16.37	MS
1186	p-Cymen-8-ol	1.10	MS, RI
1193	Methyl-salicylate	10.48	MS
1294	Thymol	33.40	MS, RI
1302	Carvacrol	6.75	MS, RI
1424	β-Caryophyllene	1.88	MS
1459	(E)-β-farnesene	1.63	MS
1492	Viridiflorene	0.59	MS
1500	α-Muurolene	0.54	MS, RI
1591	n.d.	5.37	–
1615	Tetradecanal	3.35	MS, RI
1640	t-Muurolol	1.13	MS, RI
1644	n.d.	0.68	–
1666	Bulnesol	3.39	MS, RI
1678	Methyl epi-jasmonate	0.54	MS
1767	Eicosane	2.69	MS
	Total identified	93.06
	Total detected	99.11

Compounds in major relative abundance are described in bold.

LRI: Linear retention index relative to C₇ – C₃₀n-alkanes on a HP-5MS column; MS: identification by mass spectra; RI: retention index; n.d. = not determined.

Figure 1. Pharmacological evaluation of the effects in the ambulatory activity (2 min) in mice receiving several doses (1, 3, 10 and 30 mg/kg, i.p.) of (a) hexane, (b) ethyl acetate, (c) methanol or (d) aqueous crude extracts in comparison to the control group (0), bioactive constituents such as mixture p-cymene + thymol (p + t, 3 mg/kg, i.p.), cirsimaritin (CS, 3 mg/kg, i.p.) and naringenin (N, 3 mg/kg,i.p.), and the reference drug diazepam (DZP, 0.1 mg/kg, i.p.). Bars represent the mean ± SEM of six animals.

Figure 2. Pharmacological evaluation of the effects in the cylinder exploration (5 min) in mice receiving several doses (1, 3, 10, and 30 mg/kg, i.p.) of (a) hexane, (b) ethyl acetate, (c) methanol or (d) aqueous crude extracts in comparison to the control group (0), bioactive constituents such as mixture p-cymene + thymol (p + t, 3 mg/kg, i.p.), cirsimaritin (CS, 3 mg/kg, i.p.) and naringenin (N, 3 mg/kg,i.p.), and the reference drug diazepam (DZP, 0.1 mg/kg, i.p.). Bars represent the mean ± SEM of six animals. p < 0.05, *ANOVA followed by Dunnett’s test. #Student’s t test.

Figure 3. Anxiolytic-like effects in the hole-board exploration (3 min) in mice receiving several doses (1, 3, 10 and 30 mg/kg, i.p.) of (a) hexane, (b) ethyl acetate, (c) methanol or (d) aqueous crude extracts in comparison to the control group (0), bioactive constituents such as mixture p-cymene + thymol (p + t, 3 mg/kg, i.p.), cirsimaritin (CS, 3 mg/kg, i.p.) and naringenin (N, 3 mg/kg,i.p.), and the reference drug diazepam (DZP, 0.1 mg/kg, i.p.). Bars represent the mean ± SEM of six animals. *p < 0.05, ANOVA followed by Dunnett’s test.

Figure 4. Anxiolytic-like effects in the plus-maze exploration (3 min) in mice receiving several doses (1, 3, 10 and 30 mg/kg, i.p.) of (a) hexane, (b) ethyl acetate, (c) methanol or (d) aqueous crude extracts in comparison to the control group (0), bioactive constituents such as mixture p-cymene + thymol (p + t, 3 mg/kg, i.p.), cirsimaritin (CS, 3 mg/kg, i.p.) and naringenin (N, 3 mg/kg,i.p.), and the reference drug diazepam (DZP, 0.1 mg/kg, i.p.). Bars represent the mean ± S.E.M. of six animals. *p < 0.05, ANOVA followed by Dunnett’s test.

Table 2. Pharmacological interaction of the L. graveolens leaf organic and aqueous extracts and its bioactive compounds on the sodium pentobarbital-induced hypnosis in mice.

Treatment	Dose(mg/kg, i.p.)	Latency to sedation	The onset (min) Hypnosis	Duration of hypnosis (min)
Vehicle (0.9%  saline solution)	–	1.23 ± 0.12	2.97 ± 0.32	11.93 ± 1.67
Diazepam	0.1	1.10 ± 0.08	2.00 ± 0.12	40.80 ± 3.27^b
Hexane	1	1.59 ± 0.13	3.61 ± 0.42	26.14 ± 5.65^a
	3	1.10 ± 0.21	3.80 ± 0.39	25.60 ± 2.33^a
	10	1.14 ± 0.21	3.78 ± 0.39	25.62 ± 2.33^a
	30	1.52 ± 0.09	4.01 ± 0.19	47.54 ± 6.66^b
p-Cymene + thymol	3	1.46 ± 0.12	4.03 ± 0.44	39.06 ± 3.83^b
Ethyl acetate	1	1.48 ± 0.14	3.11 ± 0.45	25.74 ± 2.21^b
	3	1.46 ± 0.21	4.00 ± 0.80	36.88 ± 2.57^b
	10	1.39 ± 0.18	2.84 ± 0.32	25.57 ± 4.28^b
	30	1.30 ± 0.21	2.80 ± 0.30	38.93 ± 5.71^b
Cirsimaritin	3	1.53 ± 0.10	2.95 ± 0.14	30.99 ± 1.72^b
Naringenin	3	1.10 ± 0.04	3.00 ± 0.26	27.32 ± 2.57^b
Methanol	1	1.79 ± 0.09	3.04 ± 0.20	25.03 ± 6.09^a^b
	3	1.09 ± 0.11	2.75 ± 0.31	38.12 ± 4.86^b
	10	1.41 ± 0.23	2.61 ± 0.22	43.81 ± 1.35^b
	30	1.30 ± 0.21	2.75 ± 0.30	35.18 ± 6.22^b
Aqueous	1	1.35 ± 0.15	4.08 ± 0.60	25.23 ± 3.64^b
	3	1.49 ± 0.18	3.38 ± 0.23	27.81 ± 2.79^b
	10	1.40 ± 0.10	3.33 ± 0.30	34.48 ± 3.10^b
	30	1.52 ± 0.15	2.91 ± 0.31	40.32 ± 5.61^b

Data represents the mean ± SEM of six animals. p < 0.05.

^a Student’s t test.

^b ANOVA followed by Dunnett’s test.