What is lemon verbena

Lemon verbena (Aloysia citrodora) also called lemon beebrush, Verbena grass Louise or Arabic tea ¹⁾, is an edible perennial flowering plant in the verbena family Verbenaceae, growing in late spring or early summer to 2–3 m high ²⁾. The 8-cm-long, glossy, pointed leaves are slightly rough to the touch and emit a powerful scent reminiscent of lemon when bruised (hence the Latin specific epithet citrodora—lemon-scented) ³⁾. Lemon verbena (Aloysia citrodora) is native to western South America and was brought to Europe by the Spanish and the Portuguese in the 17th century and cultivated for its oil ⁴⁾. Lemon verbena extracts have strong anti-oxidant capacity due to polyphenols contained in it ⁵⁾.

Sprays of tiny purple or white flowers appear . Lemon verbena is sensitive to cold, losing leaves at temperatures below 0 °C (32 °F), although the wood is hardy to −10 °C (14 °F). Due to its many culinary uses, lemon verbena is widely listed and marketed as a plant for the herb garden.

Lemon verbena leaves are used to add a lemon flavor to fish and poultry dishes, vegetable marinades, salad dressings, jams, puddings, Greek yogurt and beverages.

Figure 1. Lemon verbena

Lemon verbena uses

In Morocco, Lemon verbena is cultivated for more than a century and has been used in folk medicine as herbal tea preparations, for its antispasmodic, digestive, stomachic, sedative, and antipyretic properties ⁶⁾. The essential oil extracted from the dried Lemon verbena leaves is indicated for anxiety, stress, insomnia, some depressions, nervous fatigue, multiple sclerosis, psoriasis, tachycardia, rheumatism, enterocolitis, Crohn’s disease, anorexia, dyspepsia, intestinal parasites (amebiasis and amebic cysts), and prevention of asthma attacks ⁷⁾. The broad range of biological activities of lemon verbena essential oils could be generally correlated to the chemical composition. It is well established that sesquiterpenoids and their derivatives are credited with many biological activities such as anti-inflammatory, antibacterial, antiasthmatic, and antifungal properties ⁸⁾. Lemon verbena essential oil chemical composition: l,8-Cineole, geranial, 6-methyl-5-hepten-2-one, neral, limonene, β-caryophyllene, ar-curcumene, spathulenol ⁹⁾.

Lemon verbena leaves, commonly used to make herbal teas and refreshing beverage, demonstrated antioxidant and anti-inflammatory properties ¹⁰⁾. Lemon verbena leaves are also added to standard tea in place of actual lemon (as is common with Moroccan tea). Lemon verbena can also be used to make a sorbet.

The results of dextran sulfate sodium-induced colitis (experimental colitis in animals) in rats showed that, although the histological lesions and myeloperoxidase activity were not significantly improved, the herbal Lemon verbena (Aloysia citrodora) infusion increased colonic superoxide dismutase activity and decreased the levels of malondialdehyde ¹¹⁾. This rat study showed consumption of lemon verbena infusion offered some antioxidative protection during experimental colitis by stimulating superoxide dismutase activity and decreasing lipid peroxidation ¹²⁾.

Several test tube and animal studies have shown lemon verbena leaves water-based extracts antioxidative and anti-inflammatory effects ¹³⁾, ¹⁴⁾, ¹⁵⁾. Out of six human studies ¹⁶⁾, ¹⁷⁾, ¹⁸⁾, ¹⁹⁾, ²⁰⁾, ²¹⁾, only one human pilot study was published investigating lemon verbena extract on the muscular damage biomarker, creatine kinase and liver biomarker related to oxidative stress ²²⁾. This study showed some effects on cytokines and oxidative stress markers in neutrophils, but no functional parameters like muscle strength or muscle soreness were assessed ²³⁾. This study ²⁴⁾ preliminary findings suggest that lemon verbena extract supplementation may reduce exercise-induced muscle damage compared to placebo. In addition, several studies ²⁵⁾, ²⁶⁾, ²⁷⁾ have revealed that moderate doses of dietary polyphenols diminish this exercise-induced oxidative stress and decrease inflammatory markers.

Lemon verbena has a long history of folk uses in treating colds, fever, insomnia, and anxiety ²⁸⁾. Also, Lemon verbena leaf is used in Persian folk medicine for memory improvement, antidizziness, as analgesic for neuralgic pain, sedative, antihysteria and for treating unilateral headache pain ²⁹⁾.

Table 1. Lemon verbena aromatic water constituents results from gas chromatography–mass spectrometry analysis

Component	Lemon verbena
1,8-Cineole	3.82
Borneol	4
Carveol (trans)	0.77
Caryophyllene (trans)	9.5
Caryophyllene oxide	0.72
Geranial	13.72
Limonene	20.55
Methyl hexadecanoate	7.95
Neral	6.42
Nerol	3.42
Nerolidol (trans)	0.68
α-Pinene	2.78
α-Terpineol	6.3
Terpinene-4-ol	5.1
Thymol	4.87

[Source ³⁰⁾]

Table 2. Lemon verbena from Morocco essential oil chemical composition results from gas chromatography–mass spectrometry analysis

Peak number	Componenta	RIb	% Essential oil of Agadir	% Essential oil of Beni Mellal	% Essential oil of Berkane	% Essential oil of Demnate	% Essential oil of Marrakech
1	α-Pinene	909	0.23	0.39	0.17	0.21	0.2
2	α-Thujene	927	0.09	0.14	0.08	0.09	0.08
3	β-Pinene	964	0.14	0.14	0.09	0.12	0.09
4	Sabinene	972	0.04	0.05	0.03	0.04	0.04
5	6-Methyl-5-hepten-2-one	987	0.03	0.02	0.02	0.02	0.02
6	β-Myrcene	988	0.03	0.02	0.02	0.02	0.04
7	α-Terpinene	1017	0.12	0.1	0.08	0.08	0.09
8	Paracymene	1024	0.02	—	—	—	—
9	Limonene	1027	0.71	0.63	0.36	0.5	0.39
10	1,8-Cineole	1031	1.97	1.44	1.66	1.41	1.97
11	cis-β-Ocimene	1037	0.02	0.02	—	0.02	0.01
12	trans-β-Ocimene	1045	0.04	0.03	0.05	0.03	0.05
13	γ-Terpinene	1054	0.33	0.13	0.15	0.18	0.14
14	trans-Sabinene hydrate	1096	0.29	0.14	0.17	0.17	0.13
15	6-Camphenol	1110	0.08	0.04	0.05	0.06	0.05
16	cis-Limonene oxide	1117	0.16	0.1	0.14	0.13	0.22
17	Campholene aldehyde	1125	0.58	0.26	0.4	0.4	0.4
18	trans-p-Mentha-2,8-dienol	1127	0.18	0.17	0.16	0.1	0.12
19	cis-p-Mentha-2,8-dien-1-ol	1131	0.33	0.18	0.2	0.21	0.15
20	trans-Verbenol	1144	0.64	0.34	0.47	0.38	0.45
21	cis-Verbenol	1153	7.78	4.87	5.22	5.82	4.41
22	1,3,4-Trimethyl-3-cyclohexene-1-carboxaldehyde	1171	0.7	0.63	0.59	0.53	0.62
23	cis-p-Mentha-1(7),8-dien-2-ol	1185	0.13	0.09	0.14	0.07	0.07
24	Verbenyl ethyl ether	1186	0.31	0.3	0.24	0.35	0.31
25	2-Carene	1189	1.71	0,86	1.11	1.03	0.84
26	Myrtenol	1193	0.58	0.33	0.36	0.37	0.32
27	trans-2-Caren-4-ol	1222	0.53	0.29	0.43	0.33	0.42
28	D-Carvone	1223	0.27	0.22	0.26	0.19	0.34
29	cis-Carveol	1226	0.06	0.03	0.04	0.05	0.03
30	Nerol	1228	1.85	2.16	1.56	2.05	1.6
31	Neral	1242	10.02	7.23	8.57	8.18	6.37
32	Piperitone	1250	0.15	0.11	0.14	0.12	0.07
33	2,6,6-Trimethyl-1-cyclohexene-1-acetaldehyde	1254	0.27	0.12	0.19	0.18	0.15
34	Perillic aldehyde	1257	0.03	0.03	0.02	0.03	0.04
35	para-Cymen-7-ol	1289	0.05	0.09	0.13	0.05	0.1
36	8,11,14-Eicosatrienoic acid. (Z.Z.Z)-	1294	0.04	0.05	0.03	0.03	0.03
37	1-(1,3-Dimethyl-buta-1.3-dienyl)-3,7,7-trimethyl-2-oxa- bicyclo[3.2.0]hept-3-ene	—	0.03	0.03	0.03	0.03	0.06
38	trans-Carvyl acetate	1342	0.07	0.07	0.07	0.08	0.04
39	Eugenol	1356	0.19	0.22	0.2	0.21	0.31
40	Geranyl acetate	1365	0.66	1.22	0.91	1.29	1.06
41	α-Copaene	1375	1.25	1.73	1.27	1.45	2.16
42	Isoledene	1377	3.48	4.46	3.89	4.19	4.04
43	7-Tetracyclo [6.2.1.0 (3.8)0(3.9)] Undecanol, 4,4,11,11-tetramethyl-	—	0.1	0.17	0.12	0.14	0.13
44	Di-epi-α-cedrene	1412	0.67	0.96	0.67	0.82	0.68
45	β-Caryophyllene	1420	3.11	3.26	2.77	4.18	1.85
46	ç-Elemene	1433	2.3	3.04	2.77	2.99	2.93
47	trans-α-Bergamotene	1434	0.09	0.09	0.08	0.09	0.04
48	Aromadendrene	1440	0.06	0.05	0.06	0.1	0.05
49	α-Humulen	1453	0.6	0.49	0.59	0.61	0.2
50	Alloaromadendrene	1460	1.66	1.36	1.02	1.3	1
51	Germacrene-D	1480	0.28	0.39	0.29	0.36	0.31
52	Ar-curcumene	1483	11.47	13.38	11.28	14.15	11.3
53	β-Guaiene	1490	0.01	0.01	0.02	0.02	0.01
54	Tricyclo[5.2.2.0(1.6)]undecan-3-ol, 2-methylene-6,8,8-trimethyl-	1498	0.49	0.68	0.56	0.56	0.65
55	α-Muurolene	1499	—	0.04	—	0.04	—
56	ç-Himachalene	1505	0.34	0.6	0.47	0.46	0.64
57	Calamenene	1514	0.09	0.16	0.11	0.12	0.13
58	9-Isopropyl-1-methyl-2-methylene-5-oxatricyclo[5.4.0.0(3,8)]undecane	1522	0.05	0.09	0.07	0.08	0.09
59	γ-Cadinene	1523	0.17	0.26	0.19	0.23	0.22
60	ç-Cadinene	1524	3.89	5.04	4.57	4.99	4.86
61	β-Spathulenol	1576	13.27	10.19	15.61	9.42	13.42
62	trans-Caryophyllene oxide	1580	13.52	13.25	14.14	13.28	14.22
63	Ledene oxide-(I)	1631	1.75	2.96	2.41	2.25	3.01
64	8-Cedren-13-ol	1657	—	0.02	0.03	0.01	0.05
65	Alloaromadendrene oxide-(1)	1672	3.06	4.26	4.37	3.79	4.35
66	Alloaromadendrene oxide-(2)	1678	0.28	0.5	0.4	0.4	0.79
67	Eudesma-4,11-dien-2-ol	1690	0.31	0.46	0.46	0.45	0.62
68	trans-Nuciferol	1727	2.31	3.1	2.6	3.1	3.86
69	cis-Nuciferol	1734	2.17	3.3	2.32	2.8	3.17
70	Murolan-3,9(11)-diene-10-peroxy	—	0.36	0.53	0.5	0.48	0.73
71	Ledene oxide-(II)	2062	0.35	0.45	0.47	0.45	0.57
72	Tricyclo[5.2.2.0(1.6)]undecan-3-ol, 2-methylene-6,8,8-trimethyl-	—	0.97	1.25	1.31	1.33	1.35

Notes: ^aCompounds are listed in order of their elution from a DB-5 column. ^bLinear retention index taken from NIST 08, National Institute of Standards and Technology, Mass Spectral Library (NIST/EPA/NIH). ^cEssential oil of Agadir. ^dEssential oil of Beni Mellal. ^eEssential oil of Berkane. ^fEssential oil of Demnate. ^gEssential oil of Marrakech.

[Source ³¹⁾]

Molecules belonging to five biochemical families, namely, sesquiterpenes (Ar-curcumene 12.32%), terpene oxides (caryophyllene oxide 13.68%), sesquiterpenols (spathulenol 12.38%), monoterpene aldehydes (neral 8.07%), and monoterpenols (cis-verbenol 6.28%), constitute 53% of the essential oil’s major compounds (see Table 3).

Table 3. Major compounds of essential oil of lemon verbena analyzed by gas chromatography–mass spectrometry analysis

Molecules	% Essential oil of Agadir	% Essential oil of Beni Mellal	% Essential oil of Berkane	% Essential oil of Demnate	% Essential oil of Marrakech
trans-Caryophyllene oxide	13.52	13.25	14.14	13.28	14.22
β-Spathulenol	13.27	10.19	15.61	9.42	13.42
Ar-curcumene	11.47	13.38	11.28	14.15	11.30
Neral	10.02	7.23	8.57	8.18	6.37
cis-Verbenol	7.78	—	5.22	5.82	—

[Source ³²⁾]

Packaging methods and storage duration affect essential oil content and composition of lemon verbena ³³⁾. In packaging this study ³⁴⁾ showed that the packaging of lemon verbena leaves with nitrogen preserved the highest essential oil content at the end of 8 months of storage. Although vacuum packed lemon verbena leaves preserved the highest amount of citral during storage, the highest amount of limonene and desired contents of citral and 1,8‐cineole were found in leaves packed with nitrogen ³⁵⁾.