Lab Anim Res.  2010 Mar;26(1):63-68. 10.5625/lar.2010.26.1.63.

Anxiolytic Effect of a Combination of Green Tea Extract and L-theanine

• Lee WK
• Kim TI
• Park SK
• Park HK
• Hong JT

• KMID: 1458941
• DOI: http://doi.org/10.5625/lar.2010.26.1.63

Abstract

The purpose of this study is to investigate whether the combination of green tea extract (GTE) and L-theanine has an anxiolytic effect by oral administration through behavioral tests and neurtransmitters (or hormone) anaylses. Four week oral administration of GTE (24 mg/kg), L-theanine (4 mg/kg) or their combination showed anxiety-reducing effects determined by increasing numbers of head-dips in a hole board test and reducing retention time in a rota-rod test without changing spontaneous locomotor activity. Biochemical analyses indicated that the test materials decreased dopamine (DA), noradrenaline (NA), corticosterone (CS) and increased serotonin (5-HT) levels in brain cortex, hippocampus, and striatum, which suggests a possible mechanism of previous behavioral tests. Although the synergistic effects of GTE and L-theanine combination were not observed on the behavioral test, its effects on neurotransmitters (NA, CS) were synergistic and comparable to diazepam (2 mg/kg i.p.) with much less muscle relaxation side effect. Therefore, a combination of GTE and L-theanine may be useful as a functional food ingredient having an anxiolytic effect.

Keyword

Green tea extract; L-theanine; rota rod test; hole board test; neurotransmitters

MeSH Terms

Administration, Oral
Anti-Anxiety Agents
Brain
Corticosterone
Diazepam
Dopamine
Functional Food
Hippocampus
Motor Activity
Muscle Relaxation
Neurotransmitter Agents
Norepinephrine
Retention (Psychology)
Serotonin
Tea
Anti-Anxiety Agents
Corticosterone
Diazepam
Dopamine
Neurotransmitter Agents
Norepinephrine
Serotonin
Tea

Figure

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  Figure 1. Green tea extract (GTE) and L-theanine combination shows anxiolytic activity by increasing number of head dips in hole board test. Diazepam (DZP) was administered intraperitoneally 30 mins before test. The results are represented as mean±SE. ∗∗P<0.01 compared with non-treated control.

• 

  Figure 2. Green tea extract (GTE) and L-theanine combination shows muscle relaxant activity by rota rod test. Diazepam (DZP) was administered intraperitoneally 30 mins before test. The results are represented as mean±SE. ∗∗P<0.001 compared with nontreated control.

• 

  Figure 3. Green tea extract (GTE) and L-theanine combination shows no effect on spontaneous locomotor activity. Diazepam (DZP) was administered intraperitoneally 30 mins before test. The results are represented as mean±SE.

• 

  Figure 4. Green tea extract (GTE) and L-theanine combination shows anxiolytic activity by modulating neurotransmitters. Diazepam (DZP) was administered intraperitoneally 30 mins before test. (a) dopamine (DA), (b) noradrenaline (NA), (c) serotonin (5-HT), (d) corticosterone (CS) concentrations in various brain areas (cortex, hippocampus and striatum). The results are represented as mean±SE. ∗∗ P<0.01.

Reference

Greenberg P.E.., Sisitsky T.., Kessler R.C.., Finkelstein S.N.., Berndt E.R.., Davidson J.R.., Ballenger J.C.., Fryer A.J.1999. The economic burden of anxiety disorders in the 1990s. J. Clin. Psychiat. 60(7):427–435.

Kakuda T.., Nozawa A.., Unno T.., Okamura N.., Okai O.2000. Inhibiting effects of theanine on caffeine stimulation evaluated by EEG in the rat. Biosci. Biotechnol. Biochem.

Kim S.., Yoon S.W.1998. Analytical study for the effects of green tea with GABA about the brain wave and short term memory. J. Kor. Jungshin. Sci. Soc. 2(1):84–91.

Park S.., Kim T.I.., Lee W.K.., Park H.K.., Hong J.T.2009. Combination of green tea extract and L-theanine alleviates electric foot shock induced stress by modulating neurotransmitters in mice. Yakhak Hoeji. 53(5):241–249.

Rao T.P.., Ozeki M.., Juneja L.R.2007. Suntheanine: A pure and safe L-theanine dietary supplement for relaxation and stress relief. Neutra Cos. 1-2. 26–30.

Rex A.., Morgenstern E.., Fink H.2002. Anxiolytic-like effects of Kava-Kava in the elevated plus maze test- a comparison with diazepam. Prog. Neuropsychopharmacol. Biol. Psychiatry. 26(5):855–860.

Rogers P.J.., Smith J.E.., Heatherley S.V.., Pleydell-Pearce C.W.2008. Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together. Psychopharmacology (berl). 195(4):569–577.

Seo J.J.., Lee S.., Lee Y.., Kwon B.., Ma Y.., Hwang B.., Hong J.., Oh K.2007. Anxiolytic-like effects of obovatol isolated from Magnolia obovata: Involvement of GABA/benzodiazepine receptors complex. Prog. Neuropsychopharmacol. Biol. Psychiatry. 31(7):1363–1369.

Silva M.I.G.., de Aquino Neto M.R.., Neto P.F.T.., Moura B.A.M.., do Amaral J.F.., de Sousa D.P.., Vasconcelos S.M.M.., de Sousa F.C.F.2007. Central nervous system activity of acute administration of isopulegol in mice. Phamacol. Biochem.

Wittchen H.U.., Hoyer J.2001. ).Generalized anxiety disorders: nature and course. J. Clin. Psychiatry. 62(suppl. 11):15–21.

Yamada T.., Terashima T.., Okubo T.., Juneja L.R.., Tokogoshi H.2005. Effects of theanine, gamma-glutamylethylamide, on neurotransmitter release and its relationship with glutamic acid neurotransmission. Nutr. Neurosci. 8(4):219–226.

Yokogoshi H.., Kobayashi M.., Mochizuki M.., Terashima T.1998. Effect of theanine, r-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats.

Yoon S.W.., Kim S.1997. Analytical study for the effect of Sun-α containing drink on the brain wave and memory. J. Kor. Jungshin. Sci. Soc. 1(2):109–114.