Hypnotic effects and GABAergic mechanism of licorice (Glycyrrhiza glabra) ethanol extract and its major flavonoid constituent glabrol

Suengmok Cho, Ji Hae Park, Ae Nim Pae, Daeseok Han, Dongsoo Kim, Nam Chul Cho, Kyoung Tai No, Hyejin Yang, Minseok Yoon, Changho Lee, Makoto Shimizu, Nam In Baek

Research output: Contribution to journalArticle

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Abstract

Licorice (Glycyrrhiza glabra, GG) is one of the most frequently used herbal medicines worldwide, and its various biological activities have been widely studied. GG is reported to have neurological properties such as antidepressant, anxiolytic, and anticonvulsant effects. However, its hypnotic effects and the mechanism of GG and its active compounds have not yet been demonstrated. In this study, GG ethanol extract (GGE) dose-dependently potentiated pentobarbital-induced sleep and increased the amount of non-rapid eye movement sleep in mice without decreasing delta activity. The hypnotic effect of GGE was completely inhibited by flumazenil, which is a well-known γ-aminobutyric acid type A-benzodiazepine (GABA A-BZD) receptor antagonist, similar to other GABA A-BZD receptor agonists (e.g., diazepam and zolpidem). The major flavonoid glabrol was isolated from the flavonoid-rich fraction of GGE; it inhibited [ 3H] flumazenil binding to the GABA A-BZD receptors in rat cerebral cortex membrane with a binding affinity (K i) of 1.63 μM. The molecular structure and pharmacophore model of glabrol and liquiritigenin indicate that the isoprenyl groups of glabrol may play a key role in binding to GABA A-BZD receptors. Glabrol increased sleep duration and decreased sleep latency in a dose-dependent manner (5, 10, 25, and 50 mg/kg); its hypnotic effect was also blocked by flumazenil. The results imply that GGE and its flavonoid glabrol induce sleep via a positive allosteric modulation of GABA A-BZD receptors.

Original languageEnglish
Pages (from-to)3493-3501
Number of pages9
JournalBioorganic and Medicinal Chemistry
Volume20
Issue number11
DOIs
Publication statusPublished - 2012 Jun 1

Fingerprint

Glycyrrhiza
Hypnotics and Sedatives
Flavonoids
gamma-Aminobutyric Acid
Sleep
Ethanol
Flumazenil
GABA-A Receptors
GABA-A Receptor Agonists
Aminobutyrates
GABA-A Receptor Antagonists
Eye movements
Herbal Medicine
Anti-Anxiety Agents
Pentobarbital
Diazepam
Eye Movements
Bioactivity
Molecular Structure
Benzodiazepines

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Pharmaceutical Science
  • Drug Discovery
  • Clinical Biochemistry
  • Organic Chemistry

Cite this

Cho, Suengmok ; Park, Ji Hae ; Pae, Ae Nim ; Han, Daeseok ; Kim, Dongsoo ; Cho, Nam Chul ; No, Kyoung Tai ; Yang, Hyejin ; Yoon, Minseok ; Lee, Changho ; Shimizu, Makoto ; Baek, Nam In. / Hypnotic effects and GABAergic mechanism of licorice (Glycyrrhiza glabra) ethanol extract and its major flavonoid constituent glabrol. In: Bioorganic and Medicinal Chemistry. 2012 ; Vol. 20, No. 11. pp. 3493-3501.
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abstract = "Licorice (Glycyrrhiza glabra, GG) is one of the most frequently used herbal medicines worldwide, and its various biological activities have been widely studied. GG is reported to have neurological properties such as antidepressant, anxiolytic, and anticonvulsant effects. However, its hypnotic effects and the mechanism of GG and its active compounds have not yet been demonstrated. In this study, GG ethanol extract (GGE) dose-dependently potentiated pentobarbital-induced sleep and increased the amount of non-rapid eye movement sleep in mice without decreasing delta activity. The hypnotic effect of GGE was completely inhibited by flumazenil, which is a well-known γ-aminobutyric acid type A-benzodiazepine (GABA A-BZD) receptor antagonist, similar to other GABA A-BZD receptor agonists (e.g., diazepam and zolpidem). The major flavonoid glabrol was isolated from the flavonoid-rich fraction of GGE; it inhibited [ 3H] flumazenil binding to the GABA A-BZD receptors in rat cerebral cortex membrane with a binding affinity (K i) of 1.63 μM. The molecular structure and pharmacophore model of glabrol and liquiritigenin indicate that the isoprenyl groups of glabrol may play a key role in binding to GABA A-BZD receptors. Glabrol increased sleep duration and decreased sleep latency in a dose-dependent manner (5, 10, 25, and 50 mg/kg); its hypnotic effect was also blocked by flumazenil. The results imply that GGE and its flavonoid glabrol induce sleep via a positive allosteric modulation of GABA A-BZD receptors.",
author = "Suengmok Cho and Park, {Ji Hae} and Pae, {Ae Nim} and Daeseok Han and Dongsoo Kim and Cho, {Nam Chul} and No, {Kyoung Tai} and Hyejin Yang and Minseok Yoon and Changho Lee and Makoto Shimizu and Baek, {Nam In}",
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Cho, S, Park, JH, Pae, AN, Han, D, Kim, D, Cho, NC, No, KT, Yang, H, Yoon, M, Lee, C, Shimizu, M & Baek, NI 2012, 'Hypnotic effects and GABAergic mechanism of licorice (Glycyrrhiza glabra) ethanol extract and its major flavonoid constituent glabrol', Bioorganic and Medicinal Chemistry, vol. 20, no. 11, pp. 3493-3501. https://doi.org/10.1016/j.bmc.2012.04.011

Hypnotic effects and GABAergic mechanism of licorice (Glycyrrhiza glabra) ethanol extract and its major flavonoid constituent glabrol. / Cho, Suengmok; Park, Ji Hae; Pae, Ae Nim; Han, Daeseok; Kim, Dongsoo; Cho, Nam Chul; No, Kyoung Tai; Yang, Hyejin; Yoon, Minseok; Lee, Changho; Shimizu, Makoto; Baek, Nam In.

In: Bioorganic and Medicinal Chemistry, Vol. 20, No. 11, 01.06.2012, p. 3493-3501.

Research output: Contribution to journalArticle

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T1 - Hypnotic effects and GABAergic mechanism of licorice (Glycyrrhiza glabra) ethanol extract and its major flavonoid constituent glabrol

AU - Cho, Suengmok

AU - Park, Ji Hae

AU - Pae, Ae Nim

AU - Han, Daeseok

AU - Kim, Dongsoo

AU - Cho, Nam Chul

AU - No, Kyoung Tai

AU - Yang, Hyejin

AU - Yoon, Minseok

AU - Lee, Changho

AU - Shimizu, Makoto

AU - Baek, Nam In

PY - 2012/6/1

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