Moderate concentrations of 4-O-methylhonokiol potentiate GABAA receptor currents stronger than honokiol

Baur, Roland; Schuehly, Wolfgang; Sigel, Erwin (2014). Moderate concentrations of 4-O-methylhonokiol potentiate GABAA receptor currents stronger than honokiol. Biochimica et biophysica acta (BBA) - general subjects, 1840(10), pp. 3017-3021. Elsevier 10.1016/j.bbagen.2014.06.016

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BACKGROUND Magnolia bark preparations from Magnolia officinalis of Asian medicinal systems are known for their muscle relaxant effect and anticonvulsant activity. These CNS related effects are ascribed to the presence of the biphenyl-type neolignans honokiol and magnolol that exert a potentiating effect on GABAA receptors. 4-O-methylhonokiol isolated from seeds of the North-American M. grandiflora was compared to honokiol for its activity to potentiate GABAA receptors and its GABAA receptor subtype-specificity was established. METHODS Different recombinant GABAA receptors were functionally expressed in Xenopus oocytes and electrophysiological techniques were used determine to their modulation by 4-O-methylhonokiol. RESULTS 3μM 4-O-methylhonokiol is shown here to potentiate responses of the α₁β₂γ₂ GABAA receptor about 20-fold stronger than the same concentration of honokiol. In the present study potentiation by 4-O-methylhonokiol is also detailed for 12 GABAA receptor subtypes to assess GABAA receptor subunits that are responsible for the potentiating effect. CONCLUSION The much higher potentiation of GABAA receptors at identical concentrations of 4-O-methylhonokiol as compared to honokiol parallels previous observations made in other systems of potentiated pharmacological activity of 4-O-methylhonokiol over honokiol. GENERAL SIGNIFICANCE The results point to the use of 4-O-methylhonokiol as a lead for GABAA receptor potentiation and corroborate the use of M. grandiflora seeds against convulsions in Mexican folk medicine.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Biochemistry and Molecular Medicine

UniBE Contributor:

Baur, Roland and Sigel, Erwin

Subjects:

500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health

ISSN:

0304-4165

Publisher:

Elsevier

Language:

English

Submitter:

Barbara Järmann-Bangerter

Date Deposited:

01 Apr 2015 13:07

Last Modified:

29 May 2017 17:55

Publisher DOI:

10.1016/j.bbagen.2014.06.016

PubMed ID:

24973566

Uncontrolled Keywords:

4-O-Methylhonokiol, GABA (γ-aminobutyric acid), GABA(A) receptors, Honokiol

BORIS DOI:

10.7892/boris.65700

URI:

https://boris.unibe.ch/id/eprint/65700

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