Magnolol Explained

Magnolol is an organic compound that is classified as lignan. It is a bioactive compound found in the bark of the Houpu magnolia (Magnolia officinalis) and in M. grandiflora.^[1] The compound exists at the level of a few percent in the bark of species of magnolia, the extracts of which have been used in traditional Chinese and Japanese medicine. In addition to magnolol, related lignans occur in the extracts including honokiol, which is an isomer of magnolol.

Bioactivity

It is known to act on the GABA_A receptors in rat cells in vitro^[2] as well as having antifungal properties.^[3] Magnolol has a number of osteoblast-stimulating and osteoclast-inhibiting activities in cell culture and has been suggested as a candidate for screening for anti-osteoporosis activity.^[4] It has anti-periodontal disease activity in a rat model.^[5] Structural analogues have been studied and found to be strong allosteric modulators of GABA_A.^[6]

Magnolol is also binding in dimeric mode to PPARγ, acting as an agonist of this nuclear receptor.^[7]

Magnolol may interact with cannabinoid receptors, acting as a partial agonist of CB₂ receptors, with lower affinity for the CB₁ receptor.^[8]

Further reading

• 10.1023/A:1021116502548. 10591411. 1999. Squires. Richard F.. Honokiol and magnolol increase the number of 3H muscimol binding sites three-fold in rat forebrain membranes in vitro using a filtration assay, by allosterically increasing the affinities of low-affinity sites. Neurochemical Research. 24. 12. 1593–602. Ai. Jinglu. Witt. Michael-Robin. Kahnberg. Pia. Saederup. Else. Sterner. Olov. Nielsen. Mogens. 9070185.
• Rycek L, Puthenkalam R, Schnürch M, Ernst M, Mihovilovic MD . Metal-assisted synthesis of unsymmetrical magnolol and honokiol analogs and their biological assessment as GABAA receptor ligands . Bioorg. Med. Chem. Lett. . 25 . 2 . 400–3 . 2015 . 25510374 . 10.1016/j.bmcl.2014.10.091 . 4297288.

Notes and References

1. 21277893 . 10.1016/j.pharmthera.2011.01.010. Therapeutic applications of compounds in the Magnolia family. Pharmacology & Therapeutics. 130. 2. 157–76. 2011. Lee. Young-Jung. Lee. Yoot Mo. Lee. Chong-Kil. Jung. Jae Kyung. Han. Sang Bae. Hong. Jin Tae.
2. 10.1159/000056110. 11408830. Honokiol and Magnolol Selectively Interact with GABA_A Receptor Subtypes in vitro. Pharmacology. 63. 1. 34–41. 2001. Ai. Jinglu. Wang. Xiaomei. Nielsen. Mogens. 19327464.
3. 10.1007/BF02976465. 10728656. Antifungal activity of magnolol and honokiol. Archives of Pharmacal Research. 23. 1. 46–9. 2000. Bang. Kyu Ho. Kim. Yoon Kwan. Min. Byung Sun. Na. Min Kyun. Rhee. Young Ha. Lee. Jong Pill. Bae. Ki Hwan. 22754315.
4. 22474400. 3306956. 10.1155/2012/829650. Effect of Magnolol on the Function of Osteoblastic MC3T3-E1 Cells. Mediators of Inflammation. 2012. 1–7. 2012. Kwak. Eun Jung. Lee. Young Soon. Choi. Eun Mi. free.
5. 23573141. 3618931. 10.1155/2013/634095. Magnolol Ameliorates Ligature-Induced Periodontitis in Rats and Osteoclastogenesis: In Vivo and in Vitro Study. Evidence-Based Complementary and Alternative Medicine. 2013. 1–12. 2013. Lu. Sheng-Hua. Huang. Ren-Yeong. Chou. Tz-Chong. free.
6. Fuchs . Alexander . Baur . Roland . Schoeder . Clara . Sigel . Erwin . Müller . Christa E. . Structural analogues of the natural products magnolol and honokiol as potent allosteric potentiators of GABAA receptors . Bioorganic & Medicinal Chemistry . December 2014 . 22 . 24 . 6908–6917 . 10.1016/j.bmc.2014.10.027 . 25456080 .
7. Dreier . Dominik . Latkolik . Simone . Rycek . Lukas . Schnürch . Michael . Dymáková . Andrea . Atanasov . Atanas G. . Ladurner . Angela . Heiss . Elke H. . Stuppner . Hermann . Schuster . Daniela . Mihovilovic . Marko D. . Dirsch . Verena M. . Linked magnolol dimer as a selective PPARγ agonist – Structure-based rational design, synthesis, and bioactivity evaluation . Scientific Reports . 20 October 2017 . 7 . 1 . 13002 . 10.1038/s41598-017-12628-5 . 29057944 . 256897195 . 5651862 .
8. Rempel . Viktor . Fuchs . Alexander . Hinz . Sonja . Karcz . Tadeusz . Lehr . Matthias . Koetter . Uwe . Müller . Christa E. . Magnolia Extract, Magnolol, and Metabolites: Activation of Cannabinoid CB 2 Receptors and Blockade of the Related GPR55 . ACS Medicinal Chemistry Letters . 10 January 2013 . 4 . 1 . 41–45 . 10.1021/ml300235q . 24900561 . 4027495 .