| Honokiol | |
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2-(4-hydroxy-3-prop-2-enyl-phenyl)- 4-prop-2-enyl-phenol |
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Other names
houpa, hnk |
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| Identifiers | |
| CAS number | 35354-74-6 |
| PubChem | 72303 |
| ChemSpider | 65254 |
| KEGG | C10630 |
| ChEMBL | CHEMBL16901 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C18H18O2 |
| Molar mass | 266.334 g/mol |
| Appearance | White solid |
| Solubility in water | sparingly (25 °C) |
| Related compounds | |
| Related biphenols | diethylstilbestrol, dihydroxyeugenol |
| Related compounds | magnolol |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Honokiol is a lignan present in the cones, bark, and leaves of Magnolia grandiflora that has been used in the traditional Japanese medicine Saiboku-to as an anxiolytic, antithrombotic, anti-depressant, anti-emetic, and anti-bacterial. While early research on the effective compounds in traditional remedies have simply used whole magnolia bark extracts, known as houpu magnolia, recent work has identified honokiol and its structural isomer magnolol as the active compounds in magnolia bark. In the late 1990s, honokiol saw a revival in western countries as a potent and highly tolerable anti-tumorigenic and neurotrophic compound.
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Honokiol has shown pro-apoptotic effects in melanoma, sarcoma, myeloma, leukemia, bladder, lung, prostate, oral squamous cell carcinoma[1]and colon cancer cell lines.[2][3][4][5] Honokiol inhibits phosphorylation of Akt, p44/42 mitogen-activated protein kinase (MAPK), and src. Additionally, honokiol modulates the nuclear factor kappa B (NF-κB) activation pathway, an upstream effector of vascular endothelial growth factor (VEGF), cyclooxygenase 2 (COX-2), and MCL1, all significant pro-angiogenic and survival factors. Honokiol induces caspase-dependent apoptosis in a TRAIL-mediated manner, and potentiates the pro-apoptotic effects of doxorubicin and other etoposides. So potent is honokiol's pro-apoptotic effects that it overcomes even notoriously drug resistant neoplasms such as multiple myeloma and chronic B-cell leukemia.
Honokiol has been shown to promote neurite outgrowth and have neuroprotective effects in rat cortical neurons. Additionally, honokiol increases free cytoplasmic Ca2+ in rat cortical neurons.[6]. Honokiol is a weak cannabinoid CB2 receptor ligand but the naturally occuring derivative 4-O-methylhonokiol was shown to be a potent and selective cannabinoid CB2 receptor inverse agonist and to possess antioscteoclastic effects. </ref> Schuehly W, Paredes JM, Kleyer J, Huefner A, Anavi-Goffer S, Raduner S, Altmann KH, Gertsch J. Mechanisms of osteoclastogenesis inhibition by a novel class of biphenyl-type cannabinoid CB(2) receptor inverse agonists.Chem Biol. 2011 Aug 26;18(8):1053-64.
Honokiol inhibits platelet aggregation in rabbits in a dose-dependent manner, and protects cultured RAEC against oxidized low density lipoprotein injury. Honokiol significantly increases the prostacyclin metabolite 6-keto-PGF1alpha, potentially the key factor in honokiol's anti-thrombotic activity.[7]
Several methods for purifying honokiol have been utilized. As honokiol exists naturally with its structural isomer magnolol, which differs from honokiol only by the position of one hydroxyl group, purification has often been limited to a HPLC or electromigration. However, methods developed in 2006 by workers in the lab of Jack L. Arbiser, took advantage of the proximity of the phenolic hydroxyl groups in magnolol, which form a protectable diol, to generate a magnolol acetonide (Figure 1), with a subsequent simple purification via flash chromatography over silica.[8]
Figure 1