• Journal of Life Science
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• v.30 no.10
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• pp.867-876
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• 2020

This study investigated the repair of UVB-induced cell damage by magnolol. We performed a drug-repurposing screen, and, in the STAT3 reporter gene assay, magnolol was identified as a suppressor of STAT3 that improves the cell viability of HDF cells. HDF cells treated with IL-6, UVB, and IFNγ showed the highest expression of Jak2 and phosphorylated STAT3 (p-STAT3), and magnolol was able to decrease the expression of Jak2 and p-STAT3 in UVB-induced cells. Moreover, UVB-damaged cell growth increased significantly in correlation with both reactivation and with magnolol in a dose-dependent manner. Compared with AG490 (a Jak2 inhibitor) treatment of UVB-treated HDF cells, cell proliferation increased significantly. We confirmed that AG490 and magnolol reduced TNF-α concentrations, and Western blotting (protein level) showed decreases in Jak2 and p-STAT3 expression in only the magnolol-treated cells. The expression of Jak2, p-STAT3, and SOCS3 also increased only after treatment with magnolol. Cells were treated with magnolol and ML385 (an NRF2 inhibitor), and these secondary metabolites reduced cell proliferation and NRF2 expression. The amount of MMP9 was also increased by cotreatment with magnolol and ML385. Collectively, these results demonstrate the potential of magnolol for repairing cells after UVB-induced damage by regulating the expression of NRF2, SOCS3, Jak2, and STAT3.

• Journal of Periodontal and Implant Science
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• v.23 no.1
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• pp.145-158
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• 1993

The oral microbiota such as P. gingivalis, P. intermedia and A. actinomycetemcomitans play a primary role in the initiation and progression of the periodontal disease. The purpose of this study was to evaluate the antimicrobial effects and inhibitory effects of honokiol and magnolol on the bacterial collagenase activity, cytotoxicity and cytokine production of periodontopathic microorganisms. The antimicrobial activities of honokiol and magnolol was evaluted with minimum inhibition concentration. Honokiol was more active than magnolol, but less than chlorhexidine on antimicrobial activity. The inhibitory effects of magnolol and honokiol on the collagenolytic activity and cytotoxicity were evaluated using a Collagenokit CLN-100 and rapid colorimetric assay (MTT method) for cellular growth and survival of gingival fibroblast and periodontalligament cell and $[^3H]-thymidine$ incorporation for the gingival epithelial cell. The inhibitory effects on the collagenolytic activity was the highest in chlorhexidine, and the lowest in magnolol. Magnolol had the lowest cytotoxic effect and chlorhexidine had the highest. The inhibitory effects on cytokine production was evaluated using $interleukin-1{\beta}$ ELISA kit (Cistron Biotech.), IL-6, $TNF-{\alpha}$ ELISA kit (Genzyme) and inhibitory effects were higher than bacterial LPS and there is no difference among the honokiol, magnolol and chlorhexidine. From these results, the antimicrobial and antienzymatic activities of honokiol and magnolol were seemed to inhibit bacterial growth and enzyme activities with lesser cytotoxic activities. Therefore, it was suggested that honokiol and magnolol are very effective antimicrobial agents on periodontal pathogens.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.4
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• pp.251-261
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• 2019

Allergic asthma, is a common chronic inflammatory disease of the airway presenting with airway hyperresponsiveness and airway remodelling. T helper cells-derived cytokines are critically associated with asthma pathogenesis. Janus kinase-signal transduction and activation of transcription (JAK/STAT) signaling is found to be involved in asthma. Magnolol is a plant-derived bioactive compound with several pharmacological effects. The study aimed to assess the effects of magnolol in ovalbumin (OVA)-induced asthmatic model. BALB/c mice were sensitized and challenged with OVA. Magnolol (12.5, 25, or 50 mg/kg body weight) was administered to separate groups of animals. Dexamethasone was used as the positive control. Cellular infiltration into the bronchoalveolar lavage fluid (BALF) were reduced on magnolol treatment. The levels of Th2 and Th17 cytokines were reduced with noticeably raised levels of interferon gamma. Lung function was improved effectively along with restoration of bronchial tissue architecture. OVA-specific immunoglobulin E levels in serum and BALF were decreased by magnolol. Magnolol reduced Th17 cell population and effectively modulated the JAK-STAT and Notch 1 signaling. The results suggest the promising use of magnolol in therapy for allergic asthma.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.6
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• pp.353-358
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• 2010

This study demonstrates the ability of magnolol, a hydroxylated biphenyl compound isolated from Magnolia officinalis, to inhibit LPS-induced expression of iNOS gene and activation of NF-${\kappa}B$/Rel in RAW 264.7 cells. Immunohisto-chemical staining of iNOS and Western blot analysis showed magnolol to inhibit iNOS gene expression. Reporter gene assay and electrophoretic mobility shift assay showed that magnolol inhibited NF-${\kappa}B$/Rel transcriptional activation and DNA binding, respectively. Since p38 is important in the regulation of iNOS gene expression, we investigated the possibility that magnolol to target p38 for its anti-inflammatory effects. A molecular modeling study proposed a binding position for magnolol that targets the ATP binding site of p38 kinase (3GC7). Direct interaction of magnolol and p38 was further confirmed by pull down assay using magnolol conjugated to Sepharose 4B beads. The specific p38 inhibitor SB203580 abrogated the LPS-induced NF-${\kappa}B$/Rel activation, whereas the selective MEK-1 inhibitor PD98059 did not affect the NF-${\kappa}B$/Rel. Collectively, the results of the series of experiments indicate that magnolol inhibits iNOS gene expression by blocking NF-${\kappa}B$/Rel and p38 kinase signaling.

• Korean Journal of Medicinal Crop Science
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• v.17 no.2
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• pp.145-150
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• 2009

This study investigated the protective roles and mechanism of magnolol, from the stem bark of Magnolia officinalis against potential neurotoxin 3-hydroxykynurenine (3-HK)-induced neuronal cell death. For the evaluation of protective role of magnolol, we examined cell viability, apoptotic nuclei, change of mitochondrial membrane potential and caspase activity in human neuroblastoma SH-SY5Y cells. It was found that 3-HK induces neuronal cell death in the human neuroblastoma SH-SY5Y cell line. The reduced cell viability produced characteristic features such as cell shrinkages, plasma membrane blebbing, chromatin condensation, and nuclear fragmentation. The cells treated with 3-HK showed an increase in the concentration of reactive oxygen species (ROS) as well as in caspase activity. In addition, both are involved in the 3-HK-induced apoptosis. Magnolol attenuated the cell viability reduction by 3-HK in both a dose- and time-dependent manner. Optical microscopy showed that magnolol inhibited the cell morphological features in the 3-HK-treated cells. Furthermore, the increase in the ROS concentration and the caspase activities by 3-HK were also attenuated by magnolol. These results showed that magnolol has a protective effect on the 3-HK induced cell death by inhibiting ROS production and caspase activity.

• Biomolecules & Therapeutics
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• v.16 no.3
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• pp.270-276
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• 2008

In this study we investigated the effects of Magnolia Bark (MB) extract and its constituents, such as honokiol and magnolol, on gastritis in rats and the growth of human gastric cancer cells. The MB extract, honokiol, and magnolol showed the acid-neutralizing capacities, the antioxidant activities, and the inhibitory effect on the growth of Helicobacter pylori (H. pylori.) at the dose of $50\;{\mu}g/ml$ and over, which is equivalent to that of ampicillin ($100\;{\mu}g/ml$). Honokiol and magnolol had no significant cytotoxicity to human gastric caner cells (AGS and SNU638). However, the MB extract had cytotoxic activity against AGS gastric cancer cell. The MB extract, honokiol, and magnolol significantly inhibited HCI-ethanol-induced gastric lesions without clear change of mucus content. In pylorus ligated rats, honokiol significantly decreased the volume of gastric secretion and gastric acid output, and increased the pH. Magnolol increased the mucus content to almost the same as the control group at oral doses of 50 mg/kg. Therefore, we could guess that antigastritic action of honokiol and magnolol may be associated with the antioxidant activities, acid-neutralizing capacities, inhibition of secretion in gastric acid, and anti-H. pylori action. From these results, we could suggest that MB extract and its constituents, such as honokiol and magnolol, may be useful for the treatment and/or protection of gastritis.

• Toxicological Research
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• v.22 no.3
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• pp.293-299
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• 2006

We demonstrate that magnolol, a hydroxylated biphenyl compound isolated from Magnolia officinalis, inhibits LPS-induced expression of iNOS gene in RAW 264.7 cells(murine macrophage cell line). Treatment of RAW 264.7 cells with magnolol inhibited LPS-stimulated nitric oxide production in a dose-related manner. RT-PCR analysis showed that the decrease of NO was due to the inhibition of iNOS gene expression. Western immunoblot analysis of phosphorylate p38 kinase showed magnolol significantly inhibited the phosphorylation of p38 kinase which is important in the regulation of iNOS gene expression. The specific p38 inhibiter SB203580 abrogated the LPS-induced NO generation and iNOS expression, whereas the selective MEK-1 inhibitor PD98059 did not affect the NO induction. Immunostaining of p65 and reporter gene assay showed that magnolol inhibited NF-${\kappa}/Rel$ nuclear translocation and transcriptional activation, respectively. Collectively, this series of experiments indicates that magnolol inhibits iNOS gene expression by blocking NF-k/Rel and p38 kinase signaling. Due to the critical role that NO release plays in mediating inflammatory responses, the inhibitory effects of magnolol or iNOS suggest that magnolol may represent a useful anti-inflammatory agent.

• Mass Spectrometry Letters
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• v.4 no.2
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• pp.34-37
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• 2013

Honokiol and magnolol, the major bioactive neolignans of magnolia officinalis, are the most important constituents of the crude drug prescriptions that are used in the therapy of neuroses and various nervous disorders. There have been limited reports on the effects of neolignoid compounds on human cytochrome P450 activity. Therefore, the inhibitory effects of honokiol and magnolol on seven human cytochrome P450 s were evaluated in human liver microsomes. Honokiol and magnolol showed the most potent inhibition of CYP1A2-mediated phenacetin O-deethylase activity ($IC_{50}$ values of 3.5 and 5.4 mM, respectively) among the seven P450s tested. These in vitro data indicate that neolignan compounds can inhibit the activity of CYP1A2 and suggest that these compounds should be examined for potential pharmacokinetic drug interactions in vivo.

• Journal of the Korean Wood Science and Technology
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• v.50 no.1
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• pp.12-30
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• 2022

Many studies on plant extracts have been reported for the treatment of candidiasis caused by Candida albicans, a representative fungal infection. This study demonstrates the synergistic antifungal activity of the combination of Phellodendri Cortex and Magnoliae Cortex, previously reported to have antifungal efficacy. Considering the antifungal efficacy and the separation of the active constituents, berberine and magnolol, hot water extraction and carbon dioxide supercritical extraction were selected for Phellodendri Cortex and Magnoliae Cortex, respectively. A combination of 0.55 g/L hot water extract of Phellodendri Cortex and 0.59 g/L carbon dioxide supercritical extract of Magnoliae Cortex showed synergistic antifungal activity. The synergistic antifungal activity of 160 μM berberine and 100 μM magnolol, which are representative antifungal compounds of Phellodendri Cortex and Magnoliae Cortex, respectively, contributes to the synergistic antifungal effect of their extracts. The additive decrease in cellular ergosterol level and the increased antifungal efficacy by extracellular ergosterol suggest that disruption of the biological function of ergosterol in the cell membrane is not responsible for the synergistic antifungal activity of berberine and magnolol. Synergistic cellular release of chromosomal DNA upon mixing berberine and magnolol indicates that disruption of the cellular structure is responsible for the synergistic antifungal effect of berberine and magnolol.

• Archives of Pharmacal Research
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• v.13 no.1
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• pp.117-119
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• 1990

A combination of magnolol or honokiol with lysozyme isolated from the egg white of the Korean Ogol fowl (Korean natural monument No.265) exhibited synergistic effect of bactericidal activity against a typical cariogenic bacterium, Streptococcus mutans OMZ 176. The synergistic ratio increased with time dependence.