Comparison of antioxidant abilities of magnolol and honokiol to scavenge radicals and to protect DNA

Alleviation of kainic acid-induced brain barrier dysfunction by 4-o-methylhonokiol in in vitro and in vivo models

This experiment was designed to investigate whether 4-O-methylhonokiol (MH), a principal ingredient of Magnolia (M.) officinalis bark, alleviated acute intraperitoneal (i.p.) kainic acid- (KA-) induced brain blood barrier dysfunction (BBBD) via pathological examination and cytological analyses of the brain tissues of mice. KA (10–30 mg/kg) time- and dose-dependently increased the water content of brain tissues and induced edema and encephalopathy. However, pretreatment with MH (5 and 20 mg/kg, i.p.) significantly reduced the water content of the brain compared to that observed in the KA control group. Furthermore, MH significantly and dose-dependently reversed the remarkable variations in evan's blue dye (EBD) staining and malondialdehyde (MDA) levels that were induced by KA (10 mg/kg, i.p.). MH also decreased the elevated seizure scores that were induced by KA (10 mg/kg, i.p.) in mice in a manner similar to scavengers such as DMTU and trolox. Additionally, MH significantly scavenged intracellular ROS and Ca²⁺ within hippocampal cells. The tight junction seals mediated by claudin (Cld-5) were also found to be modulated by MH. MH efficiently reduced 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC₅₀, 52.4 mM) and ^•OH with an electron spin resonance (ESR) signal rate constant of 4 × 10⁹ M⁻¹ · S⁻¹, which is close to the reactivity of the vitamin E analog trolox. Taken together, these results suggest that MH may enhance radical scavenging in lipid and hydrophobic environments, which may be important for the physiological activity of the barrier.

Honokiol abrogates lipopolysaccharide-induced depressive like behavior by impeding neuroinflammation and oxido-nitrosative stress in mice

Depression is an inflammatory, commonly occurring and lethal psychiatric disorder having high lifetime prevalence. Preclinical and clinical studies suggest that activation of immuno-inflammatory and oxido-nitrosative stress pathways play major role in the pathophysiology of depression. Honokiol (HNK) is a biphenolic neolignan possessing multiple biological activities including antioxidant, anti-inflammatory, anxiolytic, antidepressant and neuroprotective. The present study investigated the effect of HNK (2.5 and 5 mg/kg, i.p.) pretreatment (30 min prior to LPS) on lipopolysaccharide (LPS) (0.83 mg/kg, i.p.) induced depressive like behavior, neuroinflammation, and oxido-nitrosative stress in mice. HNK pretreatment at both the doses significantly attenuated LPS induced depressive-like behavior by reducing the immobility time in forced swim and tail suspension test, and by improving the anhedonic behavior observed in sucrose preference test. HNK pretreatment ameliorated LPS induced neuroinflammation by reducing IL-1β, IL-6 and TNF-α level in hippocampus (HC) and prefrontal cortex (PFC). HNK pretreatment prevented LPS evoked oxidative/nitrosative stress via improving reduced glutathione level along with reduction in the lipid peroxidation and nitrite level in HC and PFC. Pretreatment with HNK also prevented the increase in plasma corticosterone (CORT) and decrease in hippocampal BDNF level in LPS challenged mice. In conclusion, current investigation suggested that HNK pretreatment provided protection against LPS-induced depressive like behavior which may be mediated by repression of pro-inflammatory cytokines as well as oxido-nitrosative stress in HC and PFC. Our results strongly speculated that HNK could be a therapeutic approach for the treatment of depression and other pathophysiological conditions which are closely associated with neuroinflammation and oxido-nitrosative stress.

UPLC-MS/MS-ESI assay for simultaneous determination of magnolol and honokiol in rat plasma: application to pharmacokinetic study after administration emulsion of the isomer

ETHNOPHARMACOLOGICAL RELEVANCE

Magnolia officinalis is one of the commonly used in traditional Chinese medicine for the treatment of fever, chronic bronchitis and stomach ailments. Magnolol and honokiol are isomers with hydroxylated biphenol compound in the extract of Magnolia officinalis. This study aims to determine the isomers in rat plasma and evaluate their pharmacokinetic pattern after administration emulsion.

MATERIALS AND METHODS

Sprague Dawley male rats received either an intravenous (i.v.25, mg/kg) or oral (50mg/kg) dose of the emulsion of the isomer. A sensitive and specific ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method was developed for the investigation of the pharmacokinetics of magnolol and honokiol in rats. Kaempferol was employed as an internal standard.

RESULTS

The plasma samples were deproteinized with acetonitrile, the post-treatment samples were analyzed on an Agela C18 column interfaced with a triple quadrupole tandem mass spectrometer in negative electrospray ionization mode. Acetonitrile and 5 mmol/L ammonium acetate buffer solution (65: 35, v/v) was used as the mobile phase at a flow rate of 0.2 mL/min. Following oral administration of emulsion to rats, magnolol attained mean peak plasma concentrations of 426.4 ± 273.8 ng/mL at 1.20 h, whereas honokiol reached peak plasma concentrations of 40.3 ± 30.8 ng/mL at 0.45 h. The absolute bioavailability of magnolol and honokiol is 17.5 ± 9.7% and 5.3 ± 11.7%. By comparison, the AUC0-∞ of magnolol was 5.4 times higher than that of honokiol after intravenous administration, but AUC0-∞ of magnolol was about 18-fold higher than honokiol after oral administration.

Emerging role of the peroxisome proliferator-activated receptor-gamma in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the major leading cause of cancer death worldwide. Hepatitis B virus, hepatitis C virus, alcohol consumption, non-alcoholic fatty liver disease, and diabetes are the major risks for developing HCC. Until now, recurrence and metastasis are the major cause of death in HCC patients. Therefore, identification of new effective molecular targets is an urgent need for treatment of HCC. Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated nuclear receptor which could be activated by PPARγ agonists such as thiazolidinediones, and natural PPARγ ligand (such as 15-deoxy-Δ12,14-prostaglandin J₂, 15d-PGJ₂). Increasing in vitro and in vivo evidence has demonstrated that PPARγ agonists exhibit an inhibitory role on tumor cell growth, migration, and invasion, suggesting that PPARγ activation may play an important role in the regulation of growth of HCC. It has been reported that PPARγ activation by thiazolidinediones or overexpression of PPARγ by virus-mediated gene transfer has shown growth inhibitory effects in hepatoma cells, but the expression level of PPARγ in HCC tissues still remains conflicting. Notably, a novel PPARγ agonist, honokiol, has recently been found to activate the PPARγ/RXR heterodimer, and has also exhibited significant anti-cancer effects in hepatoma cells. In the present review, we summarized studies on the role and the molecular regulation of PPARγ in HCC development in vitro and in vivo. PPARγ has the potential to be a therapeutic target for future treatment of HCC.

Pharmacokinetics of honokiol after intravenous guttae in beagle dogs assessed using ultra-performance liquid chromatography-tandem mass spectrometry

A simple, rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of honokiol in beagle dog plasma after intravenous guttae. With addition of the internal standard magnolol, plasma samples were precipitated with methanol and separated on a Shim-pack XR-ODS II (2.0 × 100 mm, 2.2 µm) with isocratic elution of methanol and water (80:20) solution at a flow rate of 0.2 mL/min. A good separation of honokiol was achieved within 3.5 min. Quantification was performed on a Waters Quattro Premier XE triple quadrupole mass spectrometer with electrospray ionization inlet in the negative multiple reaction monitoring mode. Good linearity was obtained over the concentration range of 5.12-15580 ng/mL (r(2) > 0.998). Intra- and inter-day precisions were <13.10%, and accuracy ranged from 89.21 to 99.92%. The lower limit of quantification for honokiol was 5.12 ng/mL, and honokiol was stable under various conditions (three freeze-thaw cycles, short-term temperature, post-preparative and long-term temperature conditions.). This validated method was successfully applied to the pharmacokinetic study of honokiol in dogs by intravenous guttae.

Molecular Targets of Honokiol: A Promising Phytochemical for Effective Cancer Management

Honokiol is a bioactive, biphenolic phytochemical, present in the aerial parts of plants classified under the genus Magnolia. It has been an important constituent of Asian traditional medicine and is used against many ailments. Honokiol possesses potent antioxidative, anti-inflammatory, antiangiogenic, and anticancer activities by targeting a variety of signaling molecules. Consequently, there has been immense interest in exploring its utility as a novel chemopreventive and therapeutic agent against several malignancies. In this chapter, we review the structure-function relationship of honokiol and its derivative compounds, the impact of honokiol on various phenotypes associated with cancer progression and metastasis, and its prominent molecular targets and pharmacokinetics. Clearly, the available data generate significant interest in this novel phytochemical and emerging information continues to provide strong support for its potential applicability in cancer management.