Inhibitory activity of lignan components from the flower buds of Magnoliae fargesii on the expression of cell adhesion molecules

Fargesin Inhibits EGF-Induced Cell Transformation and Colon Cancer Cell Growth by Suppression of CDK2/Cyclin E Signaling Pathway

Although the lignan compound fargesin is a major ingredient in Shin-Yi, the roles of fargesin in carcinogenesis and cancer cell growth have not been elucidated. In this study, we observed that fargesin inhibited cell proliferation and transformation by suppression of epidermal growth factor (EGF)-stimulated G₁/S-phase cell cycle transition in premalignant JB6 Cl41 and HaCaT cells. Unexpectedly, we found that signaling pathway analyses showed different regulation patterns in which fargesin inhibited phosphatidylinositol 3-kinase/AKT signaling without an alteration of or increase in mitogen activated protein kinase (MAPK) in JB6 Cl41 and HaCaT cells, while both signaling pathways were abrogated by fargesin treatment in colon cancer cells. We further found that fargesin-induced colony growth inhibition of colon cancer cells was mediated by suppression of the cyclin dependent kinase 2 (CDK2)/cyclin E signaling axis by upregulation of p21^WAF1/Cip1, resulting in G₁-phase cell cycle accumulation in a dose-dependent manner. Simultaneously, the suppression of CDK2/cyclin E and induction of p21^WAF1/Cip1 were correlated with Rb phosphorylation and c-Myc suppression. Taken together, we conclude that fargesin-mediated c-Myc suppression inhibits EGF-induced cell transformation and colon cancer cell colony growth by the suppression of retinoblastoma (Rb)-E2F and CDK/cyclin signaling pathways, which are mainly regulated by MAPK and PKB signaling pathways.

Epimagnolin A, a tetrahydrofurofuranoid lignan from Magnolia fargesii, reverses ABCB1-mediated drug resistance

BACKGROUND

Epimagnolin A is an ingredient of the Chinese crude drug Shin-i, derived from the dried flower buds of Magnolia fargesii and Magnolia flos, which has been traditionally used for the treatment of allergic rhinitis and nasal congestion, empyema, and sinusitis. The pharmacokinetic activity of epimagnolin A remains to be evaluated.

PURPOSE

In this study, we examined the possible interactions of epimagnolin A with human ATP-binding cassette (ABC) transporter ABCB1, a membrane protein vital in regulating the pharmacokinetics of drugs and xenobiotics.

STUDY DESIGN/METHODS

The interaction of epimagnolin A with ABCB1 was evaluated in calcein, ATPase, and MTT assays by using Flp-In-293/ABCB1 cells and purified ABCB1 and simulated in molecular docking studies.

RESULTS

Epimagnolin A inhibited calcein export by Flp-In-293/ABCB1 cells in a concentration-dependent manner in a calcein assay. ATPase assay revealed a concentration-dependent stimulation of the ATPase activity of ABCB1 by epimagnolin A. Epimagnolin A also showed saturation kinetics in the relationship between the compound-stimulated ATPase activity and the compound concentration, suggesting Michaelis-Menten kinetics similar to those of the control drug, verapamil. K_m and V_max values were calculated from Hanes-Woolf plots of (compound concentration) × (compound-stimulated ATPase activity)^-1 vs. (compound concentration); the K_m of epimagnolin and verapamil was 42.9 ± 7.53  μM and 12.3 ± 4.79  μM, respectively, and the corresponding V_max values were 156 ± 15.0  μM and 109 ± 3.18  μM. Molecular docking studies on human ABCB1 showed that epimagnolin A docked to the same binding pocket as verapamil, and 3-(4,5-dimethyl-2-thiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays showed that the sensitivities of Flp-In-293/ABCB1 cells against anti-cancer drugs were enhanced upon exposure to 10  μM epimagnolin A.

CONCLUSION

These results strongly suggest that epimagnolin A affects the transport activity of ABCB1 as a substrate.

Magnolin inhibits prostate cancer cell growth in vitro and in vivo

BACKGROUND

Magnolin is the most active ingredient in the herb Magnolia fargesii, which has been traditionally used in oriental medicine to treat headaches and nasal congestion. Recent researches demonstrate that Magnolin inhibits cancer cell migration and invasion.

MATERIALS AND METHODS

This study used cell culture and the BALB/c nu/nu mouse xenograft model to investigate whether or not magnolin can inhibit the growth of PC3 and Du145 prostate cancer cells. MTT assay and flow cytometry were performed to estimate the proliferation, cycle, and apoptosis of the cells in vitro. Clone formation assay was also conducted. In the animal study, Ki-67 immunostaining and TUNEL assay were carried out to evaluate cell proliferation and apoptosis, respectively. To elucidate the possible mechanism by which magnolin attenuates prostate cancer cell growth, we estimated the expression levels of Akt/p-Akt, P53, P21, BCL-2, and cleaved Caspase3 by using Western blot 48h after magnolin-treatment of the cells.

RESULTS

Magnolin inhibited the proliferation and viability of the tumor cells by triggering cell cycle arrest via P53/P21 activation and inducing apoptosis in vitro and in vivo. Magnolin downregulated the phosphorylation of Akt protein kinase and upregulated cleaved Caspase3 during anti-proliferation and pro-apoptosis.

CONCLUSION

Magnolin may be a novel medicine for prostate cancer therapy.

Magnolin inhibits cell migration and invasion by targeting the ERKs/RSK2 signaling pathway

BACKGROUND

Magnolin is a natural compound abundantly found in Magnolia flos, which has been traditionally used in oriental medicine to treat headaches, nasal congestion and anti-inflammatory reactions. Our recent results have demonstrated that magnolin targets the active pockets of ERK1 and ERK2, which are important signaling molecules in cancer cell metastasis. The aim of this study is to evaluate the effects of magnolin on cell migration and to further explore the molecular mechanisms involved.

METHODS

Magnolin-mediated signaling inhibition was confirmed by Western blotting using RSK2(+/+) and RSK2(-/-) MEFs, A549 and NCI-H1975 lung cancer cells, and by NF-κB and Cox-2 promoter luciferase reporter assays. Inhibition of cell migration by magnolin was examined by wound healing and/or Boyden Chamber assays using JB6 Cl41 and A549 human lung cancer cells. The molecular mechanisms involved in cell migration and epithelial-to-mesenchymal transition were determined by zymography, Western blotting, real-time PCR and immunocytofluorescence.

RESULTS

Magnolin inhibited NF-κB transactivation activity by suppressing the ERKs/RSK2 signaling pathway. Moreover, magnolin abrogated the increase in EGF-induced COX-2 protein levels and wound healing. In human lung cancer cells such as A549 and NCI-H1975, which harbor constitutive active Ras and EGFR mutants, respectively, magnolin suppressed wound healing and cell invasion as seen by a Boyden chamber assay. In addition, it was observed that magnolin inhibited MMP-2 and -9 gene expression and activity. The knockdown or knockout of RSK2 in A549 lung cancer cells or MEFs revealed that magnolin targeting ERKs/RSK2 signaling suppressed epithelial-to-mesenchymal transition by modulating EMT marker proteins such as N-cadherin, E-cadherin, Snail, Vimentin and MMPs.

CONCLUSIONS

These results demonstrate that magnolin inhibits cell migration and invasion by targeting the ERKs/RSK2 signaling pathway.

Magnolin protects against contrast-induced nephropathy in rats via antioxidation and antiapoptosis

Background. Magnolin is the major active ingredient of the herb Magnolia fargesii which has anti-inflammatory and antioxidative effects. Oxidative stress and apoptosis are involved in the pathogenesis of contrast-induced nephropathy (CIN). We hypothesize that Magnolin could protect against CIN through antioxidative and antiapoptotic properties. Methods. To test whether Magnolin could attenuate CIN, oxidative stress and apoptosis, in vivo and in vitro, we utilized a rat model of ioversol-induced CIN and a cell model of oxidative stress in which HK2 cells were treated with H₂O₂. Rats were assigned to 4 groups (n = 6 per group): control group, ioversol group (ioversol-induced CIN), vehicle group (CIN rats pretreated with vehicle), and Magnolin group (CIN rats pretreated with 1 mg/kg Magnolin). Results. The results showed that magnolin ameliorated the renal tubular necrosis, apoptosis, and the deterioration of renal function (P < 0.05). Furthermore, Magnolin reduced the renal oxidative stress, suppressed caspase-3 activity, and increased Bcl-2 expression in vivo and in vitro. Conclusion. Magnolin might protect CIN in rats through antioxidation and antiapoptosis.

Effects of magnoline on P-selectin's expression in diabetic rats and its reno-protection

BACKGROUND AND OBJECTIVE

Magnoline is an active ingredient of magnolia fargesii with anti-inflammatory and anti-platelet effects. The objective is to explore the renoprotection of magnoline in diabetic rats and its effects on P-selectin.

METHODS

Thirty-six rats were randomized into 4 groups-normal control group (C), diabetic group (D), small-dose magnoline treatment group (M1) and large-dose magnoline treatment group (M2) (n=9 in each group). Streptozotocin was selected to construct diabetic rat model, and group M1 and group M2 were treated with magnoline 0.5mg/Kg.d and 2mg/Kg.d respectively. Urinary albumin excretion rate, renal function, levels of P-selectin and TGF-β1 were observed after 16 weeks.

RESULTS

Levels of albuminuria and serum creatinine of group M1 (1078.9 ± 77.3μg/24h, 29.7 ± 3.9μmol/L) and M2 (852.9 ± 80.1μg/24h, 30.9 ± 2.9μmol/L) were lower than group D (1572.8 ± 176.2μg/24h, 39.4 ± 4.1μmol/L) (P <0.05). Serum levels of P-selectin in group M1 and M2 were lower than group D (P <0.05). The renal expression of P-selectin and TGF-β1 in group M1 and M2 were significantly attenuated respectively.

CONCLUSIONS

Magnoline has reno-protective effects on diabetic rats which may be related to the inhibition of P-selectin.

Effects of add-on therapy with NDC-052, an extract from Magnoliae Flos, in adult asthmatic patients receiving inhaled corticosteroids

BACKGROUND/AIMS

There is a need for new anti-asthmatic medications with fewer side effects. NDC-052, an extract of the medicinal herb Magnoliae flos, which has a long history of clinical use, was recently found to have anti-inflammatory effects. Herein, we evaluated the effects of NDC-052 as an add-on therapy in patients with mild to moderate asthma using inhaled corticosteroids (ICS).

METHODS

In a non-comparative, multi-center trial, 148 patients taking ICS received NDC-052 for eight weeks. We evaluated their forced expiratory volume in one second (FEV1), morning and evening peak expiratory flow rate (AM and PM PEFR), AM/PM asthma symptom scores, visual analogue symptom (VAS) scores, night-time wakening, frequency of short-acting β2-agonist usage, and adverse events.

RESULTS

After eight weeks, both AM and PM PEFRs were significantly improved. Asthma symptom scores, VAS scores, the frequency of nights without awakening, and the frequency of β2-agonist use were also reduced. Most of the adverse drug reactions were mild and resolved spontaneously.

CONCLUSIONS

The addition of NDC-052 to ICS had a beneficial effect on asthma control in patients with mild to moderate asthma, with good tolerability and fewer side effects. Further studies are necessary to evaluate the effects of NDC-052 in patients with severe and/or refractory asthma.

Liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry for the simultaneous determination of dimethoxyaschantin, dimethylliroresinol, dimethylpinoresinol, epimagnolin A, fargesin and magnolin in rat plasma

A rapid, selective, and sensitive liquid chromatography-atmospheric pressure chemical ionization (APCI) tandem mass spectrometry method was developed for the simultaneous determination of dimethoxyaschantin, dimethylliroresinol, dimethylpinoresinol, epimagnolin A, fargesin and magnolin, the pharmacologically active ingredients of Magnolia fargesii in rat plasma. These tetrahydrofurofuranoid lignans were extracted from rat plasma using tert-butyl methyl ether at pH 7.4. The analytes were separated on a Pinnacle DB biphenyl column with 65% methanol in 10 mm ammonium formate (pH 3.0) and detected by APCI tandem mass spectrometry in the selective reaction monitoring mode. The calibration curves were linear (r(2) ≥ 0.996) over the concentration range of 20.0-1000 ng/mL for six tetrahydrofurofuranoid lignans. The lower limit of quantification for these lignans was 20.0 ng/mL with 50 µL of plasma sample. The intra- and inter-assay coefficient of variation and relative error for the six tetrahydrofurofuranoid lignans at four quality control concentrations were 0.2-9.9% and -8.5-8.2%, respectively. There was no matrix effect for the six tetrahydrofurofuranoid lignans and tolterodine (internal standard). The pharmacokinetics of dimethylliroresinol, dimethylpinoresinol, epimagnolin A, fargesin and magnolin were evaluated after oral administration of a purified extract isolated from dried flower buds of Magnolia fargesii at doses of 5.5, 11.0 and 22.0 mg/kg in male rats.

[Volatile oil of Magnolia biondii inhibits expressions of P-selectin protein in serum and renal tissue of rats with diabetic nephropathy]

OBJECTIVE

To investigate the protection mechanism of volatile oil of Magnolia biondii Pamp. (VOMBP) against diabetic nephropathy in rats by observing its effects on level of soluble P-selectin (sP-selectin) in serum and expression of P-selectin in renal tissue.

METHODS

Fifty SD rats were randomly divided into normal control group, untreated group, and low-, medium- and high-dose VOMBP-treated group. Diabetic nephropathy was induced in rats by intraperitoneal injection of 1% streptozotocin. Before and the 1st day, 4th, 8th and 12th week after the induction, random blood glucose (RBG) and 24-hour urinary micro-albumin were detected in different groups. At the 12th week, the rats were sacrificed to collect the blood samples and renal tissues. The contents of blood urea nitrogen (BUN) and serum creatinine (SCr) were detected and the pathological change in renal tissues was observed by light microscope; the level of sP-selectin was detected by enzyme-linked immunosorbent assay and the expression of P-selectin protein in renal tissues was measured by immunohistochemical method.

RESULTS

Compared with the normal control group, RBG, 24-hour urinary micro-albumin, the contents of BUN, sP-selectin in serum and expression of P-selectin protein in renal tissue in the untreated group were significantly increased (P<0.01), the content of SCr was significantly decreased (P<0.01), and pathological change of renal tissues was also obvious. Compared with the untreated group, 24-hour urinary micro-albumin, the level of sP-selectin in serum and expression P-selectin protein in renal tissue of the three VOMBP-treated groups were all significantly decreased (P<0.01), and pathological change was lessened too. However, there were no significant differences among the three VOMBP-treated groups (P>0.05).

CONCLUSION

VOMBP can protect the kidney in rats with diabetic nephropathy by inhibiting the expressions of P-selectin protein in serum and in renal tissue.

Simultaneous determination of magnolin and epimagnolin A in rat plasma by liquid chromatography with tandem mass spectrometry: Application to pharmacokinetic study of a purified extract of the dried flower buds of Magnolia fargesii, NDC-052 in rats

A purified extract isolated from the dried flower buds of Magnolia fargesii (NDC-052) is currently being evaluated for phase III clinical trials as a new anti-asthma drug. A rapid, sensitive and selective liquid chromatography-tandem mass spectrometric (LC/MS/MS) method for the simultaneous determination of magnolin and epimagnolin A, the major bioactive components of NDC-052, in rat plasma was developed. After liquid-liquid extraction with tolterodine as an internal standard, magnolin and epimagnolin A were separated on a Luna phenyl-hexyl column with the mobile phase of 70% methanol in 10mM ammonium formate. The analytes were detected by an electrospray ionization tandem mass spectrometry in the multiple-reaction-monitoring mode. The standard curves were linear over the concentration range of 50-2500ng/mL for magnolin and epimagnolin A in rat plasma. The intra- and inter-day coefficients of variation and relative errors for magnolin and epimagnolin A at four QC concentrations were 1.5-11.4% and 5.9-12.5%, respectively. The lower limits of quantification for magnolin and epimagnolin A were 50.0ng/mL using 50microL of plasma. This method was successfully applied to the pharmacokinetic study of magnolin and epimagnolin A after an oral administration of NDC-052 in male Sprague-Dawley rats.

An update on bioactive plant lignans

Lignans are a class of secondary plant metabolites produced by oxidative dimerization of two phenylpropanoid units. Although their molecular backbone consists only of two phenylpropane (C6-C3) units, lignans show an enormous structural diversity. There is a growing interest in lignans and their synthetic derivatives due to applications in cancer chemotherapy and various other pharmacological effects. This review deals with lignans possessing anticancer, antioxidant, antimicrobial, anti-inflammatory and immunosuppressive activities, and comprises the data reported in more than 100 peer-reviewed articles, so as to highlight the recently reported bioactive lignans that could be a first step towards the development of potential new therapeutic agents.