Antimicrobial activity of honokiol and magnolol isolated from Magnolia officinalis

Honokiol induces apoptosis and autophagy in dexamethasone-resistant T-acute lymphoblastic leukemia CEM-C1 cells

Objective: To study whether and, if so, how honokiol overcome dexamethasone resistance in DEX-resistant CEM-C1 cells. Methods: We investigated the effect of honokiol (0-20 µM) on cell proliferation, cell cycle, cell apoptosis and autophagy in DEX-resistant CEM-C1 cells and DEX-sensitive CEM-C7 cells. We also determined the role of c-Myc protein and mRNA in the occurrence of T-ALL associated dexamethasone resistance western blot and reverse transcription-qPCR (RT-qPCR) analysis. Results: Cell Counting Kit (CCK)-8 assay shows that DEX-resistant CEM-C1 cell lines were highly resistant to dexamethasone with IC50 of 364.1 ± 29.5 µM for 48 h treatment. However, upon treatment with dexamethasone in combination with 1.5 µM of honokiol for 48 h, the IC50 of CEM-C1 cells significantly decreased to 126.2 ± 12.3 µM, and the reversal fold was 2.88. Conversely, the IC50 of CEM-C7 cells was not changed combination of dexamethasone and honokiol as compared to that of CEM-C7 cells treated with dexamethasone alone. It has been shown that honokiol induced T-ALL cell growth inhibition by apoptosis and autophagy via downregulating cell cycle-regulated proteins (Cyclin E, CDK4, and Cyclin D1) and anti-apoptotic proteins BCL-2 and upregulating pro-apoptotic proteins Bax and led to PARP cleavage. Honokiol may overcome dexamethasone resistance in DEX-resistant CEM-C1 cell lines via the suppression of c-Myc mRNA expression. Conclusion: The combination of honokiol and DEX were better than DEX alone in DEX-resistant CEM-C1 cell lines. Honokiol may regulate T-ALL-related dexamethasone resistance by affecting c-Myc.

Bacteria-targeted magnolol-loaded multifunctional nanocomplexes for antibacterial and anti-inflammatory treatment

Natural plant-derived small molecules have shown great potential for their antimicrobial and anti-inflammatory properties. In this study, we successfully developed a nanocomplex consisting of magnolol (Mag), a surfactant with an 18 carbon hydrocarbon chain and multi-amine head groups (C18N3), and a peptide (cyclic 9-amino acid peptide (CARG)) with targeting capabilities forStaphylococcus aureus(S. aureus). The obtained Mag/C18N3/CARG nanocomplexes exhibited strong antibacterial activity againstS. aureus. Furthermore, they demonstrated anti-inflammatory effects by reducing the secretion of pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1βfrom macrophage inflammatory cells. This was achieved through downregulating the activation of NF-κB, KEAP1, and NRF2 signaling pathways. In a murine skin infection model, the Mag/C18N3/CARG nanocomplexes effectively suppressed the growth ofS. aureusin the infected area and promoted wound healing. Additionally, in a mouse model of acute kidney injury (AKI), the nanocomplexes significantly reduced the levels of blood urea nitrogen and creatinine, leading to a decrease in mortality rate. These findings demonstrate the potential of combining natural plant-derived small molecules with C18N3/CARG assemblies as a novel approach for the development of effective and safe antibacterial agents.

Magnolol extends lifespan and improves age-related neurodegeneration in Caenorhabditis elegans via increase of stress resistance

Magnolol is a naturally occurring polyphenolic compound in many edible plants, which has various biological effects including anti-aging and alleviating neurodegenerative diseases. However, the underlying mechanism on longevity is uncertain. In this study, we investigated the effect of magnolol on the lifespan of Caenorhabditis elegans and explored the mechanism. The results showed that magnolol treatment significantly extended the  lifespan of nematode and alleviated senescence-related decline in the nematode model. Meanwhile, magnolol enhanced stress resistance to heat shock, hydrogen peroxide (H2O2), mercuric potassium chloride (MeHgCl) and paraquat (PQ) in nematode. In addition, magnolol reduced reactive oxygen species and malondialdehyde (MDA) levels, and increased superoxide dismutase and catalase (CAT) activities in nematodes. Magnolol also up-regulated gene expression of sod-3, hsp16.2, ctl-3, daf-16, skn-1, hsf-1, sir2.1, etc., down-regulated gene expression of daf-2, and promoted intranuclear translocation of daf-16 in nematodes. The lifespan-extending effect of magnolol were reversed in insulin/IGF signaling (IIS) pathway-related mutant lines, including daf-2, age-1, daf-16, skn-1, hsf-1 and sir-2.1, suggesting that IIS signaling is involved in the modulation of longevity by magnolol. Furthermore, magnolol improved the age-related neurodegeneration in PD and AD C. elegans models. These results indicate that magnolol may enhance lifespan and health span through IIS and sir-2.1 pathways. Thus, the current findings implicate magnolol as a potential candidate to ameliorate the symptoms of aging.

Assessing the Antioxidant Benefits of Topical Carvacrol and Magnolol Periodontal Hydrogel Therapy in Periodontitis Associated with Diabetes in Wistar Rats

It is well recognized that oxidative stress contributes to chronic stress-induced cytotoxicity, which is a major factor in the progression of many diseases, including periodontitis and diabetes. Formulas based on natural extracts with antioxidant properties are alternative treatment perspectives in the management of such diseases. The aim of our study was to assess how carvacrol and magnolol influence periodontitis associated with diabetes in Wistar rats. Ninety Wistar rats were distributed in nine groups: I-control group; II-diabetes group (D); III-periodontitis group (P); IV-periodontitis and diabetes group (PD); V-periodontitis and diabetes with vehicle alone (PDV); VI-periodontitis and diabetes treated with carvacrol (PDC); VII-periodontitis and diabetes treated with magnolol (PDM); VIII-periodontitis and diabetes treated with carvacrol and magnolol (PDCM); IX-healthy group with vehicle alone (CV). Blood malondialdehyde (MDA) levels and catalase activity levels (CAT) were measured as indicators of oxidative stress and antioxidant capacity, respectively. Where diabetes and periodontitis were induced, MDA was augmented and CAT was depleted significantly. Whether given alone (PDM) or in combination with carvacrol (PDCM), magnolol significantly decreased MDA. Between the PDM group and the PDCM group, there were no notable differences. In Wistar rats with periodontitis related to diabetes, topical use of hydrogels containing magnolol, either alone or in combination with carvacrol, may reduce oxidative stress.

Neuropharmacological potential of honokiol and its derivatives from Chinese herb Magnolia species: understandings from therapeutic viewpoint

Honokiol is a neolignan biphenol found in aerial parts of the Magnolia plant species. The Magnolia plant species traditionally belong to China and have been used for centuries to treat many pathological conditions. Honokiol mitigates the severity of several pathological conditions and has the potential to work as an anti-inflammatory, anti-angiogenic, anticancer, antioxidant, and neurotherapeutic agent. It has a long history of being employed in the healthcare practices of Southeast Asia, but in recent years, a greater scope of research has been conducted on it. Plenty of experimental evidence suggests it could be beneficial as a neuroprotective bioactive molecule. Honokiol has several pharmacological effects, leading to its exploration as a potential therapy for neurological diseases (NDs), including Alzheimer's disease (AD), Parkinson's disease (PD), cerebral ischemia, anxiety, depression, spinal cord injury, and so on. So, based on the previous experimentation reports, our goal is to discuss the neuroprotective properties of honokiol. Besides, honokiol derivatives have been highlighted recently as possible therapeutic options for NDs. So, this review focuses on honokiol's neurotherapeutic actions and toxicological profile to determine their safety and potential use in neurotherapeutics.

Silver Nanoparticles Prepared Using Magnolia officinalis Are an Effective Antimicrobial Agent on Candida albicans, Escherichia coli, and Staphylococcus aureus

Silver nanoparticles (AgNPs) prepared by plants are simple, eco-friendly, and economical. In this study, Magnolia officinalis (MO) extract was applied to synthesize MO@AgNPs. Ultraviolet-visible (UV-vis) spectrum analysis indicated a peak at 440 nm. Most of the particles were spherical with sizes from 1 to approximately 60 nm based on transmission electron microscopy (TEM). X-ray diffraction (XRD) patterns showed a face-centered cubic crystal structure. The zeta value of MO@AgNPs was - 36.5 ± 0.6 mV, which was stable at 25 °C and 4 °C. Growth kinetic studies and the Kirby-Bauer diffusion method showed significant inhibitory activity on Candida albicans (ATCC 10231), Escherichia coli (ATCC BAA-2340), and Staphylococcus aureus (ATCC 25923); the minimum inhibitory concentrations (MIC) were 3, 9, and 9 μg/mL, and corresponding minimum bactericidal concentrations (MBC) were 5, 11, and 9 μg/mL, respectively. MO@AgNPs exhibited better antifungal activity compared to AgNPs prepared using sodium citrate. Further research revealed that MO@AgNPs increased the permeability of bacterial cell membranes. Moreover, the effect of MO@AgNPs on Candida albicans was significantly enhanced by blocking autophagy. The reactive oxygen species (ROS) induced by MO@AgNPs in Candida albicans was limited and may be related to its good antioxidant activity. Finally, MO@AgNPs have no significant cytotoxicity to the human liver LO2 cell line under 20 μg/mL.

Inhibitory Effects of Honokiol on Substantia Gelatinosa Neurons of the Trigeminal Subnucleus Caudalis in Juvenile Mice

Inhibitory neurotransmitters such as gamma-aminobutyric acid (GABA) and glycine are known to be abundant in the substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc). Thus, it has been recognized as an initial synaptic site for regulating orofacial nociceptive stimuli. Honokiol, a principal active ingredient derived from the bark of Magnolia officinalis, has been exploited in traditional remedies with multiple biological effects, including anti-nociception on humans. However, the anti-nociceptive mechanism of honokiol on SG neurons of the Vc remains fully elusive. In this study, effects of honokiol on SG neurons of the Vc in mice were investigated using the whole-cell patch-clamp method. In a concentration-dependent manner, honokiol significantly enhanced frequencies of spontaneous postsynaptic currents (sPSCs) that were independent of action potential generation. Notably, honokiol-induced increase in the frequency of sPSCs was attributed to the release of inhibitory neurotransmitters through both glycinergic and GABAergic pre-synaptic terminals. Furthermore, higher concentration of honokiol induced inward currents that were noticeably attenuated in the presence of picrotoxin (a GABAA receptor antagonist) or strychnine (a glycine receptor antagonist). Honokiol also exhibited potentiation effect on glycine- and GABAA receptor-mediated responses. In inflammatory pain model, the increase in frequency of spontaneous firing on SG neurons induced by formalin was significantly inhibited by the application of honokiol. Altogether, these findings indicate that honokiol might directly affect SG neurons of the Vc to facilitate glycinergic and GABAergic neurotransmissions and modulate nociceptive synaptic transmission against pain. Consequently, the inhibitory effect of honokiol in the central nociceptive system contributes to orofacial pain management.

Comparative study of three plant-derived extracts as new management strategies against Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Finding innovative eco-friendly agents for pest control may be aided by investigating the plant-derived extracts' properties on economic pests. Therefore, the insecticidal, behavioral, biological and biochemical effects of Magnolia grandiflora (Magnoliaceae) leaf water and methanol extracts, Schinus terebinthifolius (Anacardiaceae) wood methanol extract, and Salix babylonica (Salicaceae) leaf methanol extract in comparison with a reference insecticide novaluron against S. littoralis were evaluated. The extracts were analyzed by High-Performance Liquid Chromatography (HPLC). The most abundant phenolic compounds were 4-hydroxybenzoic acid (7.16 mg/mL) and ferulic acid (6.34 mg/mL) in M. grandiflora leaf water extract; catechol (13.05 mg/mL), ferulic acid (11.87 mg/mL), and chlorogenic acid (10.33 mg/mL) in M. grandiflora leaf methanol extract; ferulic acid (14.81 mg/mL), caffeic acid (5.61 mg/mL), and gallic acid (5.07 mg/mL) In the S. terebinthifolius extract; cinnamic acid (11.36 mg/mL), and protocatechuic acid (10.33 mg/mL) In the methanol extract from S. babylonica extract. S. terebinthifolius extract had a highly toxic effect against second larvae after 96 h and eggs with LC₅₀ values of 0.89 and 0.94 mg/L, respectively. Despite M. grandiflora extracts didn't show any toxicity against S. littoralis stages, they had an attractant effect on fourth- and second larvae, with feeding deterrence values of - 2.7% and - 6.7%, respectively, at 10 mg/L. S. terebinthifolius extract significantly reduced the percentage of pupation, adult emergence, hatchability, and fecundity, with values of 60.2%, 56.7%, 35.3%, and 105.4 eggs/female, respectively. Novaluron and S. terebinthifolius extract drastically inhibited the activities of α-amylase and total proteases to 1.16 and 0.52, and 1.47 and 0.65 ΔOD/mg protein/min, respectively. In the semi-field experiment, the residual toxicity of tested extracts on S. littoralis gradually decreased over time compared to novaluron. These findings indicate that extract from S. terebinthifolius is a promising insecticidal agent against S. littoralis.

A Chinese herb preparation, honokiol, inhibits Streptococcus mutans biofilm formation

OBJECTIVE

This study aimed to investigate the antibiofilm and anticariogenic effects of honokiol, a traditional Chinese medicine, on the cariogenic bacterium Streptococcus mutans (S. mutans).

DESIGN

The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of honokiol on S. mutans UA159 were measured. Then, S. mutans were treated with honokiol at concentrations of 1/2 MIC and 1/4 MIC. Extracellular polysaccharide (EPS) synthesis was assessed with confocal laser scanning microscopy (CLSM) and the anthrone-sulfuric method. Crystal violet staining and scanning electron microscopy (SEM) were used to demonstrate the characteristics and morphology of S. mutans biofilms. Colony-forming unit (CFU) assay was performed to observe the antibacterial effect of honokiol. Lactic acid production of 24-h biofilms was measured by the lactic acid assay. The expression level of caries-related genes (gtfB/C/D, comD/E and ldh) was identified by quantitative real-time PCR (qRTPCR) to explore the relevant mechanism. And the cytotoxic effect on human gingival fibroblasts (HGFs) was evaluated by the Cell Counting Kit-8 (CCK-8) assay.

RESULTS

The MIC and MBC of honokiol on S. mutans were 30 μg/mL and 60 μg/mL, respectively. Honokiol inhibited biofilm formation, EPS synthesis and lactic acid production. It also decreased the expression of glucosyltransferases (Gtfs) and quorum sensing (QS) system encoding genes. Moreover, honokiol showed favorable biocompatibility with HGFs.

CONCLUSIONS

Honokiol has an inhibitory effect on S. mutans and favorable biocompatibility, with application potential as a novel anticaries agent.

Citric Acid and Magnolol Ameliorate Clostridium perfringens Challenge in Broiler Chickens

Clostridium perfringens (C. perfringens) is a common pathogenic bacterium implicated in the enteric diseases of animals. Each year, the disease is responsible for billions of dollars of losses worldwide. The development of new phytomedicines as alternatives to antibiotics is becoming a new hotspot for treating such diseases. Citric acid (CA) and magnolol (MA) have been shown to have antibacterial, antioxidant, and growth-promoting properties. Here, the bacteriostatic effects of combinations of CA and MA against C. perfringens were investigated, together with their effects on yellow-hair chickens challenged with C. perfringens. It was found that the optimal CA:MA ratio was 50:3, with a dose of 265 μg/mL significantly inhibiting C. perfringens growth, and 530 μg/mL causing significant damage to the bacterial cell morphology. In animal experiments, C. perfringens challenge reduced the growth, damaged the intestinal structure, activated inflammatory signaling, impaired antioxidant capacity, and perturbed the intestinal flora. These effects were alleviated by combined CA-MA treatment. The CA-MA combination was found to inhibit the TLR/Myd88/NF-κB and Nrf-2/HO-1 signaling pathways. In conclusion, the results suggest the potential of combined CA-MA treatment in alleviating C. perfringens challenge by inhibiting the growth of C. perfringens and affecting the TLR/MyD88/NF-κB and Nrf-2/HO-1 signaling pathways.

Screening and evaluating honokiol from Magnolia officinalis against Nocardia seriolae infection in largemouth bass (Micropterus Salmoides)

Nocardiosis caused by Nocardia seriolae is a major threat to the aquaculture industry. Given that prolonged therapy administration can lead to a growth of antibiotic resistant strains, new antibacterial agents and alternative strategies are urgently needed. In this study, 80 medicinal plants were selected for antibacterial screening to obtain potent bioactive compounds against N. seriolae infection. The methanolic extracts of Magnolia officinalis exhibited the strongest antibacterial activity against N. seriolae with the minimal inhibitory concentration (MIC) of 12.5 μg/ml. Honokiol and magnolol as the main bioactive components of M. officinalis showed higher activity with the MIC value of 3.12 and 6.25 μg/ml, respectively. Sequentially, the evaluation of antibacterial activity of honokiol in vivo showed that honokiol had good biosafety, and could significantly reduce the bacterial load of nocardia-infected largemouth bass (p < .001). Furthermore, the survival rate of nocardia-infected fish fed with 100 mg/kg honokiol was obviously improved (p < .05). Collectively, these results suggest that medicinal plants represent a promising reservoir for discovering active components against Nocardia, and honokiol has great potential to be developed as therapeutic agents to control nocardiosis in aquaculture.

An overview of the natural antimicrobial alternatives for sheep meat preservation

Sheep meat is consumed and appreciated all over the world for its nutritional value and flavor. However, this meat is very perishable and easily subjected to the action of both spoilage and pathogenic microorganisms. For this reason, in combination with cold storage, effective preservation techniques are required. There is increasing interest in the application of natural antimicrobials, such as essential oils, extracts, spices, and by-products of the food industry. This review analyses the studies on natural antimicrobials in sheep meat and sheep meat products and gathers evidence about the encouraging results achieved on the reduction and/or elimination of spoilage and pathogenic microorganisms. The use of these natural antimicrobial alternatives might open up important perspectives for industrial application, considering that this specific meat is often traded over long distances. In fact, on the basis of scientific literature, natural antimicrobials can be considered a sustainable and affordable alternative to extend the shelf life of sheep meat and guarantee its safety, although many factors need to be further investigated, such as the sensory impact, potential toxicity, and economic aspects. For all these issues, investigated in some of the studies reviewed here, it is fundamental to obtain the antimicrobial effect with the minimum amount of effective substance to avoid sensory modifications, toxic effects, and unbearable costs. This study sets foundations for the possible direction of future studies, which will contribute to identify effective solutions for industrial applications of natural antimicrobials in the sheep meat industry.

In-vitro antiproliferative efficacy of Abrus precatorius seed extracts on cervical carcinoma

Abrus precatorius is a tropical medicinal plant with multiple medicinal benefits whose seeds have not yet been studied against cervical cancer. Herein, we have assessed the antioxidant and antiproliferative properties of seed extracts (ethyl acetate and 70% ethanol) prepared from Soxhlet and Maceration extraction methods against Hep2C and HeLa Cells. We observed that the APE (Sox) extract had a significantly higher total flavonoid content, APA (Mac) extract had a high total phenolic content, and APA (Sox) extract had a high total tannin content. Further, HPLC analysis of extracts revealed the presence of tannic acid and rutin. Moreover, APA (Sox) exhibited the highest free radical scavenging activity. APE (Mac) had the best antiproliferative activity against Hep2C cells, while APA (Sox) had the best antiproliferative activity against HeLa cells. In Hep2C cells, APE (Mac) extract revealed the highest SOD, catalase activity, GSH content, and the lowest MDA content, whereas APA (Mac) extract demonstrated the highest GST activity. In HeLa cells, APA (Sox) extract showed the highest SOD, GST activity, GSH content, and the least MDA content, whereas APA (Mac) extract showed the highest catalase activity. Lastly, docking results suggested maximum binding affinity of tannic acid with HER2 and GCR receptors. This study provides evidence that A. precatorius seed extracts possess promising bioactive compounds with probable anticancer and antioxidant properties against cervical cancer for restricting tumor growth.

Characterization of Alternaria porri causing onion purple blotch and its antifungal compound magnolol identified from Caryodaphnopsis baviensis

Alternaria porri (Ellis) Clf. causes purple blotch disease on Allium plants which results in the reduction of crop yields and quality. In this study, to efficiently find natural antifungal compounds against A. porri, we optimized the culture condition for the spore production of A. porri and the disease development condition for an in vivo antifungal assay. From tested plant materials, the methanol extracts derived from ten plant species belonging to the families Cupressaceae, Fabaceae, Dipterocarpaceae, Apocynaceae, Lauraceae, and Melastomataceae were selected as potent antifungal agents against A. porri. In particular, the methanol extract of Caryodaphnopsis baviensis (Lec.) A.-Shaw completely inhibited the growth of A. porri at a concentration of 111 μg/ml. Based on chromatographic and spectroscopic analyses, a neolignan compound magnolol was identified as the antifungal compound of the C. baviensis methanol extract. Magnolol showed a significant inhibitory activity against the spore germination and mycelial growth of A. porri with IC₅₀ values of 4.5 and 5.4 μg/ml, respectively. Furthermore, when magnolol was sprayed onto onion plants at a concentration of 500 μg/ml, it showed more than an 80% disease control efficacy for the purple blotch diseases. In terms of the antifungal mechanism of magnolol, we explored the in vitro inhibitory activity on individual oxidative phosphorylation complexes I–V, and the results showed that magnolol acts as multiple inhibitors of complexes I–V. Taken together, our results provide new insight into the potential of magnolol as an active ingredient with antifungal inhibitory action to control purple blotch on onions.

Can Plant Materials Be Valuable in the Treatment of Periodontal Diseases? Practical Review

Periodontal diseases are one of the most significant challenges in dental health. It is estimated that only a few percent of the worldwide population have entirely healthy teeth, and according to WHO, oral diseases may affect up to 3.5 billion people worldwide. One of the most serious oral diseases is periodontitis, an inflammatory disease affecting periodontal tissues, caused by pathogenic bacteria and environmental factors such as the ageing population, abuse of tobacco products, and lack of adequate oral hygiene due low public awareness. Plant materials are widely and successfully used in the management of many conditions, including periodontitis. Plant materials for periodontitis exhibit antibacterial, anti-inflammatory, antioxidant activities and affect the periodontium structure. Numerous studies demonstrate the advantages of phytotherapy for periodontitis relief and indicate the usefulness of Baikal skullcap root, Pomegranate fruit peel and root cortex, Tea leaves, Chamomile flowers, Magnolia bark, Blackberry leaves and fruits, Cranberry fruits and Lippia sidoides essential oil. This review aims to analyze the use and applicability of selected plant materials in periodontitis management since it is of paramount importance to evaluate the evidence of the traditionally used plant materials in light of continuously growing interest in phytotherapy and its adjuvant role in the treatment of periodontitis.

A honokiol-mediated robust coating for blood-contacting devices with anti-inflammatory, antibacterial and antithrombotic properties

Thrombus, bacterial infections, and severe inflammation are still serious problems that have to be faced with blood-contacting materials. However, it is a great challenge to simultaneously meet the above functional requirements in a simple, economical and efficient method. As such, we put forward a robust and versatile coating strategy by covalently modifying the multi-pharmacological drug honokiol (HK) with an amine-rich polydopamine/polyethyleneimine coating, through which anticoagulant, antibacterial and anti-inflammatory properties were obtained (DPHc) simultaneously. The amine content in the DPHc coating was lower than the detection limit, while it contained abundant phenolic hydroxyl groups (49 μmol cm-2). Meanwhile, the 30 day drug release test confirmed that the drug was firmly modified on the surface of the coating without release. A systematic in vitro and ex vivo evaluation confirmed that the coating had significant anti-thrombotic properties. The antibacterial rates of the DPHc coating against Staphylococcus aureus and Escherichia coli reached 99.98% and 99.99%, respectively. In addition, subcutaneous implantation indicated that the DPHc coating also has excellent histocompatibility. To the best of our knowledge, this is the first study using HK as a coating material that can not only combat thrombosis and infection but also significantly inhibit inflammation associated with the use of blood-contacting materials, thus expanding the application of HK in the field of biomaterials.

Anti-Inflammatory and Antioxidant Properties of Carvacrol and Magnolol, in Periodontal Disease and Diabetes Mellitus

Periodontal disease and diabetes mellitus are two pathologies that are extremely widespread worldwide and share the feature of chronic inflammation. Carvacrol is a phenolic monoterpenoid, produced by a variety of herbs, the most well-known of which is Origanum vulgare. Magnolol is a traditional polyphenolic compound isolated from the stem bark of Magnolia officinalis, mainly used in Chinese medicine. The purpose of this paper is to review the therapeutic properties of these bioactive compounds, in the treatment of periodontitis and diabetes. Based on our search strategy we conducted a literature search in the PubMed and Google Scholar databases to identify studies. A total of one hundred eighty-four papers were included in the current review. The results show that carvacrol and magnolol have anti-inflammatory, antioxidant, antimicrobial, anti-osteoclastic, and anti-diabetic properties that benefit both pathologies. Knowledge of the multiple activities of carvacrol and magnolol can assist with the development of new treatment strategies, and the design of clinical animal and human trials will maximize the potential benefits of these extracts in subjects suffering from periodontitis or diabetes.

Screening of natural compounds identifies ferutinin as an antibacterial and anti-biofilm compound

Antibacterial screenings are most commonly targeted at planktonic bacteria but less effort is dedicated to the exploration of agents acting on biofilms. Here, a natural compounds library was screened against Staphylococcus aureus using a 384-well plate platform to identify compounds preventing biofilm formation. Five structurally diverse hits were selected for follow-up studies: honokiol, tschimganidin, ferutinin, oridonin and deoxyshikonin. The compounds were evaluated against different bacterial species for their capacity to prevent and disrupt biofilms. The development of resistance and cytotoxicity were also investigated. Ferutinin displayed the best antibacterial activity, with a minimum inhibitory, bactericidal and biofilm preventive concentration of 25 µM against S. aureus. It efficiently disrupted pre-formed biofilms (over 5-log reduction of viable cells) and reduced biofilm formation on a catheter in the presence of neutrophils. This work provides new information on the antibacterial activity of five natural compounds and identified ferutinin as a promising candidate against S. aureus biofilms.

Claisened Hexafluoro Inhibits Metastatic Spreading of Amoeboid Melanoma Cells

Metastatic melanoma is characterized by poor prognosis and a low free-survival rate. Thanks to their high plasticity, melanoma cells are able to migrate exploiting different cell motility strategies, such as the rounded/amoeboid-type motility and the elongated/mesenchymal-type motility. In particular, the amoeboid motility strongly contributes to the dissemination of highly invasive melanoma cells and no treatment targeting this process is currently available for clinical application. Here, we tested Claisened Hexafluoro as a novel inhibitor of the amoeboid motility. Reported data demonstrate that Claisened Hexafluoro specifically inhibits melanoma cells moving through amoeboid motility by deregulating mitochondrial activity and activating the AMPK signaling. Moreover, Claisened Hexafluoro is able to interfere with the adhesion abilities and the stemness features of melanoma cells, thus decreasing the in vivo metastatic process. This evidence may contribute to pave the way for future possible therapeutic applications of Claisened Hexafluoro to counteract metastatic melanoma dissemination.

A novel anticaries agent, honokiol-loaded poly(amido amine) dendrimer, for simultaneous long-term antibacterial treatment and remineralization of demineralized enamel

OBJECTIVE

Existing agents to induce enamel self-repair and inhibit the progression of dental caries in the early stage have been proven to be inadequate and far from satisfactory. In this study, a honokiol-loaded poly(amido amine) (PAMAM) dendrimer (PAMH) was constructed to combat early caries lesions in enamel.

METHODS

PAMH was prepared via a codissolution method. Computational simulation analysis was used to explore the mechanism of honokiol release. The cytotoxicity of PAMH was tested. The antibacterial effects of PAMH were tested by planktonic growth assays and biofilm formation inhibition assays. The remineralization effect of PAMH was examined via transverse microradiography and scanning electron microscopy after a pH cycling model. The in vivo anti-caries effect of PAMH was carried out in a rat model.

RESULTS

Honokiol released from PAMH was slower but more durable in a cariogenic pH environment than in a neutral pH environment, which could be explained through the computational simulation analysis results. Under electrostatic action, P3 beads with the same charge repelled each other and extended outwards, resulting in the rapid expansion of the PAMAM dendrimer and accelerating the release of the drug. At a low pH of 5.5, the protonated P3 beads were not charged and the protonated P1 beads were positively charged. However, the electrostatic repulsive interaction between protonated P1 beads was restricted by the P3 beads in the outermost layer of the PAMAM dendrimer, so the swelling rate was relatively slow, resulting in the slow release of drug molecules in the acidic environment. The cytotoxicity demonstration and the biocompatibility experiment in animal study showed that PAMH is biologically safe. PAMH showed excellent enamel remineralizing ability after pH cycling and showed a long-term antibacterial effect in vitro. Meanwhile, PAMH showed long-term anticaries efficacy in vivo.

SIGNIFICANCE

Our findings indicated that PAMH had great potential to combat early caries lesions in enamel for future clinical application.

Insecticidal and Attractant Activities of Magnolia citrata Leaf Essential Oil against Two Major Pests from Diptera: Aedes aegypti (Culicidae) and Ceratitis capitata (Tephritidae)

In this study, Magnolia citrata Noot and Chalermglin (Magnoliaceae) essential oil (MCEO) was evaluated for insecticidal activity against the yellow fever mosquito Aedes aegypti and attractant activity for the Mediterranean fruit fly Ceratitis capitata. The leaves of Magnolia citrata (Giổi chanh) were collected from northwestern Vietnam, and the water-distilled MCEO was analyzed by gas-chromatography and mass spectrometry (GC-MS). The major constituents of MCEO were identified as linalool 19%, geranial 16%, citronellal 14%, neral 14%, and sabinene 12%. MCEO showed 100% mortality at 1 μg/μL against 1st instar larvae of Ae. aegypti (Orlando strain, ORL), and the oil exhibited 54% (ORL) and 68% (Puerto Rico strain) mortality at 5 μg/mosquito against Ae. aegypti adult females. Initial screens showed that MCEO had weak insecticidal activity compared to the positive control permethrin. In bioassays with sterile male C. capitata, MCEO exhibited moderately strong attraction, comparable to that observed with a positive control, Tetradenia riparia essential oil (TREO). Herein, the insecticidal and attractant activities of MCEO are reported for the first time.

The genome of Magnolia biondii Pamp. provides insights into the evolution of Magnoliales and biosynthesis of terpenoids

Magnolia biondii Pamp. (Magnoliaceae, magnoliids) is a phylogenetically, economically, and medicinally important ornamental tree species widely grown and cultivated in the north-temperate regions of China. Determining the genome sequence of M. biondii would help resolve the phylogenetic uncertainty of magnoliids and improve the understanding of individual trait evolution within the Magnolia genus. We assembled a chromosome-level reference genome of M. biondii using ~67, ~175, and ~154 Gb of raw DNA sequences generated via Pacific Biosciences single-molecule real-time sequencing, 10X Genomics Chromium, and Hi-C scaffolding strategies, respectively. The final genome assembly was ~2.22 Gb, with a contig N50 value of 269.11 kb and a BUSCO complete gene percentage of 91.90%. Approximately 89.17% of the genome was organized into 19 chromosomes, resulting in a scaffold N50 of 92.86 Mb. The genome contained 47,547 protein-coding genes, accounting for 23.47% of the genome length, whereas 66.48% of the genome length consisted of repetitive elements. We confirmed a WGD event that occurred very close to the time of the split between the Magnoliales and Laurales. Functional enrichment of the Magnolia-specific and expanded gene families highlighted genes involved in the biosynthesis of secondary metabolites, plant-pathogen interactions, and responses to stimuli, which may improve the ecological fitness and biological adaptability of the lineage. Phylogenomic analyses revealed a sister relationship of magnoliids and Chloranthaceae, which are sister to a clade comprising monocots and eudicots. The genome sequence of M. biondii could lead to trait improvement, germplasm conservation, and evolutionary studies on the rapid radiation of early angiosperms.

Biphenyl-type neolignans from stem bark of Magnolia officinalis with potential anti-tumor activity

Six new biphenyl-type neolignans (1-6), and eighteen known compounds (7-24) were isolated from the EtOH extract of Magnolia officinalis. Their structures were determined by 1D and 2D NMR, and by HRMS. The anti-tumor activities of the isolated compounds were evaluated on HepG2, HCT-116, H1975 and HUVEC cell lines. Among the isolated compounds, nine compounds (3, 5, 7, 8, 12, 14, 20, 22, and 24) showed moderate cytotoxicities, and compound 23 showed the best cytotoxicity with IC₅₀ value lower than 10 μM.

Bioassay-guided isolation of two antifungal compounds from Magnolia officinalis, and the mechanism of action of honokiol

Magnolia officinalis, as a well-known herb worldwide, has been widely used to treat multiple diseases for a long time. In this study, the petroleum ether extract from M. officinalis showed effective antifungal activity against seven plant pathogens (particularly against R. solani with an inhibition rate of 100.00% at 250 μg/mL). Honokiol and magnolol, isolated by the bioassay-guided method, exhibited greater antifungal activity than tebuconazole (EC₅₀ = 3.07 μg/mL, p ≤ 0.001) against R. solani, which EC₅₀ values were 2.18 μg/mL and 3.48 μg/mL, respectively. We used transcriptomics to explore the mechanism of action of honokiol against R. solani. Results indicated that honokiol may exert antifungal effects by blocking the oxidative phosphorylation metabolic pathway. Further studies indicated that honokiol induced ROS overproduction, disrupted the mitochondrial function, affected respiration, and blocked the TCA cycle, which eventually inhibited ATP production. Besides, honokiol also damaged cell membranes and caused morphological changes. This study demonstrated that the lignans isolated from M. officinalis possess the potential to be developed as botanical fungicides.

In vitro antimicrobial and antipro-inflammation potential of honokiol and magnolol against oral pathogens and macrophages

BACKGROUND/PURPOSE

Honokiol and magnolol are natural components isolated from Magnolia bark that is used in traditional Chinese and Japanese herbal medicine. These two isomers are used as a component of dietary supplements and cosmetic products. In this study, we investigated the antimicrobial effect of honokiol and magnolol on pathogens causing oral diseases, their mechanism of action in biofilm formation and drug resistance of oral pathogens, and inflammatory regulation in mammalian cells.

METHODS

We determined the minimum inhibitory concentration and minimum bactericidal concentration of honokiol and magnolol, and their stability at different temperatures and pH. We also evaluated their effect on biofilm formation, antibiotic-resistance gene expression in MRSA, and pro-inflammatory gene expression in mammalian cells.

RESULTS

Honokiol showed better antimicrobial activity than magnolol. Both honokiol and magnolol showed stable bacterial inhibitory activity over a wide range of temperature and pH, reduced biofilm formation, and antibiotic resistance in oral pathogens. The biofilm formation- and antibiotic resistance-related gene expression was consistent with the respective phenotypes. Furthermore, these two isomers repressed the expression of pro-inflammatory genes in RAW264.7 cells.

CONCLUSION

Our study provides evidence of the potential application of honokiol and magnolol in dental medicine to cure or prevent oral diseases.

Nano delivery of natural substances as prospective autophagy modulators in glioblastoma

Glioblastoma is the most destructive type of malignant brain tumor in humans due to cancer relapse. Latest studies have indicated that cancer cells are more reliant on autophagy for survival than non-cancer cells. Autophagy is entitled as programmed cell death type II and studies imply that it is a comeback of cancer cells to innumerable anti-cancer therapies. To diminish the adverse consequences of chemotherapeutics, numerous herbs of natural origin have been retained in cancer treatments. Additionally, autophagy induction occurs via their tumor suppressive actions that could cause cell senescence and increase apoptosis-independent cell death. However, most of the drugs have poor solubility and thus nano drug delivery systems possess excessive potential to improve the aqueous solubility and bioavailability of encapsulated drugs. There is a pronounced need for more therapies for glioblastoma treatment and hereby, the fundamental mechanisms of natural autophagy modulators in glioblastoma are prudently reviewed in this article.

The Therapeutic Effects of Magnolia Officinalis Extraction on an Antibiotics-Induced Intestinal Dysbacteriosis in Mice

Magnolia officinalis bark is a traditional Chinese medicine for gastrointestinal tract disorders. In this study, we explored the effects of M. officinalis extraction on intestinal flora to reveal its mechanism. Thirty SPF mice were divided into five groups: C (control), M (M. officinalis), A (antibiotics: cefradine and gentamicin sulfate), A&M (antibiotics + M. officinalis) and A&N (antibiotics + natural recovery). Faecal samples of all groups were collected and the taxonomic composition and diversity of bacteria was characterized using the 16S rRNA gene (16S). Alpha diversity showed gut bacteria diversity significantly decreased in the A group of mice but increased markedly after administration of M. officinalis extract. Beta diversity indicated that C, M and A&M shared similar bacterial community structure while A and A&N exhibited a different bacterial community. Furthermore, RDA combined with spearman correlation heatmap suggested the five physiological indicators (weight, fur, activity and feces) were highly correlated with bacterial community structure and diversity. Finally, functional categorization of the assigned OTUs was performed using the PICRUSt tool. The changes in PICRUSt inferred that function profile and metabolic pathways were observed in A and A&M, therefore the M. officinalis extract improved the intestinal flora of A&M and normalized its metabolic pathways gradually, improving mouse weight, fur quality, activity and feces qualities.

Thin-layer chromatographic quantification of magnolol and honokiol in dietary supplements and selected biological properties of these preparations

Two isomeric biphenyl neolignans, magnolol and honokiol, are considered as constituents responsible for the healing effect of magnolia bark, a traditional Oriental medicine. To survey the increasing number of dietary supplements that contain magnolia bark or its extract, an affordable quantitative thin-layer chromatography (TLC) - densitometry method was developed. The methanol extracts were analyzed on the silica gel plates after manual sample application using n-hexane - ethyl acetate - ethanol (16:3:1, v/v/v) as a mobile phase. For quantitation, the chromatograms were scanned in the absorbance mode at the wavelength λ = 290 nm. The limits of detection and quantitation were 90 and 280 ng/zone for magnolol and 70 and 200 ng/zone for honokiol, respectively. None of the two targeted neolignans were detected in two of the six analyzed supplements. In the other four samples, the measured amounts were between 0.95-114.69 mg g^-1 for magnolol and 4.88-84.86 mg g^-1 for honokiol. Moreover, separations of these two neolignans on the TLC and high-performance TLC (HPTLC) layers were compared and HPTLC was combined with antioxidant (DPPH) and antibacterial (Bacillus subtilis and Aliivibrio fischeri) assays and mass spectrometry (MS), using the elution-based interface. Both magnolol and honokiol exhibited effects in all bioactivity assays. The HPTLC-MS tests confirmed purity of neolignan zones in the extracts of dietary supplements and supported tentative identification of the alkaloid piperine and the isoflavone daidzein as additional bioactive components of the investigated dietary supplements. Using the same mobile phase in the orthogonal directions 2D-HPTLC-MS experiments proved degradation, i.e., instability of magnolol and honokiol on the silica gel adsorbent.

Magnolol Attenuates Cisplatin-Induced Muscle Wasting by M2c Macrophage Activation

Cancer chemotherapy induces sarcopenia, which is a rapid loss of muscle mass that directly restricts daily activities and leads to poor quality of life and increased mortality. Although hormone-related therapies have been used to improve appetite and nutritional status, current treatments are considered palliative. Thus, the protection of skeletal muscle loss without adverse effects is essential to allow the maintenance of chemotherapy in cancer patients. Magnolol from Magnolia officinalis has several pharmacological effects including anti-cancer and anti-inflammatory activities, but the protection from muscle atrophy is not well-understood. In the present study, we investigated the effects of magnolol on muscle wasting and macrophage subtypes in a cisplatin-induced sarcopenia mouse model. We showed that magnolol significantly attenuated the body weight and the muscle loss induced by cisplatin injection. The diameter of the tibialis anterior muscle was markedly increased after magnolol treatment in cisplatin-treated mice. Importantly, magnolol increased macrophage infiltration into skeletal muscle while not affecting proliferation of macrophages. Magnolol attenuated the imbalance of M1/M2c macrophages by increasing CD206⁺CD163⁺ M2c tissue reparative macrophages. Further, magnolol increased insulin-like growth factor (IGF)-1 expression. This effect was also observed in bone marrow-derived macrophages upon magnolol treatment. Taken together, magnolol may be a promising chemoprotective agent for the prevention of muscle atrophy through the upregulating M2c macrophages, which are a major source of IGF-1.

Gold nano particles synthesized from Magnolia officinalis and anticancer activity in A549 lung cancer cells

Nanotechnology is creating a bang in each and every field of life science. Scientists are mounting their interest of research towards gold nanoparticles as they are capable with bigger and advanced properties.Traditionally nanoparticles have been manufactured by various chemical and physical methods but have negative impact on the environment and are also highly toxic. Synthesis of nanoparticles by using plant extracts is substituting the conventional methods and it is eco-friendly too. In the current study, we prepared gold nanoparticles (AuNPs) from Magnolia officinalis, which is identified as an eco-friendly and less toxic method. Incorporation of AuNPs was renowned by UV-absorbance and it shows peak values. Nanoparticle sizes are recognized by dynamic light scattering scrutiny and it shows a value of 128 nm. Besides, high resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray analysis (EDX) and atomic force microscopy (AFM) incorrigibly define the shape of the AuNPs which are present in the complex materials. Fourier-transform infrared spectroscopy (FTIR) findings display that the active molecules are positioned in the plane of the AuNPs. Similarly, anticancer efficacy of AuNPs have been assessed in A549 cells. our study show that AuNPs effectively provoke cytotoxicity, and apoptosis by inflecting apoptotic gene expressions in A549 cells.

Variation in the microbial community contributes to the improvement of the main active compounds of Magnolia officinalis Rehd. et Wils in the process of sweating

Background

Magnolia officinalis Rehd. et Wils, commonly called Houpo, has been used for thousands of years in China as a traditional herbal medicine. The primary processing of Houpo requires sweating treatment, which is a special drying process and is considered to be an essential embodiment of high quality and genuine medicinal materials. The sweating of Houpo leads to peculiar changes in the microbial community structure and the content of main active substances (magnolol, honokiol, syringin and magnoflorine). Variation in the microbial community was considered the cause of the change in content of active substances of Houpo, although the microbial taxa responsible for the improvement of content remain unidentified.

Methods

In this study, we used MiSeq high-throughput sequencing methods for partial bacterial 16S rRNA and 18S rRNA gene sequences to compare the bacterial and fungal community structures at different timepoints in the process of sweating. The content of the main active substances (magnolol, honokiol, syringin and magnoflorine) were determined by high-performance liquid chromatography analysis to evaluate the effects of sweating. UPLC-Q-Extractive Orbitrap mass spectrometry (UPLC-QE Orbitrap MS) was used to detection of differential metabolites of unsweated Houpo before and after co-culture with core bacterial solutions.

Results

In this study, the total contents of magnolol (MG) and honokiol (HK) were significantly increased at 4 dp (dp for day PM sample), up to 3.75%, and the contents of syringin (SG) and magnoflorine (MF) were as high as 0.12% and 0.06%, respectively. Bacterial abundance and diversity were higher in the early stage (0 day-2 da; da for day AM sample) than in the later stage (4-5 dp), while fungal abundance was more obvious in the later stage than in the early stage. Positive correlation coefficients revealed that the relative abundance of Enterobacter (P < 0.05), Klebsiella (P < 0.05), Weissella (P < 0.05), Bacillus (P < 0.05) and Candida (P < 0.05) would be conducive to improving the quality of Houpo. Negative correlation coefficients revealed that the relative abundance of Actinomycetospora, Singulisphaera, Mucilaginibacter, Deinococcus, Gemmatirosa, Methylobacterium, Sphingomonas, Hymenobacter, Halomonas and Capnobotryella could be a potential antagonist for the decrease in the quality of Houpo. After co-culture of single core strain and unsweated Houpo, there was no significant difference in the four main active components, but there were other metabolites with significant difference.

Conclusions

Our findings reveal that sweating increased the content of the main active compounds, promoted the relative abundance of potentially beneficial microbes, decreased the abundance of potentially harmful microbes, the core functional genera group together, forming a core microbiome, these genera are dominant across the different stages of the sweating process and contribute to the quality development of the characteristics of Houpo. Meanwhile, this study presented a clear scope for potential beneficial microbes that improve the quality of Houpo.

Magnolol Suppresses TGF-β-Induced Epithelial-to-Mesenchymal Transition in Human Colorectal Cancer Cells

Tumor metastasis is the end state of a multistep process that includes dissemination of tumor cells to distant organs and requires tumor cells to adapt to different tissue microenvironments. During metastasis, tumor cells undergo a morphological change known as transdifferentiation or the epithelial-to-mesenchymal transition (EMT). In normal embryonic development, the EMT occurs in the context of morphogenesis in a variety of tissues. Over the course of this process, epithelial cells lose their cell-cell adhesion and polarity properties. In this study, we investigated whether magnolol could suppress the EMT in human colorectal cancer cells. To this end, we examined the epithelial markers E-cadherin, ZO-1, and claudin and the mesenchymal markers N-cadherin, TWIST1, Slug, and Snail. Magnolol effectively inhibited EMT in human colon cancer cell lines by upregulating epithelial markers and downregulating mesenchymal markers. The EMT is induced by the TGF-β signaling pathway. To determine whether magnolol disrupts TGF-β signaling, we examined several mediators of this pathway, and found that magnolol decreased the levels of phosphorylated (i.e., active) ERK, GSK3β, and Smad. We conclude that magnolol blocks migration in HCT116 cells by suppressing TGF-β signaling.

Small-molecule compounds target paraptosis to improve cancer therapy

According to its different occurrence mechanism, programmed cell death (PCD) is divided into apoptosis, autophagy, necrosis, paraptosis and so on. Paraptosis is morphologically different from apoptosis and autophagy, which exhibit cytoplasmic vacuolation derived from the ER, independent of caspase, absence of apoptotic morphology. Recent researches have implied that a variety of small molecule compounds, such as celastrol, curcumin, can induce paraptosis-associated cell death as the reagent to enhance anti-cancer activity. A better understanding of paraptosis will lay the foundation to develop new therapeutic strategies to treat human cancers that make full use of small-molecule compounds.

Antifungal Effect of Magnolol and Honokiol from Magnolia officinalis on Alternaria alternata Causing Tobacco Brown Spot

In this study, two phenol compounds, magnolol and honokiol, were extracted from Magnolia officinalis and identified by LC-MS, 1H- and 13C-NMR. The magnolol and honokiol were shown to be effective against seven pathogenic fungi, including Alternaria alternata (Fr.) Keissl, Penicillium expansum (Link) Thom, Alternaria dauci f.sp. solani, Fusarium moniliforme J. Sheld, Fusarium oxysporum Schltdl., Valsa mali Miyabe & G. Yamada, and Rhizoctonia solani J.G. Kühn, with growth inhibition of more than 57%. We also investigated the mechanisms underlying the potential antifungal activity of magnolol and honokiol. The results showed that they inhibited the growth of A. alternata in a dose-dependent manner. Moreover, magnolol and honokiol treatment resulted in distorted mycelia and increased the cell membrane permeability of A. alternata, as determined by conductivity measurements. These results suggest that magnolol and honokiol are potential antifungal agents for application against plant fungal diseases.

A review of the phytochemistry and pharmacological activities of Magnoliae officinalis cortex

ETHNOPHARMACOLOGICAL RELEVANCE

Magnoliae Officinalis Cortex (the dried bark of Magnolia officinalis), a widely used traditional Chinese medicine, is also known as 'Houpo' (Chinese: ). Magnoliae Officinalis Cortex has a wide range of pharmacological effects and has been used to treat conditions such as abdominal distention, vomiting, diarrhea, food accumulation, Qi stagnation, constipation, phlegm and fluid retention and cough resulting from asthma.

AIMS OF THE REVIEW

The present paper reviews advances in research relating to the botany, ethnopharmacology, phytochemistry, pharmacology and toxicology of Magnoliae Officinalis Cortex. Prospects for future investigation and application of this herb are also discussed.

MATERIALS AND METHODS

Information on Magnoliae Officinalis Cortex was obtained from published materials, including ancient and modern books; PhD and MSc dissertations; monographs on medicinal plants; the pharmacopoeia of different countries and electronic databases, such as SCI finder, PubMed, Web of Science, ACS, Science Direct, Wiley, Springer, Taylor, AGRIS, Europe PMC, EBSCO host, CNKI, WanFang DATA, J-STAGE and Google Scholar.

RESULTS

More than 200 chemical compounds have been isolated from Magnoliae Officinalis Cortex, including lignans, phenylethanoid glycosides, phenolic glycosides, alkaloids, steroids and essential oils. The plant has been reported to have pharmacological effects on the digestive system, nervous system and cardiovascular and cerebrovascular systems, as well as antibacterial, anti-tumour, analgesic, anti-inflammatory and anti-oxidative effects.

CONCLUSIONS

Magnoliae Officinalis Cortex is an essential traditional Chinese medicine with pharmacological activities that mainly affect the digestive system, nervous system and cardiovascular and cerebrovascular systems. This review summarises its botany, ethnopharmacology, phytochemistry, pharmacology and toxicology. These information suggest that we should focus on the development of new drugs related to Magnoliae Officinalis Cortex, including specific constituents, so that Magnoliae Officinalis Cortex can exert greater therapeutic potential. Meanwhile, it is important to pay attention to the rational use of Magnolia resources, avoiding over-harvesting which could lead to lack of resources. We should also pursue research on Magnolia substitutes and develop resources such as Magnoliae Officinalis Flos and Magnolia Leaf.

Honokiol Improves Insulin Resistance, Hepatic Steatosis, and Inflammation in Type 2 Diabetic db/db Mice

This study focuses on the effect of honokiol (HON) on glucose homeostasis, insulin resistance, dyslipidemia, hepatic steatosis, and inflammation in type 2 diabetic db/db mice. Male C57BL/KsJ-db/db mice were fed a normal diet with or without HON (0.02%, w/w) or pioglitazone (PIO, anti-diabetic agent, 0.01%, w/w) for 5 weeks. Blood biomarker, tissue morphology and enzymatic and genetic parameters were determined. PIO significantly decreased food intake, fasting blood glucose, and glycosylated hemoglobin (HbA1c) levels, but markedly increased body weight, adipose tissue weight, and plasma leptin levels. HON did not significantly affect food intake, body weight, or levels of plasma leptin and blood glucose. However, HON led to significant decreases in adipose tissue weight, plasma insulin, blood HbA1c and HOMA-IR levels and improved glucose tolerance. The anti-diabetic and anti-adiposity effects of HON were partially related to the inhibition of gluconeogenic enzymes and their mRNA expression in the liver; and the inhibition of lipogenic enzymes in adipose tissue, respectively. Unlike PIO, HON did not affect dyslipidemia, but ameliorated hepatic steatosis by inhibiting hepatic lipogenic enzymes activity. Moreover, HON exhibited anti-inflammatory effects similar to PIO. These results suggest that HON can protect against type 2 diabetes by improving insulin resistance, glucose and lipid metabolism, and inflammation.

Honokiol alleviates sepsis-induced acute kidney injury in mice by targeting the miR-218-5p/heme oxygenase-1 signaling pathway

Background

Honokiol is a low-molecular-weight natural product and has been reported to exhibit anti-inflammatory activity.

Objectives

Our study aimed to investigate the influence of honokiol on sepsis-induced acute kidney injury (AKI) in a mouse model.

Material and methods

A cecal ligation and puncture (CLP) surgical operation was performed to establish a sepsis-induced acute kidney injury model in mice. Renal histomorphological analysis was performed with periodic acid-Schiff (PAS) staining. The levels of inflammatory markers in serum were measured by ELISA assay. The mRNA and protein levels were assayed by RT-qPCR and western blotting, respectively. Annexin V-FITC/PI staining was used to evaluate glomerular mesangial cell (GMC) apoptosis.

Results

The results revealed that honokiol significantly increased the survival rate in mice undergoing a CLP operation. Inflammatory cytokines, such as TNF-α, IL-6 and IL-1β, were significantly inhibited in honokiol-treated septic mice compared with the CLP group. In addition, honokiol showed the ability to reverse CLP-induced AKI in septic mice. Furthermore, heme oxygenase-1 (HO-1) expression levels were significantly up-regulated and miR-218-5p was markedly down-regulated in honokiol-treated septic mice as compared to CLP-operated mice. Bioinformatics and experimental measurements showed that HO-1 was a direct target of miR-218-5p. In vitro experiments showed that both honokiol and miR-218-5p inhibitors blocked lipopolysaccharide (LPS)-induced cell growth inhibition and GMC apoptosis by increasing the expression of HO-1.

Conclusions

Honokiol ameliorated AKI in septic mice and LPS-induced GMC dysfunction, and the underlying mechanism was mediated, at least partially, through the regulation of miR-218-5p/HO-1 signaling.

Electronic supplementary material

The online version of this article (10.1186/s11658-019-0142-4) contains supplementary material, which is available to authorized users.

Isolation of anti-Saprolegnia lignans from Magnolia officinalis and SAR evaluation of honokiol/magnolol analogs

To control the fish fungal pathogen Saprolegnia, the effects of the petroleum ether extracts of Magnolia officinalis were evaluated by a rapeseed (Brassicanapus) microplate method in vitro. By loading on an open silica gel column and eluting with petroleum ether-ethyl acetate-methanol, honokiol (C₁₈H₁₈O₂) and magnolol (C₁₈H₁₈O₂) were isolated from Magnolia officinalis. Saprolegnia parasitica growth was inhibited significantly when honokiol concentration was >8.0 mg/L, and magnolol concentration was >9.0 mg/L, with EC₅₀ values of 4.38 and 4.92 mg/L, respectively. Six honokiol and magnolol derivatives were designed, synthesized and evaluated for their anti-Saprolegnia activity. According to the results, double bond and hydroxyl played an important role in inhibiting Saprolegnia. Mechanistically, through the scanning electron microscope observation, honokiol and magnolol could cause the Saprolegnia parasitica mycelium tegumental damage including intensive wrinkles and nodular structures. Moreover, compared to traditional drugs kresoxim-methyl (LC₅₀ = 0.66 mg/L) and azoxystrobin (LC₅₀ = 2.71 mg/L), honokiol and magnolol showed a lower detrimental effect on zebrafish, with the LC₅₀ values of 6.00 and 7.28 mg/L at 48 h, respectively. Overall, honokiol and magnolol were promising lead compounds for the development of commercial drugs anti-Saprolegnia.

Influencing mechanism of magnolol on expression of BDNF and Bax in rats with cerebral ischemic stroke

The impact of magnolol on cerebral ischemic stroke in rats and the molecular mechanism were explored. Sprague-Dawley rat models were studied. Cerebral indexes, hematoxylin and eosin staining, TUNEL staining assay, reverse transcription-polymerase chain reaction (RT-PCR) and western blotting were applied. The cerebral index in model group was significantly higher than that in sham operation group, and the cerebral index was obviously decreased after magnolol administration. Inflammatory cells accumulated in the brain tissue of rats in the model group. Abundant apoptotic cells were produced in the model group, which was overtly improved after rats were given magnolol. RT-PCR and western blot analysis showed that expression of mRNA and protein of brain-derived neurotrophic factor (BDNF) were distinctly decreased in model group, and increased after rats were given magnolol; while mRNA and protein expression of Bcl-2-associated X protein (Bax) were significantly raised in model group, and reduced after rats were given magnolol. The results showed that there were statistically significant differences in expression of BDNF and Bax among sham operation, model and magnolol administration groups (p<0.01). In conclusion, magnolol can increase the expression of BDNF and decrease the expression of Bax, thereby inhibiting apoptosis to protect the nerves, and magnolol can improve cerebral ischemic stroke in rats.

Dietary polyphenols and their roles in fat browning

Discovery of the presence of brown adipose tissue (BAT) in newborn babies and adult humans, especially constitutively active brown fat or inducible beige fat, has led to the investigation of strategies employing BAT aimed at the development of novel therapeutic avenues for combating obesity and diabetes. Such antiobesity therapeutic tools include pharmaceutical and nutraceutical dietary polyphenols. Although there have been emerging notable advances in knowledge of and an increased amount of research related to brown and beige adipocyte developmental lineages and transcriptional regulators, current knowledge regarding whether and how food factors and environmental modifiers of BAT influence thermogenesis has not been extensively investigated. Therefore, in this review, we summarized recent updates on the exploration of dietary polyphenols while paying attention to the activation of BAT and thermogenesis. Specifically, we summarized findings pertaining to BAT metabolism, white adipose tissue (WAT) browning and thermogenic function of polyphenols (e.g., flavan-3-ols, green tea catechins, resveratrol, capsaicin/capsinoids, curcumin, thymol, chrysin, quercetin and berberine) that may foster a relatively safe and effective therapeutic option to improve metabolic health. We also deciphered the underlying proposed mechanisms through which these dietary polyphenols facilitate BAT activity and WAT browning. Characterization of thermogenic dietary factors may offer novel insight enabling revision of nutritional intervention strategies aimed at obesity and diabetes prevention and management. Moreover, identification of polyphenolic dietary factors among plant-derived natural compounds may provide information that facilitates nutritional intervention strategies against obesity, diabetes and metabolic syndrome.

Improved oral bioavailability of magnolol by using a binary mixed micelle system

The aim of this study was to prepare two novel magnolol (MO)-loaded binary mixed micelles (MO-M) using biocompatible copolymers of Soluplus (SOL) and Solutol^® HS15 (HS15), SOL and d-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS), to improve magnolol's poor solubility and its oral bioavailability. The organic solvent evaporation method was used to obtain two MO-M by optimization; one was prepared by using SOL and HS15 (MO-H), and the other was prepared by using SOL and TPGS (MO-T). The entrapment efficiency (EE%) and drug loading (DL%) of MO-T were 94.61 ± 0.91% and 4.03 ± 0.19%, respectively, and the MO-H has higher EE% and DL% (98.37 ± 1.23%, 4.12 ± 0.16%). TEM results showed that the morphology of MO-M was homogeneous and was spherical in shape. The dilution stability of MO-M did not undergo significant changes. Permeability of MO-M across a Caco-2 cell monolayer was enhanced in Caco-2 cell transport models. The pharmacokinetics study showed that the relative oral bioavailability of MO-T and MO-H increased by 2.39- and 2.98-fold, respectively, compared to that of raw MO. This indicated that MO-H and MO-T could promote absorption of MO in the gastrointestinal tract. Collectively, the mixed micelles demonstrated greater efficacy as a drug delivery system. The development of these novel mixed micelles is valuable for resolving the poor solubility and bioavailability of drugs.