Inhibitory Effects of Heartwood Extracts of Broussonetia kazinoki Sieb on the Development of Atopic Dermatitis in NC/Nga Mice

Anti-Inflammatory Herbal Extracts and Their Drug Discovery Perspective in Atopic Dermatitis

Atopic dermatitis (AD) is an allergic disorder characterized by skin inflammation. It is well known that the activation of various inflammatory cells and the generation of inflammatory molecules are closely linked to the development of AD. There is accumulating evidence demonstrating the beneficial effects of herbal extracts (HEs) on the regulation of inflammatory response in both in vitro and in vivo studies of AD. This review summarizes the anti-atopic effects of HEs and its associated underlying mechanisms, with a brief introduction of in vitro and in vivo experiment models of AD based on previous and recent studies. Thus, this review confirms the utility of HEs for AD therapy.

Comprehensive Review on Phytoconstituents-based Nanomedicine for the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is known as a chronic disease characterized by eczematous and pruritus skin lesions. The pathology behind atopic dermatitis etiology is loss of epidermal barrier, which prevents the production of protein filaggrin that can induce T-cell infiltration and inflammation. Treatment of AD is majorly based on limiting skin repair as well as reducing inflammation and itching. There are several remedies available for the treatment of AD, such as Janus kinase and calcineurin inhibitors, topical corticosteroids, and phosphodiesterase-4 inhibitors. The conventional formulations in the market have limited safety and efficacy. Hence, effective treatment of atopic dermatitis requires the development of novel, efficacious, reliable, and specific therapies. Recent research data have revealed that some naturally occurring medicinal plants have potential applications in the management of AD through different mechanisms. The nanotechnology-based therapeutics have gained a lot of attention in the last decade for the improvement in the activity of drugs having low absorption due to poor solubility, thus leading to lesser bioavailability. Therapies based on nanotechnology can be an effective way to overcome these obstacles. Due to their effective propensity to provide better drug diffusion and bioavailability as well as drug targeting potential at the desired site of action, these approaches may have decreased adverse drug effects, better penetration, and enhanced therapeutic efficacy. Hence, this review highlights the potential of phytoconstituents-based novel formulations for the treatment of atopic dermatitis. Furthermore, recent patents on therapeutic approaches to atopic dermatitis have also been briefly described.

CTLA-4 suppresses hapten-induced contact hypersensitivity in atopic dermatitis model mice

Atopic dermatitis (AD) patients with skin barrier dysfunction are considered to be at a higher risk of allergic contact dermatitis (ACD), although previous studies showed that attenuated ACD responses to strong sensitizers in AD patients compared to healthy controls. However, the mechanisms of ACD response attenuation in AD patients are unclear. Therefore, using the contact hypersensitivity (CHS) mouse model, this study explored the differences in CHS responses to hapten sensitization between NC/Nga mice with or without AD induction (i.e., non-AD and AD mice, respectively). In this study, ear swelling and hapten-specific T cell proliferation were significantly lower in AD than in non-AD mice. Moreover, we examined the T cells expressing cytotoxic T lymphocyte antigen-4 (CTLA-4), which is known to suppress T cell activation, and found a higher frequency of CTLA-4⁺ regulatory T cells in draining lymph node cells in AD than in non-AD mice. Furthermore, the blockade of CTLA-4 using a monoclonal antibody eliminated the difference in ear swelling between non-AD and AD mice. These findings suggested that CTLA-4⁺T cells may contribute to suppressing the CHS responses in AD mice.

The Genus Broussonetia: An Updated Review of Phytochemistry, Pharmacology and Applications

The Broussonetia genus (Moraceae), recognized for its value in many Chinese traditional herbs, mainly includes Broussonetia papyrifera (L.) L’Hér. ex Vent. (BP), Broussonetia kazinoki Siebold (BK), and Broussonetia luzonica (Blanco) Bureau (BL). Hitherto, researchers have found 338 compounds isolated from BP, BK, and BL, which included flavonoids, polyphenols, phenylpropanoids, alkaloids, terpenoids, steroids, and others. Moreover, its active compounds and extracts have exhibited a variety of pharmacological effects such as antitumor, antioxidant, anti-inflammatory, antidiabetic, anti-obesity, antibacterial, and antiviral properties, and its use against skin wrinkles. In this review, the phytochemistry and pharmacology of Broussonetia are updated systematically, after its applications are first summarized. In addition, this review also discusses the limitations of investigations and the potential direction of Broussonetia. This review can help to further understand the phytochemistry, pharmacology, and other applications of Broussonetia, which paves the way for future research.

Microbial Transformation and Biological Activities of the Prenylated Aromatic Compounds from Broussonetia kazinoki

Broussonetia kazinoki has been used as a traditional medicine for the treatment of burns and acne, and its extracts have been found to show tyrosinase inhibitory and anticancer activities. In this study, the tyrosinase inhibitory and cytotoxic activities of B. kazinoki were explored, leading to the isolation of kazinol C (1), kazinol E (2), kazinol F (3), broussonol N (4), and kazinol X (5), of which the compounds 4 and 5 have not been previously reported. Microbial transformation has been recognized as an efficient tool to generate more active metabolites. Microbial transformation of the major compounds 1 and 3 was conducted with Mucor hiemalis, where four glucosylated metabolites (6-9) were produced from 1, while one hydroxylated (10) and one glucosylated (11) metabolites were obtained from 3. Structures of the isolated metabolites were determined by extensive spectroscopic analyses. All compounds were evaluated for their tyrosinase inhibitory and cytotoxic activities. Compound 3 and its metabolites, kazinol Y (10) and kazinol F-4″-O-β-d-glucopyranoside (11), exhibited the most potent tyrosinase inhibitory activities with the IC₅₀ values ranging from 0.71 to 3.36 µM. Meanwhile, none of the metabolites, except for kazinol C-2',3″-di-O-β-d-glucopyranoside (7), showed moderate cytotoxic activities (IC₅₀ 17.80 to 24.22 µM) against A375P, B16F10 and B16F1 cell lines.

Alleviation effects of Rubus coreanus Miquel root extract on skin symptoms and inflammation in chronic atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin disease characterized by chronic inflammatory dermatitis with immunological manifestations. The aim of this study was to investigate the effects of polyphenol-containing Rubus coreanus Miquel root extract on skin allergy and AD. The protective effects of R. coreanus root ethanol extract against AD were investigated using the human keratinocyte cell line HaCaT, human mast cell line HMC-1, and the 2,4-dinitrochlorobenzene (DNCB)-induced AD-like skin NC/Nga mouse model. Treatment with R. coreanus root ethanol extracts reduced β-hexosaminidase and histamine release from HMC-1 cells stimulated with compound 48/80 compared to treatment with R. coreanus fruit ethanol extract. Furthermore, topical application of R. coreanus root ethanol extract dramatically reduced the severity of skin symptoms and the thickening and swelling of the dorsal skin and ear in DNCB-treated NC/Nga mice. The protein and mRNA expression of several cytokines (IL-4, IL-5, IL-12, IFN-γ, TNF-α, and TARC) and IgE was significantly lowered upon application of the R. coreanus root ethanol extract. The promising candidate for the active ingredient of R. coreanus root polyphenols was revealed to be ellagic acid. These findings clearly indicate that the R. coreanus root polyphenols show strong anti-allergic effects and suppress the symptoms of AD. Therefore, polyphenol-containing R. coreanus root ethanol extract could be a novel therapeutic candidate for the treatment of allergy and AD.

Atopic dermatitis: new insight into the etiology, pathogenesis, diagnosis and novel treatment strategies

Atopic dermatitis (AD) is the long-lasting chronic inflammatory skin condition associated with cutaneous hyper-reactivity and triggered by environmental factors. The attributes of AD include dry skin, pruritus, lichenification and frequent eczematous abrasions. This has a strong heritable aspect and typically occurs with asthma and allergic rhinitis. The complex pathological mechanism behind AD etiology is epidermal barrier destruction resulting in the lack of filaggrin protein that can induce inflammation and T-cell infiltration. T-helper 2 cell-mediated pathways also bear the responsibility of damage to the epidermal barrier. Certain causative factors for AD include microbial imbalance of skin microbiota, immunoglobulin-E-induced sensitization and neuro-inflammation. Numerous beneficial topical and oral treatments have been available to patients and there are even more drugs in the pipeline for the treatment of AD. Topical moisturizers, corticosteroids, anti-inflammatory agents such as calcineurin inhibitors, phototherapy, cAMP-specific 3, 5 half-cyclic phosphodiesterase 4 inhibitors and systemic immunosuppressants are widely available for AD treatments. Different positions and pathways inside the immune system including JAK-STAT, phosphodiesterase 4, aryl hydrocarbon receptor and T-helper 2 cytokines are targeted by above-mentioned drug treatments. Instead of the severe side effects of topical steroids and oral antihistamines, herbal plants and their derived phytoconstituents are commonly used for the treatment of AD. A clear understanding of AD's cellular and molecular pathogenesis through substantial advancement in genetics, skin immunology and psychological factors resulted in advancement of AD management. Therefore, the review highlights the recent advancements in the understanding of clinical features, etiology, pathogenesis, treatment and management and non-adherence to AD treatment.

The formulae and biologically active ingredients of Chinese herbal medicines for the treatment of atopic dermatitis

Atopic dermatitis (AD) is a common relapsing inflammatory skin disease characterized by severe pruritus that seriously affects the quality of patients' life. There is an increasingly large amount of research demonstrating that traditional Chinese medicine (TCM) including herbal formulae and bioactive ingredients exerts pharmacological effects on atopic dermatitis. It has been a long history of TCM being used to treat atopic dermatitis, especially in preventing disease recurrence, maintaining long-term remission, and reducing disease burden. Nowadays, both of TCM monomer preparations and traditional formulae are still widely used. This review focuses on TCM as well as its bioactive ingredients for the treatment of AD, from the perspectives of animal model construction, pharmacodynamic mechanisms and clinical studies of formulae. To be more specific, the regulation and molecular mechanisms of the herbal formulae and bioactive ingredients of TCM are investigated, and the latest clinical research on TCM formulae is discussed. Furthermore, it provides a summary of the strengths and utilities of TCM, and will be useful for doctors who use Chinese medicine for treatment or researchers who select candidates for clinical treatments or further high-quality clinical studies.

Prenylated Polyphenols from Broussonetia kazinoki as Inhibitors of Nitric Oxide Production

Excessive nitric oxide (NO) production by macrophages has been involved in inflammatory diseases. Seven polyphenols (1–7) were isolated from Broussonetia kazinoki (B. kazinoki) and investigated as potential inhibitors of NO overproduction in lipopolysaccharide (LPS)-activated RAW 264.7 cells. Among them, four prenylated polyphenols (2–4 and 6) with a catechol moiety efficiently suppressed the LPS-induced high level of NO with IC₅₀ values of less than 6 µM. The compounds 2–4 and 6 also attenuated protein and mRNA levels of inducible nitric oxide synthase (iNOS). Moreover, they suppressed the nuclear factor κB (NF-κB) activity by inhibiting the degradation of inhibitory-κB-α (I-κB-α) and the translocation of NF-κB into the nucleus in LPS-activated macrophages. Taken together, these findings suggest that polyphenols from B. kazinoki might be beneficial for treatment of inflammatory diseases.

Health benefit of fucosterol from marine algae: a review

Seaweeds belong to a group of marine plants known as algae, which are consumed as sea vegetables in several Asian countries. Recent studies have focused on the biological and pharmacological activities of seaweeds and their highly bioactive secondary metabolites because of their potential in the development of new pharmaceutical agents. Although several varieties of bioactive novel compounds such as phlorotannins, diterpenes and polysaccharides from seaweeds have already been well scrutinized, fucosterol as a phytosterol still needs to reinvent itself. Fucosterol (24-ethylidene cholesterol) is a sterol that can be isolated from algae, seaweed and diatoms. Fucosterol exhibits various biological therapeutics, including anticancer, antidiabetic, antioxidant, hepatoprotective, antihyperlipidemic, antifungal, antihistaminic, anticholinergic, antiadipogenic, antiphotodamaging, anti-osteoporotic, blood cholesterol reducing, blood vessel thrombosis preventive and butyrylcholinesterase inhibitory activities. In this review, we address some potential approaches for arbitrating novel fucosterol biologics in the medical field, focusing on the selection of personalized drug candidates and highlighting the challenges and opportunities regarding medical breakthroughs. We also highlight recent advances made in the design of this novel compound, as the significant health benefits from using these optimized applications apply to the nutraceutical and pharmaceutical fields.

Molecular targets of quercetin with anti-inflammatory properties in atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin disease. Over the past few decades, AD has become more prevalent worldwide. Quercetin, a naturally occurring polyphenol, shows antioxidant, anti-inflammatory, and antiallergic activities. Several recent clinical and preclinical findings suggest quercetin as a promising natural treatment for inflammatory skin diseases. Significant progress in elucidating the molecular mechanisms underlying the anti-AD properties of quercetin has been achieved in the recent years. Here, we discuss the use of quercetin as treatment for AD, with a particular focus on the molecular basis of its effect. We also briefly discuss the approaches to improve the bioavailability of quercetin.

Herbal Medicines Prevent the Development of Atopic Dermatitis by Multiple Mechanisms

Atopic dermatitis (AD) is among the most common skin disorders in humans. Although a variety of regimens are available for the treatment of AD, preventive approaches are limited. Recent studies have demonstrated that certain naturally-occurring herbal medicines are effective in preventing the development of AD via divergent mechanisms, such as inhibiting cytokine and chemokine expression, IgE production, inflammatory cell infiltration, histamine release, and/or enhancement of epidermal permeability barrier function. Yet, they exhibit few adverse effects. Since herbal medicines are widely available, inexpensive and generally safe, they could represent an ideal approach for preventing the development of AD, in both highly developed and developing countries.

The Genome-Wide Expression Profile of Saussurea lappa Extract on House Dust Mite-Induced Atopic Dermatitis in Nc/Nga Mice

Saussurea lappa has been reported to possess anti-atopic properties. In this study, we have confirmed the S. lappa's anti-atopic properties in Nc/Nga mice and investigated the candidate gene related with its properties using microarray. We determined the target gene using real time PCR in in vitro experiment. S. lappa showed the significant reduction in atopic dermatitis (AD) score and immunoglobulin E compared with the AD induced Nc/Nga mice. In the results of microarray using back skin obtained from animals, we found that S. lappa's properties are closely associated with cytokine-cytokine receptor interaction and the JAK-STAT signaling pathway. Consistent with the microarray data, real-time RT-PCR confirmed these modulation at the mRNA level in skin tissues from S. lappa-treated mice. Among these genes, PI3Kca and IL20Rβ were significantly downregulated by S. lappa treatment in Nc/Nga mouse model. In in vitro experiment using HaCaT cells, we found that the S. lappa components, including alantolactone, caryophyllene, costic acid, costunolide and dehydrocostus lactone significantly decreased the expression of PI3Kca but not IL20Rβ in vitro. Therefore, our study suggests that PI3Kca-related signaling is closely related with the protective effects of S. lappa against the development of atopic-dermatitis.

Kazinol-P from Broussonetia kazinoki enhances skeletal muscle differentiation via p38MAPK and MyoD

The activation of MyoD family transcription factors is critical for myogenic differentiation, which is fundamental to the regeneration of skeletal muscle after injury. Kazinol-P (KP) from Broussonetia kazinoki (B. kazinoki), a natural compound, has been reported to possess an anti-oxidant function. In a screen of natural compounds for agonists of the MyoD activity, we identified KP and examined its effect on myoblast differentiation. Consistently, KP enhanced the myotube formation, accompanied with upregulation of myogenic markers such as MHC, Myogenin and Troponin-T. KP treatment in C2C12 myoblasts led to strong activation of a key promyogenic kinase p38MAPK in a dose, and time-dependent manner. Furthermore, KP treatment enhanced the MyoD-mediated trans-differentiation of 10T1/2 fibroblasts into myoblasts. Taken together, KP promotes myogenic differentiation through activation of p38MAPK and MyoD transcription activities. Thus KP may be a potential therapeutic candidate to prevent fibrosis and improve muscle regeneration and repair.

Broussonetia kazinoki modulates the expression of VEGFR-2 and MMP-2 through the inhibition of ERK, Akt and p70S6K‑dependent signaling pathways: Its implication in endothelial cell proliferation, migration and tubular formation

Broussonetia kazinoki (BK) has been used as a traditional medicine to improve vision, as well as for inflammatory and infectious diseases. In the present study, we investigated the effects and molecular mechanism of the ethanolic extract of BK on cell proliferation, migration and tubular formation in vascular endothelial growth factor-A (VEGF-A)-treated human umbilical vein endothelial cells. BK treatment inhibited VEGF-A-stimulated endothelial cell proliferation through the downregulation of cell cycle-related proteins including cyclin-dependent kinases and cyclins. Moreover, BK treatment suppressed cell migration and tubular formation in response to VEGF-A. These anti-angiogenic activities of BK were associated with the inactivation of mitogenic signaling pathways including extracellular signal-regulated kinase, Akt and p70S6K, and the subsequent downregulation of VEGFR-2 and matrix metalloproteinase-2. Taken together, these findings suggest further evaluation and development of BK as a potential therapeutic agent for the treatment and prevention of angiogenesis-related diseases including cancer.

Topical herbal application in the management of atopic dermatitis: a review of animal studies

Herbs are widely used in the treatment of atopic dermatitis (AD) in Eastern Asian countries, and certain herbs regarded have anti-inflammatory properties that can help with AD. With the goal of developing a topical herbal agent for AD, we conducted a systematic review of in vivo studies of AD-like skin models for screening potential herbs. Searches were conducted from PubMed and EMBASE. After all, 22 studies were included for this review. We judged most of the domains of all studies to be at unclear risk of bias. Among 22 included studies, 21 herbs have been reported to reduce AD-like skin lesions in mouse models by suppressing Th2 cell response. Our findings may offer potential herbs for the topical application treatment of AD.

Morus alba L. suppresses the development of atopic dermatitis induced by the house dust mite in NC/Nga mice

BACKGROUND

Morus alba, a medicinal plant in Asia, has been used traditionally to treat diabetes mellitus and hypoglycemia. However, the effects of M. alba extract (MAE) on atopic dermatitis have not been verified scientifically. We investigated the effects of MAE on atopic dermatitis through in vitro and in vivo experiments.

METHODS

We evaluated the effects of MAE on the production of nitric oxide (NO) and prostaglandin E2 (PGE2) in RAW 264.7, as well as thymus and activation-regulated chemokine (TARC/CCL17) in HaCaT cells. In an in vivo experiment, atopic dermatitis was induced by topical application of house dust mites for four weeks, and the protective effects of MAE were investigated by measuring the severity of the skin reaction on the back and ears, the plasma levels of immunoglobulin E (IgE) and histamine, and histopathological changes in the skin on the back and ears.

RESULTS

MAE suppressed the production of NO and PGE2 in RAW 264.7 cells, as well as TARC in HaCaT cells, in a dose-dependent manner. MAE treatment of NC/Nga mice reduced the severity of dermatitis and the plasma levels of IgE and histamine. MAE also reduced the histological manifestations of atopic dermatitis-like skin lesions such as erosion, hyperplasia of the epidermis and dermis, and inflammatory cell infiltration in the skin on the back and ears.

CONCLUSION

Our results suggest that MAE has potent inhibitory effects on atopic dermatitis-like lesion and may be a beneficial natural resource for the treatment of atopic dermatitis.

Saussurea lappa alleviates inflammatory chemokine production in HaCaT cells and house dust mite-induced atopic-like dermatitis in Nc/Nga mice

Saussurea lappa is a traditional herbal medicine used for to treat various inflammatory diseases. In this study, we investigated the protective effects of S. lappa against atopic dermatitis using human keratinocyte HaCaT cells, murine mast cell line MC/9 cells, and a house dust mite-induced atopic dermatitis model of Nc/Nga mice. Treatment with the S. lappa caused a significant reduction in the mRNA levels and production of inflammatory chemokines and cytokine, including thymus- and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC), regulated on activation, normal T-cell expressed and secreted (RANTES), and interleukin-8 (IL-8) in tumor necrosis factor-α/interferone-γ-stimulated HaCaT cells. S. lappa exhibited the significant reduction in histamine production in MC/9 cells. In the atopic dermatitis model, S. lappa significantly reduced the dermatitis score and serum IgE and TARC levels. In addition, the back skin and ears of S. lappa-treated Nc/Nga mice exhibited reduced histological manifestations of atopic skin lesions such as erosion, hyperplasia of the epidermis and dermis, and inflammatory cell infiltration. In conclusion, an extract of S. lappa effectively suppressed the development of atopic dermatitis, which was closely related to the reduction of chemokines and cytokine. Our study suggests that S. lappa may be a potential treatment for atopic dermatitis.

Topical application of an ethanol extract prepared from Illicium verum suppresses atopic dermatitis in NC/Nga mice

ETHNOPHARMACOLOGICAL RELEVANCE

Illicium verum is a traditional herbal medicine with anti-inflammatory properties used in Asia. However, its usefulness in the treatment of allergic diseases remains unclear. This study evaluated the anti-inflammatory and antiallergic effects of I. verum extract (IVE) in a mouse model of atopic dermatitis.

MATERIALS AND METHODS

We investigated the effects of IVE on compound 48/80-induced histamine release, and phorbol 12-myristate13-acetate and calcium ionophore A23187-stimulated cytokines secretion in MC/9 mast cells. Atopic dermatitis was induced in NC/Nga mice by exposure to extract of house dust mite (Dermatophagoides farinae). After a topical application of IVE on ear and skin lesions, we evaluated the severity of skin symptoms, ear thickness, inflammatory cell infiltration, and serum levels of immunoglobulin E (IgE), histamine, interleukin (IL)-6, and intercellular adhesion molecule (ICAM)-1. In addition, we determined the expression of IL-4, IL-6, tumor necrosis factor (TNF)-α, interferon (IFN)-γ thymus- and activation-regulated chemokine (TARC), regulated on activation, normal T cell expressed and secreted (RANTES), ICAM-1, and vascular cell adhesion molecule (VCAM)-1 in ear tissues.

RESULTS

IVE inhibited secretion of histamine, IL-4, IL-6, and TNF-α from mast cells in a dose-dependent manner. Topical application of IVE significantly reduced dermatitis scores, ear thickness, and serum levels of IgE, histamine, IL-6, and ICAM-1. Histopathological analysis demonstrated decreased epidermal thickening and dermal infiltration by inflammatory cells. In the ear lesions, IVE treatment reduced expression of IL-4, IL-6, TNF-α, TARC, RANTES, ICAM-1, and VCAM-1, but not IFN-γ.

CONCLUSIONS

These results indicate that IVE inhibits atopic dermatitis-like skin lesions by suppressing the expression of cytokines, chemokines, and adhesion molecules. These results suggest that IVE may be a potential therapeutic candidate for atopic dermatitis.

Effect of Alpinia katsumadai Hayata on House Dust Mite-Induced Atopic Dermatitis in NC/Nga Mice

We evaluated the effects of Alpinia katsumadai Hayata (AKH, Zingiberaceae) extract on the production of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) in RAW 264.7 cells, thymus- and-activation-regulated chemokine (TARC/CCL17) in HaCaT cells, and histamine level in HMC-1 cells. In an in vivo experiment, atopic dermatitis was induced by topical application of house dust mites for 4 weeks, and the protective effects of AKH was investigated by measuring the severity of the skin reaction on the back and ears, and plasma levels of immunoglobulin E (IgE) and histamine. AKH extract suppressed the production of NO and PGE(2) in RAW 264.7 cells, TARC in HaCaT cells, and histamine in HMC-1 cells in a dose-dependent manner. In in vivo experiments, the severity of dermatitis, including erythema/hemorrhage, edema, erosion and scaling, and plasma levels of IgE, and histamine were lower in NC/Nga mice with atopic dermatitis, treated with AKH extract than in untreated mice. AKH extract reduced the histological manifestations of atopic dermatitis-like skin lesions such as erosion, hyperplasia of the epidermis and dermis, and inflammatory cell infiltration on the skin of the back and ear. These results suggest that AKH inhibits the development of house dust mite-induced atopic dermatitis in NC/Nga mice.

Enhanced antioxidant effect of prenylated polyphenols as Fyn inhibitor

Polyphenols have antioxidant effects. In view of the diverse biological activities of prenylated natural products, this study investigated whether polyphenols with prenyl residues have improved antioxidant and cytoprotective activity against oxidative stress, and explored the underlying basis for this effect. A set of structurally related polyphenols exhibited varying degrees of antioxidant effect in HepG2 cells, as evidenced by increases in cell viability against oxidative injury; kazinol E and C with three prenyls had greater potency than other kazinols having fewer prenyl chains. Polyphenols without prenyl (tupichinol C and resveratrol) showed weaker potency. Treatment with kazinol E diminished H(2)O(2) production and enabled cells to protect the mitochondria, as indicated by the inhibition of mitochondrial fragmentation, mitochondrial permeability transition, and cytochrome c release. Moreover, kazinol E activated LKB1 by its phosphorylation and cytoplasmic translocation, contributing to the protection of mitochondria via AMPK. In vitro or in a cell-based assay, tyrosine phosphorylation of Fyn was prohibited by kazinol E, which led to LKB1 activation, as shown by the experiments using Fyn over-expression construct or siRNA. SU6656, a known Fyn inhibitor, had a similar effect. Moreover, oxidative stress facilitated Fyn phosphorylation with repression of AMPKα and GSK3β phosphorylation, which was abolished by kazinol E treatment. The role of Fyn inhibition by kazinol E in AMPK-mediated protection of the cell viability and mitochondrial function was strengthened by ectopically expressed Fyn's reversal of these effects. In conclusion, kazinols as multi-prenylated polyphenols possess increased antioxidant and cytoprotective activity, which depends on the activation of LKB1-AMPK pathway downstream of Fyn inhibition.