(S)-3-(3-Fluoro-4-Methoxybenzyl)-5,6,7-Trimethoxychroman-4-One Suppresses the Proliferation of Huh7 Cells by Up-regulating P21 and Inducing G2/M Phase Arrest.

BACKGROUND/AIM: Hepatocellular carcinoma (HCC) is a prevalent type of cancer worldwide. Although sorafenib is the only chemotherapy agent used for HCC, there is a need to discover a more potent anticancer agent with reduced side-effects. The compound, (S)-3-(3-fluoro-4-methoxybenzyl)-5,6,7-trimethoxychroman-4-one (FMTC), was designed to inhibit tubulin assembly but its specific mechanisms of action have not been previously investigated. Herein, we investigated the regulation mechanisms by which FMTC affects the proliferation of the HCC cell line, Huh7. MATERIALS AND METHODS: The effects of FMTC on cell viability and growth were analyzed in the HCC cell line, Huh7. Cell cycle and apoptosis regulated by FMTC were analyzed using flow cytometry. To verify the regulation of mRNA and protein expression of cell proliferation-related factors by FMTC in Huh7 cells, RT-qPCR and western blot analyses were employed. RESULTS: FMTC suppressed cell division dose-dependently by triggering cell cycle arrest at the G2/M phase via p21 up-regulation. The increased phosphorylation of histone H3 on Ser-10 and the condensation of chromatin in FMTC-treated cells indicated mitotic arrest. Prolonged FMTC-induced cell cycle arrest triggered apoptosis. CONCLUSION: FMTC inhibits the proliferation of human liver cancer cells by up-regulating p21, thereby inducing cell cycle arrest at the G2/M phase. These findings highlight FMTC as a novel agent for HCC treatment.

Synthesis of proposed structure of ledebourin A.

Naturally occurring homoisoflavonoids have attracted significant attention in the field of medicinal chemistry due to their potential health benefits and diverse range of biological properties. Recently, C-prenylated homoisoflavonoids, namely ledebourin A, B, and C, were isolated from the bulbs of Ledebouria floribunda and have exhibited potent antioxidant activity. In this study, we successfully synthesized ledebourin A and its regioisomer, compounds 1 and 9. By comparing the NMR spectra of the synthesized compounds with those of reported ledebourin A, we observed discrepancies. Nonetheless, our synthesis and subsequent findings offer valuable insights into the structural revision and biological activities of these unique prenylated homoisoflavonoids. Both synthesized compounds 1 and 9 exhibited no toxicity towards Hep-G2 cells and displayed the ability to recover glyceraldehyde-induced cell death, suggesting their potential as protective agents against liver damage.

Cremastranone-Derived Homoisoflavanes Suppress the Growth of Breast Cancer Cells via Cell Cycle Arrest and Caspase-Independent Cell Death.

Breast cancer is the most common cancer and a frequent cause of cancer-related deaths among women wordlwide. As therapeutic strategies for breast cancer have limitations, novel chemotherapeutic reagents and treatment strategies are needed. In this study, we investigated the anti-cancer effect of synthetic homoisoflavane derivatives of cremastranone on breast cancer cells. Homoisoflavane derivatives, SH-17059 and SH-19021, reduced cell proliferation through G2/M cell cycle arrest and induced caspase-independent cell death. These compounds increased heme oxygenase-1 (HO-1) and 5-aminolevulinic acid synthase 1 (ALAS1), suggesting downregulation of heme. They also induced reactive oxygen species (ROS) generation and lipid peroxidation. Furthermore, they reduced expression of glutathione peroxidase 4 (GPX4). Therefore, we suggest that the SH-17059 and SH-19021 induced the caspase-independent cell death through the accumulation of iron from heme degradation, and the ferroptosis might be one of the potential candidates for caspase-independent cell death.

A small molecule compound that inhibits blue light-induced retinal damage via activation of autophagy.

Dry age-related macular degeneration (AMD) is a type of disease that causes visual impairment due to changes in the macula located in the center of the retina. The accumulation of drusen under the retina is also a characteristic of dry AMD. In this study, we identified a compound (JS-017) that can potentially degrade N-retinylidene-N-retinylethanolamine (A2E), one of the components of lipofuscin, using fluorescence-based screening, which measures A2E degradation in human retinal pigment epithelial cells. JS-017 effectively degraded A2E in ARPE-19 cells and consequently suppressed the activation of the NF-κB signaling pathway and expression of inflammatory and apoptosis genes induced by blue light (BL). Mechanistically, JS-017 induced LC3-II formation and improved autophagic flux in ARPE-19 cells. Additionally, the A2E degradation activity of JS-017 was found to be decreased in autophagy-related 5 protein-depleted ARPE-19 cells, suggesting that autophagy was required for A2E degradation mediated by JS-017. Finally, JS-017 exhibited an improvement in BL-induced retinal damage measured through fundus examination in an in vivo retinal degeneration mouse model. The thickness of the outer nuclear layer and inner/external segments, which was decreased upon exposure to BL irradiation, was also restored upon JS-017 treatment. Altogether, we demonstrated that JS-017 protected human retinal pigment epithelium (RPE) cells from A2E and BL-induced damage by degrading A2E via the activation of autophagy. The results suggest the feasibility of a novel A2E-degrading small molecule as a therapeutic agent for retinal degenerative diseases.

Candesartan, an angiotensin-II receptor blocker, ameliorates insulin resistance and hepatosteatosis by reducing intracellular calcium overload and lipid accumulation.

Insulin resistance is a major contributor to the pathogenesis of several human diseases, including type 2 diabetes, hypertension, and hyperlipidemia. Notably, insulin resistance and hypertension share common abnormalities, including increased oxidative stress, inflammation, and organelle dysfunction. Recently, we showed that excess intracellular Ca2+, a known pathogenic factor in hypertension, acts as a critical negative regulator of insulin signaling by forming Ca2+-phosphoinositides that prevent the membrane localization of AKT, a key serine/threonine kinase signaling molecule. Whether preventing intracellular Ca2+ overload improves insulin sensitivity, however, has not yet been investigated. Here, we show that the antihypertensive agent candesartan, compared with other angiotensin-II receptor blockers, has previously unrecognized beneficial effects on attenuating insulin resistance. We found that candesartan markedly reduced palmitic acid (PA)-induced intracellular Ca2+ overload and lipid accumulation by normalizing dysregulated store-operated channel (SOC)-mediated Ca2+ entry into cells, which alleviated PA-induced insulin resistance by promoting insulin-stimulated AKT membrane localization and increased the phosphorylation of AKT and its downstream substrates. As pharmacological approaches to attenuate intracellular Ca2+ overload in vivo, administering candesartan to obese mice successfully decreased insulin resistance, hepatic steatosis, dyslipidemia, and tissue inflammation by inhibiting dysregulated SOC-mediated Ca2+ entry and ectopic lipid accumulation. The resulting alterations in the phosphorylation of key signaling molecules consequently alleviate impaired insulin signaling by increasing the postprandial membrane localization and phosphorylation of AKT. Thus, our findings provide robust evidence for the pleiotropic contribution of intracellular Ca2+ overload in the pathogenesis of insulin resistance and suggest that there are viable approved drugs that can be repurposed for the treatment of insulin resistance and hypertension.

5-Hydroxytryptophan Reduces Levodopa-Induced Dyskinesia via Regulating AKT/mTOR/S6K and CREB/ΔFosB Signals in a Mouse Model of Parkinson's Disease.

Long-term administration of levodopa (L-DOPA) to patients with Parkinson's disease (PD) commonly results in involuntary dyskinetic movements, as is known for L-DOPA-induced dyskinesia (LID). 5-Hydroxytryptophan (5-HTP) has recently been shown to alleviate LID; however, no biochemical alterations to aberrant excitatory conditions have been revealed yet. In the present study, we aimed to confirm its anti-dyskinetic effect and to discover the unknown molecular mechanisms of action of 5-HTP in LID. We made an LID-induced mouse model through chronic L-DOPA treatment to 6-hydroxydopamine-induced hemi-parkinsonian mice and then administered 5-HTP 60 mg/kg for 15 days orally to LID-induced mice. In addition, we performed behavioral tests and analyzed the histological alterations in the lesioned part of the striatum (ST). Our results showed that 5-HTP significantly suppressed all types of dyskinetic movements (axial, limb, orolingual and locomotive) and its effects were similar to those of amantadine, the only approved drug by Food and Drug Administration. Moreover, 5-HTP did not affect the efficacy of L-DOPA on PD motor manifestations. From a molecular perspective, 5-HTP treatment significantly decreased phosphorylated CREB and ΔFosB expression, commonly known as downstream factors, increased in LID conditions. Furthermore, we found that the effects of 5-HTP were not mediated by dopamine1 receptor (D1)/DARPP32/ERK signaling, but regulated by AKT/mTOR/S6K signaling, which showed different mechanisms with amantadine in the denervated ST. Taken together, 5-HTP alleviates LID by regulating the hyperactivated striatal AKT/mTOR/S6K and CREB/ΔFosB signaling.

Synthesis and Structure Revision of Naturally Occurring Homoisoflavane (+)-Dracaeconolide B.

Dracaeconolide B (1), a naturally occurring homoisoflavane, was isolated from the red resin of Dracaena cochinchinensis. Efforts have been made to elucidate the exact structure of compound 1 since it was confirmed that dracaeconolide B did not contain a 7-hydroxy-5,8-dimethoxy moiety. The structure of dracaeconolide B was revised by synthesis of three homoisoflavanes containing a 5,6,7-trioxygenated moiety each and analysis by NMR spectroscopy. The revised structure of dracaeconolide B was proposed as 3-(4-hydroxybenzyl)-7-hydroxy-5,6-dimethoxychromane. Noyori's Ru-catalyzed asymmetric transfer hydrogenation was used to synthesize (+)-dracaeconolide B. The absolute configuration of the compound was revised to S based on the results obtained by the electronic circular dichroism calculation. We examined the antiangiogenic activity of (S)- and (R)-dracaeconolide B and of synthetic 5,6,7- and 5,7,8-trioxygenated homoisoflavanes. The results can potentially help in the synthesis of related natural products and support drug discovery to treat neovascular eye diseases.

Mouse Pharmacokinetics and In Vitro Metabolism of SH-11037 and SH-11008, Synthetic Homoisoflavonoids for Retinal Neovascularization.

Cremastranone is a member of the homoisoflavanone family with anti-angiogenic activity in the eyes. SH-11037, a potent and selective synthetic homoisoflavonoid derived from cremastranone, was studied here for pharmacokinetics and metabolism characterization with a special focus on esterase-mediated hydrolysis. SH-11037 was shown to be converted rapidly and nearly completely to SH-11008 following an intravenous dose in mice. SH-11008 showed a high systemic clearance well exceeding the hepatic blood flow in mice. Neither SH-11037 nor SH-11008 were detected in plasma following oral administration of SH-11037 and SH-11008 in mice. Carboxylesterase was shown to be responsible for the rapid and quantitative hydrolysis of SH-11037 to SH-11008 in mouse plasma; the hydrolytic bioconversion was much slower in dog and human plasma, with butyrylcholinesterase and paraoxonase 1 likely being responsible. In vitro metabolism studies with liver S9 fractions suggested that SH-11008 was likely to have a high hepatic metabolic clearance with a predicted hepatic extraction ratio close to 1 in both mouse and human. In conclusion, SH-11037 and SH-11008 both appear to possess pharmacokinetic profiles suboptimal as a systemic agent. SH-11008 is suggested to possess a low potential for systemic toxicity suitable as a topical ocular therapeutic agent.

Synthetic Homoisoflavane Derivatives of Cremastranone Suppress Growth of Colorectal Cancer Cells through Cell Cycle Arrest and Induction of Apoptosis.

Colorectal cancer is diagnosed as the third most prevalent cancer; thus, effective therapeutic agents are urgently required. In this study, we synthesized six homoisoflavane derivatives of cremastranone and investigated their cytotoxic effects on the human colorectal cancer cell lines HCT116 and LoVo. We further examined the related mechanisms of action using two of the potent compounds, SH-19027 and SHA-035. They substantially reduced the cell viability and proliferation in a dose-dependent manner. Treatment with SH-19027 and SHA-035 induced cell cycle arrest at the G2/M phase and increased expression of p21 both of which are implicated in cell cycle control. In addition, the apoptotic cell population and apoptosis-associated marker expression were accordingly increased. These results suggest that the synthesized cremastranone derivatives have anticancer effects through the suppression of cell proliferation and induction of apoptosis. Therefore, the synthesized cremastranone derivatives could be applied as novel therapeutic agents against colorectal cancer.

Suppressive effect of α-mangostin for cancer stem cells in colorectal cancer via the Notch pathway.

BACKGROUND: Since colon cancer stem cells (CSCs) play an important role in chemoresistance and in tumor recurrence and metastasis, targeting of CSCs has emerged as a sophisticated strategy for cancer therapy. α-mangostin (αM) has been confirmed to have antiproliferative and apoptotic effects on cancer cells. This study aimed to evaluate the selective inhibition of αM on CSCs in colorectal cancer (CRC) and the suppressive effect on 5-fluorouracil (5-FU)-induced CSCs. METHODS: The cell viability assay was performed to determine the optimal concentration of αM. A sphere forming assay and flow cytometry with CSC markers were carried out to evaluate the αM-mediated inhibition of CSCs. Western blot analysis and quantitative real-time PCR were performed to investigate the effects of αM on the Notch signaling pathway and colon CSCs. The in vivo anticancer efficacy of αM in combination with 5-FU was investigated using a xenograft mouse model. RESULTS: αM inhibited the cell viability and reduced the number of spheres in HT29 and SW620 cells. αM treatment decreased CSCs and suppressed the 5-FU-induced an increase in CSCs on flow cytometry. αM markedly suppressed Notch1, NICD1, and Hes1 in the Notch signaling pathway in a time- and dose-dependent manner. Moreover, αM attenuated CSC markers CD44 and CD133, in a manner similar to that upon DAPT treatment, in HT29 cells. In xenograft mice, the tumor and CSC makers were suppressed in the αM group and in the αM group with 5-FU treatment. CONCLUSION: This study shows that low-dose αM inhibits CSCs in CRC and suppresses 5-FU-induced augmentation of CSCs via the Notch signaling pathway.

Small-molecule inhibitors of ferrochelatase are antiangiogenic agents.

Activity of the heme synthesis enzyme ferrochelatase (FECH) is implicated in multiple diseases. In particular, it is a mediator of neovascularization in the eye and thus an appealing therapeutic target for preventing blindness. However, no drug-like direct FECH inhibitors are known. Here, we set out to identify small-molecule inhibitors of FECH as potential therapeutic leads using a high-throughput screening approach to identify potent inhibitors of FECH activity. A structure-activity relationship study of a class of triazolopyrimidinone hits yielded drug-like FECH inhibitors. These compounds inhibit FECH in cells, bind the active site in cocrystal structures, and are antiangiogenic in multiple in vitro assays. One of these promising compounds was antiangiogenic in vivo in a mouse model of choroidal neovascularization. This foundational work may be the basis for new therapeutic agents to combat not only ocular neovascularization but also other diseases characterized by FECH activity.

Externalized phosphatidylinositides on apoptotic cells are eat-me signals recognized by CD14.

Apoptotic cells are rapidly engulfed and removed by phagocytes after displaying cell surface eat-me signals. Among many phospholipids, only phosphatidylserine (PS) is known to act as an eat-me signal on apoptotic cells. Using unbiased proteomics, we identified externalized phosphatidylinositides (PIPs) as apoptotic eat-me signals recognized by CD14+ phagocytes. Exofacial PIPs on the surfaces of early and late-apoptotic cells were observed in patches and blebs using anti-PI(3,4,5)P3 antibody, AKT- and PLCδ PH-domains, and CD14 protein. Phagocytosis of apoptotic cells was blocked either by masking exofacial PIPs or by CD14 knockout in phagocytes. We further confirmed that exofacial PIP+ thymocytes increased dramatically after in vivo irradiation and that exofacial PIP+ cells represented more significant populations in tissues of Cd14-/- than WT mice, especially after induction of apoptosis. Our findings reveal exofacial PIPs to be previously unknown cell death signals recognized by CD14+ phagocytes.

Inhibitory Effect of Chlorogenic Acid Analogues Comprising Pyridine and Pyrimidine on α-MSH-Stimulated Melanogenesis and Stability of Acyl Analogues in Methanol.

In continuation of studies for α-MSH stimulated melanogenesis inhibitors, we have evaluated the design, synthesis, and activity of a new series of chlorogenic acid (CGA) analogues comprising pyridine, pyrimidine, and diacyl derivatives. Among nineteen synthesized compounds, most of them (fifteen) exhibited better inhibitions of melanin formation in B16 melanoma cells. The results illustrated that a pyridine analogue 6f and a diacyl derivative 13a of CGA showed superior inhibition profiles (IC50: 2.5 ± 0.7 µM and 1.1 ± 0.1 µM, respectively) of α-MSH activities than positive controls, kojic acid and arbutin (IC50: 54 ± 1.5 µM and 380 ± 9.5 µM, respectively). The SAR studies showed that both -CF3 and -Cl groups exhibited better inhibition at the meta position on benzylamine than their ortho and para positions. In addition, the stability of diacyl analogues of CGA in methanol monitored by HPLC for 28 days indicated the steric bulkiness of acyl substituents as a key factor in their stability.

Comparison of Pharmacokinetics and Anti-Pulmonary Fibrosis-Related Effects of Sulforaphane and Sulforaphane N-acetylcysteine.

Sulforaphane (SFN), belonging to the isothiocyanate family, has received attention owing to its beneficial activities, including chemopreventive and antifibrotic effects. As sulforaphane N-acetylcysteine (SFN-NAC), a major sulforaphane metabolite, has presented similar pharmacological activities to those of SFN, it is crucial to simultaneously analyze the pharmacokinetics and activities of SFN and SFN-NAC, to comprehensively elucidate the efficacy of SFN-containing products. Accordingly, the anti-pulmonary fibrotic effects of SFN and SFN-NAC were assessed, with simultaneous evaluation of permeability, metabolic stability, and in vivo pharmacokinetics. Both SFN and SFN-NAC decreased the levels of transforming growth factor-ß1-induced fibronectin, alpha-smooth muscle actin, and collagen, which are major mediators of fibrosis, in MRC-5 fibroblast cells. Regarding pharmacokinetics, SFN and SFN-NAC were metabolically unstable, especially in the plasma. SFN-NAC degraded considerably faster than SFN in plasma, with SFN being formed from SFN-NAC. In rats, SFN and SFN-NAC showed a similar clearance when administered intravenously; however, SFN showed markedly superior absorption when administered orally. Although the plasma SFN-NAC concentration was low owing to poor absorption following oral administration, SFN-NAC was converted to SFN in vivo, as in plasma. Collectively, these data suggest that SFN-NAC could benefit a prodrug formulation strategy, possibly avoiding the gastrointestinal side effects of SFN, and with improved SFN-NAC absorption.

Allyl Isothiocyanate Protects Acetaminophen-Induced Liver Injury via NRF2 Activation by Decreasing Spontaneous Degradation in Hepatocyte.

Acetaminophen (APAP) is one of the most frequently prescribed analgesic and anti-pyretic drugs. However, APAP-induced hepatotoxicity is a major cause of acute liver failure globally. While the therapeutic dose is safe, an overdose of APAP produces an excess of the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), subsequently resulting in hepatotoxicity. Allyl isothiocyanate (AITC), a bioactive molecule in cruciferous plants, is reported to exert various biological effects, including anti-inflammatory, anti-cancer, and anti-microbial effects. Notably, AITC is known for activating nuclear factor erythroid 2-related factor 2 (NRF2), but there is limited evidence supporting the beneficial effects on hepatocytes and liver, where AITC is mainly metabolized. We applied a mouse model in the current study to investigate whether AITC protects the liver against APAP-induced injury, wherein we observed the protective effects of AITC. Furthermore, NRF2 nuclear translocation and the increase of target genes by AITC treatment were confirmed by in vitro experiments. APAP-induced cell damage was attenuated by AITC via an NRF2-dependent manner, and rapid NRF2 activation by AITC was attributed to the elevation of NRF2 stability by decreasing its spontaneous degradation. Moreover, liver tissues from our mouse experiment revealed that AITC increases the expression of heme oxygenase-1 (HO-1), an NRF2 target gene, confirming the potential of AITC as a hepatoprotective agent that induces NRF2 activation. Taken together, our results indicate the potential of AITC as a natural-product-derived NRF2 activator targeting the liver.

Honokiol ameliorates angiotensin II-induced hypertension and endothelial dysfunction by inhibiting HDAC6-mediated cystathionine γ-lyase degradation.

Hypertension and endothelial dysfunction are associated with various cardiovascular diseases. Hydrogen sulphide (H2 S) produced by cystathionine γ-lyase (CSE) promotes vascular relaxation and lowers hypertension. Honokiol (HNK), a natural compound in the Magnolia plant, has been shown to retain multifunctional properties such as anti-oxidative and anti-inflammatory activities. However, a potential role of HNK in regulating CSE and hypertension remains largely unknown. Here, we aimed to demonstrate that HNK co-treatment attenuated the vasoconstriction, hypertension and H2 S reduction caused by angiotensin II (AngII), a well-established inducer of hypertension. We previously found that histone deacetylase 6 (HDAC6) mediates AngII-induced deacetylation of CSE, which facilitates its ubiquitination and proteasomal degradation. Our current results indicated that HNK increased endothelial CSE protein levels by enhancing its stability in a sirtuin-3-independent manner. Notably, HNK could increase CSE acetylation levels by inhibiting HDAC6 catalytic activity, thereby blocking the AngII-induced degradative ubiquitination of CSE. CSE acetylation and ubiquitination occurred mainly on the lysine 73 (K73) residue. Conversely, its mutant (K73R) was resistant to both acetylation and ubiquitination, exhibiting higher protein stability than that of wild-type CSE. Collectively, our findings suggested that HNK treatment protects CSE against HDAC6-mediated degradation and may constitute an alternative for preventing endothelial dysfunction and hypertensive disorders.

SETD1A Promotes Proliferation of Castration-Resistant Prostate Cancer Cells via FOXM1 Transcription.

Androgen deprivation therapy eventually leads to the development of castration-resistant prostate cancer (CRPC). Here, we demonstrate for the first time that the histone H3K4 methyltransferase SETD1A is a major regulator for the proliferation of metastatic CRPC (mCRPC). The expression of SETD1A was significantly correlated with the survival rate of patients with prostate cancer. SETD1A, which is expressed at a higher level in mCRPC than in primary prostate cancer cells, promotes the expression of FOXM1, a gene encoding a cell proliferation-specific transcription factor. SETD1A is recruited to the promoter region of FOXM1 (forkhead box M1) upon binding to E2F1, a protein that regulates the transcription of FOXM1 and contributes to the trimethylation of H3K4 in the FOXM1 promoter region. In addition, SETD1A is essential for the expression of stem cell factor (e.g., OCT4, octamer-binding transcription factor 4) and stem cell formation in mCRPC, suggesting the importance of SETD1A expression in mCRPC tumor formation. Notably, poor prognosis is associated with high expression of the SETD1A-FOXM1 pair in clinical data sets. Therefore, our study suggests that SETD1A plays an important role in the proliferation of mCRPC by regulating FOXM1 transcription.

Total Synthesis of Naturally Occurring 5,7,8-Trioxygenated Homoisoflavonoids.

Homoisoflavonoids are in the subclass of the larger family of flavonoids but have one more alkyl carbon than flavonoids. Among them, 5,7,8-trioxygenated homoisoflavonoids have not been extensively studied for synthesis and biological evaluation. Our current objective is to synthesize 2 5,7,8-trioxygenated chroman-4-ones and 12 5,7,8-trioxygenated homoisoflavonoids that have been isolated from the plants Bellevalia eigii, Drimiopsis maculata, Ledebouria graminifolia, Eucomis autumnalis, Eucomis punctata, Eucomis pallidiflora, Chionodoxa luciliae, Muscari comosum, and Dracaena cochinchinensis. For this purpose, 1,3,4,5-tetramethoxybenzene and 4'-benzyloxy-2',3'-dimethoxy-6'-hydroxyacetophenone were used as starting materials. Asymmetric transfer hydrogenation using Noyori's Ru catalyst provided 5,7,8-trioxygenated-3-benzylchroman-4-ones with R-configuration in high yield and enantiomeric excess. By selective deprotection of homoisoflavonoids using BCl3, the total synthesis of natural products including 10 first syntheses and three asymmetric syntheses has been completed, and three isomers of the reported dracaeconolide B could be provided. Our research on 5,7,8-trioxygenated homoisoflavonoids would be useful for the synthesis of related natural products and pharmacological applications.

SG-SP1 Suppresses Mast Cell-Mediated Allergic Inflammation via Inhibition of FcεRI Signaling.

Background: As the number of allergic disease increases, studies to identify new treatments take on new urgency. Epigallocatechin gallate (EGCG), a major component of green tea, has been shown to possess a wide range of pharmacological properties, including anti-inflammation and anti-viral infection. In previous study, gallic acid (GA), a part of EGCG, has shown anti-allergic inflammatory effect. To improve on preliminary evidence that GA has allergy mitigating effect, we designed SG-SP1 based on GA, and aimed to assess the effects of SG-SP1 on mast cell-mediated allergic inflammation using various animal and in vitro models. Methods: For in vitro experiments, various types of IgE-stimulated mast cells (RBL-2H3: mast cell-like basophilic leukemia cells, and primary cultured peritoneal and bone marrow-derived mast cells) were used to determine the role of SG-SP1 (0.1-1 nM). Immunoglobulin (Ig) E-induced passive cutaneous anaphylaxis and ovalbumin-induced systemic anaphylaxis, standard animal models for immediate-type hypersensitivity were also used. Results: For in vitro, SG-SP1 reduced degranulation of mast cells by down-regulating intracellular calcium levels in a concentration-dependent manner. SG-SP1 decreased expression and secretion of inflammatory cytokines in activated mast cells. This suppressive effect was associated with inhibition of the phosphorylation of Lyn, Syk and Akt, and the nuclear translocation of nuclear factor-κB. Due to the strong inhibitory effect of SG-SP1 on Lyn, the known upstream signaling to FcεRI-dependent pathway, we confirmed the direct binding of SG-SP1 to FcεRI, a high affinity IgE receptor by surface plasmon resonance experiment. Oral administration of SG-SP1 hindered allergic symptoms of both anaphylaxis models evidenced by reduction of hypothermia, serum IgE, ear thickness, and tissue pigmentation. This inhibition was mediated by the reductions in serum histamine and interleukin-4. Conclusions: We determined that SG-SP1 directly interacts with FcεRI and propose SG-SP1 as a therapeutic candidate for mast cell-mediated allergic inflammatory disorders via inhibition of FcεRI signaling.