A ternary correlation multi-symptom network strategy based on in vivo chemical profile identification and metabolomics to explore the molecular basis of Ephedra herb against viral pneumonia.

Ephedra herb (EH), an important medicine prescribed in herbal formulas by Traditional Chinese Medicine practitioners, has been widely used in the treatment of viral pneumonia in China. However, the molecular basis of EH in viral pneumonia remains unclear. In this study, a ternary correlation multi-symptom network strategy was established based on in vivo chemical profile identification and metabolomics to explore the molecular basis of EH against viral pneumonia. Results showed that 143 compounds of EH and 70 prototype components were identified in vivo. EH could reduce alveolar-capillary barrier disruption in rats with viral pneumonia and significantly downregulate the expression of inflammatory factors and bronchoalveolar lavage fluid. Plasma metabolomics revealed that EH may be involved in the regulation of arachidonic acid, tryptophan, tyrosine, nicotinate, and nicotinamide metabolism. The multi-symptom network showed that 12 compounds have an integral function in the treatment of viral pneumonia by intervening in many pathways related to viruses, immunity and inflammation, and lung injury. Further verification demonstrated that sinapic acid and frambinone can regulate the expression of related genes. It has been shown to be a promising representative of the pharmacological constituents of ephedra.

Mechanistic insights into targeting caspase-3 activation and alveolar macrophage pyroptosis by Ephedra and bitter almond compounds for treating pediatric pneumonia via network pharmacology and bioinformatics.

This study investigates the molecular mechanism of Ma Huang-Ku Xing Ren, a traditional Chinese medicine formula, in treating pediatric pneumonia. The focus is on the regulation of caspase-3 activation and reduction of alveolar macrophage necrosis through network pharmacology and bioinformatics analyses of Ephedra and bitter almond components. Active compounds and targets from ephedrine and bitter almond were obtained using TCMSP, TCMID, and GeneCards databases, identifying pediatric pneumonia-related genes. A protein-protein interaction (PPI) network was constructed, and core targets were screened. GO and KEGG pathway enrichment analyses identified relevant genes and pathways. An acute pneumonia mouse model was created using the lipopolysaccharide (LPS) inhalation method, with caspase-3 overexpression induced by a lentivirus. The mice were treated with Ephedra and bitter almond through gastric lavage. Lung tissue damage, inflammatory markers (IL-18 and IL-1ß), and cell death-related gene activation were assessed through H&E staining, ELISA, western blot, flow cytometry, and immunofluorescence. The study identified 128 active compounds and 121 gene targets from Ephedra and bitter almond. The PPI network revealed 13 core proteins, and pathway analysis indicated involvement in inflammation, apoptosis, and cell necrosis, particularly the caspase-3 pathway. In vivo results showed that Ephedra and bitter almond treatment significantly mitigated LPS-induced lung injury in mice, reducing lung injury scores and inflammatory marker levels. It also decreased caspase-3 activity and cell death in alveolar macrophages. In conclusion, the active ingredients of Ma Huang-Ku Xing Ren, particularly targeting caspase-3, may effectively treat pediatric pneumonia by reducing apoptosis in alveolar macrophages, as demonstrated by both network pharmacology, bioinformatics analyses, and experimental data.

Ephedra intermedia Schrenk & C. A. Mey Methanol Extract: Nanoencapsulation by Mini-Emulsion Polymerization and its Release Trend under Simulated Conditions of the Human Body.

In this research, the extract of Ephedra intermedia Schrenk & C.A.Mey. was encapsulated using the mini-emulsion polymerization method based on methyl methacrylate polymers with a nanometer size. The encapsulated extract was characterized using different analytical techniques. Furthermore, the loading efficiency and release of the plant extract were examined. FT-IR spectroscopy confirmed the formation of an expectational product. The TEM and SEM imaging showed a spherical morphology for the prepared encapsulated extract. The average size of poly-methyl-methacrylate nanoparticles containing Ephedra extract was found to be approximately 47 nm. The extract loading efficiency and encapsulation efficiency test demonstrated a dose-depending behavior on E. intermedia extract for both analyses, which is highly advantageous for traversing biological barriers. The release assay shows a controlled release for the extract at phosphate buffer solution (PBS). A 38 % release was calculated after 36 hours. The results obtained from the present study reveal that encapsulating the plant extract is a suitable alternative to control and increase their medicinal properties.

Five new compounds from the stems of Ephedra equisetina.

Five new compounds were identified from the stems of Ephedra equisetina Bunge. Their structures were elucidated by spectroscopic methods, involving UV, IR, NMR spectrum and HRESIMS analyses. The absolute configuration of compound 2 was proved by comparing their experimental and calculated ECD spectrum. The vitro bioactive assay of all compounds suggested that compound 1, 3, 4, 5 and 6 may have potential anti-asthmatic activities.

Flavonoids and phenols from the stems of Ephedra equisetina.

Twelve undescribed compounds, including five flavonoids and seven phenols, were isolated from the stems of Ephedra equisetina Bunge. Their structures were elucidated by spectroscopic methods, including NMR spectroscopy and HRESIMS analysis. Their absolute configurations were elucidated by comparing their experimental and calculated ECD spectra. In the in vitro bioactive assay, all compounds were tested for their anti-asthmatic activities by releasing ß-Hex in C48/80-induced RBL-2H3 cells. The ß-Hex release rates of compounds 3, 8, 10, and 11 were 0.8502 ± 0.0231, 0.8802 ± 0.0805, 0.7850 ± 0.0593, and 0.8361 ± 0.0728, respectively, suggesting that compounds 3, 8, 10, and 11 have potential anti-asthmatic activities.

A Modified 1H-NMR Quantification Method of Ephedrine Alkaloids in Ephedrae Herba Samples.

A previous 1H-NMR method allowed the quantification of ephedrine alkaloids; however, there were some disadvantages. The cyclized derivatives resulted from the impurities of diethyl ether were identified and benzene was selected as the better extraction solvent. The locations of ephedrine alkaloids were confirmed with 2D NMR. Therefore, a specific 1H-NMR method has been modified for the quantification of ephedrine alkaloids. Accordingly, twenty Ephedrae Herba samples could be classified into three classes: (I) E. sinica-like species; (II) E. intermedia-like species; (III) others (lower alkaloid contents). The results indicated that ephedrine and pseudoephedrine are the major alkaloids in Ephedra plants, but the concentrations vary greatly determined by the plant species and the collection locations.

Comparative pharmacokinetic studies of Ephedra herba in common cold and nephrotic syndrome rat models.

Ephedra herba is a conventional Chinese medicine to treat cold, fever, asthma, edema, and lung diseases in the clinic. At present, most pharmacokinetic studies focus on the pharmacokinetic process of alkaloids in normal animals. However, the non-alkaloid components are also active. In addition, the pharmacokinetic studies under pathological state make more sense for clarifying the material basis of efficacy. In this study, a sensitive and rapid ultra-high-performance-tandem mass spectrometry method was developed and applied to determine nine bioactive components (ephedrine, pseudoephedrine, methylephedrine, (+)-catechin, epicatechin, vitexin, vicenin-2, cinnamic acid, and ferulic acid) in normal, common cold and nephrotic syndrome rats after the oral administration of Ephedra herba. Compared to the normal group, except for ferulic acid, the exposure levels of the other eight components were significantly increased and the plasma clearance clearly declined in common cold rats. Similarly, the exposure levels of seven components other than cinnamic acid and ferulic acid were also significantly augmented and the plasma clearance decreased significantly in nephrotic syndrome rats. In brief, the pathological conditions of the common cold and nephrotic syndrome could lead to alterations in the pharmacokinetics profiles of the nine components, which provide a reference for further exploration of the pharmacodynamics basis of Ephedra herba.

Phytochemical Screening, Antioxidant Potential, and LC-ESI-MS Profiling of Ephedra alata and Ephedra altissima Seeds Naturally Growing in Tunisia.

Most Ephedra species are adapted to arid and desert conditions and are widely used in folk medicine to treat several disorders. The design of the current study was to determine the functional properties of seeds of two Ephedra species (E. alata and E. altissima) naturally growing in Tunisian arid zones by evaluating their mineral contents and bioactive compounds. The flame atomic absorption spectrometry revealed that seeds contained remarkable amounts of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), and iron (Fe). The colorimetric investigation revealed high total polyphenol, flavonoid, and condensed tannin contents. Furthermore, by utilizing high-performance liquid chromatography-electrospray ionization-mass spectrometry method (HPLC-ESI/MS), a total of 11 phenolics were identified and quantified including 7 flavonoid compounds and 4 phenolic acids that were mostly predominated by gallic acid and quercetrin. Results so far have been very encouraging and proved that Ephedra seeds are a valuable source of natural bioactive compounds and minerals which could potentially be used for industrial and pharmaceutical purposes.

Ephedrae Herba: A Review of Its Phytochemistry, Pharmacology, Clinical Application, and Alkaloid Toxicity.

Ephedrae Herba (Ephedra), known as "MaHuang" in China, is the dried straw stem that is associated with the lung and urinary bladder meridians. At present, more than 60 species of Ephedra plants have been identified, which contain more than 100 compounds, including alkaloids, flavonoids, tannins, sugars, and organic phenolic acids. This herb has long been used to treat asthma, liver disease, skin disease, and other diseases, and has shown unique efficacy in the treatment of COVID-19 infection. Because alkaloids are the main components causing toxicity, the safety of Ephedra must be considered. However, the nonalkaloid components of Ephedra can be effectively used to replace ephedrine extracts to treat some diseases, and reasonable use can ensure the safety of Ephedra. We reviewed the phytochemistry, pharmacology, clinical application, and alkaloid toxicity of Ephedra, and describe prospects for its future development to facilitate the development of Ephedra.

Ephedrae herba: A comprehensive review of its traditional uses, phytochemistry, pharmacology, and toxicology.

ETHNOPHARMACOLOGICAL RELEVANCE: Ephedrae herba (called Mahuang in China) is the dried herbaceous stem of Ephedra sinica Stapf, Ephedra intermedia Schrenk et C. A. Mey., and Ephedra equisetina Bge. Ephedrae herba has a long history of use as an herb, and it was originally recorded in Sheng Nong's herbal classic. Ephedrae herba has also been widely used as both medicine and food. In the clinic, Ephedrae herba is commonly used for treating colds, bronchial asthma, nasal congestion, and other diseases. AIM OF REVIEW: This review aims to provide a systematic summary on the traditional use, chemical constituents, pharmacological effects, clinical applications, quality control, toxicology, and pharmacokinetics of Ephedrae herba to provide a theoretical basis for further reasonable development of Ephedrae herba in clinical practice and creation of new drugs. MATERIALS AND METHODS: Information on Ephedrae herba was gathered from various sources, including the scientific databases including CNKI, PubMed, SciFinder and ScienceDirect, classical books on traditional Chinese herbal medicine, Ph.D. and M.Sc. dissertations; Baidu Scholar; and from different professional websites. RESULTS: Ephedrae herba is distributed in regions of China and other areas. Ephedra and its compound preparations can be used for colds, bronchial asthma, nasal congestion and other diseases. Approximately 281 chemical constituents have been isolated from Ephedrae herba, including alkaloids, flavonoids, tannins, polysaccharides, volatile oils, organic acids, and other compounds. Among these constituents, alkaloids and volatile oils are the most abundant and represent the major bioactive constituents. Ephedrae herba possesses multiple pharmacological activities, including diuretic effect, anti-allergic effect, blood pressure regulatory, anti-inflammatory effect, anti-oxidation effect and anti-viral effects. Ephedrine hydrochloride and pseudoephedrine hydrochloride are generally selected as indicators for the quantitative determination of Ephedrae herba. The maximum dosage of Ephedrae herba should not exceed 10 g. If overused, adverse reactions such as palpitations, sweating, irritability and insomnia will occur. CONCLUSIONS: Ephedrae herba is an ancient herbal medicine with a broad spectrum of pharmacological activities that has been used for thousands of years in China. It is one of the most commonly used herbal components of the TCM formulas. Hydrochloride and pseudoephedrine are the major bioactive constituents. However, there is a need to further understand the mechanisms of active components of Ephedrae herba. Future studies should perform an in-depth analyses of the pharmacokinetics and mechanisms of toxicity of Ephedrae herba. Quality standards should be developed to correspond to the various application methods to ensure the efficacy of drugs in actual treatment.

Overlooked switch from transient sedation to sustained excitement in the Biphasic effects of Ephedra Herb extract administered orally to mice.

ETHNOPHARMACOLOGICAL RELEVANCE: In our previous study, we reported that Ephedra Herb extract (EHE) increased the locomotor activity of mice in the open-field test and reduced the immobility time in the forced swim test. Ephedrine alkaloids (EAs) are thought to be responsible for the adverse effects of Ephedra Herb. However, there are no reports to verify that the adverse effects of Ephedra Herb are caused by the amount of EAs in the herb. Therefore, we investigated whether these adverse effects of EHE are caused by the amounts of ephedrine (Eph) and pseudoephedrine (Pse) in the herbal extract. In a preliminary study of the time course analysis of the open field test, we newly observed that EHE evoked switching from transient sedation to sustained excitement. AIM OF THE STUDY: We aimed to confirm whether EHE evokes switching from transient sedation to sustained excitement, investigate whether these actions of EHE are caused by the amount of ephedrine (Eph) and pseudoephedrine (Pse) in the herbal extract, and clarify the molecular mechanism of the transient sedative effect. MATERIALS AND METHODS: The locomotor activity of mice was tested using the open-field test. The immobility times were measured using a forced swim test, and the motor dysfunction in mice was tested using the rotarod test. RESULTS: EHE, Eph, and Pse induced transient motionlessness between 0 and 15 min after oral administration, however, they did not induce depression-like behavior and motor dysfunction in mice, suggesting that the motionlessness induced by EHE, Eph, or Pse resulted from sedation. The α2a adrenoceptor inhibitor, atipamezole, decreased their sedative effects. Thus, immediately after EHE administration, the transient sedative effect is mediated through the activation of the α2a adrenoreceptor by Eph and Pse. EHE and Eph increased total locomotor activity for 15-120 min after oral administration; however, Pse had no effect. Therefore, the slow-onset and sustained excitatory effects of EHE are mediated by Eph. CONCLUSIONS: We discovered for the first time that EHE evokes diphasic action by switching from transient sedation to sustained excitement. The transient sedation was evoked by the Eph and Pse in the herbal extract via activation of the α2a adrenoceptor and the sustained excitement was caused by the Eph in the herbal extract.

Lignans and terpenoids from the stem of Ephedra equisetina Bunge.

Seven undescribed lignans, equiselignan A-F, and six undescribed terpenoids, equiseterpenoid A-E (including two pairs of enantiomers, (+/-)-equiselignan A and (+/-)-equiseterpenoid E), were isolated from the stems of Ephedra equisetina Bunge. Their structures were elucidated by spectroscopic methods, and the absolute configurations of the undescribed compounds were determined by interpretation of their electronic circular dichroic (ECD) and optical rotation data. In ß-hexosaminidase (ß-Hex) release assay, anti-asthmatic activities of all of the compounds were evaluated by releasing ß-Hex in C48/80-induced RBL-2H3 cells. The ß-Hex release rates of equiselignan B and equiseterpenoid B were 0.86 ± 0.094 and 0.86 ± 0.012 by comparing with model group, whereupon equiselignan B and equiseterpenoid B exhibited significant anti-asthmatic activities.

A Novel Anticancer Effect of Ephedra alata Decne in Breast Cancer Cells.

Cancer is a class of diseases characterized by uncontrolled cell growth. One of the main aims of developing new therapies is to use natural resources to induce apoptosis. LC-ms/ms analysis of a methanolic extract of Ephedra alata (E.A.) allowed the identification of 20 secondary metabolites, including flavonoids, phenolic acids, and proanthocyanidins. Antiproliferative effect was assessed by crystal violet assay. Antimigration effect was tested by wound healing assay and apoptosis induction was determined by annexin binding assays, Hoechst staining, ROS production, and activation of apoptotic proteins. The results indicated that exposure of breast cancer cells to E.A. extract significantly reduced cell viability in a dose and time-dependent manner and inhibited the migration of 4T1 cells at a low dose. Moreover, treatment of cells with E.A. extract induced apoptosis, as it was detected by Annexin V/7 AAD, Hoechst staining, ROS production, and the activation of caspases.Abbreviation:BSAbovine serum albuminDMSOdimethyl sulfoxideEDTAethylenediaminetetraacetic acidLC-ms/msliquid chromatography-mass spectrometryNACN-acetyl-l-cysteinePARPpoly(ADP-ribose) polymerasePMSFphenylmethylsulfonyl fluorideRIPAradioimmunoprecipitation assay bufferROSreactive oxygen speciesRPMIRoswell park memorial instituteSDS-PAGEsodium dodecyl sulfate-polyacrylamide gel electrophoresis.

HPLC-DAD-ESI/MS profiles of bioactive compounds, antioxidant and anticholinesterase activities of Ephedra alata subsp. alenda growing in Algeria.

Ephedra (Ephedraceae) is used in medicine for various purposes as having, antioxidant, anticarcinogen, antibacterial, anti-inflammatory hepatoprotective, anti-obesity, antiviral and diuretic activities. In this study the aim was to investigate chemical constituents of Ephedra alata and understand the possible effects of those constituents in antioxidant activity and alzheimer's disease essay. For this purpose, natural compounds from E.alata were characterized by LC-DAD-ESI-MS/MS using negative and positive ionization modes, while the bioactivity was assessed by acetylcholinesterase (AChE) inhibition study and determining of antioxidant activity; DPPH radical scavenging and ß-carotene bleaching assays were used to assess the antioxidant potential. The proposed method of spectrometry provided tentative identification of 27 compounds including alkaloids and phenolic compounds as flavonoids. The methanolic extract showed high contents of total phenolic and exhibited an important antioxidant potential and demonstrated a potent inhibitory effect against acetylcholinesterase (IC50: 11,25 ± 0,25 µg/mL). The results showed that the plant possesses a therapeutic effect.

Bioactive Compounds from Ephedra fragilis: Extraction Optimization, Chemical Characterization, Antioxidant and AntiGlycation Activities.

Response surface methodology (RSM) with a Box-Behnken design (BBD) was used to optimize the extraction of bioactive compounds from Ephedra fragilis. The results suggested that extraction with 61.93% ethanol at 44.43 °C for 15.84 h was the best solution for this combination of variables. The crude ethanol extract (CEE) obtained under optimum extraction conditions was sequentially fractionated with solvents of increasing polarity. The content of total phenolic (TP) and total flavonoid (TF) as well as the antioxidant and antiglycation activities were measured. The phytochemical fingerprint profile of the fraction with the highest activity was characterized by using RP-HPLC. The ethyl acetate fraction (EAF) had the highest TP and TF contents and exhibited the most potent antioxidant and antiglycation activities. The Pearson correlation analysis results showed that TP and TF contents were highly significantly correlated with the antioxidant and antiglycation activities. Totally, six compounds were identified in the EAF of E. fragilis, including four phenolic acids and two flavonoids. Additionally, molecular docking analysis also showed the possible connection between identified bioactive compounds and their mechanisms of action. Our results suggest new evidence on the antioxidant and antiglycation activities of E. fragilis bioactive compounds that may be applied in the treatment and prevention of aging and glycation-associated complications.

Antioxidant properties and qualitative analysis of phenolic constituents in Ephedra spp. by HPTLC together with injection port derivatization GC-MS.

Ephedra herb extracts are being extensively investigated in terms of their antioxidative, antimicrobial and antiproliferative properties, with phenolic components being the general carriers of these bioactivities. Here we describe a comprehensive set of analytical methods employed to determine and characterize both the antioxidative activity and the qualitative profile of phenolic acids and flavonoids present in several Ephedra species of different geographical origin. Spectrophotometric methods were used to determine the total phenolic content, total flavonoid content and antioxidative activity. Multi-development HPTLC enabled chemical fingerprinting which can be used for species differentiation. Individual spots of the thin-layer chromatogram were subjected to GC-MS with injection port derivatization for identification, which was based on both the detected mass spectra and recorded retention indices. The results were compared and complemented with GC-MS using offline derivatization.

A Rapid and Feasible 1H-NMR Quantification Method of Ephedrine Alkaloids in Ephedra Herbal Preparations.

A highly specific and sensitive proton nuclear magnetic resonance (1H-NMR) method has been developed for the quantification of ephedrine alkaloid derivatives in Ephedra herbal commercial prescriptions. At the region of δ 4.0 to 5.0 ppm in the 1H NMR spectrum, the characteristic signals are separated well from each other, and six analogues in total, methylephedrine (ME), ephedrine (EP), norephedrine (NE), norpseudoephedrine (NP), pseudoephedrine (PE), and methylpseudoephedrine (MP) could be identified. The quantities of these compounds are calculated by the relative ratio of the integral values of the target peak for each compound to the known concentrations of the internal standard anthracene. The present method allows for a rapid and simple quantification of ephedrine alkaloid derivatives in Ephedra-related commercial prescriptions without any preliminary purification steps and standard compounds, and accordingly it can be a powerful tool to verify different Ephedra species. In comparison to conventional chromatographic methods, the advantages of this method include the fact that no standard compounds are required, the quantification can be directly performed on the crude extracts, a better selectivity for various ephedrine alkaloid derivatives, and the fact that a very significant time-gain may be achieved.

The Antimicrobial, Antioxidant, and Anticancer Activity of Greenly Synthesized Selenium and Zinc Composite Nanoparticles Using Ephedra aphylla Extract.

The current work aimed to synthesize selenium and zinc nanoparticles using the aqueous extract of Ephedra aphylla as a valuable medicinal plant. The prepared nanoparticles were characterized by TEM, zeta potential, and changes in the phytochemical constituents. Hence, the phenolic, flavonoid, and tannin contents were reduced in the case of the prepared samples of nanoparticles than the original values in the aqueous extract. The prepared extract of Ephedra aphylla and its selenium and zinc nanoparticles showed high potency as antioxidant agents as a result of the DPPH• assay. The samples were assessed as anticancer agents against six tumor cells and a normal lung fibroblast (WI-38) cell line. The selenium nanoparticles of Ephedra aphylla extract revealed very strong cytotoxicity against HePG-2 cells (inhibitory concentration (IC50) = 7.56 ± 0.6 µg/mL), HCT-116 cells (IC50 = 10.02 ± 0.9 µg/mL), and HeLa cells (IC50 = 9.23 ± 0.8 µg/mL). The samples were evaluated as antimicrobial agents against bacterial and fungal strains. Thus, selenium nanoparticles showed potent activities against Gram-negative strains (Salmonella typhimurium, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli), Gram-positive strains (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, and Staphylococcus epidermidis), and the fungal strain Candida albicans. In conclusion, the preparation of nanoparticles of either selenium or zinc is crucial for improved biological characteristics.

Inhibitory activity of flavonoids from Ephedrae Herba on hypoxia signaling in PANC-1 cells and the evaluation of their mechanisms.

Pancreatic cancer is a lethal disease with a very poor prognosis. Recent reports indicate that hypoxia signaling mediated by hypoxia-inducible factor (HIF) contributes to the progression of pancreatic cancer. Therefore, elucidating the inhibitor of hypoxia signaling may lead to the development of a candidate for new anticancer agents. During our screening program for HIF inhibitor from crude drug extracts, new acylated kaempferol glycosides, kaempferol 3-O-[4″-(E)-p-coumaroyl-3″-O-dihydroxypalmityl] rhamnoside (1) and kaempferol 3-O-[4″-(E)-p-coumaroyl-2″-O-dihydroxypalmityl] rhamnoside (2), were isolated from an acetone extract of Ephedrae Herba, together with eight known flavonol glycosides (3-10). The structures of novel compounds 1 and 2 were elucidated based on spectroscopic and chemical analyses. Using a cell-based HRE-driven luciferase reporter assay in a PANC-1 pancreatic cancer cell line, we found that these compounds demonstrated potent inhibitory activity on hypoxia signaling with IC50 values of 18.0 ± 0.6 and 13.3 ± 2.2 µM, respectively. Mechanistically, 2 reduced the amount of HIF-1α protein in the nuclear at 30 µM via the ubiquitin-proteasome pathway with no effect on the nuclear translocation of HIF proteins from cytosol and subsequently decreased Glut1 mRNA. These results indicate that 2 inhibits hypoxia signaling through a mechanism involving the reduction of HIF-1α protein levels and Glut1 mRNA and may have anti-pancreatic cancer effects.

Ephedra Herb, Mao, Inhibits Antigen-Induced Mast Cell Degranulation by Induction of the Affinity Receptor for IgE Internalization.

PURPOSE: Ephedra herb (Mao) exerts potent anti-allergic effects. This study aimed to examine the underlying mechanisms of Mao on allergic inflammation using in vitro cultured mast cells (MCs) and an in vivo model of MC-dependent anaphylaxis. METHODS: Bone marrow-derived MCs (BMMCs) were presensitized with anti-2,4-dinitrophenol (DNP) immunoglobulin E (IgE) and challenged with antigens (Ag; DNP-human serum albumin). Degranulation responses and cell surface high-affinity receptor for IgE (FcεRI) expression were assessed with/without Mao treatment. Passive systemic anaphylaxis (PSA)-treated mice were administered Mao and the pathophysiological responses were evaluated. RESULTS: Mao inhibited Ag-induced BMMC degranulation, but not polyclonal activation with phorbol 12-myristate 13-acetate (PMA) and ionomycin, indicating that Mao inhibits IgE-dependent activation of BMMCs. Mao-treated BMMCs exhibited significant reductions in expression of surface IgE and its receptor FcεRI. Analysis of subcellular localization revealed that Mao induces FcεRI internalization in BMMCs without degranulation. In the PSA mouse model, Mao administration prevented antigen-induced hypothermia. Mao administration significantly reduced cell surface expression of IgE-bound FcεRI on peritoneal MCs. CONCLUSIONS: Mao induced FcεRI internalization in MCs, thereby inhibiting Ag-induced IgE-dependent degranulation. The inhibitory effects of Mao on MC degranulation may offer a novel therapeutic approach for allergic diseases.