Effect of Ethanol Extracts of Three Chinese Medicinal Plants With Anti-diarrheal Properties on Ion Transport of the Rat Intestinal Epithelia

Deciphering the pharmacological mechanisms of Fraxini Cortex for ulcerative colitis treatment based on network pharmacology and in vivo studies

BACKGROUND

Ulcerative colitis (UC) is a common type of inflammatory bowel disease. Due to the elusive pathogenesis, safe and effective treatment strategies are still lacking. Fraxini Cortex (FC) has been widely used as a medicinal herb to treat some diseases. However, the pharmacological mechanisms of FC for UC treatment are still unclear.

METHODS

An integrated platform combining network pharmacology and experimental studies was introduced to decipher the mechanism of FC against UC. The active compounds, therapeutic targets, and the molecular mechanism of action were acquired by network pharmacology, and the interaction between the compounds and target proteins were verified by molecular docking. Dextran sulfate sodium (DSS)-induced colitis model was employed to assess the therapeutic effect of FC on UC, and validate the molecular mechanisms of action predicted by network pharmacology.

RESULTS

A total of 20 bioactive compounds were retrieved, and 115 targets were predicted by using the online databases. Ursolic acid, fraxetin, beta-sitosterol, and esculetin were identified as the main active compounds of FC against UC. PPI network analysis identified 28 FC-UC hub genes that were mainly enriched in the IL-17 signaling pathway, the TNF signaling pathway, and pathways in cancer. Molecular docking confirmed that the active compounds had high binding affinities to the predicted target proteins. GEO dataset analysis showed that these target genes were highly expressed in the UC clinical samples compared with that in the healthy controls. Experimental studies showed that FC alleviated DSS-induced colitis symptoms, reduced inflammatory cytokines release, and suppressed the expression levels of IL1β, COX2, MMP3, IL-17 and RORγt in colon tissues.

CONCLUSION

FC exhibits anti-UC properties through regulating multi-targets and multi-pathways with multi-components. In vivo results demonstrated that FC alleviated DSS-induced colitis.

Chemical diversity, biological activities and Traditional uses of and important Chinese herb Sophora

BACKGROUND

Sophora flavescens Aiton (SF), also known as Kushen (Chinese:), has been an important species in Chinese medicine since the Qin and Han dynasties. It is also recognized as a plant resource suitable for the globalization of Chinese medicine. Traditionally, it has been used in various ethnic medical systems in East Asia, especially in China, to kill insects and dispel dampness. Sophora flavescens is commonly used for clearing heat-clearing, killing worms, and diuretic. Nowdays, accumulating studies demonstrated its anticancer and cardioprotection.

OBJECTIVE OF THE REVIEW

This paper aims to systematically review information on the genus, pharmacological and toxicological significance, chemical composition and biological activity of Sophora flavescens. To promoting its development and application. To summarize recent findings regarding to the metabolism, pharmacological/toxicological effects of Sophora flavescens.

MATERIAL AND METHODS

Online academic databases (including PubMed, Google Scholar, Web of Science and CNKI) were searched using search terms of "Sophora flavescens Aiton", "Ku shen", "Pharmacology", "Active ingredient", "Toxicology" and combinations to include published studies of Sophora flavescens Aiton primarily from 1970-2021. Several critical previous studies beyond this period were also included and other related terms.

CONCLUSION

Sophora flavescens has a broad spectrum of biological activities associated with Sophora flavescens has been considered a valuable resource in both traditional and modern medicine. However, there is a lack of in-depth studies on the medicinal uses of Sophora flavescens. Moreover, further studies on single chemical components should be conducted based on the diversity of chemical structures, significant biological activities and clinical applications. The discovery of its bioactive molecules and multi-component interactions would be of great importance for the clinical application of Sophora flavescens spp. Detailed pharmacological and toxicological studies on the classic prescriptions of Sophora flavescens are also needed. It is more beneficial to the wide application of SF plant and facilitates the worldwide promotion of modern Chinese medicine. However, an increasing number of reports indicate that the administration of Sophora flavescens has serious adverse effects. Its main toxic effects are neurotoxicity and acute toxicity, which have caused widespread concern worldwide. In addition, the alkaloids of Sophora flavescens are distributed in the heart, liver, stomach and large intestine. They are excreted from the body through gluconeogenesis, which is the mode of action of certain therapeutic mechanisms of action such as anticancer. The detailed metabolic study of alkaloids and other components of Sophora flavescens in vivo needs to be further investigated. It is important to improve the pharmacological effects and reduce the toxicity of Sophora flavescens. For this purpose, structural modification of active components of Sophora flavescens or combination with other drugs is very essential.

Regulation of Electrolyte Permeability by Herbal Monomers in Edematous Disorders

Edema is a gradual accumulation of fluid in the interstitial tissues or luminal cavities, which is regulated by ion transport pathways and reflects dysfunction of fluid and salt homeostasis. Increasing evidence suggests that some herbal monomers significantly reduce organ/tissue edema. In this review, we briefly summarized the electrolyte permeability involved in pathomechanisms of organ edema, and the benefits of herbal monomers on ionic transport machinery, including Na+-K+-ATPase, Na+ and Cl- channels, Na+-K+-2Cl- co-transporter, etc. Pharmaceutical relevance is implicated in developing advanced strategies to mitigate edematous disorders. In conclusion, the natural herbal monomers regulate electrolyte permeability in many edematous disorders, and further basic and clinical studies are needed.

Fraxetin prevented sodium fluoride-induced chronic pancreatitis in rats: Role of anti-inflammatory, antioxidant, antifibrotic and anti-apoptotic activities

Chronic pancreatitis is considered a common gastrointestinal disorder, with significant morbidity and mortality. Fluoride is an important agent for the development of our body systems, especially for bone and teeth, however on its excess consumption, it deposits in different body tissues, especially the pancreas, causing its chronic inflammation and destruction. Fraxetin proved to possess versatile activities including; antioxidant, anti-inflammatory, antifibrotic, and anti-apoptotic activities. In the present study, we have evaluated the fraxetin potentiality to prevent fluoride-induced chronic pancreatitis in rats, by evaluating animal body weights and body weight gain rate, serum amylase, and lipase activities, pancreatic oxidative stress markers, cytokines, apoptotic markers, myeloperoxidase, and hydroxyproline levels, and histopathological changes. Nine-weeks-old male Wistar rats drank distilled water containing 500 ppm sodium fluoride (NaF) for 60 days to induce chronic pancreatitis. Oral fraxetin (20, 40, and 80 mg/kg/day) received simultaneously to prevent chronic pancreatitis development. Fraxetin in a dose-dependent manner alleviated chronic pancreatitis induced by NaF, as it restored the decreased body weight and weight gain rate, decreased the elevated serum amylase and lipase activities, pancreatic IL-6, TNF-α, MDA, caspase-3, MPO and hydroxyproline levels, and Bax/Bcl-2 ratio, enhanced pancreatic CAT and SOD activities, and GSH levels, besides it augmented the elevated IL-10 level, with the restoration of normal pancreatic architecture. Therefore, fraxetin could be a promising agent recommended for the prevention of fluoride-induced chronic pancreatitis in endemic areas.

New Pyrimidinone-Fused 1,4-Naphthoquinone Derivatives Inhibit the Growth of Drug Resistant Oral Bacteria

Background: Dental caries is considered to be a preventable disease, and various antimicrobial agents have been developed for the prevention of dental disease. However, many bacteria show resistance to existing agents. Methods/Principal Findings: In this study, four known 1,4-naphthoquinones and newly synthesized 10 pyrimidinone-fused 1,4-naphthoquinones, i.e. KHQ 701, 702, 711, 712, 713, 714, 715, 716, 717 and 718, were evaluated for antimicrobial activity against Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis, Actinomyces viscosus and Fusobacterium nucleatum. Pyrimidinone-fused 1,4-naphthoquinones were synthesized in good yields through a series of chemical reactions from a commercially available 1,4-dihydroxynaphthoic acid. MIC values of KHQ 711, 712, 713, 714, 715, 716, 717 and 718 were 6.25–50 μg/mL against E. faecalis (CCARM 5511), 6.25–25 μg/mL against E. faecium (KACC11954) and S. aureus (CCARM 3506), 1.56–25 μg/mL against S. epidermidis (KACC 13234), 3.125–100 μg/mL against S. mutans (KACC16833), 1.56–100 μg/mL against S. sobrinus (KCTC5809) and P. gingivalis (KCTC 5352), 3.125–50 μg/mL against A. viscosus (KCTC 9146) and 3.125–12.5 μg/mL against F. nucleatum (KCTC 2640) with a broth microdilution assay. A disk diffusion assay with KHQ derivatives also exhibited strong susceptibility with inhibition zones of 0.96 to 1.2 cm in size against P. gingivalis. Among the 10 compounds evaluated, KHQ 711, 712, 713, 715, 716 and 717 demonstrated strong antimicrobial activities against the 9 types of pathogenic oral bacteria. A pyrimidin-4-one moiety comprising a phenyl group at the C2 position and a benzyl group at the N3 position appears to be essential for physiological activity. Conclusion/Significance: Pyrimidinone-fused 1,4-naphthoquinones synthesized from simple starting compounds and four known 1,4-naphthoquinones were synthesized and showed strong antibacterial activity to the 9 common oral bacteria. These results suggest that these derivatives should be prospective for the treatment of dental diseases caused by oral bacteria, including drug-resistant strains.

Fraxinus: A Plant with Versatile Pharmacological and Biological Activities

Fraxinus, a member of the Oleaceae family, commonly known as ash tree is found in northeast Asia, north America, east and western France, China, northern areas of Pakistan, India, and Afghanistan. Chemical constituents of Fraxinus plant include various secoiridoids, phenylethanoids, flavonoids, coumarins, and lignans; therefore, it is considered as a plant with versatile biological and pharmacological activities. Its tremendous range of pharmacotherapeutic properties has been well documented including anticancer, anti-inflammatory, antioxidant, antimicrobial, and neuroprotective. In addition, its bioactive phytochemicals and secondary metabolites can be effectively used in cosmetic industry and as a competent antiaging agent. Fraxinus presents pharmacological effectiveness by targeting the novel targets in several pathological conditions, which provide a spacious therapeutic time window. Our aim is to update the scientific research community with recent endeavors with specifically highlighting the mechanism of action in different diseases. This potentially efficacious pharmacological drug candidate should be used for new drug discovery in future. This review suggests that this plant has extremely important medicinal utilization but further supporting studies and scientific experimentations are mandatory to determine its specific intracellular targets and site of action to completely figure out its pharmacological applications.

Crotonis Fructus Extract Inhibits 12-O-Tetradecanoylphorbol-13-Acetate-Induced Expression of Matrix Metalloproteinase-9 via the Activator Protein-1 Pathway in MCF-7 Cells

Purpose

Metastatic cancers spread from the primary site of origin to other parts of the body. Matrix metalloproteinase-9 (MMP-9) is essential in metastatic cancers owing to its major role in cancer cell invasion. Crotonis fructus (CF), the mature fruits of Croton tiglium L., have been used for the treatment of gastrointestinal disturbance in Asia. In this study, the effect of the ethanol extract of CF (CFE) on MMP-9 activity and the invasion of 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated MCF-7 cells was examined.

Methods

The cell viability was evaluated using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The expression of MMP-9 was examined by Western blotting, zymography, and real-time polymerase chain reaction. An electrophoretic mobility gel shift assay was performed to detect activator protein-1 (AP-1) DNA binding activity and cell invasiveness was measured by an in vitro Matrigel invasion assay.

Results

CFE significantly suppressed MMP-9 expression and activation in a dose-dependent manner. Furthermore, CFE attenuated the TPA-induced activation of AP-1.

Conclusion

The results indicated that the inhibitory effects of CFE against TPA-induced MMP-9 expression and MCF-7 cell invasion were dependent on the protein kinase C δ/p38/c-Jun N-terminal kinase/AP-1 pathway. Therefore, CFE could restrict breast cancer invasiveness owing to its ability to inhibit MMP-9 activity.

Poor permeability and absorption affect the activity of four alkaloids from Coptis

Coptidis rhizoma (Coptis) and its alkaloids exert various pharmacological functions in cells and tissues; however, the oral absorption of these alkaloids requires further elucidation. The present study aimed to examine the mechanism underlying the poor absorption of alkaloids, including berberine (BER), coptisine (COP), palmatine (PAL) and jatrorrhizine (JAT). An ultra‑performance liquid chromatography (UPLC) method was validated for the determination of BER, COP, PAL and JAT in the above experimental medium. In addition, the apparent oil‑water partition coefficient (Po/w); apparent permeability coefficient (Papp), determined using a parallel artificial membrane permeability assay (PAMPA) plate; membrane retention coefficient (R %); and effect of P‑glycoprotein (P‑gp) inhibitor on the Papp of the four alkaloids were investigated. The intestinal absorption rate constant (Ka) and absorption percentage (A %) of the four alkaloids were also determined. The results of the present study demonstrated that the Po/w of the four alkaloids in 0.1 mol·l‑1 HCl medium was significantly higher (P<0.01), compared with those of the alkaloids in phosphate buffer (pH 7.4). The Papp of BER was 1.0‑1.2x10‑6 cm·s‑1, determined using a PAMPA plate, and the Papp of BER, COP, PAL and JAT decreased sequentially. The concentrations of the four alkaloids on the apical‑to‑basolateral (AP‑BL) surface and the basolateral‑to‑apical (BL‑AP) surface increased in a linear manner, with increasing concentrations between 10 and 100 µmol. In addition, the transportation of BER on the BL‑AP surface was significantly faster (P<0.01), compared with that on the AP‑BL surface and, following the addition of verpamil (a P‑gp inhibitor), the Papp (AP‑BL) of the four alkaloids increased, whereas the Papp (BL‑AP) was significantly decreased (P<0.01). The rat intestinal perfusion experiment demonstrated that the four alkaloids were poorly absorbed; however, the Ka of BER was significantly higher, compared with the three other alkaloids. Furthermore, the A % and Ka provided evidence that the absorption of BER was increased in the jejunum, compared with in the ileum. In conclusion, the four alkaloids from Coptis appeared to be poorly absorbed, determined using a shake flask, pre‑coated PAMPA plates, a Caco‑2 cell monolayer model and intestinal perfusion; however, absorption was higher in the jejunum than in the ileum. Among the four alkaloids, the permeability of BER was markedly higher than the others, and P‑gp efflux had a significant effect on the absorption of those alkaloids.

Sophora flavescens Ait.: Traditional usage, phytochemistry and pharmacology of an important traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Sophora flavescens (Fabaceae), also known as Kushen (Chinese: ), has been an important species in Chinese medicine since the Qin and Han dynasties. The root of Sophora flavescens has a long history in the traditional medicine of many countries, including China, Japan, Korea, India and some countries in Europe. In traditional Chinese medicine (TCM), Sophora flavescens has been used extensively, mainly in combination with other medicinal plants in prescriptions to treat fever, dysentery, hematochezia, jaundice, oliguria, vulvar swelling, asthma, eczema, inflammatory disorders, ulcers and diseases associated with skin burns. The aim of this review is to provide updated and comprehensive information regarding the botany, ethnopharmacology, phytochemistry, biological activities and toxicology of Sophora flavescens and to discuss possible trends and opportunities for further research on Sophora flavescens.

MATERIALS AND METHODS

We systematically searched major scientific databases (PubMed, Elsevier, SpringerLink, Google Scholar, Medline Plus, ACS, "Da Yi Yi Xue Sou Suo (http://www.dayi100.com/login.jsp)", China Knowledge Resource Integrated (CNKI) and Web of Science) for information published between 1958 and 2015 on Sophora flavescens. Information was also acquired from local classic herbal literature, conference papers, government reports, and PhD and MSc dissertations.

RESULTS

The broad spectrum of biological activities associated with Sophora flavescens has been considered a valuable resource in both traditional and modern medicine. Extracts are taken either orally or by injection. More than 200 compounds have been isolated from Sophora flavescens, and the major components have been identified as flavonoids and alkaloids. Recent in vitro and in vivo studies indicate that at least 50 pure compounds and crude extracts from Sophora flavescens possess wide-ranging antitumor, antimicrobial, antipyretic, antinociceptive, and anti-inflammatory pharmacological abilities. The anticancer and anti-infection abilities of these components are especially attractive areas for research.

CONCLUSIONS

Sophora flavescens is a promising traditional medicine, but there is a need for more precise studies to test the safety and clinical value of its main active crude extracts and pure compounds and to clarify their mechanisms of action. Moreover, some existing studies have lacked systematic methods and integration with the existing literature, and some of the experiments were isolated, used small sample sizes and were unreliable. More validated data are therefore required.

Antiproliferative activity and nitric oxide production of a methanolic extract of Fraxinus micrantha on Michigan Cancer Foundation-7 mammalian breast carcinoma cell line

AIM

Methanolic extract of a Fraxinus micrantha (MeFM) was evaluated for antiproliferative activity in vitro using Michigan Cancer Foundation-7 (MCF-7) breast carcinoma cell line. This plant was selected and studied for naturally available bioactive compound as different synthetic drugs available for cancer treatment has certain limitations and side effects.

MATERIALS AND METHODS

The anti-proliferative activity of a methanolic extract from the aerial parts of F. micrantha was assessed on MCF-7 breast cancer cell line using 3(4,5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide assay. Furthermore, to understand the mechanism of anti-proliferation, production of nitric oxide (NO) and DNA fragmentation was also determined on MCF-7 cells. Different phytoconstituents of the extract were determined qualitatively based on various biochemical assays.

RESULTS

The results demonstrated anti-proliferative activity of an MeFM in a concentration and time-dependent manner. The percentage viability determined was 31.24% at 125 µg/ml as compared to 80.46% in negative control group. An MeFM has also shown NO production in a concentration (0.2-125 µg/ml) and time-dependent manner (24-48 h). DNA fragmentation studies showed that a methanolic extract was causing DNA fragmentation thus inducing apoptosis in MCF-7 breast carcinoma cells. Biochemical analysis result showed the presence of flavonoids, polyphenols, and sterols in an MeFM.

CONCLUSION

In conclusion, F. micrantha possesses potent anti-proliferative activity on the malignant MCF-7 cell line which is correlated with the production of NO and DNA fragmentation. Further studies are required to identify, isolate, and characterize the phytochemicals present in the methanolic extract that might have antiproliferative potential in the treatment of different cancer conditions.

Crotonis Fructus and Its Constituent, Croton Oil, Stimulate Lipolysis in OP9 Adipocytes

Introduction. Crotonis fructus (CF) is the mature fruit of Croton tiglium L. and has been used for the treatment of gastrointestinal disturbance in Asia. It is well known that the main component of CF is croton oil (CO). The present study is to investigate the effects of CF extracts (CFE) and CO on lipolysis in OP9 adipocytes. Methods. Glycerol release to the culture supernatants was used as a marker of adipocyte lipolysis. Results. Treatment with various concentrations of CFE and CO stimulates glycerol release in a dose-dependent manner. The increase in glycerol release by CFE is more potent than isoproterenol, which is a β-adrenergic agonist as a positive control in our system. The increased lipolysis by CFE and CO was accompanied by an increase of phosphorylated hormone sensitive lipase (pHSL) but not nonphosphorylated HSL protein and mRNA. Pretreatment with H89, which is a protein kinase A inhibitor, significantly abolished the CFE- and CO-induced glycerol release in OP9 adipocytes. These results suggest that CFE and CO may be a candidate for the development of a lipolysis-stimulating agent in adipocytes.

Glucosylated Sesquiterpene Alcohols from Fraxinus griffithii

Phytochemical investigation of the leaves of Fraxinus griffithii has led to the isolation of two new glucosylated acyclic sesquiterpene alcohols, griffithosides D (1) and E (2), along with iridoid and secoiridoid glycosides. The molecular structures of these compounds were elucidated using NMR, MS and other spectroscopic techniques, as well as comparison with literature data. The isolated compounds were tested for radical-scavenging activity and cytotoxicity against A549 human lung adenocarcinoma cells and Leishmania major parasites.

The mechanism of vasorelaxation induced by ethanol extract of Sophora flavescens in rat aorta

AIM OF THE STUDY

Sophora flavescens (SF) is a known medicinal herb for the treatment of cardiovascular symptoms associated with arrhythmia in China. However, the pharmacological action mechanisms involved have not been well studied. The aim of the present study was to define effects of roots of SF on the vascular tension and responsible mechanisms in rat thoracic aorta.

MATERIALS AND METHODS

Ethanol extract of the roots of SF (ESF) was examined for their vascular relaxant effect in isolated phenylephrine-precontracted rat thoracic aorta.

RESULTS

ESF (0.1-100 μg/ml) induced relaxation of the phenylephrine-precontracted aortic rings in a concentration-dependent manner. Endothelium-denudation abolished the ESF-induced vasorelaxation. Pretreatment of the endothelium-intact aortic rings with l-NAME, an inhibitor of nitric oxide synthase, and ODQ, an inhibitor of soluble guanylyl cyclase (sGC), inhibited ESF-induced vasorelaxation. ESF increased cGMP levels of the aortic rings in a concentration-dependent manner and the effect was blocked by l-NAME and ODQ. Inhibition of K(+) channels with glibenclamide and tetraethylammonium, cyclooxygenase inhibition with indomethacin, and β-adrenergic and muscarinic receptors blockade had no effect on the ESF-induced vasorelaxation.

CONCLUSION

These findings suggest that ESF relaxes vascular smooth muscle via endothelium-dependent NO-sGC-cGMP signaling pathway.

Antibacterial activity of sophoraflavanone G isolated from the roots of Sophora flavescens against methicillin-resistant Staphylococcus aureus

In this study, sophoraflavanone G obtained from Sophora flavescens was evaluated against 10 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA), either alone or in combination with ampicillin or oxacillin, via checkerboard assay. At the end point of an optically clear well, the minimum inhibitory concentrations (MICs) ranged from 0.5 to 8 microg/ml for sophoraflavanone G, from 64 to 1024 microg/ml for ampicillin, and from 256 to 1024 microg/ml for oxacillin. The combination of sophoraflavanone G and ampicillin or oxacillin yielded a fractional inhibitory concentration index ranging from 0.188 to 0.375, thereby indicating a principally synergistic effect. The synergistic interaction was verified by time-kill studies using sophoraflavanone G and/or antibiotics. Thirty minutes of treatment with sophoraflavanone G with ampicillin or oxacillin resulted in an increase in the rate of killing in units of CFU/ml to a greater degree than was observed with Sophoraflavanone G alone. These findings indicated that the application of the tested sophoraflavanone G alone or in combination with antibiotics might prove useful in the control and treatment of MRSA infections.

Identification of E. dysenterica laxative peptide: a novel strategy in the treatment of chronic constipation and irritable bowel syndrome

Plants have contributed over the years to the discovery of various pharmacological products. Amongst the enormous diversity of herbs with remarkable medicinal use and further pharmacological potential, here in this report we evaluated pulp extracts from Eugenia dysenterica fruits and further identified the active principle involved in such laxative activity in rats. For protein isolation, fruits were macerated with an extraction solution following precipitation with (NH(4))(2)SO(4) (100%). After dialysis, the peptide was applied onto a reversed-phase semi-preparative HPLC column, and the major fraction was eluted with 26% and 66% acetonitrile. The evaluation of molecular masses by MALDI-TOF and Tris/Tricine SDS-PAGE of HPLC fractions showed the presence of a major peptide with approximately 7 kDa. The N-terminal amino acid peptide sequence was determined and showed no similarity to other proteins deposited in the Data Bank. Peptide from E. dysenterica was able to enhance rats' intestinal motility by approximately 20.8%, probably being responsible for laxative activity. Moreover, these proteins were non-toxic to mammals, as observed in histopathology and hemolytic analyses. In conclusion, results here reported indicate that, in the near future, proteins synthesized by E. dysenterica fruits could be utilized in the development of novel biotechnological pharmaceutics with laxative properties for use in chronic constipation and irritable bowel syndrome treatment.

Kujin suppresses histamine signaling at the transcriptional level in toluene 2,4-diisocyanate-sensitized rats

Kujin, the dried root of Sophorae flavescensis, has been used in Chinese folklore medicine against allergy. Evaluation of its anti-allergic potential as well as its mechanism of action has rarely been established. We investigated the effect of Kujin on toluene-2,4-diisocyanate (TDI)-induced allergic behavior and related histamine signaling including mRNA levels of histamine H(1) receptor (H1R) and histidine decarboxylase (HDC), H1R and HDC activities, and histamine content in rat nasal mucosa. We also investigated the effect of Kujin on the mRNA levels of helper T cell type 2 (Th2)-cytokine genes closely related to histamine signaling. TDI provocation caused acute allergic symptoms accompanied with up-regulations of H1R and HDC mRNAs and increases in HDC activity, histamine content, and [(3)H]mepyramine binding activity in the nasal mucosa, all of which were significantly suppressed by pretreatment with Kujin for 3 weeks. Kujin also suppressed the TDI-induced IL-4 and IL-5 mRNA elevations. These data suggest that oral administration of Kujin showed anti-allergic activity through suppression of histamine signaling by the inhibition of TDI-induced H1R and HDC mRNA elevations followed by decrease in H1R, HDC protein level, and histamine content in the nasal mucosa of TDI-sensitized rats. Suppression of Th2-cytokine signaling by Kujin also suggests that it could affect the histamine-cytokine network.