Dictamnus dasycarpus Turcz. attenuates airway inflammation and mucus hypersecretion by modulating the STAT6-STAT3/FOXA2 pathway

BACKGROUND

Effects of Dictamnus dasycarpus Turcz. on allergic asthma and their underlying mechanisms remain unclarified. Thus, we investigated the effects of D. dasycarpus Turcz. water extract (DDW) on mucus hypersecretion in mice with ovalbumin (OVA)-induced asthma and human bronchial epithelial cells.

METHODS

BALB/c mice were used to establish an OVA-induced allergic asthma model. Mice were grouped into the OVA sensitization/challenge, 100 and 300 mg/kg DDW treatment, and dexamethasone groups. In mice, cell counts in bronchoalveolar lavage fluid (BALF), serum and BALF analyses, and histopathological lung tissue analyses were performed. Furthermore, we confirmed the basic mechanism in interleukin (IL)-4/IL-13-treated human bronchial epithelial cells through western blotting.

RESULTS

In OVA-induced asthma mice, DDW treatment reduced inflammatory cell number and airway hyperresponsiveness and ameliorated histological changes (immune cell infiltration, mucus secretion, and collagen deposition) in lung tissues and serum total immunoglobulin E levels. DDW treatment lowered BALF IL-4, IL-5, and IL-13 levels; reduced levels of inflammatory mediators, such as thymus- and activation-regulated chemokine, macrophage-derived chemokine, and interferon gamma-induced protein; decreased mucin 5AC (MUC5AC) production; decreased signal transducer and activator of transcription (STAT) 6 and STAT3 expression; and restored forkhead box protein A2 (FOXA2) expression. In IL-4/IL-13-treated human bronchial epithelial cells, DDW treatment inhibited MUC5AC production, suppressed STAT6 and STAT3 expression (related to mucus hypersecretion), and increased FOXA2 expression.

CONCLUSIONS

DDW treatment modulates MUC5AC expression and mucus hypersecretion by downregulating STAT6 and STAT3 expression and upregulating FOXA2 expression. These findings provide a novel approach to manage mucus hypersecretion in asthma using DDW.

Extensive analysis of the cultivated medicinal herbal drug Origanum dictamnus L. and antimicrobial activity of its constituents

Phytochemical investigations of the methanol extract from Origanum dictamnus L. (Lamiaceae) resulted in the isolation of forty compounds belonging to the classes of terpenes, resorcinol derivatives, flavonoids, depsides, neolignans and jasmonates. Chromatographic isolations were targeted by using two analytical platforms, NMR and HPLC-PDA-MS. In parallel, HPLC-PDA-MS of individual fractions enabled the unambiguous identification of additionally eight components. In total 48 constituents were isolated/identified. Among the isolated constituents are four undescribed compounds, one resorcinol derivative, one monoterpene, one diterpene and one acylated flavonoid glycoside. The structures of the isolated compounds were elucidated on the basis of spectroscopic analyses, including 1D and 2D NMR, and HPLC-ESI-MS and HRMS experiments. Representative compounds were tested for their antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. I4-II7-dicarvacrol was the most potent constituent.

[Chemical constituents and pharmacological effects of Dictamni Cortex: a review]

Dictamni Cortex, the dried root bark of Dictamnus dasycarpus, has many chemical constituents, such as alkaloids, limonoids, flavonoids, sesquiterpenoids, glycosides, and steroids.It has the effects of anti-inflammation, anti-fungi, anti-arteriosclerosis, stopping bleeding, anti-cancer, neuroprotection, and antioxidation.The chemical constituents of Dictamni Cortex are the important material basis for its medicinal effects.This paper reviewed the chemical constituents and pharmacological activities of Dictamni Cortex and analyzed the research trend and present research progress on this medicinal, with a view to its further development and utilization.

[Clinical cases and experimental evaluation of liver injury related to anti-psoriasis Keyin Pills]

Keyin Pills is a kind of traditional Chinese medicine for the treatment of psoriasis, but it has been reported that it can cause serious liver injury. In this paper, we used the integrated evidence chain method to retrieve and reevaluate the adverse drug reaction database, CNKI literature and cases of liver injury relating to Keyin Pills in specialist hepatology hospitals. We screened out 23 cases with the causal relationship of the possible grade and above. Among them, 11 cases showed the positive causal relationship only with Keyin Pills, accounting for 47.83%, suggesting that there was objective liver injury caused by Keyin Pills. The incubation period of liver injury caused by Keyin Pills is 1-90 days, and the cumulative dosage span is 20-1 800 g. There were obvious individual diffe-rences. There was no relationship between liver injury as well as dose and course of treatment, suggesting that Keyin Pills could induce immune idiosyncratic liver injury. Furthermore, based on the liver injury model induced by immunological stress, it was confirmed that Keyin Pills could induce acute liver injury in a dose-dependent manner in rats with immunological stress. The toxic dose(14 g·kg~(-1)) of a single dose was 6.7 times of the clinical equivalent dose, and had no significant effect on the biochemical index of liver function and histopathology in normal rats. Decomposition experiments showed that Dictamnus dasycarpus in Keyin Pills is the main medicinal flavor that causes special liver injury, and the other three medicines had neither liver injury nor compatibility attenuation effect. The results suggest that clinical medication shall pay attention to the risk of liver injury caused by Keyin Pills in patients with immunological stress.

Three new compounds from Dictamnus dasycarpus and their anti-inflammatory activities

Three new compounds (1-3), named dasycarine G (1), dasycarether (2), and dasycarester (3), along with seven known compounds (4-10) obtained from the genus Dictamnus for the first time, were isolated from the root bark of Dictamnus dasycarpus. Their structures were elucidated on the basis of spectroscopic data (UV, IR, HR-ESI-MS, 1D and 2D NMR, and CD). In the in vitro assay, compounds 1, 5, 6, 9, and 10 exhibited NO inhibitory effects of LPS-induced BV-2 cells with IC₅₀ values in the range of 10.4 μM to 27.2 μM.

Anti-inflammatory quinoline alkaloids from the root bark of Dictamnus dasycarpus

Six undescribed quinoline alkaloids, named dasycarines A-E, and 18 known ones were isolated from the root bark of Dictamnus dasycarpus. All the structures were elucidated on the basis of comprehensive analysis of UV, IR, NMR, and HRMS spectroscopic data, and the absolute configurations were assigned via comparison of the calculated and experimental ECD data. (+)-Dasycarine A (1a) and (-)-Dasycarine A (1b) are a pair of enantiomers of dimeric furoquinoline alkaloid, which are the first dimeric via [2 + 2] cycloaddition of furan. The structure and absolute configuration of (-)-dasycarine A was determined via X-ray crystallography. Additionally, all the isolated compounds were tested for their inhibitory effects on NO production stimulated by LPS in BV-2 microglial cells. Three compounds showed strong inhibition with IC₅₀ values below 5.0 μM; nine compounds exhibited inhibition with IC₅₀ values in the range of 7.8-28.4 μM. Furthermore, we demonstrated that preskimmianine suppressed the levels of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and nuclear factor kappa B (NF-κB) in LPS-induced BV-2 microglial cells.

Chinese medicinal herb extract inhibits PQS-mediated quorum sensing system in Pseudomonas aeruginosa

ETHNOPHARMACOLOGICAL RELEVANCE

Chinese medicinal herbs have long been recognized as important resources that can be used for the struggle against diseases and a significant component of health care system for thousands of years.

AIM OF THE STUDY

In order to understand their roles in the treatment against bacterial infections, we examined the underlying mechanisms of one of the medicinal herb extracts (MHE) (Artemisiae argyi Folium, the root bark of Cortex dictamni and the root of Solanum melongena) on the human opportunistic pathogen Pseudomonas aeruginosa.

MATERIALS AND METHODS

We combined phenotypic assays, transcriptional analysis and chemical investigations to identify the mechanisms underlying MHE inhibition. The standard sample was prepared and transcriptional reporters for quorum sensing systems were constructed. Electrophoretic mobility shift assays were used to clarify the mechanism. GC-MS and molecular docking were used to identify the chemicals in MHE and potential binding agents.

RESULTS

We found that co-culturing of MHE with bacterial cells did not change the growth rate but substantially attenuate the production of virulence factors such as phenazine pyocyanin, siderophore pyoverdine and biofilm formation. Transcriptional responses of three major quorum sensing (QS) systems of P. aeruginosa to MHE showed that Pseudomonas quinolone signaling (PQS) system was completely repressed, rhlR/rhlI QS system was moderately inhibited, while lasR/lasI QS system was only slightly affected, suggesting that MHE might selectively target the PQS system to inhibit bacterial virulence. Furthermore, electrophoretic mobility shift assays (EMSA) showed that MHE inhibited the binding of MvfR the corresponding pqsA promoter region, suggesting that MHE serves as a competitive agent to quench the QS functionality in P. aeruginosa.

CONCLUSION

We prove that MHE functions as an effective countermeasure against bacterial infections.

An ethnopharmacological and historical analysis of "Dictamnus", a European traditional herbal medicine

ETHNOPHARMACOLOGICAL RELEVANCE AND BACKGROUND

"Dictamnus" was a popular name for a group of medicinal herbaceous plant species of the Rutaceae and Lamiaceae, which since the 4th century have been used for gynaecological problems and other illnesses BCE and still appear in numerous ethnobotanical records.

AIMS

This research has as four overarching aims: Determining the historical evolution of medical preparations labelled "Dictamnus" and the different factors affecting this long-standing herbal tradition. Deciphering and differentiating those medicinal uses of "Dictamnus" which strictly correspond to Dictamnus (Rutaceae), from those of Origanum dictamnus and other Lamiaceae species. Quantitatively assessing the dependence from herbal books, and pharmaceutical tradition, of modern Dictamnus ethnobotanical records. Determining whether differences between Western and Eastern Europe exist with regards to the Dictamnus albus uses in ethnopharmacology and ethnomedicine.

METHODS

An exhaustive review of herbals, classical pharmacopoeias, ethnobotanical and ethnopharmacological literature was conducted. Systematic analysis of uses reported which were standardized according to International Classification of Diseases - 10 and multivariate analysis using factorial, hierarchical and neighbour joining methods was undertaken.

RESULTS AND DISCUSSION

The popular concept "Dictamnus" includes Origanum dictamnus L., Ballota pseudodictamnus (L.) Benth. and B. acetabulosa (L.) Benth. (Lamiaceae), as well as Dictamnus albus L. and D. hispanicus Webb ex Willk. (Rutaceae), with 86 different types of uses. Between 1000 and 1700 CE numerous complex preparations with "Dictamnus" were used in the treatment of 35 different pathologies. On biogeographical grounds the widespread D. albus is a far more likely prototypical "Dictamnus" than the Cretan endemic Origanum dictamnus. However both form integral parts of the "Dictamnus" complex. Evidence exists for a sufficiently long and coherent tradition for D. albus and D. hispanicus, use to treat 47 different categories of diseases.

CONCLUSIONS

This approach is a model for understanding the cultural history of plants and their role as resources for health care. "Dictamnus" shows how transmission of traditional knowledge about materia medica, over 26 centuries, represents remarkable levels of development and innovation. All this lead us to call attention to D. albus and D. hispanicus which are highly promising as potential herbal drug leads. The next steps of research should be to systematically analyse phytochemical, pharmacological and clinical evidence and to develop safety, pharmacology and toxicology profiles of the traditional preparations.

Medicinal uses, phytochemistry and pharmacology of the genus Dictamnus (Rutaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Seven species from the genus Dictamnus are distributed throughout Europe and North Asia and only two species grow in China. One is Dictamnus dasycarpus Turcz., which could be found in many areas of China and has been recorded in Chinese Pharmacopoeia. The other is Dictamnus angustifolius G. Don ex Sweet, which is only present in Xinjiang province and has been used as an alternative for Dictamnus dasycarpus in the local for the treatment of rheumatism, bleeding, itching, jaundice, chronic hepatitis and skin diseases. The present paper reviewed the traditional uses, phytochemistry, pharmacology and toxicology of the genus Dictamnus.

MATERIALS AND METHODS

Information on the Dictamnus species was collected from classic books about Chinese herbal medicine and globally accepted scientific databases including PubMed, Elsevier, ASC, Scopus, Google Scholar, Web of Science, CNKI and others.

RESULTS

About 170 chemical compounds, which include quinoline alkaloids, limonoids, sesquiterpenes, coumarins, flavonoids and steroids, have been isolated from the genus Dictamnus. The characteristic and active constituents of Dictamnus species are considered to be quinoline alkaloids and limonoids, which exhibited a broad spectrum of biological activities such as anti-cancer, anti-inflammation, anti-microbe, anti-platelet-aggregation, vascular-relaxation, anti-insect, anti-HIV, anti-allergy and neuroprotection. Moreover, quinoline alkaloids and limonoids could be used as quality control markers to distinguish different species from the genus Dictamnus. However, there were also some reports on the toxic hepatitis and phototoxic effect of Dictamnus species, and the related research needs to be further studied.

CONCLUSION

In this review, we summarized the chemical constituents, pharmacology, quality control and toxicology of the species from genus Dictamnus. Phytochemical investigations indicated that quinoline alkaloids and limonoids were the major bioactive components with potential cytotoxic, neuroprotective, anti-inflammatory, antimicrobial, anti-platelet-aggregation and vascular relaxing activities. These two kinds of compounds have attracted great interests in the past few years and may have great potential to be new drug lead compounds.

Effects of Dictamnus dasycarpus Turcz., root bark on ICAM-1 expression and chemokine productions in vivo and vitro study

ETHNOPHARMACOLOGICAL RELEVANCE

The root bark of Dictamnus dasycarpus Turcz., family Rutaceae is a well known anti-inflammatory agent for skin diseases such as eczema, pruritus and urticaria in Eastern countries.

MATERIALS AND METHODS

We investigated the effects of methanol extract of Dictamnus dasycarpus root bark (MEDD) on Intercellular Adhesion Molecule-1 (ICAM-1) expression, epidermal hyperplasia and immune cell infiltration in 1-fluoro-2,4-dinitrofluorobenzene (DNFB)-induced contact dermatitis (CD) mice. We also investigated its effects on the expression of ICAM-1, binding capacity to THP-1 cells, cytokine and chemokine production, and phosphorylation of NF-κB in human keratinocytes (HaCaT cells).

RESULTS

Topical application of MEDD effectively inhibited ICAM-1 expression and epidermal hyperplasia in inflamed tissues. MEDD treatment also inhibited immune cell infiltration induced by DNFB. In addition, treatment with MEDD reduced surface expression and total amount of ICAM-1in HaCaT cells and effectively lowered the capacity to bind to THP-1 cells. MEDD also lowered the levels of IL-6, IL-8, monokine induced by gamma interferon (MIG), monocyte chemotactic protein-1 (MCP-1) and regulated on activation, normal T cell expressed and secreted (RANTES). Finally, MEDD treatment prevented activation of the NF-κB pathway induced by TNF-α in HaCaT cells.

CONCLUSIONS

These data indicate that root bark of Dictamnus dasycarpus has the potential for treatment of inflammatory skin diseases as a complementary or alternative medicine to corticosteroids. In addition, they suggest that the anti-inflammatory effects of Dictamnus dasycarpus on CD are involved in the regulation of ICAM-1 expression and cytokine and chemokine secretion through down-regulation of the NF-κB signaling pathway in keratinocytes.

Antimicrobial, antioxidant and cytotoxic properties of essential oil from Dictamnus angustifolius

ETHNOPHARMACOLOGICAL RELEVANCE

Dictamnus angustifolius (Rutaceae) has been used as an alternative for folk medicine, Dictamnus dasycarpus in the treatment of rheumatism, bleeding, itching, jaundice, chronic hepatitis, and skin diseases in Xinjiang Province of China. The aim of this study was to evaluate the antimicrobial and antioxidant activities of essential oil (EO) from Dictamnus angustifolius, correlated with their chemical composition and evaluate their cytotoxicity.

MATERIALS AND METHODS

The EO were extracted by water-distillation using a Clevenger-type apparatus. The chemical composition of EO was identified by GC-MS analysis. The antimicrobial activity was evaluated against five microorganisms by the agar disc diffusion method and minimal inhibitory concentration (MIC) assay. The antioxidant activity was measured by employing DPPH and FRAP assays. The cytotoxic activity was evaluated in the mammalian cells lines A549, MCF7, B16 and LoVo using the MTT method to assess cell viability.

RESULTS

52 compounds representing the 97.2% of the total oil were identified by GC/MS. The major constituents of the oil were tetramethylenecyclobutane (42.07%) and fraxinellone (19.06%). The antimicrobial activity showed that the EO possess significant inhibition in Monilia albican ATCC 10231 and Staphylococcus aureus ATCC 6538. The antioxidant activity suggested that the EO possess significant reducing power. The cytotoxic activity of the EO in MCF7 and LoVo cells was significant stronger than in the other cell lines.

CONCLUSION

This study is the first characterization of the chemical composition and biological activities of EO from Dictamnus angustifolius. All experimental data indicate that the EO have not only remarkable antioxidant properties but also potential antimicrobial activity and cytotoxic activities.

Anti-inflammatory activities of Dictamnus dasycarpus Turcz., root bark on allergic contact dermatitis induced by dinitrofluorobenzene in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The root bark of Dictamnus dasycarpus Turcz. is widely used as a medicinal herb for treatment of skin diseases such as eczema, pruritus and urticaria in China, Japan and Korea.

MATERIALS AND METHODS

We investigated the effects of methanol extract of Dictamnus dasycarpus Turcz., root bark (MEDD) on ear thickness, ear weights, histopathological changes such as hyperplasia, edema, spongiosis and immune cell infiltration and cytokine productions in 1-fluoro-2,4-dinitrofluorobenzene (DNFB)-induced contact dermatitis (CD) mice. We also investigated its effects on degranulation of histamine and β-hexosaminidase and related mechanisms using RBL-2H3 cells.

RESULTS

Topical application of MEDD effectively inhibited enlargement of ear thickness and weight (P<0.05). MEDD treatment also inhibited hyperplasia, edema and spongiosis induced by DNFB. Treatment with 300 μg/ear of MEDD suppressed the increase in IFN-γ and TNF-α levels (P<0.05). In addition, treatment with >50 μg/mL MEDD reduced the level of β-hexosaminidase release, while >100 μg/mL MEDD lowered the level of histamine release in a dose-dependent manner (P<0.05). Finally, MEDD treatment prevented phosphorylation of p38 MAPK induced by phorbol 12-myristate 13-acetate (PMA) and calcium ionophore A23187 in RBL-2H3 cells.

CONCLUSIONS

These data indicate that root bark of Dictamnus dasycarpus Turcz. has the potential for use in the treatment of allergic skin diseases. Furthermore, they suggest that root bark of Dictamnus dasycarpus Turcz. is involved in decreasing degranulation of MCs via inhibition of the p38 MAPK pathway as well as in the inhibition of Th1 skewing reactions.

Cortex Dictamni extract induces apoptosis of activated hepatic stellate cells via STAT1 and attenuates liver fibrosis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Chinese medicines, Cortex Dictamni is prescribed for the treatment of a variety of inflammatory diseases such as acute rheumatoid arthritis, skin inflammation and jaundice.

AIM OF THE STUDY

This study was designed to investigate the effect of ethanol extract of Cortex Dictamni on treatment of hepatic fibrosis and its possible mechanisms.

MATERIALS AND METHODS

The in vivo effect of Cortex Dictamni extract (CDE) was evaluated by measuring histological changes and collagen content in CCl(4)-indcued hepatic fibrosis mice. Viability, apoptosis and protein expression of hepatic stellate cells (HSC) were analyzed by MTT, Annexin V staining and Western blot respectively.

RESULTS

CDE alleviated CCl(4)-induced hepatic fibrosis in mice and showed a much stronger inhibition of cell viability in activated HSC cell line HSC-T6 than that in normal hepatocyte L02 cells. Furthermore, CDE induced apoptosis of HSC-T6 cells associated with increased expressions of cleaved PARP and cleaved caspase-3. Interestingly, CDE activated STAT1 in HSC-T6 cells and the effect of CDE on apoptosis of HSC-T6 cells could be neutralized using JAK/STAT1 signaling inhibitor AG490.

CONCLUSIONS

These findings suggest that CDE possesses anti-fibrosis activity with selectively induction of activated HSC apoptosis via activating STAT1, which might be a novel strategy for hepatic fibrosis therapy.