Dimeric furanocoumarins from the roots of Angelica dahurica

Seven new 3,4-dihydro-furanocoumarin derivatives from Angelica dahurica

Objective

To study the chemical constituents of the roots of Angelica dahurica, a well-known Chinese herbal medicine named Baizhi in Chinese.

Methods

Compounds were separated by various chromatographies, and the structures of new compounds were elucidated based on the analysis of their spectroscopic and spectrometric data (1D, 2D NMR, HRESI MS, IR, and UV). The absolute configurations of new compounds were determined by the calculated electronic circular dichroism and chemical derivatization. The inhibitory activities of all isolates against nitric oxide (NO) production were evaluated using lipopolysaccharide-activated RAW 264.7 macrophage cells.

Results

Seven new 3,4-dihydro-furanocoumarin derivatives (1a/1b, 2a/2b, 3a/3b, 4) together with a known furanocoumarin (5) were isolated from the roots of A. dahurica. The new compounds included three pairs of enantiomers, (4S, 2''R)-angelicadin A (1a)/(4R, 2''S)-angelicadin A (1b), (4S, 2''S)-angelicadin A (2a)/(4R, 2''R)-angelicadin A (2b), and (4S, 2''S)-secoangelicadin A (3a)/(4R, 2''R)-secoangelicadin A (3b), together with (4R, 2''R)-secoangelicadin A methyl ester (4). The known xanthotoxol (5) inhibited the NO production with the half-maximal inhibitory concentration (IC50) value of (32.8 ± 0.8) µmol/L, but all the new compounds showed no inhibitory activities at the concentration of 100 µmol/L.

Conclusion

This is the first report of the discovery of 3,4-dihydro-furanocoumarins from A. dahurica. The results are not only meaningful for the understanding of the chemical constituents of A. dahurica, but also enrich the reservoir of natural products.

Chemical comparison and discrimination of two plant sources of Angelicae dahuricae Radix, Angelica dahurica and Angelica dahurica var. formosana, by HPLC-Q/TOF-MS and quantitative analysis of multiple components by a single marker

INTRODUCTION

Angelica dahurica(BZ) and Angelica dahurica var. formosana(HBZ) are two plant sources of Angelicae dahuricae Radix. Although BZ and HBZ are commonly used herbal medicines with great medicinal and dietary values, study on their phytochemicals and bioactive compositions is limited.

OBJECTIVE

To compare the chemical compositions of BZ and HBZ and find the chemical makers for discrimination and quality evaluation of the two botanical origins of Angelicae dahuricae Radix.

METHODOLOGY

A high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method was established for chemical profiling of BZ and HBZ. Then, a quantitative analysis of multiple components by a single marker method was developed for simultaneous determination of nine bioactive coumarins (xanthotoxol, oxypeucedanin hydrate, byakangelicin, xanthotoxin, bergapten, oxypeucedanin, phellopterin, imperatorin and isoimperatorin). Moreover, chemometrics were performed to compare and discriminate BZ and HBZ samples.

RESULTS

A total of 30 coumarins compounds were identified, and the chemical compositions in BZ and HBZ were quite similar. The quantitative analysis showed that there were significant differences in the contents of bioactive coumarins, and the chemometric analysis indicated five coumarins (xanthotoxol, xanthotoxin, bergapten, phellopterin and isoimperatorin) were responsible for the significant differences between BZ and HBZ, which could be used as chemical markers to distinguish the two original plant sources of Angelicae dahuricae Radix.

CONCLUSION

The present work provided useful information for understanding the chemical differences between BZ and HBZ and also provided feasible methods for quality evaluation and discrimination of herbal medicines originating from multiple botanical sources.

The Angelica dahurica: A Review of Traditional Uses, Phytochemistry and Pharmacology

Angelica dahurica (A. dahurica) root is a famous edible medicinal herb that has been used in China for thousands of years. To date, more than 300 chemical constituents have been discovered from A. dahurica. Among these ingredients, coumarins and volatile oils are the major active compounds. Moreover, a few other compounds have also been isolated from the root of A. dahurica, such as alkaloids, phenols, sterols, benzofurans, polyacetylenes and polysaccharides. Modern pharmacological studies demonstrated that the root of A. dahurica and its active components displayed various bioactivities such as anti-inflammation, anti-tumor, anti-oxidation, analgesic activity, antiviral and anti-microbial effects, effects on the cardiovascular system, neuroprotective function, hepatoprotective activity, effects on skin diseases and so on. Based on these studies, this review focused on the research publications of A. dahurica and aimed to summarize the advances in the traditional uses, phytochemistry and pharmacology which will provide reference for the further studies and applications of A. dahurica.

Imperatorin Relieved Ulcerative Colitis by Regulating the Nrf-2/ARE/HO-1 Pathway in Rats

Ulcerative colitis is a common intestinal inflammatory disease. Imperatorin (IMP) has been reported to alleviate mast cell-mediated allergic responses by suppressing the expression of Nrf-2, ARE, and HO-1. However, whether IMP can relieve ulcerative colitis by regulating Nrf-2/ARE/HO-1 pathway is unclear. Thus, this study aims to investigate the effect of IMP on ulcerative colitis in rats and elucidate the potential mechanism. In our study, rats were treated with 2,4,6-trinitro-benzenesulfonic acid (TNBS) to induce the animal model of ulcerative colitis. Next, these rats were treated with diverse doses of IMP (15 mg/kg, 30 mg/kg, and 60 mg/kg) and sacrificed at different time points (3 days, 7 days, and 14 days). The levels of inflammatory factors (TNF-α and IL-6) in colon tissues were detected with ELISA kits. H&E staining was performed to observe the pathologic changes of the colon tissues. The expression of Nrf-2, ARE, and HO-1 in colon tissues was determined with the immunofluorescence and Western blotting. The results showed that application of IMP alleviated the symptoms of ulcerative colitis and inhibited the secretion of TNF-α and IL-6. Besides, treatment of IMP promoted the expression of Nrf-2, ARE, and HO-1 in the early stage of this disease (the third day), but suppressed the expression of Nrf-2, ARE, and HO-1 in the advanced stage of the ulcerative colitis (the fourteenth day). Collectively, IMP relieved the symptoms of ulcerative colitis by regulating the Nrf-2/ARE/HO-1 pathway, which might provide a new therapeutic drug to support the clinical treatment of ulcerative colitis.

Imperatorin suppresses IL-1β-induced iNOS expression via inhibiting ERK-MAPK/AP1 signaling in primary human OA chondrocytes

Joint inflammation is a key player in the pathogenesis of osteoarthritis (OA). Imperatorin, a plant-derived small molecule has been reported to have anti-inflammatory properties; however, its effect on chondrocytes is not known. Here, we investigated the effects of Imperatorin on interleukin-1β (IL-1β) induced expression of inducible nitric oxide synthase (iNOS) and nitric oxide production in primary human OA chondrocytes and cartilage explants culture under pathological conditions and explored the associated signaling pathways. We pretreated chondrocytes or explants with Imperatorin (50 μM) followed by IL-1β (1 ng/ml), and the culture supernatant was used to determine the levels of nitrite production by Griess assay and chondrocytes were harvested to prepare cell lysate or RNA for gene expression analysis of iNOS by Western blot or qPCR and in explants by immunohistochemistry (IHC). Pretreatment of primary chondrocytes and cartilage explants with Imperatorin suppressed IL-1β induced expression of iNOS and NO production. Imperatorin blocked the IL-1β-induced phosphorylation of ERK-MAPK/AP1 signaling pathway to suppress iNOS expression. The role of ERK in the regulation of iNOS expression was verified by using ERK inhibitor. Interestingly, we also found that Imperatorin binds to iNOS protein and inhibits its activity in vitro. Our data demonstrated that Imperatorin possess strong anti-inflammatory activity and may be developed as a therapeutic agent for the management of OA.

Imperatorin alleviates ROS-mediated airway remodeling by targeting the Nrf2/HO-1 signaling pathway

In this study, we investigated the role and mechanism of imperatorin (IMP) in chronic inflammation and airway remodeling. The levels of TNF-α, IL-1β, IL-6, IL-8, VEGF, α-SMA, and ROS were detected by ELISA, immunohistochemistry (IHC), immunofluorescence, and Western blot. In addition, we evaluated the effect of IMP on MAPK, PI3K/Akt, NF-κB, and Nrf2/HO-1 signaling pathways. IMP treatment obviously attenuated the production of inflammatory cytokines and inflammatory cells in bronchoalveolar lavage fluid of OVA-induced airway remodeling model. Meanwhile, it significantly inhibited inflammatory cell infiltration, goblet cell hyperplasia, collagen deposition, VEGF production, α-SMA, and ROS expression. Our study has shown that IMP could regulate the signaling pathways including MAPK, PI3K/Akt, NF-κB, and Nrf2/HO-1 to release the inflammatory responses. IMP might attenuate airway remodeling by the down-regulation of Nrf2/HO-1/ROS/PI3K/Akt, Nrf2/HO-1/ROS/MAPK, and Nrf2/HO-1/ROS/NF-κB signaling pathways.

Furanocoumarins from the Roots of Angelica dahurica with Inhibitory Activity against Intracellular Reactive Oxygen Species Accumulation

Five new furanocoumarins, dahuribirin H (1), dahuribirin I (2), (2'S)-(+)-5-(2'-hydroxy-3'-methylbut-3'-enyloxy)-8-(3''-methylbut-2″-enyloxy)psoralen (3), (2'R)-(+)-5-(2',3'-epoxy-3'-methylbutoxy)-8-(3″-methylbut-2″-enyloxy)psoralen (4), and 5-methoxy-8-((Z)-4'-(3″-methylbutanoate)-3'-methylbut-2'-enyloxy)psoralen (5), along with 15 known compounds (6-20), were isolated from the roots of Angelica dahurica. The structures of the new compounds were elucidated by spectroscopic analysis, along with electronic circular dichroism calculations and Mosher ester analysis. Compounds 3, 4, 11, 13, and 16 reduced H₂O₂-induced cell death in HepG2 cells and attenuated reactive oxygen species (ROS) formation without showing cytotoxicity, suggesting that these compounds might have cytoprotective effects against H₂O₂-induced oxidative damage via ROS scavenging activities.

Botanical Sources, Chemistry, Analysis, and Biological Activity of Furanocoumarins of Pharmaceutical Interest

The aim of this work is to provide a critical review of plant furanocoumarins from different points of view, including their chemistry and biosynthetic pathways to their extraction, analysis, and synthesis, to the main biological activities found for these active compounds, in order to highlight their potential within pharmaceutical science. The limits and the possible improvements needed for research involving these molecules are also highlighted and discussed.

Imperatorin Suppresses Anaphylactic Reaction and IgE-Mediated Allergic Responses by Inhibiting Multiple Steps of FceRI Signaling in Mast Cells: IMP Alleviates Allergic Responses in PCA

This study is to investigate the effects of imperatorin (IMP) on allergic responses mediated by mast cells, both in vitro and in vivo. Passive cutaneous anaphylaxis (PCA) model was established. Histological detection was performed to assess the ear histology. ELISA and Western blot analysis were used to detect the levels of corresponding cytokines and signalling pathway proteins. IMP decreased the leakage of Evans blue and the ear thickness in the PCA models, in a dose-dependent manner, and alleviated the degranulation of mast cells. Moreover, IMP reduced the expression of TNF-α, IL-4, IL-1β, IL-8, and IL-13. Furthermore, IMP inhibited the phosphorylation levels of Syk, Lyn, PLC-γ1, and Gab2, as well as the downstream MAPK, PI3K/AKT, and NF-κB signaling pathways. In addition, IMP inhibited the mast cell-mediated allergic responses through the Nrf2/HO-1 pathway. IMP attenuates the allergic responses through inhibiting the degranulation and decreasing the expression levels of proinflammatory cytokines in the mast cells, involving the PI3K/Akt, MAPK, NF-κB, and Nrf2/HO-1 pathways.

Natural Products Research in China From 2015 to 2016

This review covers the literature published by chemists from China during the 2015-2016 on natural products (NPs), with 1,985 citations referring to 6,944 new compounds isolated from marine or terrestrial microorganisms, plants, and animals. The emphasis is on 730 new compounds with a novel skeleton or/and significant bioactivity, together with their source organism and country of origin.

Simultaneous Quantification of Nine New Furanocoumarins in Angelicae Dahuricae Radix Using Ultra-Fast Liquid Chromatography with Tandem Mass Spectrometry

A series of new furanocoumarins with long-chain hydrophobic groups, namely andafocoumarins A–H and J, have been isolated from the dried roots of Angelica dahurica cv. Hangbaizhi (Angelicae Dahuricae radix) in our previous study, among which andafocoumarins A and B were demonstrated to have better anti-inflammatory activity than the positive controls. In this work, a sensitive, accurate, and efficient ultra-fast liquid chromatography coupled with triple quadrupole mass spectrometer (UFLC-MS/MS) method was developed and validated for simultaneous quantification of above-mentioned nine compounds in four cultivars of Angelicae Dahuricae Radix. Chromatographic separation was performed on a Kinetex 2.6u C18 100 Å column (100 × 2.1 mm, 2.6 µm). The mobile phases were comprised of acetonitrile and water with a flow rate of 0.5 mL/min. Using the established method, all components could be easily separated within 12 min. With the multiple reaction monitor mode, all components were detected in positive electrospray ionization. The method was validated with injection precision, linearity, lower limit of detection, lower limit of quantification, precision, recovery, and stability, respectively. The final results demonstrated that the method was accurate and efficient, which could be used to simultaneously quantify the nine andafocoumarins in Angelicae Dahuricae Radix. The results also indicated that in different batches of Angelicae Dahuricae Radix, some of the andafocoumarins were significantly different in terms of content.