New synthetic method of 8-oxocoptisine starting from natural quaternary coptisine as anti-ulcerative colitis agent

Trifluoromethylation of dihydrocoptisines and the effect on structural stability and XBP1-activating activity

In order to obtain new dihydrocoptisine-type compounds with stable structure and activating XBP1 transcriptional activity, (±)-8-trifluoromethyldihydrocoptisine derivatives as target compounds were synthesized from quaternary ammonium chlorides of coptisine alkaloids as starting materials by a one-step reaction. The structures of the synthesized compounds were confirmed by ¹H-, ¹³C-, and ¹⁹F-NMR as well as HRESIMS methods. These compounds showed more significant structural stability and activating XBP1 transcription activity in vitro than dihydrocoptisine as positive control. No obvious cytotoxicity on normal cell in vitro was observed with (±)-8-trifluoromethyldihydrocoptisines. Trifluoromethylation can be used as one of the fluorine modification strategies for dihydrocoptisines to guide follow-up studies on structural modification of coptisine-type alkaloids and on anti-Ulcerative colitis drugs with coptisines.

Gut Microbiota-Mediated Transformation of Coptisine Into a Novel Metabolite 8-Oxocoptisine: Insight Into Its Superior Anti-Colitis Effect

Coptisine (COP) is a bioactive isoquinoline alkaloid derived from Coptis Chinemsis Franch, which is traditionally applied for the management of colitis. However, the blood concentration of COP was extremely low, and its gut microbiota-mediated metabolites were thought to contribute to its prominent bioactivities. To comparatively elucidate the protective effect and underlying mechanism of COP and its novel gut microbiota metabolite (8-oxocoptisine, OCOP) against colitis, we used dextran sulfate sodium (DSS) to induce colitis in mice. Clinical symptoms, microscopic alternation, immune-inflammatory parameters for colitis were estimated. The results indicated that OCOP dramatically ameliorated disease activity index (DAI), the shortening of colon length and colonic histopathological deteriorations. OCOP treatment also suppressed the mRNA expression and release of inflammatory mediators (TGF-β, TNF-α, IL-6, IL-18, IL-1β and IFN-γ) and elevated the transcriptional and translational levels of anti-inflammatory cytokine (IL-10) as well as the mRNA expression levels of adhesion molecules (ICAM-1 and VCAM-1). Besides, the activation of NF-κB pathway and NLRP3 inflammasome was markedly inhibited by OCOP. Furthermore, OCOP displayed superior anti-colitis effect to COP, and was similar to MSZ with much smaller dosage. Taken together, the protective effect of OCOP against DSS-induced colitis might be intimately related to inhibition of NF-κB pathway and NLRP3 inflammasome. And the findings indicated that OCOP might have greater potential than COP to be further exploited as a promising candidate in the treatment of colitis.

Herbal pair Huangqin-Baishao: mechanisms underlying inflammatory bowel disease by combined system pharmacology and cell experiment approach

BACKGROUND

Inflammatory bowel disease (IBD) is a severe digestive system condition, characterized by chronic and relapsing inflammation of the gastrointestinal tract. Scutellaria baicalensis Georgi (Huangqin, HQ) and Paeonia lactiflora Pall (Baishao, BS) from a typical herbal synergic pair in traditional Chinese medicine (TCM) for IBD treatments. However, the mechanisms of action for the synergy are still unclear. Therefore, this paper aimed to predict the anti-IBD targets and the main active ingredients of the HQ-BS herbal pair.

METHODS

A systems pharmacology approach was used to identify the bioactive compounds and to delineate the molecular targets and potential pathways of HQ-BS herbal pair. Then, the characteristics of the candidates were analyzed according to their oral bioavailability and drug-likeness indices. Finally, gene enrichment analysis with DAVID Bioinformatics Resources was performed to identify the potential pathways associated with the candidate targets.

RESULTS

The results showed that, a total of 38 active compounds were obtained from HQ-BS herbal pair, and 54 targets associated with IBD were identified. Gene Ontology and pathway enrichment analysis yielded the top 20 significant results with 54 targets. Furthermore, the integrated IBD pathway revealed that the HQ-BS herbal pair probably acted in patients with IBD through multiple mechanisms of regulation of the nitric oxide biosynthetic process and anti-inflammatory effects. In addition, cell experiments were carried out to verify that the HQ-BS herbal pair and their Q-markers could attenuate the levels of nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-stimulated THP-1-derived macrophage inflammation. In particular, the crude materials exerted a much better anti-inflammatory effect than their Q-markers, which might be due to their synergistic effect.

CONCLUSION

This study provides novel insight into the molecular pathways involved in the mechanisms of the HQ-BS herbal pair acting on IBD.

Syntheses and Structure-Activity Relationships in Antibacterial Activity against Clostridium difficile and XBP1 Activation Property of 13-[(N-Alkylamino)methyl]-8-oxodihydrocoptisines

13-[(N-Alkylamino)methyl]-8-oxodihydrocoptisines were synthesized to evaluate antibacterial activity against Clostridium difficile and activating x-box-binding protein 1 (XBP1) activity, biological properties both associated with ulcerative colitis. Improving structural stability and ameliorating biological activity were major concerns. Different substituents on the structural modification site were involved to explore the influence of diverse structures on the bioactivities. The target compounds exhibited the desired activities with definite structure-activity relationship. In the series of 13-[(N-n-alkylamino)methyl]-8-oxodihydrocoptisines, the length of n-alkyl groups has a definite effect on the bioactivity, elongation of the length increasing the antibacterial activity. The synthesized compounds were determined to display strong or weak XBP1-activating activity in vitro. The preliminary results of this study warrant further medicinal chemistry studies on these synthesized compounds.

Coptisine from Coptis chinensis exerts diverse beneficial properties: A concise review

Coptisine is a natural small-molecular compound extracted from Coptis chinensis (CC) with a history of using for thousands of years. This work aimed at summarizing coptisine's activity and providing advice for its clinical use. We analysed the online papers in the database of SciFinder, Web of Science, PubMed, Google scholar and CNKI by setting keywords as 'coptisine' in combination of 'each pivotal pathway target'. Based on the existing literatures, we find (a) coptisine exerted potential to be an anti-cancer, anti-inflammatory, CAD ameliorating or anti-bacterial drug through regulating the signalling transduction of pathways such as NF-κB, MAPK, PI3K/Akt, NLRP3 inflammasome, RANKL/RANK and Beclin 1/Sirt1. However, we also (b) observe that the plasma concentration of coptisine demonstrates obvious non-liner relationship with dosage, and even the highest dosage used in animal study actually cannot reach the minimum concentration level used in cell experiments owing to the poor absorption and low availability of coptisine. We conclude (a) further investigations can focus on coptisine's effect on caspase-1-involved inflammasome assembling and pyroptosis activation, as well as autophagy. (b) Under circumstance of promoting coptisine availability by pursuing nano- or microrods strategies or applying salt-forming process to coptisine, can it be introduced to clinical trial.

Syntheses and structure-activity relationships on antibacterial and anti-ulcerative colitis properties of quaternary 13-substituted palmatines and 8-oxo-13-substituted dihydropalmatines

In this study, quaternary palmatine is used as a lead compound to design and synthesize derivatives to evaluate bioactivities, with twenty-seven compounds of four series being obtained. Antibacterial activity was examined by determining the minimal inhibitory concentration (MIC) values on Staphylococcus aureus, Escherichia coli, and Candida albicans, three series of derivatives being found to exhibit activity in vitro with significant structure-activity relationship (SAR). Elongating the carbon chain led to the antibacterial activity increased, with quaternary 13-hexanoylpalmatine chloride, quaternary 13-(ω-ethoxycarbonyl)heptylpalmatine chloride, and 8-oxo-13-(N-n-nonyl)aminomethyldihydropalmatine, all of which possess the longest aliphatic carbon chain in the corresponding series of derivatives, showing the MIC values of 62.5, 7.81, and 15.63 µg/ml against S. aureus, respectively. The property of anti-ulcerative colitis (anti-UC) was assessed at the levels of both in vitro and in vivo, with X-box-binding protein 1 (XBP1) being targeted in vitro. Seven compounds were found not only to be hypocytotoxic toward intestinal epithelial cells, but also to exhibit activity of activating the transcription of XBP1 in vitro. Five compounds were found to possess significant dose-effect relationship with EC₅₀ values at a level of 10^-7 µM in vitro. 8-Oxo-13-formyldihydropalmatine as an intermediate was found to display significant curative effect on UC in vivo based on the biomarkers of body weight change, colon length change, and calculated values of disease activity index and colon macroscopic damage index of the experimental animals, as well as the examination into the pathological changes of the colon tissue of the modeled animals.

Protective effect of coptisine free base on indomethacin-induced gastric ulcers in rats: Characterization of potential molecular mechanisms

AIMS

The aim of this study was to comparatively investigate the potential gastroprotective effect and underlying mechanisms of coptisine free base (CFB, 8-hydroxy-7, 8-dihydrocoptisine), berberine and lansoprazole against indomethacin-induced gastric ulcer in rats.

MATERIALS AND METHODS

CFB (10, 20 and 40mg/kg), berberine (20mg/kg) and lansoprazole (30mg/kg) were orally administrated to rats prior to indometacin ingestion, and gastric lesions were evaluated macroscopically and histologically, and further analyzed by ELISA, qRT-PCR and Western blot.

KEY FINDINGS

CFB exerted comparable or superior gastroprotective effect to berberine in protecting against indomethacin-induced gastric injury. CFB pretreatment significantly enhanced the levels of superoxide dismutase (SOD) and glutathione (GSH), and markedly decreased the malonaldehyde (MDA) content. CFB administration effectively suppressed the levels of myeloperoxidase (MPO), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and angiotensin II (Ang II). Besides, CFB substantially up-regulated the mRNA expressions of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), and promoted gastric mucosal prostaglandin E₂ level (PGE₂). Furthermore, CFB pretreatment remarkably increased the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) from cytosol into the nucleus, and the expression of heme oxygenase-1 (HO-1), while significantly decreased the expression of mitogen activated protein Kinase Kinase 6 (MKK6) and translocation of p38 mitogen-activated protein kinase (p38 MAPK).

SIGNIFICANCE

This was the first investigation reporting the anti-ulcer effect of protoberberine alkaloid free base on in vivo rodent model. The gastroprotective mechanism of CFB might involve favorable regulation of antioxidant and anti-inflammatory status mediated, at least partially, by the Nrf2 signaling pathway and p38 MAPK translocation.

Versatile methods for synthesizing organic acid salts of quaternary berberine-type alkaloids as anti-ulcerative colitis agents

Two versatile methods to synthesize kinds of organic acid salts of quaternary berberine-type alkaloids were investigated in order to determine which is more efficient to improve the liposolubility of the target compounds and to explore the efficacy of the target compounds as anti-ulcerative colitis (UC) agents. Overall evaluation according to the reaction results and yields of the final products indicated that the synthetic method using tertiary (±)-8-acylmethyldihydroberberine-type alkaloids as key intermediates is superior to that of using tertiary dihydroberberine-type alkaloids as intermediates. Ten target compounds were synthesized using quaternary berberine chloride and quaternary coptisine chloride as starting materials, respectively, and the anti-UC activity of some target compounds was evaluated in an in vitro x-box-binding protein 1 (XBP1) transcriptional activity assay using dual luciferase reporter detection. At 10 μM, the tested compounds were found to activate the transcription of XBP1 target at almost the same level as that of quaternary coptisine chloride. The synthesized target compounds were also found to share higher liposolubility than the inorganic acid salts of quaternary berberine-type alkaloid.

Synthesis and Structure-Activity Relationships of N-Dihydrocoptisine-8-ylidene Aromatic Amines and N-Dihydrocoptisine-8-ylidene Aliphatic Amides as Antiulcerative Colitis Agents Targeting XBP1

In this study, natural quaternary coptisine was used as a lead compound to design and synthesize structurally stable and actively potent coptisine analogues. Of the synthesized library, 13 N-dihydrocoptisine-8-ylidene amines/amides were found not only to be noncytotoxic toward intestinal epithelial cells (IECs), but they were also able to activate the transcription of X-box-binding protein 1 (XBP1) targets to varying extents in vitro. Antiulcerative colitis (UC) activity levels were assessed at the in vitro molecular level as well as in vivo in animals using multiple biomarkers as indices. In an in vitro XBP1 transcriptional activity assay, four compounds demonstrated good dose-effect relationships with EC50 values of 0.0708-0.0132 μM. Moreover, two compounds were confirmed to be more potent in vivo than a positive control, demonstrating a curative effect for UC in experimental animals. Thus, the findings of this study suggest that these coptisine analogues are promising candidates for the development of anti-UC drugs.

Cembranoids from the Gum Resin of Boswellia carterii as Potential Antiulcerative Colitis Agents

Eight new cembranoids, boscartins A-H (1, 2, and 4-9), and the known incensole oxide were isolated from the gum resin of Boswellia carterii. The absolute configurations of 1, 2, 4, and incensole oxide were unequivocally resolved using single-crystal X-ray diffraction analysis with Cu Kα radiation, and the absolute configuration of 5 was resolved via electronic circular dichroism data. The antiulcerative colitis activities of the compounds were evaluated in an in vitro x-box-binding protein 1 (XBP 1) transcriptional activity assay using dual luciferase reporter detection. At 10 μM, compounds 1, 5, 6, and 7 significantly activated XBP 1 transcription with EC50 values of 0.34, 1.14, 0.88, and 0.42 μM, respectively, compared with the pGL3-basic vector control.