An integrated investigation of 16S rRNA gene sequencing and proteomics to elucidate the mechanism of Corydalis bungeana Turcz. on dextran sulfate sodium-induced colitis

Corydalis bungeana Turcz. (CBT) is frequently used to treat inflammatory illnesses, the mechanisms underlying its use to ulcerative colitis (UC) remain unclear. A dextran sulfate sodium (DSS)-induced UC mice model was established. The disease activity index (DAI), colonic length, histological inspection by hematoxylin-eosin staining, the cytokines levels in the colon, proteomics and intestinal flora in mice were investigated to evaluate the effect of CBT. The results showed that CBT can significantly reduce the DAI, increase the length of colon, improve the pathological injury of colon tissue, decrease the level of TNF-α, IL-6, IL-1β and increase the level of IL-10 in UC mice. Gut microbe sequencing showed that CBT could enhance the abundance of the intestinal microbiome, decrease possibly harmful bacteria and promote potentially helpful microbes. Proteomics investigation showed that 20 overlapping differentially expressed proteins (DEPs) were discovered in the control, model, and CBT administration groups. The DEPs in the CBT administration group were connected to biological procedures mainly involving detoxification. Extracellular matrix (ECM) receptor-associated proteins such as Col6a1 and CD36 may be important targets for CBT treatment of UC. Overall, this integrated methodology identified a comprehensive multi-omics network, composed of a certain set of gut microbiota and proteins, which may be potential targets for CBT treatment with UC.

Insights on Antitumor Activity and Mechanism of Natural Benzophenanthridine Alkaloids

Benzophenanthridine alkaloids are a class of isoquinoline compounds, which are widely found in the plants of papaveraceae, corydalis, and rutaceae. Biological activities and clinical studies have shown that benzophenanthridine alkaloids have inhibitory effects on many cancers. Considering that the anticancer activities and mechanisms of many natural benzophenanthridine alkaloids have been discovered in succession, the purpose of this paper is to review the anticancer effects of benzophenanthridine alkaloids and explore the application potential of these natural products in the development of antitumor drugs. A literature survey was carried out using Scopus, Pubmed, Reaxys, and Google Scholar databases. This review summarizes and analyzes the current status of research on the antitumor activity and antitumor mechanism of natural products of benzophenanthridine from different sources. The research progress of the antitumor activity of natural products of benzophenanthridine from 1983 to 2023 was reviewed. The antitumor activities of 90 natural products of benzophenanthridine and their related analogues were summarized, and the results directly or indirectly showed that natural products of benzophenanthridine had the effects of antidrug-resistant tumor cell lines, antitumor stem cells, and inducing ferroptosis. In conclusion, benzophenanthridine alkaloids have inhibitory effects on a variety of cancers and have the potential to counteract tumor resistance, and they have great application potential in the development of antitumor drugs.

Corybungines A-K: Isoquinoline alkaloids from Corydalis bungeana with dopamine D2 receptor activity

Eleven undescribed isoquinoline alkaloids corybungines A-K including a protoberberine-type alkaloid, an isoquinoline alkaloid with a unique 6-norprotoberberine skeleton, one 13,14-seco-protoberberine-type alkaloid, two 1a,14-seco-protoberberine-type alkaloids with a 4-(hydroxymethyl)phenoxy moiety and six aporphine alkaloids, together with seven known alkaloids, have been isolated from the whole herb extract of Corydalis bungeana Turcz. Their structures and absolute configurations were elucidated based on an analysis of spectroscopic data and electronic circular dichroism (ECD) spectra. (R)-stephanine displayed high antagonistic activity against the dopamine D2 receptor with an IC₅₀ value of 0.85 ± 0.09 μM in CHO-D2 cells. Additionally, corybungines D, F, H, (R)-roemerine, (R)-vireakine and (R)-tuduranine showed moderate D2 antagonism (IC₅₀ 5.20-26.07 μM). The preliminary structure-activity relationships (SARs) of aporphine alkaloids were discussed.

Systematic review of the alkaloid constituents in several important medicinal plants of the Genus Corydalis

The genus Corydalis is a botanical source of various pharmaceutically active components. Its member species have been widely used in traditional medicine systems in Southeast Asia, especially in China for thousands of years. They have been administered to treat the common cold, hypertension, hepatitis, hemorrhage, edema, gastritis, cardiovascular and cerebrovascular diseases, and neurological disorders. Analgesia is the most important effect of Corydalis products, which are relatively non-addictive and associated with low tolerance compared with other analgesics. Certain Corydalis species are rich in alkaloids, which have strong biological activity, and also contain coumarins, flavonoids, steroids, organic acids and other chemical components. These constituents have pharmacological efficacy against diseases of the nervous, cardiovascular and digestive systems. Numerous investigations have been performed on these plants and their components. Here, we systemically summarized the chemical constituents of important medicinal member species of Corydalis that have been reported since 1962. A total 381 alkaloids were enumerated, including 117 quaternary isoquinoline type, 60 Benzophenanthridine type, 37 aporphine type, 10 protopine type, 59 phthalide isoquinoline type, 52 simple isoquinoline-type, 25 lignin amides and 21 other alkaloids. Thus, we have provided a basis for further explorations into the pharmacologically active constituents of Corydalissp.(Papaveraceae) to develop medicines that exert strong effects, are relatively non-addictive, and result in few side effects.

Discovery of natural anti-inflammatory alkaloids: Potential leads for the drug discovery for the treatment of inflammation

Inflammation is an adaptive response of the immune system to tissue malfunction or homeostatic imbalance. Corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs) are frequently applied to treat varieties of inflammatory diseases but are associated with gastrointestinal, cardiovascular, and kidney side effects. Developing more effective and less toxic agents remain a challenge for pharmaceutical chemist due to the complexity of the different inflammatory processes. Alkaloids are widely distributed in plants with diverse anti-inflammatory activities, providing various potential lead compounds or candidates for the design and discovery of new anti-inflammatory drug candidates. Therefore, re-examining the anti-inflammatory alkaloid natural products is advisable, bringing more opportunities. In this review, we summarized and described the recent advances of natural alkaloids with anti-inflammatory activities and possible mechanisms in the period from 2009 to 2020. It is hoped that this review of anti-inflammatory alkaloids can provide new ideas for researchers engaged in the related fields and potential lead compounds for the discovery of anti-inflammatory drugs.

A single residue determines substrate preference in benzylisoquinoline alkaloid N-methyltransferases

N-methylation is a recurring feature in the biosynthesis of many plant specialized metabolites, including alkaloids. A crucial step in the conserved central pathway that provides intermediates for the biosynthesis of benzylisoquinoline alkaloids (BIAs) involves conversion of the secondary amine (S)-coclaurine into the tertiary amine (S)-N-methylcoclaurine by coclaurine N-methyltransferase (CNMT). Subsequent enzymatic steps yield the core intermediate (S)-reticuline, from which various branch pathways for the biosynthesis of major BIAs such as morphine, noscapine and sanguinarine diverge. An additional N-methylation yielding quaternary BIAs is catalyzed by reticuline N-methyltransferase (RNMT), such as in the branch pathway leading to the taxonomically widespread and ecologically significant alkaloid magnoflorine. Despite their functional differences, analysis of primary sequence information has been unable to accurately distinguish between CNMT-like and RNMT-like enzymes, necessitating laborious in vitro screening. Furthermore, despite a recent emphasis on structural characterization of BIA NMTs, the features and mechanisms underlying the CNMT-RNMT functional dichotomy were unknown. We report the identification of structural variants tightly correlated with function in known BIA NMTs and show through reciprocal mutagenesis that a single residue acts as a switch between CNMT- and RNMT-like functions. We use yeast in vivo screening to show that this discovery allows for accurate prediction of activity strictly from primary sequence information and, on this basis, improve the annotation of previously reported putative BIA NMTs. Our results highlight the unusually short mutational distance separating ancestral CNMT-like enzymes from more evolutionarily advanced RNMT-like enzymes, and thus help explain the widespread yet sporadic occurrence of quaternary BIAs in plants. While this is the first report of structural variants controlling mono-versus di-methylation activity among plant NMT enzymes, comparison with bacterial MT enzymes also suggests possible convergent evolution.

Molecular Origins of Functional Diversity in Benzylisoquinoline Alkaloid Methyltransferases

O- and N-methylations are ubiquitous and recurring features in the biosynthesis of many specialized metabolites. Accordingly, the methyltransferase (MT) enzymes catalyzing these modifications are directly responsible for a substantial fraction of the vast chemodiversity observed in plants. Enabled by DNA sequencing and synthesizing technologies, recent studies have revealed and experimentally validated the trajectories of molecular evolution through which MTs, such as those biosynthesizing caffeine, emerge and shape plant chemistry. Despite these advances, the evolutionary origins of many other alkaloid MTs are still unclear. Focusing on benzylisoquinoline alkaloid (BIA)-producing plants such as opium poppy, we review the functional breadth of BIA N- and O-MT enzymes and their relationship with the chemical diversity of their host species. Drawing on recent structural studies, we discuss newfound insight regarding the molecular determinants of BIA MT function and highlight key hypotheses to be tested. We explore what is known and suspected concerning the evolutionary histories of BIA MTs and show that substantial advances in this domain are within reach. This new knowledge is expected to greatly enhance our conceptual understanding of the evolutionary origins of specialized metabolism.