Two new compounds with Nrf2 inducing activity from Glycyrrhiza uralensis

Systematic review of natural coumarins in plants (2019-2024): Chemical structures and pharmacological activities

Coumarins constitute one of the most substantial classes of secondary metabolites, characterised by a fundamental α-benzopyranone skeleton, which serves as an overarching nomenclature for o-hydroxycinnamyl lactone moieties. These chemical constituents are widely distributed in various plant species. Based on the nature and loci of their substituents, these compounds can be further classified into simple coumarins, furanocoumarins, pyranocoumarins, isocoumarins, biscoumarins and other coumarins. Contemporary pharmacological research has revealed that coumarins exhibit a spectrum of properties, including antibacterial, antioxidant, anticancer, anti-inflammatory and hypoglycaemic activities. Owing to their diverse of structures and pharmacological actions, coumarins are widely used in cuisine, cosmetics and pharmaceutical industries. An extensive body of scholarly literature has been produced in this domain, although a notable paucity in the compilation and updating of references has been identified since 2019. Herein, the chemical structures and pharmacological activities of coumarins reported for the first time between 2019 and 2024 were systematically summarised. In total, 220 scholarly articles involving 574 coumarins reported for the first time in plants were included in this review. In addition, the biosynthetic pathways of some common types of coumarins (simple coumarins, furanocoumarins, and pyranocoumarins) are also preliminarily summarised in this paper. Meticulously analyzing and synthesising the published literature will lay a solid foundation for further investigation and extensive utilisation of coumarin derivatives.

Induction of Nrf2-EpRE-mediated gene expression by hydroxyanthraquinones present in extracts from traditional Chinese medicine and herbs

Hydroxyanthraquinones that can be present in traditional Chinese medicine (TCM) and herbal extracts have claimed beneficial intestinal effects. We examined the ability of a panel hydroxyanthraquinones, and methanolic extracts from selected TCM and herbal granules to activate Nrf2-EpRE mediated gene expression using a reporter-gene assay. The results indicate that purpurin, aloe-emodin, 2-hydroxy-3-methylanthraquinone and rhein induced Nrf2 mediated gene expressions with a high induction factor (IFs>10), with BMCL₁₀ values (the lower confidence limit of the concentration giving 10% added response above background) of 16 μM, 1.1 μM, 23 μM and 2.3 μM, respectively, while aurantio-obtusin, obtusifolin, rubiadin 1-methyl ether and emodin were less potent (IFs<5), with BMCL₁₀ values for added response above background level of 4.6 μM, 15 μM, 9.8 μM and 3.8 μM, respectively. All TCM extracts and the herbal extracts of Aloe Vera, Polygonum multiflorum, Rubia (cordifolia) and Rheum officinale activated the Nrf2-EpRE pathway. Of the TCM extracts, Chuan-Xin-Lian-Kang-Yan-Pian was the most potent Nrf2-inducer. LC-MS/MS analysis indicated the presence of selected hydroxyanthraquinones in the extracts and herbs, in part explaining their Nrf2-EpRE mediated activity. In conclusion, different hydroxyanthraquinones have different potencies of Nrf2 activation. The Nrf2 activation by extracts from TCM and herbs can be partially explained by the presence of selected hydroxyanthraquinones.

Natural source, bioactivity and synthesis of 3-Arylcoumarin derivatives

3-arylcoumarins with different pharmacological properties widely exist in a variety of natural plants. The extensive research on 3-arylcoumarins was attributed to its therapeutic and relatively easy isolation. Therefore, 3-arylcoumarins can be recognised as useful structures for the design of novel compounds with potential pharmacological interest, particularly in the fields of anti-inflammatory, anti-cancer, antioxidant, Monoamine oxidase (MAO) enzyme inhibition, etc. The current review highlights the biological activities, design, and chemical synthetic methods of 3-arylcoumarins derivatives as well as their important natural product sources.

Efficacy of the Nourishing Yin and Clearing Heat Therapy Based on Traditional Chinese Medicine in the Prevention and Treatment of Radiotherapy-Induced Oral Mucositis in Nasopharyngeal Carcinomas: A Systematic Review and Meta-Analysis of Thirty Randomized Controlled Trials

This study aimed to evaluate the efficacy of nourishing Yin and clearing heat therapy (NYCH therapy) based on traditional Chinese medicine (TCM) in the treatment of radiotherapy-induced oral mucositis (RTOM) in nasopharyngeal carcinomas (NPCs). A total of eight online databases were searched from inception to September 2021 for randomized controlled trials (RCTs). The control group was treated with Western medicine (WM) alone, whereas the experimental group was treated with a combined NYCH and WM therapy. A total of 30 RCTs involving 2562 participants were ultimately included. NYCH therapy combined with conventional WM delayed the onset time (days) of RTOM (MD = 10.80, p < 0.001), and at that time, a higher cumulative radiotherapy dose (Gy) (MD = 5.72, p < 0.001) was completed in the experimental group. The combination regimen also reduced the incidence of severe oral mucositis (Grade III–IV) (RR = 0.25, p < 0.001). In addition, the treatment efficacy of the experimental group was significantly better than that of the control group (RR = 1.31, p < 0.001). Compared with the patients in the control group, the experimental group had lower xerostomia scores (MD = -1.07, p < 0.001) and more saliva (MD = 0.36, p < 0.001). NYCH combined with WM improved the efficacy of treating RTOM in NPC. This study provides a sufficient basis for conducting further large RCTs to prove the efficacy of NYCH.

Coumarins as Tool Compounds to Aid the Discovery of Selective Function Modulators of Steroid Hormone Binding Proteins

Steroid hormones play an essential role in a wide variety of actions in the body, such as in metabolism, inflammation, initiating and maintaining sexual differentiation and reproduction, immune functions, and stress response. Androgen, aromatase, and sulfatase pathway enzymes and nuclear receptors are responsible for steroid biosynthesis and sensing steroid hormones. Changes in steroid homeostasis are associated with many endocrine diseases. Thus, the discovery and development of novel drug candidates require a detailed understanding of the small molecule structure–activity relationship with enzymes and receptors participating in steroid hormone synthesis, signaling, and metabolism. Here, we show that simple coumarin derivatives can be employed to build cost-efficiently a set of molecules that derive essential features that enable easy discovery of selective and high-affinity molecules to target proteins. In addition, these compounds are also potent tool molecules to study the metabolism of any small molecule.

Effect of Yijin-Tang, an Oriental Traditional Formula, on Allergic Responses Using an Ovalbumin-Induced Murine Asthma Model

Yijin-tang is an oriental traditional herb used to treat inflammatory diseases. In the present study, we investigated the protective effects of Yijin-tang water extract (YTE) using an ovalbumin- (OVA-) induced asthma model, focusing on the antioxidant and anti-inflammatory properties of the herb. BALB/c mice were intraperitoneally injected with OVA on days 0 and 14 and then challenged with OVA on days 21, 22, and 23. The animals were orally administered YTE (200 and 400 mg/kg) from days 18 to 23, and this was found to significantly decrease airway hyperresponsiveness and release of inflammatory cells, cytokines, and OVA-specific immunoglobulin E in mice with asthma. In addition, YTE was associated with a marked reduction in airway inflammation and mucus production in lung tissue of mice with asthma. Furthermore, YTE suppressed the expression of matrix metalloproteinase-9 and phosphorylation of ERK in the lungs, which in turn led to a reduction in inducible nitric oxide synthases and an elevation in reduced glutathione and heme oxygenase-1. In conclusion, YTE effectively suppressed allergic responses in mice with asthma and the effect was closely related to antioxidant and anti-inflammatory properties of the herb. Our results indicate that YTE may be a potential agent for the treatment of allergic asthma.

Phenoxychromone and 4-hydroxyisoflavans from the roots of Glycyrrhiza uralensis

In an attempt to find species specific markers, a phenoxychromone (1) and eight isoflavonoids including six isoflavans (2-7) and two isoflavanones (8 and 9) were isolated from the root of Glycyrrhiza uralensis. Among the isolated phenolic compounds, glycyurelone (1), glycyurelvanins A and B (2 and 3) were found to be undescribed while others, (-)-vestitol (4), conferol A (5), glyasperin C (6), glyasperin D (7), (-)-licoisoflavanone (8), and (-)-3'-(γ,γ-dimethylallyl)kievitone (9) were previously reported. All compounds except 4 and 5 were prenylated and majority of these possess isoflavan scaffold with highly conserved stereo specificity at C-3 center. Structure elucidation was mainly based on extensive NMR, ECD and mass spectral data analysis.