Homoeriodictyol protects human endothelial cells against oxidative insults through activation of Nrf2 and inhibition of mitochondrial dysfunction

Integrated transcriptomics and metabolomics elucidate how arbuscular mycorrhizal fungi alleviate drought stress in Juglans sigillata

Walnut (Juglans sigillata), an economically significant ecotype of the Juglans genus in the Juglandaceae family, is cultivated mainly in southwest China, a region prone to seasonal drought. Drought significantly reduced both the yield and quality of walnuts in this area. Arbuscular mycorrhizal fungi (AMF) are symbiotic fungi that colonize plant roots and play crucial roles in enhancing plant drought resistance. This study investigated the effects of AMF on the alleviation of drought stress. Compared to non-inoculated drought-stressed plants, AMF inoculation improved plant growth, increased photosynthetic capacity, enhanced reactive oxygen species (ROS) scavenging ability, and significantly activities of superoxide Dismutase, peroxidase, and catalase were significantly increased by 19.90 %, 18.43 %, and 8.39 %, respectively. malondialdehyde, Superoxide anion, and Hydrogen peroxide levels decreased by 18.39 %, 20.75 %, and 21.44 %, respectively, and soluble sugar and proline concentrations also significantly increased (P < 0.05), helping to maintain the osmotic balance. In addition, transcriptome results showed that ATP-binding cassette transporter related to drought resistance were significantly enriched in plants inoculated with AMF, and genes related to growth, such as IAA and CKT synthesis, transcription factors (BZIP, WRKY, and GTE), and related antioxidant enzymes. The mitogen-activated protein kinases pathway-related genes were upregulated in the inoculated drought treatment group, whereas pinobanksin and homoeriodictyol were upregulated in the inoculated drought treatment group, both of which provide support for drought resistance. In summary, AMF alleviated drought stress and promoted Juglans sigillata growth by modulating key physiological, biochemical, and molecular mechanisms involved in drought resistance. This study offers important theoretical insights that support the application of AMF in sustainable agricultural practices.

Material Composition Characteristics of Aspergillus cristatus under High Salt Stress through LC-MS Metabolomics

Aspergillus cristatus is a crucial edible fungus used in tea fermentation. In the industrial fermentation process, the fungus experiences a low to high osmotic pressure environment. To explore the law of material metabolism changes during osmotic pressure changes, NaCl was used here to construct different osmotic pressure environments. Liquid chromatography-mass spectrometry (LC-MS) combined with multivariate analysis was performed to analyze the distribution and composition of A. cristatus under different salt concentrations. At the same time, the in vitro antioxidant activity was evaluated. The LC-MS metabolomics analysis revealed significant differences between three A. cristatus mycelium samples grown on media with and without NaCl concentrations of 8% and 18%. The contents of gibberellin A3, A124, and prostaglandin A2 related to mycelial growth and those of arabitol and fructose-1,6-diphosphate related to osmotic pressure regulation were significantly reduced at high NaCl concentrations. The biosynthesis of energy-related pantothenol and pantothenic acid and antagonism-related fluvastatin, aflatoxin, and alternariol significantly increased at high NaCl concentrations. Several antioxidant capacities of A. cristatus mycelia were directly related to osmotic pressure and exhibited a significant downward trend with an increase in environmental osmotic pressure. The aforementioned results indicate that A. cristatus adapts to changes in salt concentration by adjusting their metabolite synthesis. At the same time, a unique set of strategies was developed to cope with high salt stress, including growth restriction, osmotic pressure balance, oxidative stress response, antioxidant defense, and survival competition.

Probiotic-fermented tomato with hepatic lipid metabolism modulation effects: analysis of physicochemical properties, bioactivities, and potential bioactive compounds

Lactiplantibacillus plantarum NCUH001046 (LP)-fermented tomatoes exhibited the potential to alleviate obesity in our previous study. This subsequent study further delves deeper into the effects of LP fermentation on the physicochemical properties, bioactivities, and hepatic lipid metabolism modulation of tomatoes, as well as the analysis of potential bioactive compounds exerting obesity-alleviating effects. Results showed that after LP fermentation, viable bacterial counts peaked at 9.11 log CFU mL-1 and sugar decreased, while organic acids, umami amino acids, total phenols, and total flavonoids increased. LP fermentation also improved the inhibition capacities of three digestive enzyme activities and Enterobacter cloacae growth, as well as antioxidant activities. Western blot results indicated that fermented tomatoes, especially live probiotic-fermented tomatoes (LFT), showed improved effects compared to unfermented tomatoes in reducing hepatic lipid accumulation by activating the AMPK signal pathway. UHPLC-Q-TOF/MS-based untargeted metabolomics analysis showed that chlorogenic acid, capsiate, tiliroside, irisflorentin, and homoeriodictyol levels increased after fermentation. Subsequent cell culture assays demonstrated that irisflorentin and homoeriodictyol reduced lipid accumulation via enhancing AMPK expression in oleic acid-induced hyperlipidemic HepG2 cells. Furthermore, Spearman's correlation analysis indicated that the five phenols were positively associated with hepatic AMPK pathway activation. Consequently, it could be inferred that the five phenols may be potential bioactive compounds in LFT to alleviate obesity and lipid metabolism disorders. In summary, these findings underscored the transformative potential of LP fermentation in enhancing the bioactive profile of tomatoes and augmenting its capacity to alleviate obesity and lipid metabolism disorders. This study furnished theoretical underpinnings for the functional investigation of probiotic-fermented plant-based foods.

Construction of Magnolol Nanoparticles for Alleviation of Ethanol-Induced Acute Gastric Injury

Ethanol (EtOH) has been identified as a potential pathogenic factor in gastric ulcer development primarily due to its association with gastric injury and excessive production of reactive oxygen species. Magnolol (Mag), the principal active compound in Magnolia officinalis extract, is well studied for its notable anti-inflammatory and antioxidant properties. However, its limited solubility, propensity for agglomeration, and low absorption and utilization rates significantly restrict its therapeutic use. This study aims to overcome these challenges by developing a Mag nanoparticle system targeting the treatment and prevention of EtOH-induced gastric ulcers in mice. Utilizing a click chemistry approach, we successfully synthesized this system by reacting thiolated bovine serum albumin (BSA·SH) with Mag. The in vitro analysis revealed effective uptake of the BSA·SH-Mag nanoparticle system by human gastric epithelial cells (GES-1), showcasing its antioxidant and anti-inflammatory capabilities. Additionally, BSA·SH-Mag exhibited gradual disintegration and release in simulated gastric fluid, resulting in a notable reduction of oxidative stress in gastric tissues and mucosal tissue repair and effectively reducing inflammatory expression. Furthermore, BSA·SH-Mag attenuated EtOH-induced gastric inflammation by decreasing the level of NOX4 protein expression and augmenting the level of Nrf2 protein expression. In conclusion, our findings indicate that BSA·SH-Mag represents a promising candidate as an oral therapeutic for gastric ulcer treatment.

Engineering a Plant Polyketide Synthase for the Biosynthesis of Methylated Flavonoids

Homoeriodictyol and hesperetin are naturally occurring O-methylated flavonoids with many health-promoting properties. They are produced in plants in low abundance and as complex mixtures of similar compounds that are difficult to separate. Synthetic biology offers the opportunity to produce various flavonoids in a targeted, bottom-up approach in engineered microbes with high product titers. However, the production of O-methylated flavonoids is currently still highly inefficient. In this study, we investigated and engineered a combination of enzymes that had previously been shown to support homoeriodictyol and hesperetin production in Escherichia coli from fed O-methylated hydroxycinnamic acids. We determined the crystal structures of the enzyme catalyzing the first committed step of the pathway, chalcone synthase from Hordeum vulgare, in three ligand-bound states. Based on these structures and a multiple sequence alignment with other chalcone synthases, we constructed mutant variants and assessed their performance in E. coli toward producing methylated flavonoids. With our best mutant variant, HvCHS (Q232P, D234 V), we were able to produce homoeriodictyol and hesperetin at 2 times and 10 times higher titers than reported previously. Our findings will facilitate further engineering of this enzyme toward higher production of methylated flavonoids.

Structural Requirements for the Neuroprotective and Anti-Inflammatory Activities of the Flavanone Sterubin

Alzheimer's disease (AD) is the most frequent age-associated disease with no treatments that can prevent, delay, slow, or stop its progression. Thus, new approaches to drug development are needed. One promising approach is the use of phenotypic screening assays that can identify compounds that have therapeutic efficacy in target pathways relevant to aging and cognition, as well as AD pathology. Using this approach, we identified the flavanone sterubin, from Yerba santa (Eriodictyon californicum), as a potential drug candidate for the treatment of AD. Sterubin is highly protective against multiple initiators of cell death that activate distinct death pathways, potently induces the antioxidant transcription factor Nrf2, and has strong anti-inflammatory activity. Moreover, in a short-term model of AD, it was able to prevent decreases in short- and long-term memory. In order to better understand which key chemical functional groups are essential to the beneficial effects of sterubin, we compared the activity of sterubin to that of seven closely related flavonoids in our phenotypic screening assays. Surprisingly, only sterubin showed both potent neuroprotective activity against multiple insults as well as strong anti-inflammatory activity against several distinct inducers of inflammation. These effects correlated directly with the ability of sterubin to strongly induce Nrf2 in both nerve and microglial cells. Together, these results define the structural requirements underlying the neuroprotective and anti-inflammatory effects of sterubin and they provide the basis for future studies on new compounds based on sterubin.

The Beneficial Role of Nrf2 in the Endothelial Dysfunction of Atherosclerosis

Cardiovascular disease (CVD) is a serious public health issue in China, accounting for more than 40% of all mortality, and it is the leading cause of death worldwide. Atherosclerosis is the pathological basis for much CVD, including coronary heart disease, acute myocardial infarction, and stroke. Endothelial dysfunction is an initiating and exacerbating factor in atherosclerosis. Recent research has linked oxidative stress and mitochondrial damage to endothelial dysfunction. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor with antioxidant effects that is strongly connected to several CVDs. However, the mechanism by which Nrf2 reduces CVD is unknown. Research indicates that Nrf2 improves endothelial function by resisting oxidative stress and mitochondrial damage, thereby delaying atherosclerosis. This article examines the mechanisms and potential targets of Nrf2 affecting endothelial cell function to improve atherosclerosis and to provide ideas for the development of new CVD treatments.

Thesium chinense Turcz.: An ethnomedical, phytochemical and pharmacological review

ETHNOPHARMACOLOGICAL RELEVANCE

Thesium chinense Turcz. has been used to treat mastitis, pulmonitis, tonsillitis, iaryngopharyngitis and upper respiratory tract infections in the indigenous medicine of China for a long history. Presently, several pharmaceutics prepared by this medical herb have been clinically used for the therapy of infectious diseases.

AIM OF THE REVIEW

This review aims to comprehensively summarize the current researches on the ethnomedical, phytochemical and pharmacological aspects of T. chinense, and discuss their possible opportunities for the future research.

MATERIALS AND METHODS

Extensive database searches, including Web of Science, SciFinder, Google Scholar and China Knowledge Resource Integrated, were performed using keywords such as 'Thesium chinense', 'Bai Rui Cao', and their chemical constituents. In addition, local classic herbal literature on ethnopharmacology and relevant textbooks were consulted to provide a comprehensive survey of this ethnomedicine.

RESULTS

Thirty four chemical constituents, including flavonoids, alkaloids, and terpenoids, have been identified from T. chinense. Of which, flavonoids are the predominant and characteristic constituents. The crude extracts, the purified constituents, and commercial available pharmaceutics have displayed diverse in vitro and in vivo pharmacological functions (e.g. anti-inflammation, antimicrobial activity, analgesic effect, hepaprotection), and are particularly useful as a potential therapeutic agent against inflammation-related diseases.

CONCLUSIONS

T. chinense is an important ethnomedical medicine and possesses a satisfying effect for treating inflammation, microbial infection, and upper respiratory diseases. It has received plenty of researches on its phytochemical and pharmacological aspects since 1970s. These findings definitely establish the link between chemical composition and pharmacological application, and support the ethnomedical use of T. chinense in the indigenous medicine of China. However, chemical composition of this plant and the molecular mechanisms of purified constituents have not been comprehensively investigated, and thus the trace constituents and the therapeutic targets of bioactive constituents deserve a further exploration. Collectively, the researchers should pay more attention to a better understanding and application of this ethnomedical plant.

Natural Antioxidants Improve the Vulnerability of Cardiomyocytes and Vascular Endothelial Cells under Stress Conditions: A Focus on Mitochondrial Quality Control

Cardiovascular disease has become one of the main causes of human death. In addition, many cardiovascular diseases are accompanied by a series of irreversible damages that lead to organ and vascular complications. In recent years, the potential therapeutic strategy of natural antioxidants in the treatment of cardiovascular diseases through mitochondrial quality control has received extensive attention. Mitochondria are the main site of energy metabolism in eukaryotic cells, including myocardial and vascular endothelial cells. Mitochondrial quality control processes ensure normal activities of mitochondria and cells by maintaining stable mitochondrial quantity and quality, thus protecting myocardial and endothelial cells against stress. Various stresses can affect mitochondrial morphology and function. Natural antioxidants extracted from plants and natural medicines are becoming increasingly common in the clinical treatment of diseases, especially in the treatment of cardiovascular diseases. Natural antioxidants can effectively protect myocardial and endothelial cells from stress-induced injury by regulating mitochondrial quality control, and their safety and effectiveness have been preliminarily verified. This review summarises the damage mechanisms of various stresses in cardiomyocytes and vascular endothelial cells and the mechanisms of natural antioxidants in improving the vulnerability of these cell types to stress by regulating mitochondrial quality control. This review is aimed at paving the way for novel treatments for cardiovascular diseases and the development of natural antioxidant drugs.

Two new compounds with Nrf2 inducing activity from Glycyrrhiza uralensis

Two new compounds including a new 3-arylcoumarin liquiritcoumarin (1), and a new flavonoid glycoside crotoliquiritin (2), together with twelve known compounds (3-14) were isolated from the radix and rhizome of Glycyrrhiza uralensis. Their structures were elucidated on the basis of extensive spectroscopic data analyses. All of the compounds were evaluated for the cytotoxic activities. Only compound 5 showed moderate effects with IC₅₀ of 11.46 μM for A549 cells and IC₅₀ of 7.38 μM for NCI-H292 cells. Compounds 1 and 2 were demonstrated to be Nrf2 pathway activators by using a stable antioxidant response element (ARE)-dependent reporter gene assay together with immunoblot and immunofluorescence analysis.

Old age-associated phenotypic screening for Alzheimer's disease drug candidates identifies sterubin as a potent neuroprotective compound from Yerba santa

Alzheimer's disease (AD) is the most frequent age-associated dementia with no treatments that can prevent or slow its progression. Since age is by far the major risk factor for AD, there is a strong rationale for an alternative approach to drug discovery based upon the biology of aging. Phenotypic screening assays that reflect multiple, age-associated neurotoxicity pathways rather than single molecular targets can identify compounds that have therapeutic efficacy by targeting aspects of aging that contribute to AD pathology. And, while the suitability of any single assay can be questioned, a combination of assays can make reliable predictions about the neuroprotective effects of compounds in vivo. Therefore, our lab has developed a combination of phenotypic screening assays that are ideally suited not only to identify novel neuroprotective compounds for the treatment of AD but also their target pathways, thereby potentially providing new therapeutic targets for disease treatment. Using these assays, we screened a large library of extracts from plants with identified pharmacological uses. Analysis of one of these extracts from the plant Yerba santa (Eriodictyon californicum) identified the flavanone sterubin as the active component and further studies showed it to be a potent neuroprotective and anti-inflammatory compound.

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Phenotypic screening of a curated library of plant extracts identifies Yerba santa.

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The flavonoid sterubin is the main active component of Yerba santa.

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Sterubin is very neuroprotective against multiple toxicities of the aging brain.

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Sterubin has potent anti-inflammatory activity that is dependent on Nrf2 induction.

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Sterubin is also an iron chelator which could enhance its neuroprotective activity.