Caseinate-coated zein nanoparticles as potential delivery vehicles for guavinoside B from guava: Molecular interactions and encapsulation properties

Guavinoside B (GUB) is a characteristic constituent from guava with strong antioxidant activity; however, its low water solubility limits its utilization. Herein, we investigated the interaction between GUB and zein, a prolamin with self-assembling property, using multiple spectroscopic methods and fabricated GUB-zein-NaCas nanoparticles (GUB-Z-N NPs) via the antisolvent coprecipitation approach. GUB caused fluorescence quenching to zein via the static quenching mechanism. Fourier-transform infrared spectroscopy and computational analysis revealed that GUB bound to zein via van der Waals interaction, hydrogen bond, and hydrophobic forces. The GUB-Z-N NPs were in the nanometric size range (< 200 nm) and exhibited promising encapsulation efficiency and redispersibility after freeze-drying. These particles remained stable for up to 31 days at 4 °C and great resistance to salt and pH variation, and displayed superior antioxidant activity to native GUB. The current study highlights the potential of zein-based nanoparticles as delivery vehicles for GUB in the food industry.

Naturally-derived modulators of the Nrf2 pathway and their roles in the intervention of diseases

Cumulative evidence has verified that persistent oxidative stress is involved in the development of various chronic diseases, including pulmonary, neurodegenerative, kidney, cardiovascular, and liver diseases, as well as cancers. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a pivotal role in regulating cellular oxidative stress and inflammatory reactions, making it a focal point for disease prevention and treatment strategies. Natural products are essential resources for discovering leading molecules for new drug research and development. In this review, we comprehensively outlined the progression of the knowledge on the Nrf2 pathway, Nrf2 activators in clinical trials, the naturally-derived Nrf2 modulators (particularly from 2014-present), as well as their effects on the pathogenesis of chronic diseases.

Psidium guajava: An Insight into Ethnomedicinal Uses, Phytochemistry, and Pharmacology

BACKGROUND

Psidium guajava (guava) is widely distributed in tropical and subtropical regions and adapted to various environmental conditions. Guava is an important economic fruit widely used as food and folk medicine. It contains flavonoids, alkaloids, tannins, triterpenoids, reducing sugars, essential oils, carotenoids, polyphenols, etc. The presence of triterpenoid acids such as guavacoumaric, ursolic, jacoumaric, guajavanoic, guavenoic, and Asiatic acids helps to develop novel drugs against various diseases. It is used traditionally for medicinal purposes, mainly for antioxidant, antimicrobial, antispasmodic, antidiabetic, anticancer, antiallergy, anti-inflammatory, and hepato-protective properties.

OBJECTIVE

The systematic literature study aims to summarize its botanical description, phytochemicals, pharmacological activities, and clinical trials. This review focuses on the plant's chemical composition and scientific approaches to human welfare.

METHODS

A systematic literature search was done on Psidium guajava through previous literature and online databases such as Google Scholar, Pubmed, Science Direct, etc., to explain its ethnomedicinal uses, phytochemistry, and pharmacological applications.

RESULTS

Previous literature studies of Psidium guajava suggest it can serve as antioxidant, antimicrobial, antispasmodic, antidiabetic, anticancer, anti-allergy, anti-inflammatory, and hepatoprotective effects. Successful clinical trials performed on the plant extracts against infantile rotaviral enteritis and infectious gastroenteritis showed future directions to work with the plant for clinical applications.

CONCLUSION

In this review, an attempt is made to show all literature studied, especially in phytochemistry, pharmacology, clinical trials and uses as traditional folk medicine around the world. The leaves have been used by folklore over the years to treat various ailments such as skin ulcers, diarrhoea, vaginal irritation, cough, conjunctivitis, etc. Further studies are required to explore more therapeutic remedies and to develop new medicines for future perspectives.

Influence of the Extraction Method on the Polyphenolic Profile and the Antioxidant Activity of Psidium guajava L. Leaf Extracts

The leaves of Psidium guajava L. are an agro-industrial by-product with an outstanding content of polyphenolic compounds; however, there are many factors which can affect the phytochemical profile when valuing this type of plant material, such as temperatures and extraction times involving in the extraction methods applied. In this context, this study analyzed the impact of different extraction methods (Soxhlet, maceration and ultrasound-assisted extraction) on the phytochemical profile (FTIR and UPLC-MS) and the antioxidant activity (ABTS, FRAP and Folin-Ciocalteu) of guava leaf extracts. A yield of phenolic compounds per gram of guava leaf was obtained within the range of 16 to 45 mg/g; on the other hand, the IC50 values determined with the ABTS assay ranged between 78 ± 4 to 152 ± 12 µg/mL. The methanolic extract obtained by Soxhlet was the one with the best reducing power, both in the FRAP assay and in the Folin-Ciocalteu assay. Finally, bioactive compounds such as quercetin, kaempferol and avicularin were identified in the guava leaf extract. It was concluded that the purification of polyphenolics compounds improves the antioxidant capacity, and that the extraction method greatly influences the phytochemical profile and activity of the extracts.

Natural Products for Acetaminophen-Induced Acute Liver Injury: A Review

The liver plays a vital role in metabolism, synthesis, and detoxification, but it is susceptible to damage from various factors such as viral infections, drug reactions, excessive alcohol consumption, and autoimmune diseases. This susceptibility is particularly problematic for patients requiring medication, as drug-induced liver injury often leads to underestimation, misdiagnosis, and difficulties in treatment. Acetaminophen (APAP) is a widely used and safe drug in therapeutic doses but can cause liver toxicity when taken in excessive amounts. This study aimed to investigate the hepatotoxicity of APAP and explore potential treatment strategies using a mouse model of APAP-induced liver injury. The study involved the evaluation of various natural products for their therapeutic potential. The findings revealed that natural products demonstrated promising hepatoprotective effects, potentially alleviating liver damage and improving liver function through various mechanisms such as oxidative stress and inflammation, which cause changes in signaling pathways. These results underscore the importance of exploring novel treatment options for drug-induced liver injury, suggesting that further research in this area could lead to the development of effective preventive and therapeutic interventions, ultimately benefiting patients with liver injury caused by medicine.

Discovery of hepatoprotective activity components from Thymus quinquecostatus celak. by molecular networking, biological evaluation and molecular dynamics studies

Thymus quinquecostatus Celak. is an edible herb that widely cultivated in Asia and possesses hepatoprotective activity, but the underlying non-volatile components of this protective activity are not well studied. In this study, combining molecular networking visualization and bioassay-guided fractionation strategies, a pair of novel skeleton diterpenoid enantiomers, (+)- and (-)-thymutatusone A [(+)- and (-)-1], along with one new and one known biogenetically related compounds (2-3) and 16 other known compounds (4-19), were identified from T. quinquecostatus. Their structures were exhaustively characterized by comprehensive spectroscopic data, X-ray diffraction analysis, and ECD calculations. Compounds (±)-1, (-)-1, and (+)-1, with a rare tricyclo [7.3.1.02,7] tridecane skeleton, exhibited potent hepatoprotective activity in HepG2 cells injured by acetaminophen, with EC50 values of 11.5 ± 2.8, 8.4 ± 1.9, and 12.2 ± 0.3 μM respectively. They were more potent than positive drug bifendate (EC50 15.2 ± 1.3). Further, the underlying mechanism for the hepatoprotective activity of compound (-)-1 related to activating the Nrf 2 signaling pathway. What's more, molecular docking and molecular dynamics simulation analysis showed that compound (-)-1 could dock with the active site of Nrf 2 protein and form a stable system through hydrogen bonding. These results suggest that T. quinquecostatus can be used as a valuable source of hepatoprotective activity compounds.

USP25 regulates KEAP1-NRF2 anti-oxidation axis and its inactivation protects acetaminophen-induced liver injury in male mice

Nuclear factor erythroid 2-related factor 2 (NRF2) is a transcription factor responsible for mounting an anti-oxidation gene expression program to counter oxidative stress. Under unstressed conditions, Kelch-like ECH-associated protein 1 (KEAP1), an adaptor protein for CUL3 E3 ubiquitin ligase, mediates NRF2 ubiquitination and degradation. We show here that the deubiquitinase USP25 directly binds to KEAP1 and prevents KEAP1's own ubiquitination and degradation. In the absence of Usp25 or if the DUB is inhibited, KEAP1 is downregulated and NRF2 is stabilized, allowing the cells to respond to oxidative stress more readily. In acetaminophen (APAP) overdose-induced oxidative liver damage in male mice, the inactivation of Usp25, either genetically or pharmacologically, greatly attenuates liver injury and reduces the mortality rates resulted from lethal doses of APAP.

Protection of taraxasterol against acetaminophen-induced liver injury elucidated through network pharmacology and in vitro and in vivo experiments

BACKGROUND

Drug-induced liver injury (DILI) is primarily caused by drugs or their metabolites. Acetaminophen (APAP) is an over-the-counter antipyretic analgesic that exhibits high hepatotoxicity when used for long-term or in overdoses. Taraxasterol is a five-ring triterpenoid compound extracted from traditional Chinese medicinal herb Taraxacum officinale. Our previous studies have demonstrated that taraxasterol exerts protective effects on alcoholic and immune liver injuries. However, the effect of taraxasterol on DILI remains unclear.

HYPOTHESIS/PURPOSE

This study aimed to elucidate the effects and mechanisms of action of taraxasterol on APAP-induced liver injury using network pharmacology and in vitro and in vivo experiments.

METHODS

Online databases of drug and disease targets were used to screen the targets of taraxasterol and DILI, and a protein-protein interaction network (PPI) was constructed. Core target genes were identified using the tool of Analyze of Cytoscape, gene ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analyses were performed. Oxidation, inflammation and apoptosis were evaluated to determine the effect of taraxasterol on APAP-stimulated liver damage in AML12 cells and mice. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to explore the potential mechanisms of taraxasterol against DILI.

RESULTS

Twenty-four intersection targets for taraxasterol and DILI were identified. Among them, 9 core targets were identified. GO and KEGG analysis showed that core targets are closely related to oxidative stress, apoptosis, and inflammatory response. The in vitro findings showed that taraxasterol alleviated mitochondrial damage in AML12 cells treated with APAP. The in vivo results revealed that taraxasterol alleviated pathological changes in the livers of mice treated with APAP and inhibited the activity of serum transaminases. Taraxasterol increased the activity of antioxidants, inhibited the production of peroxides, and reduced inflammatory response and apoptosis in vitro and in vivo. Taraxasterol promoted Nrf2 and HO-1 expression, suppressed JNK phosphorylation, and decreased the Bax/Bcl-2 ratio and caspase-3 expression in AML12 cells and mice.

CONCLUSION

By integrating network pharmacology with in vitro and in vivo experiments, this study indicated that taraxasterol inhibits APAP-stimulated oxidative stress, inflammatory response and apoptosis in AML12 cells and mice by regulating the Nrf2/HO-1 pathway, JNK phosphorylation, and apoptosis-related protein expression. This study provides a new evidence for the use of taraxasterol as a hepatoprotective drug.

S100A6 Activates Kupffer Cells via the p-P38 and p-JNK Pathways to Induce Inflammation, Mononuclear/macrophage Infiltration Sterile Liver Injury in Mice

Noninfectious liver injury, including the effects of chemical material, drugs and diet, is a major cause of liver diseases worldwide. In chemical and drugs-induced liver injury, innate inflammatory responses are mediated by extracellular danger signals. The S100 protein can act as danger signals, which can promote the migration and chemotaxis of immune cells, promote the release of various inflammatory cytokines, and regulate the body's inflammatory and immune responses. However, the role of S100A6 in inflammatory response in chemical and drugs-induced sterile liver injury remains unclear. We constructed the model of sterile liver injury induced by carbon tetrachloride (CCl₄)/Paracetamol (APAP) and performed RNA sequencing (RNA-seq) on the liver tissues after injury (days 2 and 5). We analyzed inflammatory protein secretion in the liver tissue supernatant by enzyme-linked immunosorbent assay (ELISA), determined the inflammation response by bioinformatic analysis during sterile liver injury, and assessed mononuclear/macrophage infiltration by immunohistochemistry and flow cytometry. Immunohistochemistry was used to analyze the location of S100A6. We conducted inflammatory factor expression analysis and molecular mechanistic studies in Kupffer cells (KCs) induced by S100A6 using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), ELISA, and western blot in vitro experiments. We performed chemokine CCL2 expression analysis and molecular mechanism studies using the same method. We used a Transwell assay to show the infiltration of mononuclear/macrophage. We here observed that aggravated inflammatory response was shown in CCl₄ and APAP-administrated mice, as evidenced by enhanced production of inflammatory cytokines (TNF-α, IL-1β), and elevated mononuclear/macrophage infiltration and activation of immunity. The expression of S100A6 was significantly increased on day 2 after sterile liver injury, which is primarily produced by injured liver cells. Mechanistic studies established that S100A6 activates Kupffer cells (KCs) via the p-P38, p-JNK and P65 pathways to induce inflammation in vitro. Furthermore, TNF-α can stimulate liver cells via the p-P38 and p-JNK pathways to produce CCL2 and promote the infiltration of mononuclear/macrophage. In summary, we showed that S100A6 plays an important role in regulating inflammation, thus influencing sterile liver injury. Our findings provide novel evidence that S100A6 can as a danger signal that contributes to pro-inflammatory activation through p-P38 and p-JNK pathways in CCl₄ and APAP-induced sterile liver injury in mice. In addition, the inflammatory factor TNF-α induces a large amount of CCL2 production in normal liver cells surrounding the injured area through a paracrine action, which is chemotactic for blood mononuclear/macrophage infiltration.

Kaempferol prevents acetaminophen-induced liver injury by suppressing hepatocyte ferroptosis via Nrf2 pathway activation

Acetaminophen (APAP)-induced liver injury (AILI) has become a growing public health problem. Ferroptosis, an iron-dependent form of cell death associated with lipid peroxide accumulation, has been recently implicated in AILI. The activation of the Nrf2 signaling pathway is a potential therapy for AILI. Kaempferol (KA), a flavonoid widely existing in edible plants, has been reported to exert profound anti-inflammatory and antioxidant activities. This study aimed to investigate whether KA exerts anti-AILI effects via the Nrf2 signaling pathway. Mice were fasted for 22 h and injected intraperitoneally with APAP (250 mg kg^-1) to induce AILI. Mice were pre-injected intragastrically with KA for 2 h followed by APAP injection. The hepatic injury was observed by H&E staining. Biochemical parameters of the serum and liver were measured using kits. KA alleviated hepatic injury and inflammatory response in AILI mice and ameliorated APAP-induced hepatic iron overload and oxidative stress in mice. In addition, the protective effects of KA against APAP-induced hepatotoxicity were examined in L02 cells in vitro. Cell viability was assayed by the CCK8 assay. Mitochondrial reactive oxygen species (ROS) in L02 cells were detected by MitoSox fluorescence. KA reversed the APAP-induced decrease in cell viability and GSH levels and inhibited the accumulation of intracellular ROS. Furthermore, KA activated the Nrf2 pathway and upregulated Gpx4 in mouse livers and L02 cells to inhibit ferroptosis induced by APAP. Finally, molecular docking indicated the potential interaction of KA with Keap1. Taken together, KA ameliorated oxidative stress and ferroptosis-mediated AILI by activating Nrf2 signaling.

Highly Accessible Computational Prediction and In Vivo/In Vitro Experimental Validation: Novel Synthetic Phenyl Ketone Derivatives as Promising Agents against NAFLD via Modulating Oxidoreductase Activity

Nonalcoholic fatty liver disease (NAFLD) has reached epidemic proportions with no pharmacological treatment approved. Several highly accessible computational tools were employed to predict the activities of twelve novel compounds prior to actual chemical synthesis. We began our work by designing two or three hydroxyl groups appended to the phenyl ketone core, followed by prediction of drug-likeness and targets. Most predicted targets for each compound overlapped with NAFLD targets (≥80%). Enrichment analysis showed that these compounds might regulate oxidoreductase activity. Then, these compounds were synthesized and confirmed by IR, MS, ¹H, and ¹³C NMR. Their cell viability demonstrated that twelve compounds exhibited appreciable potencies against NAFLD (EC₅₀ values ≤ 13.5 μM). Furthermore, the most potent compound 5f effectively prevented NAFLD progression as evidenced by the change in histological features. 5f significantly reduced total cholesterol and triglyceride levels in vitro/in vivo, and the effects of 5f were significantly stronger than those of the control drug. The proteomic data showed that oxidoreductase activity was the most significantly enriched, and this finding was consistent with docking results. In summary, this validated presynthesis prediction approach was cost-saving and worthy of popularization. The novel synthetic phenyl ketone derivative 5f holds great therapeutic potential by modulating oxidoreductase activity to counter NAFLD.

The crude guava polysaccharides ameliorate high-fat diet-induced obesity in mice via reshaping gut microbiota

Guava is a popular fruit consumed worldwide with beneficial effects in regulation of glucose and lipid metabolism. Although polysaccharides are a major phytochemical component of guava, to date, the alleviative effects of polysaccharides from the guava fruit against diet-induced obesity remain unclear. The relationship between the anti-obesity effects of guava polysaccharide (GP) and gut microbiota is unknown. In current study, seven-week-old C57BL/6 mice were fed high-fat diet (HFD) supplemented with GP (100 mg/kg) by oral gavage for 11 weeks. GP supplementation alleviated HFD-induced body weight gain and visceral obesity, and reduced serum cholesterol, triglyceride, and LDL-C levels. In addition, GP ameliorated insulin resistance and prevented hepatic lipid accumulation and meta-inflammation in both liver and adipose tissues in obese mice. Remarkably, GP treatment restored the Firmicutes/Bacteroidetes ratio, induced growth of beneficial bacteria including Clostridium XlVa, Parvibacter, and Enterorhabdus, and decreased in inflammation-related bacteria Mucispirillum in mice fecal samples, accompanied with enhanced production of colonic short chain fatty acids especially butyric acid. However, the metabolic benefits of GP diminished in antibiotics-treated HFD-fed mice. Overall, GP improved metabolic profiles in HFD-induced obese mice via the mediation of gut microbiota-dependent pathways. GP might be developed and utilized as prebiotics in nutraceutical and food industry.

Discovery, preparation and characterization of lipid-lowering alkylphenol derivatives from Syzygium jambos fruit

The chemical characteristics and hypolipidemic effects of alkylphenols in the fruit of Syzygium jambos were investigated in this study. Three cardanols (1-3; 1 as a new compound) and three alkylresorcinols (4-6) were isolated and identified from S. jambos fruit. Cardanols 1 and 2 (10-40 μM) suppressed lipids accumulation and reduced triglyceride content in oleic acid-overloaded HepG2 cells via the activation of AMPK/PPARα signaling pathways. Furthermore, the biological distribution of cardanols after an oral intake in mice was investigated. Compound 2 was detected in mice plasma, feces, and adipose tissues after a single oral intake (80 mg/kg body weight). In addition, an alkylphenols-enriched S. jambos fruit extract containing two bioactive compounds (95.9 and 198.6 μg/mg of compounds 1 and 2, respectively) was prepared. Findings from the current study highlight the potential usage of cardanols as well as S. jambos fruit for the management of dyslipidemia.

Broussonetia papyrifera Polysaccharide Alleviated Acetaminophen-Induced Liver Injury by Regulating the Intestinal Flora

Liver injury caused by an overdose of acetaminophen (APAP) is a major public health problem. This study aimed to evaluate the effects of Broussonetia papyrifera polysaccharide (BPP) on liver injury and intestinal flora induced by APAP. The results showed that BPP could protect against APAP-induced liver injury, alleviate liver apoptosis, improve antioxidant capacity and enhance the liver’s detoxification ability to APAP. At the same time, BPP improved the intestinal flora disorder caused by APAP. More importantly, we found that the hepatoprotective effect of BPP disappeared after the depletion of gut microbiota in mice. Further, we reconstructed the intestinal flora structure of mice through fecal microbiota transplantation and found that the symptoms of APAP—induced liver injury were effectively alleviated. Overall, BPP was a potential hepatoprotective drug that could protect against APAP-induced liver injury and might be mediated by intestinal flora.

Antiulcer Potential of Psidium guajava Seed Extract Supported by Metabolic Profiling and Molecular Docking

One of the most severe human health problems is gastric ulceration. The main aim of our study is to explore the gastroprotective effect of the Psidium guajava seeds extract (PGE). Metabolic profiling based on LC-HRMS for the extract led to the dereplication of 23 compounds (1–23). We carried out a gastric ulcer model induced by indomethacin in male albino rats in vivo and the extract of PGE was investigated at a dose of 300 mg/kg in comparison to cimetidine (100 mg/kg). Furthermore, the assessment of gastric mucosal lesions and histopathology investigation of gastric tissue was done. It has been proved that Psidium guajava seeds significantly decreased the ulcer index and protected the mucosa from lesions. The antiulcer effect of Psidium guajava seed extract, which has the power of reducing the ensuing inflammatory reactions, can counteract the inflammation induced by indomethacin by the downregulation of relative genes expression (IL-1β, IL-6, and TNF-α). Moreover, PGE significantly downregulated the increased COX-2, TGF-β, and IGF-1 relative genes expression, confirming its beneficial effect in ulcer healing. Moreover, the possible PGE antioxidant potential was determined by in vitro assays using hydrogen peroxide and superoxide radical scavenging and revealed high antioxidant potential. Additionally, on the putatively annotated metabolites, an in silico study was conducted, which emphasized the extract’s antiulcer properties might be attributed to several sterols such as stigmasterol and campesterol. The present study provided evidence of Psidium guajava seeds considered as a potential natural gastroprotective agent.

AKAP12 ameliorates liver injury via targeting PI3K/AKT/PCSK6 pathway

A kinase anchor protein 12（AKAP12）is a scaffold protein that is critical for cell structure maintenance and signal transduction. However, the role of AKAP12 in liver injury remains unclear. Here, we attempt to explore the potential contribution of AKAP12 in liver injury and elucidate its underlying molecular mechanism. We found that AKAP12 deletion in acute liver injury (ALI) activates the PI3K/AKT phosphorylation signaling pathway, induces the increased expression of PCSK6 and its downstream inflammation-related genes, and prompts macrophages to produce a large number of inflammatory factors. And knockdown of PCSK6 by in vivo siRNA assay reversed in liver injury AKAP12^Δhep mice, demonstrating that PCSK6 has an important role in ALI. Furthermore, we found that signal transducer and activator of transcription 3 (STAT3) and serine/threonine kinase Akt (AKT) were upregulated in AKAP12^Δhep mice of chronic liver injury. To sum up, our study here demonstrates that AKAP12 has a protective role in ALI and chronic liver fibrosis, at least in part through inhibition of the PI3K/AKT/PCSK6 pathway. Our findings provide a new potential treatment for liver injury with important clinical implications.

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The PI3K-AKT pathway is activated in the liver of AKAP12^Δhep mice upon ALI.

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Increased PCSK6 expression is the main cause of aggravated ALI in AKAP12^Δhep mice.

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Increased phosphorylation levels of STAT3 and AKT promote liver fibrosis in AKAP12^Δhep mice.

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AKAP12 ameliorates liver injury through reprogramming PI3K/AKT/PCSK6 pathway.

Antioxidant Effects of Irisin in Liver Diseases: Mechanistic Insights

Oxidative stress is a crucial factor in the development of various liver diseases. Irisin, a metabolic hormone discovered in 2012, is mainly produced by proteolytic cleavage of fibronectin type III domain containing 5 (FNDC5) in skeletal muscles. Irisin is induced by physical exercise, and a rapidly growing body of literature suggests that irisin is, at least partially, responsible for the beneficial effects of regular exercise. The major biological function of irisin is believed to be involved in the maintenance of metabolic homeostasis. However, recent studies have suggested the therapeutic potential of irisin against a variety of liver diseases involving its antioxidative function. In this review, we aim to summarize the accumulating evidence demonstrating the antioxidative effects of irisin in liver diseases, with an emphasis on the current understanding of the potential molecular mechanisms.

Inhibitory activity and mechanism of guavinoside B from guava fruits against α-glucosidase: Insights by spectroscopy and molecular docking analyses

Guavinoside B (GUB) is the main active substance in guava fruit and shows promising biological activities. In this study, the inhibitory activity and mechanism of GUB on α-glucosidase were studied by using spectroscopic techniques, kinetic analysis, and molecular docking. Results indicated that GUB possessed significant inhibition ability on α-glucosidase, which was about 10 times that of acarbose. The GUB was a mixed-type inhibitor, which suppressed the activity of α-glucosidase through a reversible process. Fluorescence analysis revealed that GUB quenched the fluorescence of α-glucosidase statically, the formation of GUB-α-glucosidase complex was a spontaneous and exothermic process, van der Waals forces, hydrogen bonding, and hydrophobic interaction were the predominant driving forces, only one single-binding site on α-glucosidase was involved in the binding process. GUB inserted into the hydrophobic pocket of α-glucosidase with 11 hydrogen bonds and two π-π stacking formed. The presence of GUB changed the microenvironment near the fluorescent amino acids of α-glucosidase, and the structure of α-glucosidase was slightly changed, eventually leading to the decrease of α-glucosidase activity. PRACTICAL APPLICATIONS: Diabetes mellitus (DM) is a worldwide chronic metabolic disease threatening human health seriously. Guava fruit is a popular fruit, and its extracts were reported to show many biological activities. GUB is the main benzophenone glycoside in guava fruits. However, the inhibitory activity and mechanism of its specific active compound GUB are still unclear. Studies have shown that GUB could reversibly inhibit the activity of α-glucosidase, and its inhibitory ability was about 10 times that of acarbose. The kinetics and mechanism of inhibition were revealed. These will facilitate the further research and application of guava fruit and GUB in functional and healthy foods against hyperglycinaemia or even DM.

Cancer Chemopreventive Role of Dietary Terpenoids by Modulating Keap1-Nrf2-ARE Signaling System—A Comprehensive Update

ROS, RNS, and carcinogenic metabolites generate excessive oxidative stress, which changes the basal cellular status and leads to epigenetic modification, genomic instability, and initiation of cancer. Epigenetic modification may inhibit tumor-suppressor genes and activate oncogenes, enabling cells to have cancer promoting properties. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that in humans is encoded by the NFE2L2 gene, and is activated in response to cellular stress. It can regulate redox homoeostasis by expressing several cytoprotective enzymes, including NADPH quinine oxidoreductase, heme oxygenase-1, UDP-glucuronosyltransferase, glutathione peroxidase, glutathione-S-transferase, etc. There is accumulating evidence supporting the idea that dietary nutraceuticals derived from commonly used fruits, vegetables, and spices have the ability to produce cancer chemopreventive activity by inducing Nrf2-mediated detoxifying enzymes. In this review, we discuss the importance of these nutraceuticals in cancer chemoprevention and summarize the role of dietary terpenoids in this respect. This approach was taken to accumulate the mechanistic function of these terpenoids to develop a comprehensive understanding of their direct and indirect roles in modulating the Keap1-Nrf2-ARE signaling system.

The Dietary Supplement γ-Oryzanol Attenuates Hepatic Ischemia Reperfusion Injury via Inhibiting Endoplasmic Reticulum Stress and HMGB1/NLRP3 Inflammasome

The purpose of this study is to investigate the protective effect of γ-oryzanol (ORY) against hepatic ischemia reperfusion (HIR) injury and the potential protective mechanisms of ORY. ORY is an important biologically active ingredient isolated from rice bran oil, which has anti-inflammatory and antiapoptotic effects. However, it is still unknown whether ORY can protect the liver from the HIR damage. In this study, ORY was administered orally for seven days, after which the animals were subjected to liver ischemia for 60 minutes and reperfused for 6 hours. Related indicators were analyzed. The results showed that ORY pretreatment significantly reduced the levels of AST and ALT, relieved hepatocellular damage and apoptosis, and attenuated the exhaustion of SOD and GSH and accumulation of MDA and MPO. Interestingly, ORY treatment could significantly decreased ER stress. Furthermore, ORY pretreatment remarkably reduced the protein expressions of HMGB1, NLRP3, caspase-1 (p20), and IL-1β to protect the liver from I/R-induced inflammasome activation and apoptosis. In conclusion, we demonstrated the potential effect of ORY in modulating oxidative stress, endoplasmic reticulum stress, and inflammasome activation during HIR.

Guava (Psidium guajava L.): a glorious plant with cancer preventive and therapeutic potential

Guava (Psidium guajava L.) tree (Myrtaceae family) bears fruit rich in vitamins, fiber, and other nutrients. While native to Latin America, guava is grown in many tropical and subtropical regions across the globe where it has long been used in traditional medicine to treat a myriad of ailments. Guava has been shown to exhibit a number of biological and pharmacological activities, such as antioxidant, anti-inflammatory, immunomodulatory, antimicrobial, antidiabetic, and anticancer properties. Several parts of the plant, including the leaves, fruits, seeds, peels, pulp, bark, and oil, produce phytochemicals with medicinal properties. Emerging research has found that guava bioactive phytochemicals exert antitumorigenic effects against various human malignancies through multiple mechanisms. While there are numerous individual studies that document the anticancer effects of guava constituents, an up-to-date, comprehensive, and critical review of available research data has not been performed. Therefore, the purpose of this review is to present a complete analysis of the cancer preventive and anticancer therapeutic potential of guava-derived products and guava constituents, with a focus on the cellular and molecular mechanisms of action. The bioavailability, pharmacokinetics, and toxicity of guava as well as limitations, challenges, and future directions of research have also been discussed.

Chemical Characterization and Hepatoprotective Effects of a Standardized Triterpenoid-Enriched Guava Leaf Extract

Nutraceutical/pharmaceutical agents capable of maintaining redox and inflammation homeostasis are considered as candidates for the prevention and/or treatment of liver diseases. Psidium guajava (commonly known as guava) leaf is a commercially available functional food that has been reported to possess hepatoprotective property. However, the hepatoprotective constituents in guava leaf are not known. In the current study, a standardized triterpenoid-enriched extract of guava leaves (TGL) was developed. A new ursolic acid derivative, namely 2α,3β,6β,23,30-pentahydroxyurs-11,13(18)-dien-28,20β-olide (1), and 23 known triterpenoids were isolated and identified from TGL. The hepatoprotective effects of TGL were evaluated through a model using acetaminophen (APAP)-exposed C57BL/6 male mice. Pretreatment of TGL (75 and 150 mg/kg) restored the mice hepatic architecture, improved the serum ALT and AST levels, and reduced the hepatic ROS and MDA contents. Further molecular mechanistic study revealed that TGL modulated Nrf2 and MAPK signaling pathways to alleviate APAP-induced oxidative and inflammatory stress in liver. In addition, the new compound 1 from TGL showed protective effects against APAP-induced cytotoxicity via activation of the Nrf2 pathway in HepG2 cells. Overall, this is the first report on the hepatoprotective effects of a standardized triterpenoid-enriched extract of guava leaves, which supports its potential nutraceutical application in liver disease management.

Protective effect of Que Zui tea hot-water and aqueous ethanol extract against acetaminophen-induced liver injury in mice via inhibition of oxidative stress, inflammation, and apoptosis

The tender leaves and buds of Vaccinium dunalianum Wight have been traditionally processed as folk tea, known as Que Zui tea (QT), with a wide range of benefits to humans. In this study, Que Zui tea hot-water extract (QTW) and aqueous-ethanol extract (QTE) were tested for their effectiveness to alleviate acetaminophen (APAP)-induced liver damage. QTW and QTE significantly inhibited the alanine aminotransaminase, aspartate aminotransaminase, tumor necrosis factor-α, interleukin-6, and interleukin-1β levels in the serum. Both extracts also ameliorated pathological damage and inhibited oxidative stress in the liver of APAP-induced mice. In addition, QTW and QTE activated the nuclear erythroid related factor 2 signal pathway, and inhibited mitogen-activated protein kinase activation. QTW and QTE also suppressed hepatocyte apoptosis by improvement of Bcl-2/Bax and inhibition of caspase-3 and caspase-9 expression. The results demonstrated that QTW and QTE could effectively protect APAP hepatotoxicity, which might be attributed to their antioxidant, anti-inflammatory and anti-apoptosis activities.