Oxyresveratrol and Gnetol Glucuronide Metabolites: Chemical Production, Structural Identification, Metabolism by Human and Rat Liver Fractions, and In Vitro Anti-inflammatory Properties

The genus Gnetum: Traditional use, phytochemistry, nutritional value, biosynthesis, synthesis, pharmacology, toxicology, synthetic advance, and pharmacokinetics

BACKGROUND

Gnetum is the sole genus within the family Gnetaceae. Numerous species are edible, their seeds can be roasted, and the leaves can be consumed as vegetables. Gnetum plants have been highly esteemed in traditional folk medicine worldwide for many years. An extensive review highlighting the significant value of this genus is currently unavailable.

OBJECTIVE

This study aims to systematically present the state of the art in phytochemistry, food chemistry, biosynthesis, synthesis, pharmacology, toxicology, synthetic advance, and pharmacokinetics.

METHOD

The relevant references were collected from various electronic sources, including Google Scholar, Web of Science, and reputable journals. "Gnetum" was the primary keyword used to search for publications. Data collection was conducted from 1978 to now, and more than 150 articles have been reviewed.

RESULTS

Among the 261 identified phytochemicals, 180 compounds were elucidated as stilbenoids. Gnetum metabolites also contained other classes, such as lignans, flavonoids, monophenols, alkaloids, and fatty acids. The major compound, isorhapontigenin, is considered the most important agent in the genus Gnetum. It is also noted that Gnetum plants are rich in nutritional content, including fibers, carbohydrates, vitamins, essential amino acids, and minerals. Gnetum plant extracts are safe, with low toxicity levels. In general, oxidative reactions among radicals are responsible for the biosynthesis of Gnetum stilbenoids, whereas glucuronidation of hydroxyl groups is the main pharmacokinetic action. Pharmacological activities of Gnetum constituents have been reported to include anticancer, antioxidative, anti-inflammatory, antimicrobial, antidiabetic, antihyperuricemic, anti-obesity, antimalarial, antiviral, antiplatelet, estrogenic, and protective actions for various organs. Various in vitro and in vivo pharmacological assays have successfully explained these activities through molecular mechanisms, such as the MAPK (mitogen-activated protein kinase) or NF-κB (nuclear factor-kappa B) signaling pathways.

CONCLUSION

Further pharmacological assessments are warranted, particularly focusing on minor and newly discovered compounds. Enhancements in bioavailability and the development of novel synthetic agents derived from Gnetum are anticipated.

Unlocking Gut Health: The Potent Role of Stilbenoids in Intestinal Homeostasis

Stilbenoids are a class of naturally occurring phenolic compounds found in various plant species, characterized by a stilbene backbone with diverse substituents that confer a range of biological activities. These compounds exhibit antioxidant, anti-inflammatory, and antimicrobial properties, making them promising candidates for improving intestinal health. The intestinal tract plays a critical role in nutrient digestion, absorption, and immune defense, and maintaining its integrity is vital for animal growth. Stilbenoids contribute to gut health by enhancing intestinal morphology, supporting mucosal immune responses, regulating gut microbiota composition, modulating metabolic pathways, and maintaining mitochondrial health. This review provides a comprehensive analysis of key stilbenoids, including resveratrol, pterostilbene, piceatannol, and oxyresveratrol, focusing on their biological effects and regulatory mechanisms. By highlighting their roles in mitigating intestinal inflammation and promoting gut function, this review provides a basis for the practical application of stilbenoids in animal health and husbandry.

Protective Role of Dietary Polyphenols in the Management and Treatment of Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM), a serious metabolic disorder, is a worldwide health problem due to the alarming rise in prevalence and elevated morbidity and mortality. Chronic hyperglycemia, insulin resistance, and ineffective insulin effect and secretion are hallmarks of T2DM, leading to many serious secondary complications. These include, in particular, cardiovascular disorders, diabetic neuropathy, nephropathy and retinopathy, diabetic foot, osteoporosis, liver damage, susceptibility to infections and some cancers. Polyphenols such as flavonoids, phenolic acids, stilbenes, tannins, and lignans constitute an extensive and heterogeneous group of phytochemicals in fresh fruits, vegetables and their products. Various in vitro studies, animal model studies and available clinical trials revealed that flavonoids (e.g., quercetin, kaempferol, rutin, epicatechin, genistein, daidzein, anthocyanins), phenolic acids (e.g., chlorogenic, caffeic, ellagic, gallic acids, curcumin), stilbenes (e.g., resveratrol), tannins (e.g., procyanidin B2, seaweed phlorotannins), lignans (e.g., pinoresinol) have the ability to lower hyperglycemia, enhance insulin sensitivity and improve insulin secretion, scavenge reactive oxygen species, reduce chronic inflammation, modulate gut microbiota, and alleviate secondary complications of T2DM. The interaction between polyphenols and conventional antidiabetic drugs offers a promising strategy in the management and treatment of T2DM, especially in advanced disease stages. Synergistic effects of polyphenols with antidiabetic drugs have been documented, but also antagonistic interactions that may impair drug efficacy. Therefore, additional research is required to clarify mutual interactions in order to use the knowledge in clinical applications. Nevertheless, dietary polyphenols can be successfully applied as part of supportive treatment for T2DM, as they reduce both obvious clinical symptoms and secondary complications.

Unearthing the Potential Therapeutic Effects of Oxyresveratrol Based on Intrinsic Links between Pharmacological Effects: Implications for the Gut-Liver-Brain Axis

Oxyresveratrol is a stilbene compound with a simple chemical structure and various therapeutic potentials. This study summarized and analyzed the multiple pharmacological effects and mechanisms of oxyresveratrol, identifying its prominent performance in neuroprotection, hepatoprotection, and anti-inflammatory activities in the intestines. By integrating the pharmacological effects of oxyresveratrol with insights from the network pharmacology and molecular docking of its interactions with targets linked to gut-liver-brain axis disorders, it has been shown that oxyresveratrol may hold promise for the treatment of gut-liver-brain axis-related disorders. The synergistic effect between various mechanisms has inspired further research and the development of oxyresveratrol's application value.

Enhancing Solubility and Bioefficacy of Stilbenes by Liposomal Encapsulation-The Case of Macasiamenene F

Stilbenes in food and medicinal plants have been described as potent antiphlogistic and antioxidant compounds, and therefore, they present an interesting potential for the development of dietary supplements. Among them, macasiamenene F (MF) has recently been shown to be an effective anti-inflammatory and cytoprotective agent that dampens peripheral and CNS inflammation in vitro. Nevertheless, this promising molecule, like other stilbenes and a large percentage of drugs under development, faces poor water solubility, which results in trickier in vivo administration and low bioavailability. With the aim of improving MF solubility and developing a form optimized for in vivo administration, eight types of conventional liposomal nanocarriers and one type of PEGylated liposomes were formulated and characterized. In order to select the appropriate form of MF encapsulation, the safety of MF liposomal formulations was evaluated on THP-1 and THP-1-XBlue-MD2-CD14 monocytes, BV-2 microglia, and primary cortical neurons in culture. Furthermore, the cellular uptake of liposomes and the effect of encapsulation on MF anti-inflammatory effectiveness were evaluated on THP-1-XBlue-MD2-CD14 monocytes and BV-2 microglia. MF (5 mol %) encapsulated in PEGylated liposomes with an average size of 160 nm and polydispersity index of 0.122 was stable, safe, and the most promising form of MF encapsulation keeping its cytoprotective and anti-inflammatory properties.

Characterization of the molecular interactions between resveratrol derivatives and death-associated protein kinase 1

Death-associated protein kinase 1 (DAPK1), a Ca2+/calmodulin-regulated serine/threonine kinase, regulates cell apoptosis and autophagy and has been implicated in the pathogenesis of Alzheimer's disease (AD). Targeting DAPK1 may be a promising approach for treating AD. In our previous study, we found that a natural polyphenol, resveratrol (1), is a moderate DAPK1 inhibitor. In the present study, we investigated the interactions between natural and synthetic derivatives of 1 and DAPK1. Binding assays including intrinsic fluorescence quenching, protein thermal shift and isothermal titration calorimetry indicated that oxyresveratrol (3), a hydroxylated derivative, and pinostilbene (5), a methoxylated derivative, bind to DAPK1 with comparable affinity to 1. The enzymatic assay showed that 3 more effectively inhibits the intrinsic ATPase activity of DAPK1 compared with 1. Crystallographic analysis revealed that the binding modes of the methoxylated derivatives were different from those of 1 and 3, resulting in a unique interaction. Our results suggest that 3 may be helpful in treating AD and provide a clue for the development of promising DAPK1 inhibitors.