Screening and tissue distribution of protein tyrosine phosphatase 1B inhibitors in mice following oral administration of Garcinia mangostana L. ethanolic extract

Toxicokinetics and bioavailability of indoxacarb enantiomers and their new metabolites in rats

Indoxacarb is a chiral insecticide that consists of two enantiomers, S-(+)-indoxacarb and R-(-)-indoxacarb, of which only S-(+)-indoxacarb has insecticidal activity. Previous enantioselective toxicology studies of indoxacarb focused mostly on simple environmental model organisms. The lack of a toxicology evaluation of indoxacarb conducted in a mammalian system could mean that the extent of the potential health risk posed by the insecticide to humans is not adequately known. In this study, we reported on a new pair of enantiomers, S-IN-RM294 and R-IN-RM294, derived from the metabolic breakdown of S-(+)-indoxacarb and R-(-)-indoxacarb, respectively, in rats. The toxicokinetics of S-(+)-indoxacarb, R-(-)-indoxacarb, S-IN-RM294, and R-IN-RM294 in rats were evaluated to provide a more comprehensive risk assessment of these molecules. The bioavailability and excretion rates of both S-(+)-indoxacarb and R-(-)-indoxacarb were relatively low, which may be due to their faster metabolism and accumulation in the tissues. In addition, there were significant differences in the metabolism and distribution between the two indoxacarb enantiomers and their metabolites in vivo. S-(+)-Indoxacarb was found to be more easily metabolized in the blood compared with R-(-)-indoxacarb, as shown by the differences in pharmacokinetic parameters between oral and intravenous administration. Analysis of their tissue distribution showed that S-(+)-indoxacarb was less likely to accumulate in most tissues. The results obtained for the two metabolites were consistent with those of the two parent compounds. S-IN-RM294 was more readily cleared from the blood and less likely to accumulate in the tissues compared with R-IN-RM294. Therefore, whether from the perspective of insecticidal activity or from the perspective of mammalian and environmental friendliness, the application of optically pure S-(+)-indoxacarb in agriculture may be a more efficient and safer strategy.

Some evidence supporting the use of optically pure R-(-)-diniconazole: Toxicokinetics and configuration conversion on chiral diniconazole

Diniconazole is a chiral pesticide that exists in two enantiomers, R-(-)-diniconazole and S-(+)-diniconazole, with the R-enantiomer being much more active than the S-enantiomer. Previous enantioselective toxicology studies of diniconazole focused mostly on simple environmental model organisms. In this study, we evaluated the toxicokinetics of the two diniconazole enantiomers in rats and mice to provide a more comprehensive risk assessment. The two enantiomers displayed clear differences in their stereoselective contents in vivo. The t1/2 of R-(-)-diniconazole was 7.06 ± 3.35 h, whereas that of S-(+)-diniconazole was 9.14 ± 4.60 h, indicating that R-(-)-diniconazole was eliminated faster in vivo. The excretion rates of R-(-)-diniconazole and S-(+)-diniconazole were 4.08 ± 0.50 % and 2.68 ± 0.58 %, respectively, indicating more excretion of R-(-)-diniconazole. S-(+)-diniconazole had a higher bioavailability than R-(-)-diniconazole (52.19 % vs. 42.44 %). S-(+)-Diniconazole was also found in relatively high abundance in tissues such as the stomach, large intestine, small intestine, cecum, liver, kidney, brain, and testes, with the abundance being 1.71-2.48-fold that of R-(-)-diniconazole. The selective degradation of both enantiomers in the tissues and their mutual conversion in vivo were not observed, and this could indicate that configuration conversion did not contribute to the differences in the content of enantiomers in the tissues. Instead, such differences were mainly caused by the differences in affinity of each enantiomer for the tissues. Furthermore, investigation of the interconversion between optically pure R-(-)-diniconazole and S-(+)-diniconazole monomers in soil revealed no interconversion. All of the above results indicated no interconversion between R-(-)-diniconazole and S-(+)-diniconazole in vivo and in the soil, and that S-(+)-diniconazole tends to have a greater potential to accumulate in vivo. Thus, if only R-(-)-diniconazole is used as a pesticide, the negative impact on mammals and the environment will be reduced, suggesting that in agriculture, the application of optically pure R-(-)-diniconazole may be a better strategy.

Anti-Angiogenic Effects of Natural Compounds in Diet-Associated Hepatic Inflammation

Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are the most common causes of chronic liver disease and are increasingly emerging as a global health problem. Such disorders can lead to liver damage, resulting in the release of pro-inflammatory cytokines and the activation of infiltrating immune cells. These are some of the common features of ALD progression in ASH (alcoholic steatohepatitis) and NAFLD to NASH (non-alcoholic steatohepatitis). Hepatic steatosis, followed by fibrosis, lead to a continuous progression accompanied by angiogenesis. This process creates hypoxia, which activates vascular factors, initiating pathological angiogenesis and further fibrosis. This forms a vicious cycle of ongoing damage and progression. This condition further exacerbates liver injury and may contribute to the development of comorbidities, such as metabolic syndrome as well as hepatocellular carcinoma. Increasing evidence suggests that anti-angiogenic therapy may have beneficial effects on these hepatic disorders and their exacerbation. Therefore, there is a great interest to deepen the knowledge of the molecular mechanisms of natural anti-angiogenic products that could both prevent and control liver diseases. In this review, we focus on the role of major natural anti-angiogenic compounds against steatohepatitis and determine their potential therapeutic benefits in the treatment of liver inflammation caused by an imbalanced diet.

Botanical characteristics, chemical components, biological activity, and potential applications of mangosteen

Garcinia mangostana L. (Mangosteen), a functional food, belongs to the Garcinaceae family and has various pharmacological effects, including anti-oxidative, anti-inflammatory, anticancer, antidiabetic, and neuroprotective effects. Mangosteen has abundant chemical constituents with powerful pharmacological effects. After searching scientific literature databases, including PubMed, Science Direct, Research Gate, Web of Science, VIP, Wanfang, and CNKI, we summarized the traditional applications, botanical features, chemical composition, and pharmacological effects of mangosteen. Further, we revealed the mechanism by which it improves health and treats disease. These findings provide a theoretical basis for mangosteen's future clinical use and will aid doctors and researchers who investigate the biological activity and functions of food.

Fast Screening of Protein Tyrosine Phosphatase 1B Inhibitor from Salvia miltiorrhiza Bge by Cell Display-Based Ligand Fishing

Salvia miltiorrhiza Bge is a medicinal plant (Chinese name "Danshen") widely used for the treatment of hyperglycemia in traditional Chinese medicine. Protein tyrosine phosphatase 1B (PTP1B) has been recognized as a potential target for insulin sensitizing for the treatment of diabetes. In this work, PTP1B was displayed at the surface of E. coli cells (EC-PTP1B) to be used as a bait for fishing of the enzyme's inhibitors present in the aqueous extract of S. miltiorrhiza. Salvianolic acid B, a polyphenolic compound, was fished out by EC-PTP1B, which was found to inhibit PTP1B with an IC₅₀ value of 23.35 µM. The inhibitory mechanism of salvianolic acid B was further investigated by enzyme kinetic experiments and molecular docking, indicating salvianolic acid B was a non-competitive inhibitor for PTP1B (with Ki and Kis values of 31.71 µM and 20.08 µM, respectively) and its binding energy was -7.89 kcal/mol. It is interesting that in the comparative work using a traditional ligand fishing bait of PTP1B-immobilized magnetic nanoparticles (MNPs-PTP1B), no ligands were extracted at all. This study not only discovered a new PTP1B inhibitor from S. miltiorrhiza which is significant to understand the chemical basis for the hypoglycemic activity of this plant, but also indicated the effectiveness of cell display-based ligand fishing in screening of active compounds from complex herbal extracts.

Toxicokinetics of Two Oxathiapiprolin Enantiomers in Rats and Their Stereoselective Interaction with Oxysterol Binding Protein

Oxathiapiprolin is a chiral fungicide, and it can affect the metabolism of the cholesterol compounds by inhibiting oxysterol binding protein (OSBP) to exert its fungicidal effect. The application of oxathiapiprolin in agriculture is widespread, and its residue in the environment is a threat to both human and animal health. The two oxathiapiprolin enantiomers differ in their fungicidal activity, biotoxicity, and degradation by environmental forces. However, their biotoxicity has not been reported in animals. The toxicokinetics of a pesticide should be a crucial component for the evaluation of its toxicity in vivo. In this study, we investigated the absorption, bioavailability, tissue distribution, and excretion of the two oxathiapiprolin enantiomers in rats to verify their toxicokinetic process in animals. An ultrahigh-performance liquid chromatography triple quadrupole tandem mass spectrometry (UHPLC-QQQ/MS) method was established to quantify the two oxathiapiprolin enantiomers in vivo. The two oxathiapiprolin enantiomers were found to have approximately the same absorption rate and bioavailability, and both were excreted mainly in the feces. The half-life of R-(-)-oxathiapiprolin was nearly twice that of S-(+)-oxathiapiprolin. R-(-)-oxathiapiprolin also had greater distribution than S-(+)-oxathiapiprolin in the liver, lungs, heart, spleen, kidneys, stomach, large intestine, small intestine, brain, and pancreas, supporting the notion that R-(-)-oxathiapiprolin could better bind with OSBP. The stereoselectivity of S-(+)-oxathiapiprolin in these tissues may be responsible for it being readily metabolized in vivo. The molecular docking technique was subsequently used to verify the more superior binding between R-(-)-oxathiapiprolin and OSBP compared with the binding between S-(+)-oxathiapiprolin and OSBP. The findings of this study could provide more reliable data for determining the toxicokinetics of a single enantiomer of oxathiapiprolin in animals, thereby providing some theoretical basis for its subsequent toxicological study.

Inhibitory Effects against Alpha-Amylase of an Enriched Polyphenol Extract from Pericarp of Mangosteen (Garcinia mangostana)

The pericarp of mangosteen, a by-product of the mangosteen, is rich in polyphenols. In this study, an efficient and environmentally friendly method for preparative enrichment of polyphenols from mangosteen pericarp (MPPs) was developed, and the inhibitory effects on starch digestion were also evaluated. It was found that the optimal extract method of MPPs was at a solid to solvent ratio of 1:50 g/mL, pH of 2, and at 80 °C for 2 h. The IC₅₀ of MPPs for α-amylase was 0.28 mg/mL. Based on the fluorescence quenching results, we presumed that MPPs could alter the natural structure of α-amylase, resulting in inhibitory activity on α-amylase. In addition, MPPs significantly reduced the blood glucose peak and AUC of glucose responses in rats after ingestion of the starch solution. Taken together, MPPs may have the potential as a functional supplement for blood glucose control and diabetes prevention.

Potential active constituents responsible for treating acute pharyngitis in the flowers of Hosta plantaginea (Lam.) Aschers and their pharmacokinetics

In Asia, the flower of Hosta plantaginea (Lam.) Aschers (hosta flower) is both an edible food and medicine. The hosta flower is often used as a material for cooking porridge...

Approaches to Decrease Hyperglycemia by Targeting Impaired Hepatic Glucose Homeostasis Using Medicinal Plants

Liver plays a pivotal role in maintaining blood glucose levels through complex processes which involve the disposal, storage, and endogenous production of this carbohydrate. Insulin is the hormone responsible for regulating hepatic glucose production and glucose storage as glycogen, thus abnormalities in its function lead to hyperglycemia in obese or diabetic patients because of higher production rates and lower capacity to store glucose. In this context, two different but complementary therapeutic approaches can be highlighted to avoid the hyperglycemia generated by the hepatic insulin resistance: 1) enhancing insulin function by inhibiting the protein tyrosine phosphatase 1B, one of the main enzymes that disrupt the insulin signal, and 2) direct regulation of key enzymes involved in hepatic glucose production and glycogen synthesis/breakdown. It is recognized that medicinal plants are a valuable source of molecules with special properties and a wide range of scaffolds that can improve hepatic glucose metabolism. Some molecules, especially phenolic compounds and terpenoids, exhibit a powerful inhibitory capacity on protein tyrosine phosphatase 1B and decrease the expression or activity of the key enzymes involved in the gluconeogenic pathway, such as phosphoenolpyruvate carboxykinase or glucose 6-phosphatase. This review shed light on the progress made in the past 7 years in medicinal plants capable of improving hepatic glucose homeostasis through the two proposed approaches. We suggest that Coreopsis tinctoria, Lithocarpus polystachyus, and Panax ginseng can be good candidates for developing herbal medicines or phytomedicines that target inhibition of hepatic glucose output as they can modulate the activity of PTP-1B, the expression of gluconeogenic enzymes, and the glycogen content.

Ferulic Acid Ameliorates Hepatic Inflammation and Fibrotic Liver Injury by Inhibiting PTP1B Activity and Subsequent Promoting AMPK Phosphorylation

Chronic inflammation in response to persistent exogenous stimuli or damage results in liver fibrosis, which subsequently progresses into malignant liver diseases with high morbidity and mortality. Ferulic acid (FA) is a phenolic acid widely isolated from abundant plants and exhibits multiple biological activities including anti-oxidant, anti-inflammation and enhancement of immune responses. Adenosine monophosphate-activated protein kinase (AMPK) functions as a critical energy sensor and is regulated through the phosphorylation of liver kinases like LKB1 or dephosphorylation by protein tyrosine phosphatases (PTPs). However, the role of FA in carbon tetrachloride (CCl₄)-induced chronic inflammation and liver fibrosis and AMPK activation has not been elucidated. Here we reported that FA ameliorated CCl₄-induced inflammation and fibrotic liver damage in mice as indicated by reduced levels of serum liver function enzyme activities and decreased expression of genes and proteins associated with fibrogenesis. Additionally, FA inhibited hepatic oxidative stress, macrophage activation and HSC activation via AMPK phosphorylation in different liver cells. Mechanically, without the participation of LKB1, FA-induced anti-inflammatory and anti-fibrotic effects were abrogated by a specific AMPK inhibitor, compound C. Combining with the results of molecular docking, surface plasmon resonance and co-immunoprecipitation assays, we further demonstrated that FA directly bound to and inhibited PTP1B, an enzyme responsible for dephosphorylating key protein kinases, and eventually leading to the phosphorylation of AMPK. In summary, our results indicated that FA alleviated oxidative stress, hepatic inflammation and fibrotic response in livers through PTP1B-AMPK signaling pathways. Taken together, we provide novel insights into the potential of FA as a natural product-derived therapeutic agent for the treatment of fibrotic liver injury.

Gelatin-Graphene Oxide Nanocomposite Hydrogels for Kluyveromyces lactis Encapsulation: Potential Applications in Probiotics and Bioreactor Packings

Nutraceutical formulations based on probiotic microorganisms have gained significant attention over the past decade due to their beneficial properties on human health. Yeasts offer some advantages over other probiotic organisms, such as immunomodulatory properties, anticancer effects and effective suppression of pathogens. However, one of the main challenges for their oral administration is ensuring that cell viability remains high enough for a sustained therapeutic effect while avoiding possible substrate inhibition issues as they transit through the gastrointestinal (GI) tract. Here, we propose addressing these issues using a probiotic yeast encapsulation strategy, Kluyveromyces lactis, based on gelatin hydrogels doubly cross-linked with graphene oxide (GO) and glutaraldehyde to form highly resistant nanocomposite encapsulates. GO was selected here as a reinforcement agent due to its unique properties, including superior solubility and dispersibility in water and other solvents, high biocompatibility, antimicrobial activity, and response to electrical fields in its reduced form. Finally, GO has been reported to enhance the mechanical properties of several materials, including natural and synthetic polymers and ceramics. The synthesized GO-gelatin nanocomposite hydrogels were characterized in morphological, swelling, mechanical, thermal, and rheological properties and their ability to maintain probiotic cell viability. The obtained nanocomposites exhibited larger pore sizes for successful cell entrapment and proliferation, tunable degradation rates, pH-dependent swelling ratio, and higher mechanical stability and integrity in simulated GI media and during bioreactor operation. These results encourage us to consider the application of the obtained nanocomposites to not only formulate high-performance nutraceuticals but to extend it to tissue engineering, bioadhesives, smart coatings, controlled release systems, and bioproduction of highly added value metabolites.