Phenolic Compound, Antioxidant, Antibacterial, and In Silico Studies of Extracts from the Aerial Parts of Lactuca saligna L.

Medicinal plants are considered a major source for discovering novel effective drugs. To our knowledge, no studies have reported the chemical composition and biological activities of Moroccan Lactuca saligna extracts. In this context, this study aims to characterize the polyphenolic compounds distributed in hydro-methanolic extracts of L. saligna and evaluate their antioxidant and antibacterial activities; in addition, in silico analysis based on molecular docking and ADMET was performed to predict the antibacterial activity of the identified phenolic compounds. Our results showed the identification of 29 among 30 detected phenolic compounds with an abundance of dicaffeoyltartaric acid, luteolin 7-glucoronide, 3,5-di-O-caffeoylquinic acid, and 5-caffeoylquinic acid with 472.77, 224.30, 196.79, and 171.74 mg/kg of dried extract, respectively. Additionally, antioxidant activity assessed by DPPH scavenging activity, ferric reducing antioxidant power (FRAP) assay, and ferrous ion-chelating (FIC) assay showed interesting antioxidant activity. Moreover, the results showed remarkable antibacterial activity against Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and Listeria monocytogenes with minimum inhibitory concentrations between 1.30 ± 0.31 and 10.41 ± 0.23 mg/mL. Furthermore, in silico analysis identified three compounds, including Apigenin 7-O-glucuronide, Quercetin-3-O-glucuronide, and 3-p-Coumaroylquinic acid as potent candidates for developing new antibacterial agents with acceptable pharmacokinetic properties. Hence, L. saligna can be considered a source of phytochemical compounds with remarkable activities, while further in vitro and in vivo studies are required to explore the main biological activities of this plant.

In-utero exposure to polybrominated biphenyl (PBB) and menstrual cycle function in adulthood.

BACKGROUND: There is evidence that in-utero exposure to PBBs, and similar chemicals, are associated with several adverse reproductive health outcomes including altered pubertal timing. However, less is known about the effects of in-utero exposure to PBBs on menstrual cycle function and reproductive hormone levels in adulthood. METHODS: For this menstrual cycle study, we recruited reproductive-aged women in the Michigan PBB Registry who were not pregnant, lactating, or taking hormonal medications (2004-2014). A total of 41 women who were born after the PBB contamination incident (1973-1974) and were prenatally exposed to PBBs, were included in this analysis. We estimated in-utero PBB exposure using maternal serum PBB measurements taken after exposure and extrapolated to time of pregnancy using a PBB elimination model. Women were followed for up to 6 months during which they provided daily urine samples and completed daily diaries. The urine samples were assayed for estrone 3-glucuronide (E13G), pregnanediol 3-glucuronide (Pd3G), and follicle stimulating hormone (FSH). RESULTS: Women in our study were, on average, 27.5 (SD:5.3) years old and contributed 4.9 (SD:1.9) menstrual cycles of follow-up. Compared to women with low in-utero PBB exposure (≤1 ppb), women with medium (>1.0-3.0 ppb) and high (>3.0 ppb) exposure had higher maximum 3-day mean Pd3G levels during the luteal phase. Specifically, the age- and creatinine-adjusted maximum 3-day mean luteal phase Pd3G levels (95% CI) in increasing categories of in-utero PBB exposure were 9.2 (4.6,13.9), 14.8 (11.6,18.0), and 16.1 (12.9,19.3) µg/mg creatinine. There were no meaningful differences in average cycle length, follicular or luteal phase cycle length, bleed length, or creatinine-adjusted E13G or FSH levels by category of in-utero PBB exposure. CONCLUSION: Higher exposure to PBB in-utero was associated with increased progesterone levels across the luteal phase, however, most other menstrual cycle characteristics were largely unassociated with in-utero PBB exposure. Given our modest sample size, our results require cautious interpretation.

Chrysin 7-O-ß-D-glucuronide, a dual inhibitor of SARS-CoV-2 3CLpro and PLpro, for the prevention and treatment of COVID-19.

The emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) resulted in the coronavirus disease 2019 (COVID-19) pandemic. Given the advent of subvariants, there is an urgent need to develop novel drugs. The aim of this study was to find SARS-CoV-2 inhibitors from Scutellaria baicalensis Georgi targeting the proteases 3CLpro and PLpro. After screening 25 flavonoids, chrysin 7-O-ß-D-glucuronide was found to be a potent inhibitor of SARS-CoV-2 on Vero E6 cells, with half-maximal effective concentration of 8.72 µM. Surface plasmon resonance assay, site-directed mutagenesis and enzymatic activity measurements indicated that chrysin-7-O-ß-D-glucuronide inhibits SARS-CoV-2 by binding to H41 of 3CLpro, and K157 and E167 of PLpro. Hydrogen-deuterium exchange mass spectrometry analysis showed that chrysin-7-O-ß-D-glucuronide changes the conformation of PLpro. Finally, chrysin 7-O-ß-D-glucuronide was shown to have anti-inflammatory activity, mainly due to reduction of the levels of the pro-inflammatory cytokines interleukin (IL)-1ß and IL-6.

Design, synthesis of auristatins-glucuronide conjugates targeting the ß-glucuronidase in tumor microenvironment.

Auristatins-glucuronide conjugates designed targeting the ß-Glucuronidase in tumor microenvironment were synthesized and evaluated on stabilities, the release of auristatins and the antitumor activities in this study. Conjugates 20 and 21 showed remarkable stabilities in phosphate buffer and bovine serum solution, and excellent selectivity between the in vitro antiproliferative activities against ß-glucuronidase pretreated and untreated cancer cells (IC50 = 5.7 nM âˆ¼ 9.7 nM, IC50 (-Enz) > 1 µM). Furthermore, conjugate 20 showed potent antitumor efficacy in HCT-116 xenograft mouse model without inducing side effects.

Anti-Inflammatory and Antioxidant Effects of Diosmetin-3-O-ß-d-Glucuronide, the Main Metabolite of Diosmin: Evidence from Ex Vivo Human Skin Models.

Diosmin is used to relieve chronic venous disease (CVD) symptoms. This study aimed to investigate the anti-inflammatory and antioxidant effects of diosmetin-3-O-ß-d-glucuronide, the major metabolite of diosmin, using human skin explants. The explants were exposed to substance P (inflammation model) or UVB irradiation (oxidative model) and to five diosmetin-3-O-ß-d-glucuronide concentrations. Inflammation was evaluated through interleukin-8 (IL-8) secretion measurements and capillary dilation observation, and oxidation was evaluated by measuring the hydrogen peroxide levels and observing cyclobutane pyrimidine dimers (CPDs). In substance-P-exposed explants, diosmetin-3-O-ß-d-glucuronide induced a significant decrease in IL-8 secretions, with a maximal effect at 2700 pg/mL (-49.6%), and it reduced the proportion of dilated capillaries and the mean luminal cross-sectional area (p < 0.0001 at all tested concentrations), indicating a vasoconstrictive effect. In UVB-irradiated fragments, diosmetin-3-O-ß-d-glucuronide induced a significant decrease in hydrogen peroxide production and in the number of CPD-positive cells, reaching a maximal effect at the concentration of 2700 pg/mL (-48.6% and -52.0%, respectively). Diosmetin-3-O-ß-d-glucuronide induced anti-inflammatory and antioxidant responses, with the maximal effect being reached at 2700 pg/mL and corresponding to the peak plasma concentration estimated after the oral intake of 600 mg of diosmin, the daily dose usually recommended for the treatment of CVD. These ex vivo findings suggest a protective role of diosmetin-3-O-ß-d-glucuronide against inflammatory and oxidative stress affecting the vascular system in CVD pathophysiology.

Flavonoid quercetin and its glucuronide and sulfate conjugates bind to 67-kDa laminin receptor and prevent neuronal cell death induced by serum starvation.

Quercetin, a dietary flavonoid, has been shown to protect against various neurodegenerative diseases with mechanisms largely unknown. After oral administration, quercetin is rapidly conjugated, and the aglycone is not detectable in the plasma and brain. However, its glucuronide and sulfate conjugates are present only at low nanomolar concentrations in the brain. Since quercetin and its conjugates have limited antioxidant capability at low nanomolar concentrations, it is crucial to determine whether they induce neuroprotection by binding to high-affinity receptors. Previously we found that (-)-epigallocatechin-3-gallate (EGCG), a polyphenol from green tea, induces neuroprotection by binding to the 67-kDa laminin receptor (67LR). Therefore, in this study, we determined whether quercetin and its conjugates bind 67LR to induce neuroprotection and compared their ability with EGCG. Based on the quenching of intrinsic tryptophan fluorescence of peptide G (residues 161-180 in 67LR), we found quercetin, quercetin-3-O-glucuronide, and quercetin-3-O-sulfate bind to this peptide with a high affinity comparable to EGCG. Molecular docking using the crystal structure of 37-kDa laminin receptor precursor supported the high-affinity binding of all these ligands to the site corresponding to peptide G. A pretreatment with quercetin (1-1000 nM) did not effectively protect Neuroscreen-1 cells from death induced by serum starvation. Contrarily, a pretreatment with low concentrations (1-10 nM) of quercetin conjugates better protected these cells than quercetin and EGCG. The 67LR-blocking antibody substantially prevented neuroprotection by all these agents, suggesting the role of 67LR in this process. Collectively, these studies reveal that quercetin induces neuroprotection primarily through its conjugates via high affinity binding to 67LR.

Oroxylin a glucuronide as a novel class of reversible inhibitors of Sortase a, combats MRSA-induced infections.

AIMS: The main purpose of this study was to study the therapeutical effect of oroxylin A glucuronide (OAG) on methicillin-resistant Staphylococcus aureus (MRSA). METHODS AND RESULTS: By substrate peptide reaction-based fluorescence resonance energy transfer (FRET) screening, we identified that OAG was an efficient inhibitor of Sortase A (SrtA) with an IC50 of 45.61 µg mL-1, and achieved efficacy in the treatment of Staphylococcus aureus (S. aureus) infections. We further demonstrated that OAG inhibited the adhesion of the S. aureus to fibrinogen, the surface protein A anchoring and diminished biofilm formation. Results obtained from fluorescence quenching assay elucidated a direct interaction between OAG and SrtA. Employing molecular dynamics simulations, we proved that OAG binds to the binding sites of R197, G192, E105, and V168 in the SrtA. Notably, OAG exhibited a robust therapeutic effect in a MRSA-induced pneumonia model. CONCLUSIONS: We identified that OAG as a novel class of reversible inhibitors of SrtA, combats MRSA-induced Infections.

Citrus flavanone metabolites significantly modulate global proteomic profile in pancreatic ß-cells under high-glucose-induced metabolic stress.

Hesperidin and narirutin are the major citrus flavanones. Several studies have associated these compounds with pancreatic ß-cell survival through their capacity to reduce oxidative stress, inflammation, and inhibit apoptosis. However, the molecular mechanisms of action of flavanones in pancreatic ß-cells under high-glycemic stress is still largely unknown. Therefore, this study aimed to decipher molecular mechanisms of flavanone metabolites in pancreatic ß-cells treated with high glucose concentration using untargeted shotgun proteomics. We identified 569 proteins differentially expressed in cells exposed to hesperetin 7-glucuronide (H7G) and 265 in cells exposed to 3-(4'-hydroxyphenyl) propanoic acid (PA). Comparison of global proteomic profiles suggest that these metabolites could counteract changes in protein expression induced by high glucose stress. The bioinformatic analyses suggested that H7G and PA modulated the expression of proteins involved in cell adhesion, cell signaling, metabolism, inflammation, and protein processing in endoplasmic reticulum (ER) pathways. Taken together, this study suggests that H7G and PA can modulate the expression of proteins that may prevent dysfunction of pancreatic ß-cells under stress induced by high glucose.

A host-gut microbial amino acid co-metabolite, p-cresol glucuronide, promotes blood-brain barrier integrity in vivo.

The sequential activity of gut microbial and host processes can exert a powerful modulatory influence on dietary components, as exemplified by the metabolism of the amino acids tyrosine and phenylalanine to p-cresol by gut microbes, and then to p-cresol glucuronide (pCG) by host enzymes. Although such glucuronide conjugates are classically thought to be biologically inert, there is accumulating evidence that this may not always be the case. We investigated the activity of pCG, studying its interactions with the cerebral vasculature and the brain in vitro and in vivo. Male C57Bl/6 J mice were used to assess blood-brain barrier (BBB) permeability and whole-brain transcriptomic changes in response to pCG treatment. Effects were then further explored using the human cerebromicrovascular endothelial cell line hCMEC/D3, assessing paracellular permeability, transendothelial electrical resistance and barrier protein expression. Mice exposed to pCG showed reduced BBB permeability and significant changes in whole-brain transcriptome expression. Surprisingly, treatment of hCMEC/D3 cells with pCG had no notable effects until co-administered with bacterial lipopolysaccharide, at which point it was able to prevent the permeabilizing effects of endotoxin. Further analysis suggested that pCG acts as an antagonist at the principal lipopolysaccharide receptor TLR4. The amino acid phase II metabolic product pCG is biologically active at the BBB, antagonizing the effects of constitutively circulating lipopolysaccharide. These data add to the growing literature showing glucuronide conjugates to be more than merely metabolic waste products and highlight the complexity of gut microbe to host communication pathways underlying the gut-brain axis.

Pharmacologic characterization of TBP1901, a prodrug form of aglycone curcumin, and CRISPR-Cas9 screen for therapeutic targets of aglycone curcumin.

Curcumin (aglycone curcumin) has antitumor properties in a variety of malignancies via the alteration of multiple cancer-related biological pathways; however, its clinical application has been hampered due to its poor bioavailability. To overcome this limitation, we have developed a synthesized curcumin ß-D-glucuronide sodium salt (TBP1901), a prodrug form of aglycone curcumin. In this study, we aimed to clarify the pharmacologic characteristics of TBP1901. In ß-glucuronidase (GUSB)-proficient mice, both curcumin ß-D-glucuronide and its active metabolite, aglycone curcumin, were detected in the blood after TBP1901 injection, whereas only curcumin ß-D-glucuronide was detected in GUSB-impaired mice, suggesting that GUSB plays a pivotal role in the conversion of TBP1901 into aglycone curcumin in vivo. TBP1901 itself had minimal antitumor effects in vitro, whereas it demonstrated significant antitumor effects in vivo. Genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 screen disclosed the genes associated with NF-κB signaling pathway and mitochondria were among the highest hit. In vitro, aglycone curcumin inhibited NF-kappa B signaling pathways whereas it caused production of reactive oxygen species (ROS). ROS scavenger, N-acetyl-L-cysteine, partially reversed antitumor effects of aglycone curcumin. In summary, TBP1901 can exert antitumor effects as a prodrug of aglycone curcumin through GUSB-dependent activation.

Metabolite Identification of a Novel Anti-Leishmanial Agent OJT007 in Rat Liver Microsomes Using LC-MS/MS.

The purpose of this study was to identify potential metabolic pathways and metabolites of OJT007, a methionine aminopeptidase 1 (MetAP1) inhibitor. OJT007 is a novel drug with potent antiproliferative effects against Leishmania Major. We conducted in vitro Phase I oxidation and Phase II glucuronidation assays on OJT007 using rat liver microsomes. Four unknown metabolites were initially identified using a UPLC-UV system from microsomal incubated samples. LC-MS/MS analysis was then used to identify the structural characteristics of these metabolites via precursor ion scan, neutral loss scan, and product ion scan. A glucuronide metabolite was further confirmed by ß-glucuronidase hydrolysis. The kinetic parameters of OJT007 glucuronidation demonstrated that OJT007 undergoes rapid metabolism. These results demonstrate the liver's microsomal ability to mediate three mono-oxidated metabolites and one mono-glucuronide metabolite. This suggests hepatic glucuronidation metabolism of OJT007 may be the cause of its poor oral bioavailability.

Interactions of resveratrol and its metabolites (resveratrol-3-sulfate, resveratrol-3-glucuronide, and dihydroresveratrol) with serum albumin, cytochrome P450 enzymes, and OATP transporters.

Resveratrol (RES) is a widely-known natural polyphenol which is also contained by several dietary supplements. Large doses of RES can result in high micromolar levels of its sulfate and glucuronide conjugates in the circulation, due to the high presystemic metabolism of the parent polyphenol. Pharmacokinetic interactions of RES have been extensively studied, while only limited data are available regarding its metabolites. Therefore, in the current study, we examined the interactions of resveratrol-3-sulfate (R3S), resveratrol-3-glucuronide, and dihydroresveratrol (DHR; a metabolite produced by the colon microbiota) with human serum albumin (HSA), cytochrome P450 (CYP) enzymes, and organic anion transporting polypeptides (OATP) employing in vitro models. Our results demonstrated that R3S and R3G may play a major role in the RES-induced pharmacokinetic interactions: (1) R3S can strongly displace the site I marker warfarin from HSA; (2) R3G showed similarly strong inhibitory action on CYP3A4 to RES; (3) R3S proved to be similarly strong (OATP1B1/3) or even stronger (OATP1A2 and OATP2B1) inhibitor of OATPs tested than RES, while R3G and RES showed comparable inhibitory actions on OATP2B1.

In vitro metabolic biomodulation of irinotecan to increase potency and reduce dose-limiting toxicity by inhibition of SN-38 glucuronide formation.

OBJECTIVES: Colorectal cancer continues to have one of the highest incidents of occurrence with a rising rate of diagnosis among people under the age of 50. Chemotherapy with irinotecan results in severe gastrointestinal dose-limiting toxicity that is caused by the glucuronidated form of the active metabolite (SN-38G). This study evaluates herbal compounds and analogs to biomodulate the metabolism of IR to decrease dose-limiting toxicity while increasing the amount of the active metabolite. METHODS: In vitro metabolism using human liver microsomes was conducted with white willow bark (WWB) extract, select specific components of WWB, and analogues to evaluate biomodulation of the IR metabolism. Samples were analyzed using liquid chromatography-tandem mass spectrometry to measure metabolites between reactions with and without herbals components. RESULTS: WWB showed an optimal decrease (>80%) in SN-38G and a corresponding increase in SN-38 levels (128%) at a concentration of near 200 µg/mL. Tannic acid produced a 75% decrease in SN-38G with a 130% increase in SN-38 at 10 µg/mL, whereas the treatment with beta-pentagalloyl glucose and various analogues decreased SN-38G by 70% and increased SN-38 by 20% at 10 µg/mL. CONCLUSIONS: These results suggest naturally occurring compounds from WWB may have the potential to increase potency by increasing the conversion of IR to SN-38 and decrease dose-limiting toxicity of IR chemotherapy by reducing glucuronidation of SN-38.

Structure, Biological Activities and Metabolism of Flavonoid Glucuronides.

BACKGROUND: Flavonoid glucuronides are a kind of natural products presenting a flavone linked directly with one or several glucuronides through O-glycoside bond. They had become of interest in natural product research in the past decades for their antioxidant, anti-inflammatory, and antibacteria activities. In particular, the compound breviscapine has a notable effect on cardiocerebrovascular diseases. Several other compounds even have antitumor activity. METHODS: Through searching the database and reading a large number of documents, we summarized the related findings of flavonoid glucuronides. RESULTS: We summarized 211 naturally occurring flavonoid glucuronides in 119 references with their chemical structures, biological activities, and metabolism. A total of 220 references from 1953 to 2020 were cited in this paper according to literature databases such as CNKI, Weipu, Wanfang data, Elsevier, Springer, Wiley, NCBI, PubMed, EmBase, etc. Conclusion: Flavonoid glucuronides are a class of compounds with various chemical structures and a diverse range of biological activities. They are thought to be potential candidates for drug discovery, but the specific study on their mechanisms is still limited until now. We hope this article can provide references for natural product researchers and draw more attention to flavonoid glucuronides' biological activities and mechanisms.

In Vitro Evidence of Potential Interactions between CYP2C8 and Candesartan Acyl-ß-D-glucuronide in the Liver.

Growing evidence suggests that certain glucuronides function as potent inhibitors of CYP2C8. We previously reported the possibility of drug-drug interactions between candesartan cilexetil and paclitaxel. In this study, we evaluated the effects of candesartan N2-glucuronide and candesartan acyl-ß-D-glucuronide on pathways associated with the elimination of paclitaxel, including those involving organic anion-transporting polypeptide (OATP) 1B1, OATP1B3, CYP2C8, and CYP3A4. UDP-glucuronosyltransferase (UGT) 1A10 and UGT2B7 were found to increase candesartan N2-glucuronide and candesartan acyl-ß-D-glucuronide formation in a candesartan concentration-dependent manner. Additionally, the uptake of candesartan N2-glucuronide and candesartan acyl-ß-D-glucuronide by cells stably expressing OATPs is a saturable process with K m of 5.11 and 12.1 µM for OATP1B1 and 28.8 and 15.7 µM for OATP1B3, respectively; both glucuronides exhibit moderate inhibition of OATP1B1/1B3. Moreover, the hydroxylation of paclitaxel was evaluated using recombinant CYP3A4 and CYP3A5. Results show that candesartan, candesartan N2-glucuronide, and candesartan acyl-ß-D-glucuronide inhibit the CYP2C8-mediated metabolism of paclitaxel, with candesartan acyl-ß-D-glucuronide exhibiting the strongest inhibition (IC50 is 18.9 µM for candesartan acyl-ß-D-glucuronide, 150 µM for candesartan, and 166 µM for candesartan N2-glucuronide). However, time-dependent inhibition of CYP2C8 by candesartan acyl-ß-D-glucuronide was not observed. Conversely, the IC50 values of all the compounds are comparable for CYP3A4. Taken together, these data suggest that candesartan acyl-ß-D-glucuronide is actively transported by OATPs into hepatocytes, and drug-drug interactions may occur with coadministration of candesartan and CYP2C8 substrates, including paclitaxel, as a result of the inhibition of CYP2C8 function. SIGNIFICANCE STATEMENT: This study demonstrates that the acyl glucuronidation of candesartan to form candesartan acyl-ß-D-glucuronide enhances CYP2C8 inhibition while exerting minimal effects on CYP3A4, organic anion-transporting polypeptide (OATP) 1B1, and OATP1B3. Thus, candesartan acyl-ß-D-glucuronide might represent a potential mediator of drug-drug interactions between candesartan and CYP2C8 substrates, such as paclitaxel, in clinical settings. This work adds to the growing knowledge regarding the inhibitory effects of glucuronides on CYP2C8.

Synthesis and toxicity profile in 293 human embryonic kidney cells of the ß D-glucuronide derivatives of ortho-, meta- and para-cresol.

The formation of ß-glucuronides is a major route by which mammals detoxify and remove breakdown products, such as l-tyrosine, as well as many xenobiotics, from their systems. In humans, dietary l-tyrosine is broken down largely by the action of the anaerobic gut bacterium C. difficile to p-cresol, providing a competitive advantage in the gut microbiota. Ortho- (o-) and meta- (m-), cresols, also present in the environment, may share a common degradative pathway. Relatively little work has been done on cresyl glucuronides. Here, a direct synthesis of o-, m-, and p-cresyl ß-D-glucuronides from methyl 1,2,3,4 tetra-O-acetyl-ß-d-glucuronate and the respective cresol employing trimethylsilyltriflate as promoter is presented. The protected intermediates were hydrolysed using aqueous sodium carbonate to yield the cresyl ß-glucuronides. The toxicities of the o-, m- and p-cresyl ß-D-glucuronides were compared. All three were less toxic to HEK293 cells than their respective cresol precursors: toxicity followed the order o < m < p for Na+ salts and o < p < m for Ca2+ salts. The m-cresyl-glucuronide Ca2+ salt and p-cresyl-glucuronide Na+ salt reduced colony formation by 11% and 9% (v. 30% reduction from the aglycone) respectively, whereas o-cresyl-glucuronide (both Na+ and Ca2+ salts), mildly stimulated HEK293 cell growth.

Oroxyloside ameliorates acetaminophen-induced hepatotoxicity by inhibiting JNK related apoptosis and necroptosis.

ETHNOPHARMACOLOGICAL RELEVANCE: Oroxyloside is a natural flavonoid isolated from Scutellaria baicalensis Georgi (Lamiaceae) which is a Chinese herb widely used for liver diseases. However, its mechanisms on protecting against drug induced liver injury has not been investigated yet. AIM OF THE STUDY: To investigate the protecting effects and the primary mechanisms of oroxyloside on acetaminophen (APAP)-induced liver injury. MATERIALS AND METHODS: After a 12 h fasting period with free access to water, C57BL/6 mice were injected with APAP (300 mg/kg) intragastrically (i.g.) and 1 h later with oroxyloside (100 mg/kg, i.g.). When mice sacrificed, blood samples were collected from fundus venous plexus and liver tissues were collected. In addition, cells were incubated with 10 mM APAP alone and 10 mM APAP combined with 100 µM oroxyloside for 24 h. ELISA, TUNEL assay, qRT-PCR et al. were used to assess the effect of oroxyloside on ameliorating APAP-induced hepatotoxicity in vitro and in vivo. Western bolt and immunohistochemistry were used in the signaling pathway analysis. RESULTS: Oroxyloside administration significantly decreased the accumulations of CYP2E1, CYP1A2, IL-6, IL-1ß, ALT and AST induced by APAP in vivo. In addition, oroxyloside inhibited the APAP-induced JNK related apoptosis by enhancing the antioxidant defenses, reversing ER-stress and keeping the mito-balance of liver cells in vivo and in vitro. Furthermore, oroxyloside protected the liver cells from necroptosis by affecting JNK pathway. CONCLUSION: Oroxyloside acted as a protective agent against APAP-induced liver injury through inhibiting JNK-related apoptosis and necroptosis.

Curcumin ß-D-glucuronide exhibits anti-tumor effects on oxaliplatin-resistant colon cancer with less toxicity in vivo.

The NF-kappa B (NF-κB) pathway plays a pivotal role in tumor progression and chemoresistance, and its inhibition has been shown to suppress tumor growth in a variety of preclinical models. Recently, we succeeded in synthesizing a water-soluble injectable type of curcumin ß-D-glucuronide (CMG), which is converted into a free-form of curcumin by ß-glucuronidase in vivo. Herein, we aimed to clarify the efficacy, safety and pharmacokinetics of CMG in a xenograft mouse model. First, we confirmed that the presence of KRAS/TP53 mutations significantly increased the IC50 of oxaliplatin (L-OHP) and NF-κB activity in HCT116 cells in vitro. Then, we tested the efficacy of CMG in an HCT116 colon cancer xenograft mice model. CMG demonstrated superior anticancer effects compared to L-OHP in an L-OHP-resistant xenograft model. With regard to safety, significant bodyweight loss, severe myelosuppression and AST/ALT elevation were observed in L-OHP-treated mice, whereas none of these toxicity was noted in CMG-treated mice. The combination of CMG and L-OHP exhibited additive effects in these xenograft models without increasing toxicity. Pharmacokinetic analysis revealed that high levels of free-form curcumin were maintained in the tumor tissue after 48 hours following CMG administration, but it was not detected in other major organs, such as the heart, liver and spleen. Immunohistochemistry revealed reduced NF-κB activity in the tumor tissue extracted from CMG-treated mice compared with that from control mice. These results indicated that CMG could be a promising anticancer prodrug for treating colon cancer with minimal toxicity.

The bioactivity of flavonoid glucuronides and free aglycones in the context of their absorption, II phase metabolism and deconjugation at the inflammation site.

One of the most spread group of phenolics are flavonoids. Many studies focusing on the digestion and bioavailability of flavonoids have been carried out. Several possible directions of flavonoid metabolism are suspected and described in the literature. The aim of the present study was to evaluate the bioactivity of 8 flavonoid 3-O- and 7-O- glucuronides and 7 free aglycones on inflammatory response of PMNs and HUVECs in the context of their fate in humans after oral intake. The present study for the first time compared the activity of several most popular in plant flavonol and flavone aglycones and their beta-glucuronides. The results showed that in all in vitro experiments only aglycones have anti-inflammatory activity in PMNs and HUVECs models in the concentration range 1-50 µM. The most significant influence on the inflammatory response was observed in the case of HUVECs. Compounds were able to down-regulate levels of adhesion molecules (ICAM, VCAM and E-selectin). The possible deconjugation phenomenon at the inflammation site was evaluated using enzymes produces by stimulated PMNs. This is the first report suggesting the role of ß-glucuronidase in the inflammatory process taking place on the inflammation site. Additionally, the anti-inflammatory effect was significantly better for flavones.

Targeting 1,25(OH)2D-mediated calcium absorption machinery in proximal colon with calcitriol glycosides and glucuronides.

High intestinal calcium (Ca) absorption efficiency is associated with high peak bone mass in adolescents and reduced bone loss in adulthood. Transepithelial intestinal Ca absorption is mediated by 1,25-dihydroxyvitamin D (1,25(OH)2D, calcitriol) through the vitamin D receptor (VDR). Most research on Ca absorption focuses on the proximal small intestine but evidence shows that large intestine plays a crucial role in whole body Ca homeostasis. We directly assessed and compared Ca absorption capacity at the proximal colon and duodenum using in situ ligated loops (2 mM Ca, 10 min). In C57BL/6 J mice, the proximal colon (26.2 ±â€¯3.7 %) had comparable ability to absorb Ca as the duodenum (30.0 ±â€¯6.7 %). In VDR knockout (KO) mice, Ca absorption efficiency was reduced by 67 % in duodenum and 48 % in proximal colon. These data suggest that large intestine could be targeted to improve Ca absorption and protect bone in at risk-groups (e.g. bariatric patients). Glycoside forms of calcitriol found in Solanum Glaucophyllum (Sg) leaf are biologically inert but can be activated in the colon upon bacterial cleavage of the glycosides. We conducted a study to test whether Sg leaf, as well as a novel, synthetic 1,3-diglucuronide form of calcitriol (1,3-diG) could target the proximal colon and upregulate genes involved in Ca absorption (i.e. Trpv6, S100g). 13-week-old female C57BL6/J mice were fed AIN93 G diet containing increasing levels of one of the two compounds for 2 weeks (delivering 0, 0.25, 0.5, 1, or 2 ng calcitriol equivalent per day). Both compounds induced a dose-dependent upregulation of Cyp24a1 and Trpv6 gene expression in the proximal colon. 1,3-diG also induced S100g gene expression in the proximal colon. Duodenal expression of Trpv6 was upregulated at higher doses of 1,3-diG but not Sg leaf. These data suggest that both glycosylated and glucuronidated calcitriol could be used to target the proximal colon but that dosing must be optimized to limit systemic effects that could cause hypercalcemia. Future studies will test the translational potential of these compounds to determine if they can increase Ca absorption at proximal colon and whether this can help protect bone.