Acid Conjugates Research Articles

Synthesis, in vitro and in silico evaluation of new flavonoids-trifluoroacetylated amino acid conjugates as anti-acetylcholinesterase and anti-proliferative agents

A series of halogenated 3-hydroxyflavones (3HFs) (3a-3f) and their conjugates with two trifluoroacetylated amino acids, namely glycine and L-alanine, were synthesized and characterized by 1H NMR, 13C NMR and ESI-HRMS. All the compounds were evaluated for their ability to inhibit the acetylcholinesterase enzyme and for their anti-proliferative effect against MCF-7, HCT-116 and OVCAR-3 cancer cell lines by standard MTT assay. Most of 3HFs-amino acids conjugates demonstrated promising cytotoxic activities, significantly higher than the corresponding 3HFs. Among them, compounds 8f and 9a showed the best cytotoxic activity against MCF-7 (IC50 = 5.5 and 5.3 µM, respectively), HCT-116 (IC50 = 6.2 and 5.5 µM, respectively) and OVCAR-3 (IC50 = 9.2 and 8.9 µM, respectively). The derivatives 9c and 9b exhibited the highest anti-acetylcholinesterase activity with IC50 values of 50.1 and 55.2 µM, respectively. The structure-activity relationship (SAR) is discussed based on molecular docking simulations.

Upregulation of Taurine Biosynthesis and Bile Acid Conjugation with Taurine through FXR in a Mouse Model with Human-like Bile Acid Composition.

Taurine, the end product in the sulfur-containing amino acid pathway, is conjugated with bile acids (BAs) in the liver. The rate-limiting enzymes in both taurine synthesis and BA conjugation may be regulated by a nucleus receptor, FXR, that promotes BA homeostasis. However, it is controversial because BAs act as natural FXR agonists or antagonists in humans and mice, respectively, due to the species differences in BA synthesis. The present study evaluated the influences of different BA compositions on both pathways in the liver by comparing Cyp2a12-/-/Cyp2c70-/- mice with a human-like BA composition (DKO) and wild-type (WT) mice. The DKO liver contains abundant natural FXR agonistic BAs, and the taurine-conjugated BA proportion and the taurine concentration were significantly increased, while the total BA concentration was significantly decreased compared to those in the WT liver with natural FXR antagonistic BAs. The mRNA expression levels of the enzymes Bacs and Baat in BA aminations and Cdo and Fmo1 in the taurine synthesis, as well as Fxr and its target gene, Shp, were significantly higher in the DKO liver than in the WT liver. The present study, using a model with a human-like BA composition in the liver, confirmed, for the first time in mice, that both the taurine synthesis and BA amidation pathways are upregulated by FXR activation.

Synthesis and Antineoplastic Efficacy of Anthraquinone and Saturated Fatty Acid Conjugates

AbstractThe clinical use of anthraquinone antibiotics such as doxorubicin in cancer chemotherapy is limited due to their toxic cardiomyopathy effects. The conjugation of anthraquinones with fatty acids is known to enhance bioactivity by increasing lipophilicity and facilitating cell membrane permeation. Short‐chain saturated fatty acids such as capric, caprylic, caproic acids, and lauric acids are known for their inherent anticancer properties on human colorectal cancer cells. In this study, 2‐hydroxyanthraquinone and saturated fatty acid esters were synthesized and evaluated against human colon cancer cell line HT‐29 and Colo‐205, breast cancer cell lines MDA‐MB‐231 and MCF‐7, and leukemia cell line K‐562 for their in vitro anticancer properties using a sulforhodamine B (SRB) assay. The anthraquinone‐saturated fatty acid conjugates produced excellent activity against human colon and breast cancer cell lines. The octanoic acid and hexanoic acid derivatives of 2‐hydroxy anthraquinone showed excellent anticancer activity with GI50 values of 0.2 nM and 1.0 nM against human colon cancer cell line Colo‐205 and the human breast cancer cell line MCF‐7, respectively, and emerged as the most active compounds. Furthermore, the in vitro cytotoxicity study against peripheral blood mononuclear cells showed that these derivatives are non‐toxic in nature.

Temozolomide-fatty acid conjugates for glioblastoma multiforme: In vitro and in vivo evaluation.

Glioblastoma multiforme (GBM) is the deadliest brain tumor with a poor prognosis and limited therapeutic options. Temozolomide (TMZ) is the first-line chemotherapeutic agent used for the treatment of GBM; however, it suffers from several limitations, including short half-life, rapid metabolism, <1% brain bioavailability, methyl guanine methyl transferase (MGMT) based chemoresistance, and hematological toxicities. Several approaches have been adopted to overcome these limitations, particularly by using nanotechnology-based systems, but its physicochemical properties make TMZ challenging to load into these nanocarriers. In the current research, we conjugated TMZ with different fatty acids, i.e., linoleic acid (LA), oleic acid (OA), and palmitic acid (PA), to obtain TMZ-fatty acid conjugates, which are comparatively hydrophobic, less prone to degradation and potent. These conjugates were thoroughly characterized using 1H NMR spectroscopy, high-resolution mass spectrometry (HR-MS), and reverse phase-high performance liquid chromatography (RP-HPLC). The synthesized conjugates, namely Temozolomide-oleic acid (TOA,6R1), Temozolomide-linoleic acid (TLA, 6R2), and Temozolomide-palmitic acid (TPA, 6R3), showed an IC50 of 101.4, 67.97, and 672.04μM, respectively in C6 cells and 428.257, 366.43 and 413.69μM, respectively in U87-MG cells. On the other hand, the free TMZ showed an IC50 of >1000μM and 564.23μM in C6 and U87-MG, respectively. Further, the in vivo efficacy of the TMZ-fatty acid conjugates was evaluated in the C6-induced orthotropic rat glioblastoma model, wherein the TMZ-fatty acid conjugate showed improved survival rate (1.6 folds) and overall health of the animals. Collectively, the conjugation of fatty acids with TMZ improves its anticancer potential against glioblastoma multiforme (GBM).

A mitochondria-targeting ROS-activated nanoprodrug for self-augmented antitumor oxidation therapy.

Mitochondrion is an ideal target for amplifying ROS attack in antitumor treatment. Benefiting from distinctive properties of mitochondria, the precise delivery of ROS generator to mitochondria could maximumly utilize ROS for oxidation therapy. Herein, we prepared an innovative ROS-activatable nanoprodrug (HTCF) which dually targets tumor cells and mitochondria for antitumor therapy. Cinnamaldehyde (CA) was conjugated to ferrocene (Fc) and triphenylphosphine by thioacetal linker, to synthesize mitochondria-targeting ROS-activated prodrug (TPP-CA-Fc), which subsequently self-assembled into nanoprodrug via host-guest interactions between TPP-CA-Fc and cyclodextrin-decorated hyaluronic acid conjugate. Under mitochondrial high ROS condition, especially in tumor cells, HTCF selectively initiate in-situ Fenton reaction to catalyze H2O2 into highly cytotoxic •OH, ensuring maximum generation and utilization of •OH for precision CDT. Meanwhile, the mitochondrial high ROS trigger thioacetal bond cleavage and CA release. The released CA stimulate mitochondrial oxidative stress aggravation and H2O2 regeneration, which in turn react with Fc for more •OH generation, forming self-amplifying positive feedback cycle of CA release and ROS burst. With self-augmented Fenton reaction and mitochondria-specific destruction, HTCF ultimately induce intracellular ROS burst and severe mitochondrial dysfunction for amplified ROS-mediated antitumor therapy. Such an ingenious organelles-specialized nanomedicine exhibited prominent antitumor effect both in vitro and in vivo, revealing underlying perspectives to amplify tumor-specific oxidation therapy.

Synthesis of mannan oligosaccharide-sialic acid conjugates and its inhibition on Aβ42 aggregation

In this work, a mannan-oligosaccharide conjugate with sialic acid capable of perturbing Aβ42 aggregation was designed and synthesized. Mannan oligosaccharides with degree polymerization of 3–13 were obtained by stepwise hydrolysis of locust bean gum using β-mannanase and α-galactosidase, named as LBOS. The activated LBOS was further chemically conjugated with sialic acid (Sia, N-acetylneuraminic acid) by fluoro-mercapto chemical coupling to synthesize a conjugate LBOS-Sia, and then phosphorylated to obtain pLBOS-Sia. The successful synthesis of pLBOS-Sia was confirmed by infrared1 chromatography, mass spectrometry, and 1H NMR. The soluble protein analysis, microscopic observation, thioflavin T-labeling, and circular dichroism spectroscopy revealed that both LBOS-Sia and pLBOS-Sia can inhibit Aβ42 aggregation. MTT assay showed that LBOS-Sia and pLBOS-Sia had no cytotoxicity to BV-2 cells, and could substantially reduce the release of pro-inflammatory factor TNF-α induced by Aβ42 in BV-2 cells, and inhibit the occurrence of neuroinflammation. In future, this novel structure of mannan oligosaccharide-sialic acid conjugate can be potentially used to for the development of glycoconjugates against AD targeting Aβ.

What Is Wrong with Hyaluronic Acid Chemistry? A 15N/13C Solid-State NMR Re-Evaluation of Its Dopamine Conjugates

In this work, a systematic 15N/13C solid-state NMR investigation is performed on three dopamine (DA) conjugates of hyaluronic acid, considered in both its native (HA) and NaIO4-oxidized (HAOx) forms. Two of them, here named HAEDC-DA and HAOx-DA, have been previously introduced as covalent conjugates involving DA amine nitrogen: the former by EDC-mediated amide bond formation, and the latter by reaction of the Schiff base with the aldehyde moieties presumed to exist in HAOx. The third conjugate, HA-DA, is reported here for the first time; it is obtained by simply mixing hyaluronan with DA∙HCl at pH 5. The 15N ss-NMR spectra were found to be consistent in all the systems, and the DA molecules were found to be in their charged -NH3+ form, which contradicts the HAEDC-DA/HAOx-DA covalent bonding schemes proposed in the literature. The 13C ss-NMR results add useful new insights into the structure and interaction patterns of the conjugates. All of our findings are relevant for future practical applications, for instance in developing novel HA-based hydrogels. In addition, the present study demonstrates the importance of using the most appropriate analytical tools when investigating composite systems due to the complexity of hyaluronic acid conjugates. Solid-state NMR proved essential to answering the question in the title: actually, there is nothing wrong with hyaluronic acid chemistry; the claimed covalent bonds between DA and the HA(HAOx) chain do not exist in these systems, because the conditions for their formation do not hold in practice.

Formation and Structure Research of a Molecular Conjugate in the L-Ascorbic Acid – Isomaltite System

The formation of L-ascorbic acid molecular complexes with various biologically active substances opens the way to the production of a new drug type promising for the pharmaceutical, food and cosmetic industries use. The research concerns the possibility study of obtaining a conjugate of L-ascorbic acid with isomaltite in an aqueous ethanol (40 %) medium. The method of the target product isolating involves thermostating a solution containing equimolar amounts (0.001 mmol) of components (50 °C, 1 hour), followed by slow solvent removal for 24 hours (25 °C). The authors examined formation processes dynamics by molecular spectroscopy methods through sequential sampling. The optical density values at 350 Nm in the electronic spectra and 1,674 and 1,754 cm−1 bands position in the IR-Fourier solution spectra indicate the components destruction absence during thermostate control. When treated with carbon tetrachloride or diethyl ether, the syrupy mass obtained after solvent removal containing significant solvent amounts crystallizes a yellowish powder (0.32 g, ice point at 146.6 °C). A man studied its structure by the IR-Fourier spectroscopy. The authors recorded the spectra in the transmission mode (in the KBr tablets) and using the diffusion reflection method enabling to record changes in the absorption bands characteristic positions of the molecular complex formation. The transmission spectra of the high-frequency area indicate the 1-O-glycosylated isomaltite component involvement in the conjugation with ascorbic acid. The shifts of the C=C, C−O and C−O−H bond oscillation bands in the diffusion reflection spectrum of the isolated product relative to their position in the initial component spectra in the low-frequency area indicate the endiol ascorbic acid fragment interaction with the secondary OH groups of the acyclic isomaltite component. Structural analogues of the studied molecular conjugate are promising antioxidant preparations. This determines the further study relevance of its properties.

Insights into the catalytic mechanism of a bacterial deglycase essential for utilization of fructose-lysine.

Amadori rearrangement products are stable sugar-amino acid conjugates that are formed nonenzymatically during preparation, dehydration, and storage of foods. Because Amadori compounds such as fructose-lysine (F-Lys), an abundant constituent in processed foods, shape the animal gut microbiome, it is important to understand bacterial utilization of these fructosamines. In bacteria, F-Lys is first phosphorylated, either during or after uptake to the cytoplasm, to form 6-phosphofructose-lysine (6-P-F-Lys). FrlB, a deglycase, then converts 6-P-F-Lys to L-lysine and glucose-6-phosphate. Here, to elucidate the catalytic mechanism of this deglycase, we first obtained a 1.8-Å crystal structure of Salmonella FrlB (without substrate) and then used computational approaches to dock 6-P-F-Lys on this structure. We also took advantage of the structural similarity between FrlB and the sugar isomerase domain of Escherichia coli glucosamine-6-phosphate synthase (GlmS), a related enzyme for which a structure with substrate has been determined. An overlay of FrlB-6-P-F-Lys on GlmS-fructose-6-phosphatestructures revealed parallels in their active-site arrangement and guided our selection of seven putative active-site residues in FrlB for site-directed mutagenesis. Activity assays with eight recombinant single-substitution mutants identified residues postulated to serve as the general acid and general base in the FrlB active site and indicated unexpectedly significant contributions from their proximal residues. By exploiting native mass spectrometry (MS) coupled to surface-induced dissociation, we distinguished mutations that impaired substrate binding versus cleavage. As demonstrated with FrlB, an integrated approach involving x-ray crystallography, in silico approaches, biochemical assays, and native MS can synergistically aid structure-function and mechanistic studies of enzymes.

1262-P: Circulating Lysophosphatidic Acid Levels Suggest a Metabolic Pathway in T3cDM and Distinguish It from T2DM

Introduction: Diabetes associated with chronic pancreatitis (T3cDM) has distinct clinical features. We investigated metabolomics signature to distinguish T3cDM from T2DM. Methods: Study participants (n=200); treatment naïve nonalcoholic calcific chronic pancreatitis [CP] patients (n=106, age 34.4±11.1 years, BMI 20.9±2.8), T2DM patients (n=68, age 46±10.7 years BMI 27.0±5.8), healthy controls (n=26, age 31.0±5.3 years, BMI 25.0±2.8) were recruited prospectively. OGTT was performed to define diabetes (ADA criteria) with 60% CP patients being normoglycemic, 19% having prediabetes and 21% with diabetes. Metabolomics was done on fasting plasma samples using liquid chromatography/mass spectrometry and quantifications were measured on tandem mass spectrometry. Student’s t-test, PLS-DA, ROCs were used to compare and compute to assess the performance of identified metabolites in distinguishing diabetes subtypes (T3cDM and T2DM). Regression analysis was employed to develop a prediction model. Results: A total of 5493 and 4104 metabolites were detected in T3cDM and T2DM respectively. Untargeted metabolome profiling identified significant differences in fatty acid conjugates in CP. Fatty acid conjugates were 28% in normoglycemic CP, 60% in prediabetic CP, 13% in T3cDM as compared to 42% in controls. Among them, 57 fatty acid conjugates showed increased peak intensities. Comparison of absolute quantifications identified higher lysophosphatidic acid (LPA) in T3cDM 40.50±6.55, T2DM 21.65 ± 1.75; p=0.01 in comparison to controls 16.20±3.4 ng/ml. Sensitivity and specificity for LPA were 81.8%, 78.6% with AUC 80% (p&amp;lt;0.0001), 95% CI (70.6-87.8). Prediction model (null and full model p&amp;lt;0.0001) and its performance (Hosmer-Lemeshow test p=0.9) indicated high accuracy (AUC 87%; 95% CI, 77.8-92.7). Conclusion: Increased Lysophosphatidic acid levels implicate glycerolipid pathway in the pathogenesis of T3cDM and can be used to distinguish T3cDM from T2DM. Disclosure V. Ketavarapu: None. M. Aslam: None. R. Talukdar: None. R. Amanchy: None. P. Sripadi: None. A.C. Powers: None. K. Narayan: None. K.C. Coate: None. L.R. Staimez: None. R. Jagannathan: None. N. D: None. M. Sasikala: None. Funding Science and Engineering Research Board, India Project (CRG/2019/005125)

Induced resistance to rice sheath blight (Rhizoctonia solani Kühn) by β-amino-butyric acid conjugate of phenazine-1-carboxylic acid

Rice sheath blight caused by Rhizoctonia solani Kühn is a major fungal disease that plagues commercially grown rice. Occurring mainly in leaf sheaths and leaves, the disease leads to great losses in food production. β-amino-butyric acid (BABA) has been demonstrated to activate an induced resistance response and is a potent inducer of broad-spectrum disease resistance in different plant species. In this study, β-amino-butyric acid conjugate of phenazine-1-carboxylic acid (PCA) with prominent induced resistance to rice sheath blight was tested. The in vitro fungicidal activity, as well as in vivo efficacy, systemicity, induced resistance and defense enzyme activity of BABA conjugate of PCA against R. solani in rice seedlings was systematically evaluated. The results indicated that in vitro fungicidal activity of PCA-β-aminobutyric acid (4e) against R. solani was lower than that of PCA, but in vivo curative ability of 4e was the highest among all tested compounds. The systemicity tests in rice seedlings revealed that PCA did not possess phloem mobility, while 4e exhibited moderate phloem mobility but much lower thanα-amino-butyric acid conjugate of PCA (4d). In addition, Compound 4e showed the highest induced activity against rice sheath blight. The observed effects of defense enzymes help to explain this high level of induced activity. The current research results indicate that in rice seedlings, BABA conjugate of PCA induce observable resistance to rice sheath blight and exhibit moderate phloem mobility, which could be used as an induced resistance fungicide against rice sheath blight in commercial rice production. The BABA conjugate of PCA might provide a useful example of induced resistance to R. solani.

Proteome Analysis of the Antiproliferative Activity of the Novel Chitooligosaccharide-Gallic Acid Conjugate against the SW620 Colon Cancer Cell Line.

Chitooligosaccharide (COS) and gallic acid (GA) are natural compounds with anti-cancer properties, and their conjugate (COS-GA) has several biological activities. Herein, the anti-cancer activity of COS-GA in SW620 colon cancer cells was investigated. MTT assay was used to evaluate cell viability after treatment with 62.5, 122, and 250 µg/mL of COS, GA, and COS-GA for 24 and 48 h. The number of apoptotic cells was determined using flow cytometry. Proteomic analysis was used to explore the mechanisms of action of different compounds. COS-GA and GA showed a stronger anti-cancer effect than COS by reducing SW620 cell proliferation at 125 and 250 µg/mL within 24 h. Flow cytometry revealed 20% apoptosis after COS-GA treatment for 24 h. Thus, GA majorly contributed to the enhanced anti-cancer activity of COS via conjugation. Proteomic analysis revealed alterations in protein translation and DNA duplication in the COS group and the structural constituents of the cytoskeleton, intermediate filament organization, the mitochondrial nucleoid, and glycolytic processes in the COS-GA group. Anti-cancer-activity-related proteins were altered, including CLTA, HSPA9, HIST2H2BF, KRT18, HINT1, DSP, and VIM. Overall, the COS-GA conjugate can serve as a potential anti-cancer agent for the safe and effective treatment of colon cancer.

Nine-valent oleanolic acid conjugates as potent inhibitors blocking the entry of influenza A virus

The influenza pandemic remains a major public health challenge that endangers the lives of many vulnerable and immune-compromised individuals worldwide. The high infectivity and genetic variability of influenza virus make it particularly challenging to design effective drugs to inhibit the virus. In previous studies, we determined that oleanolic acid (OA) and its derivatives block interactions between influenza and host cells, thus endowing OA with anti-viral efficacy. Inspired by the role of cluster glycosides in the interactions between hemagglutinins (HA) and sialic acid receptors (SA), we designed and synthesized a series of OA nonamers via the CuAAC reaction, and evaluated their anti-viral activities in vitro. We determined that among these nonamers, compound 15 displayed the highest potency (IC50 = 5.23 μM), equivalent to the antiviral drug oseltamivir which is routinely prescribed for influenza A virus strain A/WSN/33 (H1N1). In addition, these compounds also displayed antiviral activity against influenza B. Mechanistic experiments indicated that OA nonamers can effectively target the influenza HA protein. This study collectively demonstrates that multivalent structure-activity binding strategy is an effective method for designing influenza virus inhibitors.

Amino acid permease RcAAP1 increases the uptake and phloem translocation of an L-valine-phenazine-1-carboxylic acid conjugate.

Amino acid conjugates of pesticides can promote the phloem translocation of parent ingredients, allowing for the reduction of usage, and decreased environmental pollution. Plant transporters play important roles in the uptake and phloem translocation of such amino acid-pesticide conjugates such as L-Val-PCA (L-valine-phenazine-1-carboxylic acid conjugate). However, the effects of an amino acid permease, RcAAP1, on the uptake and phloem mobility of L-Val-PCA are still unclear. Here, the relative expression levels of RcAAP1 were found to be up-regulated 2.7-fold and 2.2-fold by the qRT-PCR after L-Val-PCA treatments of Ricinus cotyledons for 1h and 3h, respectively. Subsequently, expression of RcAAP1 in yeast cells increased the L-Val-PCA uptake (0.36 μmol/107 cells), which was 2.1-fold higher than the control (0.17 μmol/107 cells). Pfam analysis suggested RcAAP1 with its 11 transmembrane domains belongs to the amino acid transporter family. Phylogenetic analysis found RcAAP1 to be strongly similar to AAP3 in nine other species. Subcellular localization showed that fusion RcAAP1-eGFP proteins were observed in the plasma membrane of mesophyll cells and phloem cells. Furthermore, overexpression of RcAAP1 for 72h significantly increased the phloem mobility of L-Val-PCA in Ricinus seedlings, and phloem sap concentration of the conjugate was 1.8-fold higher than the control. Our study suggested that RcAAP1 as carrier was involved in the uptake and phloem translocation of L-Val-PCA, which could lay foundation for the utilization of amino acids and further development of vectorized agrochemicals.

Urinary concentrations of GHB and its novel amino acid and carnitine conjugates following controlled GHB administration to humans

Gamma-hydroxybutyrate (GHB) remains a challenging clinical/forensic toxicology drug. Its rapid elimination to endogenous levels mainly causes this. Especially in drug-facilitated sexual assaults, sample collection often occurs later than the detection window for GHB. We aimed to investigate new GHB conjugates with amino acids (AA), fatty acids, and its organic acid metabolites for their suitability as ingestion/application markers in urine following controlled GHB administration to humans. We used LC–MS/MS for validated quantification of human urine samples collected within two randomized, double-blinded, placebo-controlled crossover studies (GHB 50 mg/kg, 79 participants) at approximately 4.5, 8, 11, and 28 h after intake. We found significant differences (placebo vs. GHB) for all but two analytes at 4.5 h. Eleven hours post GHB administration, GHB, GHB-AAs, 3,4-dihydroxybutyric acid, and glycolic acid still showed significantly higher concentrations; at 28 h only GHB-glycine. Three different discrimination strategies were evaluated: (a) GHB-glycine cut-off concentration (1 µg/mL), (b) metabolite ratios of GHB-glycine/GHB (2.5), and (c) elevation threshold between two urine samples (> 5). Sensitivities were 0.1, 0.3, or 0.5, respectively. Only GHB-glycine showed prolonged detection over GHB, mainly when compared to a second time- and subject-matched urine sample (strategy c).

Anticancer Activity of 3,5-Bis(dodecyloxy)Benzoate-PAMAM Conjugates with Indomethacin or Mefenamic Acid.

The synthesis of conjugates with nonsteroidal anti-inflammatory drugs could improve their activity with less toxicity and these compounds could be used for the treatment of cancer. The aim of the present investigation was the synthesis of 3,5-bis(dodecyloxy)benzoate - PAMAM conjugates with indomethacin and mefenamic acid to examine their anticancer activity. The anticancer activity was studied of the conjugates against six human cancer cells U- 251, PC-3, K-562, HCT-15, MCF-7, SKLU-1, and the COS-7 (as a control) cell lines. The conjugates with indomethacin and mefenamic acid were characterized by 1H, 13C NMR one- and twodimension spectroscopy. All the conjugates synthetized with indomethacin or mefenamic acid showed anticancer activity against all the human cancer cell lines. The first generation of indomethacin conjugates showed better activity against the PC-3 (human prostatic adenocarcinoma) cell line than the second generation. But the second generation with indomethacin showed better activity against PC-3 than the first generation. The second-generation conjugate with mefenamic acid had strong selectivity to PC-3 cells with an IC50 value of 10.23 ± 1.2 μM in vitro. In the paper, we report the synthesis and spectroscopic analyses of new indomethacin or mefenamic acid conjugates. The overall results showed that the conjugate of the second generation with mefenamic acid could be a potential nanocarrier for human prostatic adenocarcinoma cancer treatment, our research will be continued.

Formulation and optimization of aceclofenac loaded hyaluronic-oleic acid based micellar gel for the management of osteoarthritis

Aceclofenac is a non-steroidal anti-inflammatory drug used to manage osteoarthritis. However, its limited solubility, short half-life, and gastrointestinal side effects on chronic use limit its delivery via the oral route. This study used hyaluronic acid tailored with oleic acid via esterification to formulate micelles for aceclofenac topical delivery. The prepared micelles were characterized for average particle size, size distribution, surface charge, drug loading, entrapment efficiency, and surface morphology. The drug loading, entrapment efficiency, mean particle size, and zeta potential of micelles were 8.21 ± 0.3%, 81.25 ± 2.98%, 245.93 ± 7.68 nm, and −17.6 ± 1.95 mV, respectively. The prepared micelles were found to be spherical. The micelles were further loaded in chitosan gel and evaluated for drug release, skin permeation, and deposition. The hydrogel showed shear thinning behavior, sustained drug release, enhanced skin permeation, and deposition of aceclofenac. Further, the pharmacodynamic study revealed a significant reduction in pain and inflammatory response with an improved radiological and histopathological condition in the animal models. These results show the potential of hyaluronic acid oleic acid conjugate micellar gel as a promising carrier to deliver the poorly soluble small molecules like aceclofenac topically to manage the inflammatory condition.

Assessment of acrylamide exposure in Spain by human biomonitoring: Risk and predictors of exposure

Acrylamide (AA), a chemical compound currently classified as “reasonably anticipated to be a human carcinogen”, is formed through the Maillard reaction in processed carbohydrate-rich foods and is also present in tobacco smoke. The primary sources of AA exposure in the general population are dietary intake and inhalation. Within a 24-h period, humans eliminate approximately 50% of AA in the urine, predominantly in the form of mercapturic acid conjugates such as N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA), N-acetyl-S-(2-carbamoyl-2- hydroxyethyl)-L-cysteine (GAMA3), and N-acetyl-3-[(3-amino-3-oxopropyl)sulfinyl]-L-alanine (AAMA-Sul). These metabolites serve as short-term biomarkers for AA exposure in human biomonitoring studies. In this study, we analysed first-morning urine samples from the adult population (aged 18–65 years) residing in the Valencian Region, Spain, (n = 505). AAMA, GAMA-3 and AAMA-Sul were quantified in 100% of the analysed samples, with geometric means (GM) of 84, 11 and 26 μg L−1, respectively, while the estimated daily intake of AA in the studied population ranged from 1.33 to 2.13 μg·kg-bw−1·day−1 (GM). Statistical analysis of the data indicated that the most significant predictors of AA exposure were smoking and the amount of potato fried products and, biscuits and pastries consumed last 24 h. Based on risk assessment approaches conducted, the findings suggest that exposure to AA could pose a potential health risk. Therefore, it is crucial to closely monitor and continuously evaluate AA exposure to ensure the well-being of the population.

Bioinspired Tumor-Targeting and Biomarker-Activatable Cell-Material Interfacing System Enhances Osteosarcoma Treatment via Biomineralization.

Osteosarcoma is an aggressive malignant tumor that primarily develops in children and adolescents. The conventional treatments for osteosarcoma often exert negative effects on normal cells, and chemotherapeutic drugs, such as platinum, can lead to multidrug resistance in tumor cells. Herein, this work reports a new bioinspired tumor-targeting and enzyme-activatable cell-material interface system based on DDDEEK-pY-phenylboronic acid (SAP-pY-PBA) conjugates. Using this tandem-activation system, this work selectively regulates the alkaline phosphatase (ALP) triggered anchoring and aggregation of SAP-pY-PBA conjugates on the cancer cell surface and the subsequent formation of the supramolecular hydrogel. This hydrogel layer can efficiently kill osteosarcoma cells by enriching calcium ions from tumor cells and forming a dense hydroxyapatite layer. Owing to the novel antitumor mechanism, this strategy neither hurts normal cells nor causes multidrug resistance in tumor cells, thereby showing an enhanced tumor treatment effect than the classical antitumor drug, doxorubicin (DOX). The outcome of this research demonstrates a new antitumor strategy based on a bioinspired enzyme-responsive biointerface combining supramolecular hydrogels with biomineralization.

Whey protein-tannic acid conjugate stabilized high internal phase Pickering emulsions: Interfacial stability based on covalent crosslinking

Protein-stabilized high internal phase Pickering emulsions (HIPEs) have potential usage in food and cosmetic fields. However, the poor interfacial activity of proteins in HIPEs is still a key bottleneck. In this work, whey protein (WP)-tannic acid (TA) conjugates by covalent crosslinking were used to fabricate HIPEs, and then the emulsifying ability and stability of HIPEs were also studied. The result indicated that covalent bonds formed between WP and TA. WP-TA conjugates had better oil-water interfacial activities and more suitable wettabilities than free WP. WP-TA conjugate stabilized HIPEs had a narrower size distribution, a more compact droplet structure and a denser gel network compared with free WP stabilized HIPEs, especially at high TA mass ratios and alkaline conditions. At the same time, the conjugates stabilized HIPEs exhibited better stability against heat treatment and centrifugation. Covalent crosslinking in WP-TA conjugates formed network based on TA molecules as bridges among emulsion droplets and played an important role in stabilizing HIPEs. This study expects to provide a new perspective for investigating the stabilizing mechanism of protein-polyphenol conjugate stabilized HIPEs.