Development of an orally delivered GLP-1 receptor agonist through peptide engineering and drug delivery to treat chronic disease.

Peptide therapeutics are increasingly used in the treatment of disease, but their administration by injection reduces patient compliance and convenience, especially for chronic diseases. Thus, oral administration of a peptide therapeutic represents a significant advance in medicine, but is challenged by gastrointestinal instability and ineffective uptake into the circulation. Here, we have used glucagon-like peptide-1 (GLP-1) as a model peptide therapeutic for treating obesity-linked type 2 diabetes, a common chronic disease. We describe a comprehensive multidisciplinary approach leading to the development of MEDI7219, a GLP-1 receptor agonist (GLP-1RA) specifically engineered for oral delivery. Sites of protease/peptidase vulnerabilities in GLP-1 were removed by amino acid substitution and the peptide backbone was bis-lipidated to promote MEDI7219 reversible plasma protein binding without affecting potency. A combination of sodium chenodeoxycholate and propyl gallate was used to enhance bioavailability of MEDI7219 at the site of maximal gastrointestinal absorption, targeted by enteric-coated tablets. This synergistic approach resulted in MEDI7219 bioavailability of ~ 6% in dogs receiving oral tablets. In a dog model of obesity and insulin resistance, MEDI7219 oral tablets significantly decreased food intake, body weight and glucose excursions, validating the approach. This novel approach to the development of MEDI7219 provides a template for the development of other oral peptide therapeutics.

Quality-by-Design-Based Development of n-Propyl-Gallate-Loaded Hyaluronic-Acid-Coated Liposomes for Intranasal Administration.

The present study aimed to develop n-propyl gallate (PG)-encapsulated liposomes through a novel direct pouring method using the quality-by-design (QbD) approach. A further aim was to coat liposomes with hyaluronic acid (HA) to improve the stability of the formulation in nasal mucosa. The QbD method was used for the determination of critical quality attributes in the formulation of PG-loaded liposomes coated with HA. The optimized formulation was determined by applying the Box-Behnken design to investigate the effect of composition and process variables on particle size, polydispersity index (PDI), and zeta potential. Physiochemical characterization, in vitro release, and permeability tests, as well as accelerated stability studies, were performed with the optimized liposomal formulation. The optimized formulation resulted in 90 ± 3.6% encapsulation efficiency, 167.9 ± 3.5 nm average hydrodynamic diameter, 0.129 ± 0.002 PDI, and -33.9 ± 4.5 zeta potential. Coated liposomes showed significantly improved properties in 24 h in an in vitro release test (>60%), in vitro permeability measurement (420 µg/cm2) within 60 min, and also in accelerated stability studies compared to uncoated liposomes. A hydrogen-peroxide-scavenging assay showed improved stability of PG-containing liposomes. It can be concluded that the optimization of PG-encapsulated liposomes coated with HA has great potential for targeting several brain diseases.

Gallate Contact Dermatitis: Product Update and Systematic Review.

Allergic contact dermatitis related to cosmetic use can result from allergens not routinely evaluated by standard patch test protocols. Propyl, octyl, and dodecyl gallates are commonly used antioxidant preservatives with reports of associated allergic contact dermatitis in the literature. The objectives of this review were to investigate the role of gallates in allergic contact dermatitis and to explore products containing these preservatives. A systematic review of the literature through April 2016 was performed to explore cases of reported gallate allergy. Food and cosmetic product databases were searched for products containing gallates. Seventy-four cases of gallate contact allergy have been reported. In addition, a variety of commercially available cosmetic products and foods contain gallate chemicals. Propyl gallate is the most commonly reported gallate contact allergen and often causes facial and/or hand dermatitis.

Effect of JEZTC, a synthetic compound, on proliferation and phenotype maintenance of rabbit articular chondrocytes in vitro.

Antioxidant may provide anti-arthritic effect that contributes to resolution of inflammation. Gallic acid (GA) and its derivatives were reported to be effective in treatment of arthritis. But GA-suppressed cell proliferation may compromise its effect on chondro-protection. In this study, we synthesized sulfonamido-based gallate-JEZTC and investigated its effect on rabbit articular chondrocytes through examination of the cell proliferation, morphology, viability, glycosaminoglycan (GAG) synthesis, and cartilage-specific gene expression. Results showed that JEZTC could effectively promote chondrocyte growth and enhance secretion and synthesis of cartilage extracellular matrix (ECM) by upregulating expression levels of aggrecan, collagen II, and Sox9 genes. Expression of collagen I which marked chondrocyte dedifferentiation was effectively downregulated by JEZTC. In addition, hypertrophy that may lead to chondrocyte ossification could not be detected in JEZTC groups. The results indicated JEZTC can well preserve the phenotype of chondrocytes. Range of 2.344 to 9.375 µg/ml is the recommended dose of JEZTC, which showed increased cell proliferation. Especially, JEZTC of 4.688 µg/ml showed the best performance. This study might provide a basis for development of a novel agent for the treatment of symptomatic chondral and osteochondral lesions.

Geno- and cytotoxicity of propyl gallate food additive.

Synthetic phenolic food additives, such as propyl 3,4,5-trihydroxybenzoate (propyl galate; PG), have been used as an antioxidant in the food industry to prevent oils from spoiling. Their toxicity is one of the challengeable issues resulting from the widespread usage of them in food-related industrials. In this study, we investigated the anticell proliferation effects of PG on A549 lung cancer cells. The result showed that PG dose and time dependently decreased the growth of A549 cells with an half-maximal inhibitory concentration of approximately 1 × 10(-3) and 5 × 10(-4)M of PG at 48 and 72 hours, respectively. In addition, DNA strand breaks have been observed through the comet assay technique. Also, morphology of 4',6-diamidino-2-phenylindole (DAPI)-stained cells showed an obvious fragmentation in the chromatin and DNA rings within the nucleus of PG-treated cells, and, finally, flow cytometry analyses of the cells confirmed DAPI staining assay and determined early and late apoptosis in treated cells.

Propyl gallate plays a nephroprotective role in early stage of diabetic nephropathy associated with suppression of glomerular endothelial cell proliferation and angiogenesis.

There is growing evidence suggesting that glomerular endothelial cell proliferation and angiogenesis may be responsible for the pathophysiological events in the early stage of diabetic nephropathy. This study was designed to investigate the factors related to glomerular endothelial cell proliferation and glomerular angiogenesis and assess the effect of propyl gallate on preventing these disorders in diabetic rats. We found that glomerular hypertrophy, glomerular mesangial matrix expansion, and albuminuria were significantly increased in DN rats. CD31+ endothelial cells significantly increased in glomerulus of diabetic rats. Double immunofluorescence staining showed some structurally defective vasculus tubes in glomerulus. Real-time PCR and western blot demonstrated the glomerular eNOS expression remained at the same level, while remarkable decreased NO productions and suppressed eNOS activities were observed in diabetic rats. Treatment with propyl gallate improved glomerular pathological changes, reduced endothelial cell proliferation, decreased albuminuria, and restored eNOS activity, but did not alter eNOS expression. These data suggest that endothelial cell proliferation and immature angiogenesis may be the contributors to progression of DN. Propyl gallate is a potential novel therapeutic agent on prevention of diabetic nephropathy.

Effects of n-propyl gallate on neuronal survival after forebrain ischemia in rats.

THE AIM OF THE STUDY: The present study was conducted to assess the effects of intraperitoneal administration of n-propyl gallate (PG) on hippocampal neuronal survival after forebrain ischemia. METHODS: Forty male Sprague-Dawley rats were randomly assigned to one of 6 groups. Animals in the PG-I-10, PG-I-8 and PG-S groups received intraperitoneal injection of PG (100mg/kg) 72, 48, 24h and 30 min before severe (10 min) or moderate (8 min) ischemia or sham operation, respectively, while animals in the V-I-10, V-I-8 and V-S groups received the vehicle (10% DMSO) in the same manner. Forebrain ischemia was produced by bilateral carotid occlusion combined with hypotension (35 mmHg) under isoflurane anesthesia. Animals were killed 7 days after reperfusion. Histological assessments were performed using hematoxylin and eosin staining. In separate groups of animals that received PG or vehicle, m-RNA levels of hypoxia-inducible factor 1α (HIF-1α), erythropoietin (EPO) and vascular endothelial growth factor (VEGF) were measured using the reverse transcription-PCR protocol. RESULTS: The number of normal neurons was significantly higher in the PG-I-8 group compared with that in the V-I-8 group, whereas it was similar between the PG-I-10 and V-I-10 groups. Animals that received PG had significantly higher levels of HIF-1α, EPO and VEGF expression compared with those that received vehicle. CONCLUSION: The results indicated that intraperitoneal administration of PG may have neuroprotective effects in a model of moderate, but not severe, forebrain ischemia in rats.

Propyl gallate, a strong antioxidant, increases the Ca2+ sensitivity of cardiac myofilament.

Ca(2+) sensitizers are cardiotonic agents that directly increase the Ca(2+) sensitivity of cardiac myofilament. To find a novel Ca(2+) sensitizer, we have screened a group of phenolic compounds by examining their effects on the Ca(2+)-dependent force generation in cardiac muscle fibers. We found that propyl gallate, a strong antioxidant, increased the Ca(2+) sensitivity of cardiac myofilament in a dose-dependent and reversible manner. The present study indicates that propyl gallate is a novel type of Ca(2+) sensitizer with antioxidant activity, which might be more beneficial for the treatment of congestive heart failure associated with oxidative stress than existing Ca(2+) sensitizers.

[Effects of propyl gallate on serum inflammatory factors and protein expression of COX-2 and ICAM-1 in ischemic myocardium of rats with acute myocardial infarction].

OBJECTIVE: To investigate the effects of Propyl Gallate (PrG) on serum inflammatory factors and protein expression of cyclooxygenase-2 (COX-2) and intercellular adhesion molecule-1 (ICAM-1) in ischemic myocardium of rats with acute myocardial infarction (AMI). METHODS: AMI model was induced by ligating the left anterior descending (LAD) branch of coronary artery in Wistar rats, and the perfect modeling was certified with ST segment elevation by standard limb lead II of electrocardiogram. Rats were randomly divided into 6 groups: Group A of normal rats, Group B of rats through sham operation, Group C of AMI model rats, Group D of model rats treated with high dose PrG (80 mg x kg(-1) x d(-1), via peritoneal injection), Group E of model rats treated with low dose PrG (40 mg x kg(-1) x d(-1), via peritoneal injection), and Group F of model rats treated with aspirin (25 mg x kg(-1) x d(-1), via gastrogavage), all the treatments were given in succession for 7 days. Radioimmunoassay (RIA) was used to determine serum contents of interleukin (IL)-1beta and tumor necrosis factor-alpha (TNF-alpha), immunohistochemistry was used to determine the level of COX-2 and ICAM-1 protein expression in myocardium. RESULTS: Compared with Group B, the serum level of TNF-alpha increased significantly, but not the level of IL-1beta in Group C. Besides, the COX-2 and ICAM-1 protein expressions in ischemic myocardium increased in Group C. All the above-mentioned changes were reversed to certain extent in Group E after treatment. CONCLUSIONS: PrG (40 mg x kg(-1) d(-1)) could decrease the serum level of inflammatory factor TNF-alpha, and slightly inhibit COX-2 and ICAM-1 protein expression in ischemic myocardium of AMI rats.

Gallate, the component of HIF-inducing catechins, inhibits HIF prolyl hydroxylase.

Catechins have recently been reported to increase the cellular content of the hypoxia-inducible factor (HIF)-1alpha within mammalian cells. These catechins have a gallate moiety as a common structure. We now report that n-propyl gallate (nPG) also increases the HIF-1alpha protein in the rat heart-derived H9c2 cells. The increase was dose-dependent and reached a maximum at 2-4h after the addition of nPG to the cells. nPG did not change the HIF-1alpha mRNA level, showing that the increase is a posttranscriptional event. Although nPG did not inhibit the HIF prolyl hydroxylase, gallate, the hydrolysis product of nPG, inhibited the enzyme completely at submillimolar concentrations. Model building studies on the human HIF prolyl hydroxylase 2 showed that the two phenolate oxygen atoms of gallate form a chelate with the active site Fe(2+), while the carboxyl group of gallate forms a strong ionic/hydrogen bonding interaction with Arg383, explaining why nPG, which has an esterified carboxyl group, is unable to inhibit the hydroxylase. Together with the observation that gallate was detected in the H9c2 cells treated with nPG, these results suggest that nPG incorporated into the cells is hydrolyzed and the released gallate inhibits the HIF prolyl hydroxylase, thereby reducing the HIF degradation rate and increasing the HIF-1alpha content.

Effects of propyl gallate on interaction between TNF-alpha and sTNFR-I using an affinity biosensor.

AIM: To study the effects of propyl gallate on the interaction of tumor necrosis factor-alpha (TNF-alpha) with its soluble receptor, sTNFR-I. METHODS: Interactions between TNF-alpha and sTNFR-I were analyzed using an IAsys biosensor. sTNFR-I was immobilized on the carboxymethyl dextran (CMD) surface of the IAsys biosensor cuvettes, and TNF-alpha preincubated with different concentrations of propyl gallate was added to the cuvettes. The resonant angle shift caused by the binding between TNF-alpha and sTNFR-I was then recorded. RESULTS: sTNFR-I was immobilized on the CMD surface at a density of 2.76 ng/mm(2). TNF-alpha then bound the immobilized sTNFR-I specifically, and propyl gallate was able to enhance the binding between TNF-alpha and sTNFR-I in a dose-dependent manner. CONCLUSION: The binding between TNF-alpha and sTNFR-I is one of the targets that propyl gallate can act on in vivo. The IAsys biosensor offers a new clue as to the study on the mechanisms of action of propyl gallate.

[Application of cationic propyl gallate as inducer of thrombocyte aggregation for evaluating the platelet function of platelet donors].

The purpose of study was to investigate the feasibility of the application of cationic propyl gallate (C-PG) as inducer of platelet aggregation for evaluating the platelet function of single-donor plateletpheresis and identifying the incidence of defective platelet function among donors. Experiments were as follows: 3 healthy volunteers' platelet aggregation induced by 100-300 micromol/L C-PG was determined by LG-PABER analyzer to observe the effect of C-PG concentration on platelet aggregation; 30 healthy volunteers' platelet aggregation before and 24 hours after administration of 200-400 mg acetylsalicylic acid (ASA) was examined after induction by 200 micromol/L C-PG for determining the cut-off value to discriminate platelet dysfunction donors; the platelet aggregation of 483 platelet donors was detected and the activated plasma clotting time (APCT) of donors who have deficiency in platelet aggregation was examined for investigating the incidence of defective platelet function among donors. The results showed that platelets were activated by C-PG induction in a dose dependent manner, when concentration of C-PG reached 200 micromol/L, the percentage of platelet aggregation was highest. It significantly decreased after 24 hours with ASA than that before the administration (P < 0.001), especially in 180 seconds induced by C-PG. If cut-off point was fixed on the platelet aggregation < 20% in 180 seconds, donors of platelet dysfunction can be selected effectively. 25 of defective platelet aggregation function among 483 donors were detected, and 11 out of 25 platelet dysfunction donors had the deficiency in procoagulant activity with prolonged APCT. It is concluded that C-PG as inducer of platelet aggregation is feasible to screen the platelet function of donors. Five percent of platelet donors has function defect examined by C-PG as inducer of platelet aggregation.

Effect of dietary treatment with n-propyl gallate or vitamin E on the survival of mice exposed to phosgene.

Phosgene, widely used in industrial processes, can cause life-threatening pulmonary edema and acute lung injury. One mechanism of protection against phosgene-induced lung injury may involve the use of antioxidants. The present study focused on dietary supplementation in mice using n-propyl gallate (nPG)--a gallate acid ester compound used in food preservation--and vitamin E. Five groups of male mice were studied: group 1, control-fed with Purina rodent chow 5002; group 2, fed 0.75% nPG (w/w) in 5002; group 3, fed 1.5% nPG (w/w) in 5002; group 4 fed 1% (w/w) vitamin E in 5002; and group 5, fed 2% (w/w) vitamin E also in 5002. Mice were fed for 23 days. On day 23 mice were exposed to 32 mg m-3 (8 ppm) phosgene for 20 min (640 mg. min m-3) in a whole-body exposure chamber. Survival rates were determined at 12 and 24 h. In mice that died within 12 h, the lungs were removed and lung wet weights, dry weights, wet/dry weight ratios, lipid peroxidation (thiobarbituric acid reactive substances, TBARS) and glutathione (GSH) were assessed. Vitamin E had no positive effect on any outcome measured. There was no significant difference between 1.5% nPG and any parameter measured or survival rate compared with 5002 + phosgene. However, dietary treatment with 0.75% nPG significantly increased survival rate (P

Active-oxygen involvement in canine NK-mediated cytotoxicity.

We examined the relationship between natural killer (NK) cell-mediated cytotoxicity, the produced active-oxygen and cytotoxic factor (CF) release in co-culturing canine NK cells with tumor cells (CL-1 target cells). In co-culturing, the adding of n-propyl gallate (active-oxide scavenger) removed the produced active-oxygen, which inhibited NK cell-mediated cytotoxicity and the CF release. Moreover, adding of this agent inhibited the tyrosine phosphorylation of NK intracellular protein which observed in co-culturing. Therefore, the active-oxygen produced from canine NK cells are thought to relate the signal transduction in NK-mediated cytotoxicity.

Influence of dosing vehicles on the preclinical pharmacokinetics of phenolic antioxidants.

Phenolic antioxidants, such as butylated hydroxyanisole (BHA) and propyl gallate (PG), have demonstrated paradoxical cancer initiating and preventive actions in animals. Studies examining the disposition and biological effects of these agents have used solutions in ethanol-saline, PEG400-saline, corn oil, or DMSO. The aim of this study was to compare the pharmacokinetics of BHA and PG in mice following dosing in either a "control" dosing vehicle (ethanol-saline, 2:3) or a solution of an inclusion complex of each agent with hydroxypropyl-beta-cyclodextrin (HPB) in saline. Results demonstrate that BHA or PG are rapidly absorbed and eliminated in mice following i.p. or p.o. dosing in either dosing vehicle. Pharmacokinetic parameters of BHA estimated in mice correlated with those reported for other species, including humans ("Interspecies Scaling"), suggesting that exposures are proportional to body weight across species. Therefore, rodents are appropriate animal models to study these phenolic antioxidants. The oral absorption of PG was influenced by dosing vehicle in mice, suggesting the need for cautious selection of traditional nonaqueous vehicles (such as DMSO, ethanol, etc.) in the investigation of biological activities of these xenobiotics. Indeed, DMSO elevated plasma alanine aminotransferase (ALT) and alkaline phosphatase (ALP) concentrations following subchronic i.p. administration of various blank vehicles to mice. Such elevations in plasma concentrations of these enzymes are considered biomarkers of hepatotoxicity. The absolute oral bioavailability of PG (administered as an HPB complex) in rats was low (5%) suggesting extensive metabolism or incomplete absorption. The low oral bioavailability of these phenolic antioxidants in rodents suggests that the risk assessment of these antioxidants should include an evaluation of their metabolites as well.

Attenuation of reperfusion injury by the antioxidant n-propyl gallate.

We studied the effects of n-propyl gallate (n-PG) on Langendorff preparations of isolated rat hearts. Perfusion of the hearts with Krebs-Henseleit (KH) solution containing 20 microM n-PG did not cause a statistically significant change in either left ventricular systolic pressure (LVSP), end-diastolic pressure (LVEDP), developed pressure (LVDP), or heart rate (HR), indicating that n-PG has little acute myocardial toxicity. The effects of n-PG on the reperfused and ischemic myocardium were tested in hearts subjected to 15-min global P4 the ischemic hearts with KH buffer resulted in the recovery of the LVDP to 66 +/- 7% (mean +/- SEM, n = 11) and the recovery of the rate-pressure product (RPP) to 65 +/- 7% of their preischemic values. The LVEDP of the reperfused hearts was 30 +/- 5 mm Hg as compared with the preischemic LVEDP of 5.2 +/- 0.9 mm Hg. The difference between the coronary flow rate of the preischemic hearts (15.4 +/- 0.8 ml/min) and the reperfused hearts (13.9 +/- 0.9 ml/min) was not statistically significant (p > 0.05). Addition of n-PG, at the time of reperfusion, resulted in with KH buffer containing 20 microM n-PG had LVEDP of 6.2 +/- 0.4 mm Hg, and both LVDP and RPP recovered to 92 +/- 4% of the preischemic control.(ABSTRACT TRUNCATED AT 250 WORDS)

Propyl gallate on liposomes.

A hypothesis suggesting that the allergic potential of propyl gallate is boosted by its attachment to liposomes in cosmetics is put forward. 13 women with allergy to propyl gallate are presented.

Effect of propyl gallate feeding on glutathione content in ageing Zaprionus paravittiger (Diptera).

Glutathione content increased during the reproductive period and decreased thereafter up to the 43rd day of age in whole body as well as mitochondrial homogenates of ageing Zaprionus paravittiger. However, females exhibited higher levels of glutathione as compared to males. In whole body homogenates, propyl gallate (PG; 25 micrograms/ml) increased the glutathione content significantly up to the 22nd day of life whereas in mitochondria it increased during all age intervals in the two sexes with the exception of the 36th and 43rd day of survival in males. In conclusion, the higher level of glutathione on PG feeding might be one of the factors leading to the prolonged life span of flies.

Allergic contact dermatitis from propyl gallate: dose response comparison using various application methods.

The antioxidant propyl gallate, in a deodorant product, caused an allergic contact dermatitis in 1 subject during developmental controlled use testing. Subsequent dose response elicitation studies with this subject revealed a differing threshold of sensitivity to propyl gallate dependent upon application method. Increasing the level of occlusion increased the elicitation response. Responsiveness from greatest to least was: occluded patch on the upper arm greater than semi-occluded axilla greater than open application on the antecubital fossa. The thresholds determined for propyl gallate (w/v in 25:75 ethanol:water) were: (a) 0.0025% for the upper arm occluded patch; (b) 0.0035% for the underarm without shaving; (c) 0.005% for the underarm with shaving; (d) 0.015% for the antecubital fossa. Occluded patch responsiveness to propyl gallate was monitored and remained unchanged throughout a 2-year period. These data are useful in understanding the relationship between occlusive allergic contact dermatitis patch testing and clinical contact dermatitis.