Factors that stimulate mitochondrial biogenesis in skeletal muscle include AMPK, calcium, and circulating FFAs. Chronic treatment with either AICAR, a chemical activator of AMPK, or increasing circulating FFAs with a high fat diet increases mitochondria in rat skeletal muscle. The purpose of this study was to determine whether the combination of chronic chemical activation of AMPK and high fat feeding would have an additive effect on skeletal muscle mitochondria levels. We treated Wistar male rats with a high fat diet (HF), AICAR injections (AICAR), or a high fat diet and AICAR injections (HF+AICAR) for six weeks. At the end of the treatment period, markers of mitochondrial content were examined in white quadriceps, red quadriceps, and soleus muscles, predominantly composed of unique muscle-fiber types. In white quadriceps, there was a cumulative effect of treatments on LCAD, cytochrome c, and PGC-α protein, as well as on citrate synthase and β-HAD activity. In contrast, no additive effect was noted in the soleus and in the red quadriceps only β-HAD activity increased additively. The additive increase of mitochondrial markers observed in the white quadriceps may be explained by a combined effect of two separate mechanisms: high fat diet-induced post transcriptional increase in PGC-α protein and AMPK mediated increase in PGC-α protein via a transcriptional mechanism. These data show that chronic chemical activation of AMPK and a high fat diet have a muscle type specific additive effect on markers of fatty acid oxidation, the citric acid cycle, the electron transport chain, and transcriptional regulation.

Phospholipids, such as phosphatidylserine (PS) have been shown to work synergistically with tocopherols to extend the shelf life of oil-in-water emulsions. However, the high cost of PS prevents it from being used as a food additive. This work investigated the potential use of a high PS enzyme-modified lecithin to be used along with α-tocopherol to extend the lag phase of oil-in-water emulsions stabilized using Tween 20. Phospholipase D from Streptomyces sp. and L-serine were used to modify lecithin to increase PS concentration. Enzyme activity was optimized as a function of pH and temperature using a high PC soybean lecithin. The high PS modified lecithin was examined for its ability to enhance the activity of α-tocopherol in Tween 20-stabilized oil-in-water emulsions. The modification was also performed in high PC sunflower lecithin and egg lecithin which were later analyzed for their efficiency in controlling lipid oxidation. α-Tocopherol (3.0 µmol/kg emulsion) alone increased the lag phase of hydroperoxide and hexanal lag phases by 3 and 4 days compared to the control. Authentic PS (15.0 µmol/kg emulsion) increased hydroperoxide and hexanal lag phases by 1 and 3 days, respectively, whereas high PS soy lecithin increased hydroperoxide and hexanal lag phases by 3 and 4 days, respectively. The addition of high PS sunflower and egg lecithin did not have any considerable effects on lag phases compared to the control. Authentic PS (15.0 µmol/kg emulsion) and a-tocopherol (3.0 µmol/kg emulsion) decreased lipid oxidation by increasing the hydroperoxide and hexanal lag phase to 6 and 9 days. The combination of phospholipase D modified high PS lecithins (15.0 µmol/kg emulsion) and a-tocopherol (3.0 µmol/kg emulsion) were able to synergistically increase the antioxidant activity of a-tocopherol increasing the hydroperoxide and hexanal lag phase by 6 and 9 days for soy, 5 days, and 7 days for sunflower and 4 and 6 days for egg lecithin, respectively. This resulted in synergistic antioxidant activity (interaction index > 1.0) except for a-tocopherol and high PS Egg lecithin which showed an additive effect. This research shows that the combination of enzyme-modified high PS lecithin and α-tocopherol could be an effective and commercially viable clean label antioxidant strategy to control lipid oxidation in emulsions.

Using various synthetic strategies, we designed several libraries of novel polysaccharide mixed ester derivatives for oral drug delivery applications. Cellulose and cellulose esters have been extensively studied and utilized for different applications such as separation membranes, sustainable plastics, and enteric coatings in oral drug delivery carriers. We sought to exploit the ring-opening of cyclic anhydrides, succinic and glutaric anhydride, to append ω-carboxyl groups to commercially available cellulose and cellulose ester substrates. We used scalable synthetic strategies and widely available and cheap reagents to show a proof-of-concept for the manufacturability of these different polymer derivatives. We incorporated different degrees of substitution of ω-carboxyl groups to impart a range of water solubility in these polymers. The derivatives displayed excellent <i>T</i>g values for ASD applications, adequate water solubility, and good amphiphilic properties. We designed very effective amorphous solid dispersion (ASD) oral drug delivery polymers that prevented recrystallization of felodipine for hours and had excellent congruent polymer-drug release from the formulation at 20% drug loading. During the ring-opening reactions of the cellulose derivatives with glutaric anhydride we discovered that crosslinking and gelation can occur, especially with cellulose and cellulose ester substrates with a high degree of substitution (DS) of hydroxy groups. We isolated and characterized these gelled products using rheology, and solid-state 1D and 2D NMR spectroscopy, to evaluate whether the gels are physical or chemical in nature and proposed a mechanism for gelation. We determined that the gels are mostly physical but can proceed to chemical crosslinking over time. We designed a library of cellulose ester derivatives, and we investigated their performance as amorphous solid dispersion (ASD) drug delivery vehicles for the lipophilic drug felodipine, through <i>in vitro</i> experiments. Aside from felodipine, many other active pharmaceutical ingredients (APIs) are also highly crystalline and poorly water-soluble. ASDs are used to disrupt the crystalline packing of these drugs through dispersing them in amorphous polymeric carriers, facilitating their water-solubility, and preventing their recrystallization. We showed that our polymers performed remarkably well in the <i>in vitro</i> studies and inhibited crystallization of model compound felodipine for several hours while providing optimal drug release, affording highly promising ASD polymers. If company formulators are unable to develop an effective oral-delivery carrier to prevent a drug from recrystallizing, then the drug cannot be tested in <i>in vivo</i> toxicology studies, and therefore cannot be brought to market because of its poor aqueous solubility and subsequent low bioavailability. To test the robustness of our polymers, we also performed <i>in vitro</i> ASD experiments at the pharmaceutical company AbbVie with their most rapidly crystallizing pipeline compounds, and several commercially available drugs (Compound A, axitinib, and ziprasidone). We demonstrated that our polymers could also prevent drug recrystallization with these rapid crystallizers, outperforming commercial polymers like FDA-approved hydroxypropyl methyl cellulose acetate succinate (HPMCAS (MF)), even at exceptionally high drug loading ratios of 40 times the concentration of polymer. α-1,3-Glucans are an emerging class of polysaccharides and are structurally different than cellulose due to their α (1→3) linkage versus the cellulose β (1→4) glycosidic linkage. We demonstrated that we could modify these derivatives using a variety of esterification strategies and TEMPO-mediated C6 selective oxidation, affording a myriad of different novel polymer products, some of which are structural analogs of the cellulose ester derivatives we previously created. The polymers had higher <i>T</i>g values than the cellulose ester polymers, which may be useful for applications where heat resistance is desired. In the future, we will screen some of these α-1,3-glucan derivatives with poorly water-soluble enzalutamide, posaconazole and celecoxib model drugs, to evaluate their crystallization inhibition properties and the influence of polymer morphology upon structure-property relationships. We expect that these synthetic polymer strategies will offer scalable routes to novel ASD polymers, which we demonstrated to be highly effective drug crystallization inhibitors against a variety of different hydrophobic pharmaceutical compounds. / Doctor of Philosophy / Polysaccharides are polymers comprised of many linked sugar molecules and are an incredibly abundant and renewable resource. They are found everywhere in nature such as the wood from trees, the shells of crabs, the exoskeletons of bugs, and the mushrooms that sprout in damp forests. The research in this dissertation focuses on the use and chemical modification of polysaccharides for designing new, polysaccharide-based oral drug delivery systems called amorphous solid dispersions (ASDs), which significantly aid in the solubility and bioavailability of important medications. We started with the chemical modification of cellulose, the most abundant plant polysaccharide on planet Earth, and previously modified commercial cellulose substrates (known as cellulose esters) to create novel polymers for ASDs. We successfully modified these polymers, characterized them, and evaluated their potential as oral drug delivery vehicles by formulating them with several different classes of potent drugs used to treat a variety of diseases such as hypertension and schizophrenia. We showed that our designed cellulose ester polymers kept these hydrophobic drugs water-soluble for long-enough so that they can be adequately absorbed in the human body through the gastrointestinal tract, significantly outperforming commercial polymers in many cases. During the chemical modification of the cellulose esters, we also observed that they were prone to form gels, and we investigated this gelation phenomena in more detail through rheometry, 1D and 2D solid-state nuclear magnetic resonance spectroscopy (similar in principle to the medical diagnostic method, magnetic resonance imaging or MRI). We discovered that these gels can be physically and/or chemically linked together, and that different gelation mechanisms can dominate depending on the polysaccharide substrate and the esterification reagent used. We extended our research to other polysaccharide derivatives called α-1,3-glucans, which can be sourced from fungi, and/or enzymatically synthesized in the lab. Using various synthetic esterification and oxidation chemical methods to functionalize this polysaccharide, we designed a library of entirely novel polymers with different physical structures relative to the cellulose ester polymers. The polymers displayed thermal properties that show promise in drug delivery vehicle applications and in applications where high heat resistance is required. Overall, we developed next-generation polymers for amorphous solid dispersion oral drug delivery applications. We displayed the versatility of using a select few chemistry strategies to create a variety of different polymers with very different physicochemical properties. We hope that this work will help researchers design sustainable, plant-based polymers for ASD applications and we hope to nurture future structure-function studies to improve ASD performance for the benefit of patients in need.

Aims: The purpose of this thesis was to synthesize the current literature on alpha amylase as an emerging biomarker of microaspiration in mechanically ventilated patient. Methods: The methodology included a review and synthesis of pertinent research articles from 1981-2018, written in English language. Criteria for inclusion in the review were all articles that evaluated α- amylase in tracheal secretions or bronchoalveolar lavage fluid (BAL) as a diagnostic tool for identifying microaspiration. The search yielded 11 studies that were reviewed. Findings: The findings suggest that once aspiration occurs, the duration of α-amylase in the lungs requires further exploration to assist in interpretation of positive values. After these values are identified they need be used consistently used throughout practice of mechanically ventilated patients. Inconsistencies in the defining parameters of α-amylase were used with the thirteen studies. Conclusion: Testing amylase levels can require financial stability, standardized training, and timeliness of collecting the specimen. Alpha-amylase is a biomarker of microaspiration. Further research should be conducted to evaluate the biomarker capabilities of α-amylase to assist in early identification and/or prevention of microaspiration in mechanically ventilated patients. Implications for nursing policy practice, education, and considerations for upcoming research of α-amylase were reviewed with limitations to the study.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23796号 / 医博第4842号 / 新制||医||1058(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 森信 暁雄, 教授 椛島 健治, 教授 杉田 昌彦 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24086号 / 医博第4862号 / 新制||医||1059(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 井上 治久, 教授 渡邉 大, 教授 高橋 淳 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Thesis advisor: Amir H. Hoveyda / We have devised a broadly applicable catalytic cross-metathesis method for stereoretentive synthesis of Z- and E-trisubstituted α,β-unsaturated esters. Several new Mo-bisaryloxide complexes were prepared, and they showed superior efficiency in synthesizing the Z-trisubstituted enoates (vs. corresponding mono-aryloxide pyrrolide complexes). Synthetic utility of the method was demonstrated through several concise syntheses of bioactive triterpenoids and value-added derivatives of prenyl-containing compounds such as citronellal, citronellol, and geraniol, all of which are isolated from essential oils. This transformation offers a valuable alternative to carbonyl olefination approaches such as Wittig and Horner-Wadsworth-Emmons reactions. / Thesis (MS) — Boston College, 2021. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Activated neutrophils release a neutrophil serine proteinase (NSP) called Proteinase 3 (PR3). In granulomatosis with polyangiitis (GPA), an autoimmune vasculitis, enhanced PR3 release results in endothelial damage. Serine proteinase inhibitors (serpins) such as α-1 proteinase inhibitor (API) inhibit NSPs through the serpin’s reactive center loop (RCL). However, API is known to bind PR3 with a low specificity, compared to its main inhibitory target Human Neutrophil Elastase (HNE). The current treatment for GPA is immunosuppression, which leaves patients immunocompromised. Thus, the overall aim of this study was to engineer an API variant with a higher specificity to PR3 than HNE, which could serve as a possible novel therapeutic strategy for GPA. We created an API expression library, hypervariable at RCL residues A355-I356-P357-M358-S359, and expressed it in a T7 bacteriophage display system. This phage library was then biopanned for PR3 binding. Two conditions were used for each round of biopanning: experimental, with PR3, and the negative control, without PR3. The library was biopanned for a total of five consecutive rounds, with the product of one screen serving as the starting material for the next. A bacterial mass lysate screen was also employed to further probe the library with PR3. The phage-display and bacterial lysate screens resulted in the selection of two novel variants API-DA (D357/A358) and API-N (N359). Serpin-proteinase gel complexing assays indicated that API-N formed complex with PR3 similar to API-WT (wild-type), while API-DA was mainly cleaved as a substrate. There was no significant difference between the second order rate constants of API-N and API-WT reactions with PR3. Rate constants for API-DA binding to PR3 or for API-HNE reactions were not completed due to novel coronavirus (COVID-19) restrictions. However, this project successfully demonstrated the ability to screen a hypervariable API phage library with PR3, yielding two new novel API variants. / Thesis / Master of Science in Medical Sciences (MSMS) / When harmful substances enter our body such as bacteria or viruses, we have ways of protecting ourselves from them. One of those ways is through a cell called the neutrophil. This is an immune cell that can release “fighting tools” into our blood to combat the harm. Some of these tools are called proteins. One of those proteins is Proteinase 3. However, sometimes our neutrophils can be activated without the presence of viruses or bacteria by products made in our bodies called autoantibodies. When this happens, too many of the “fighting tool” Proteinase 3 is released leading to damage to the tubes or vessels that our blood flows through. This project aimed to find a new possible way to stop these extra fighting tools from doing harm to our body. We did this by creating a library of different proteins that can stop Proteinase 3 once it is released by the neutrophil.

La enfermedad de Parkinson (PD) es un desorden progresivo del movimiento y es la segunda enfermedad relacionada con la edad más común, luego de la enfermedad de Alzheimer. Se la considera como un desorden multifactorial y complejo que involucra tanto factores epidemiológicos como genéticos y toxicológicos, y cuya principal característica es la pérdida progresiva de las neuronas dopaminérgicas. A pesar de los recientes avances que intentan comprender las bases moleculares de esta patología, el mecanismo exacto que desencadena la degeneración de las neuronas dopaminérgicas todavía no se conoce. Numerosos estudios previos destacan dos características comunes de las lesiones de la substancia nigra pars compacta de los cerebros con PD: i) alteraciones en el contenido de los metales de transición y, en consecuencia, aumento del estrés oxidativo (OS) y ii) sobreexpresión y agregación patológica de la proteína α-sinucleína (α-sin). El desbalance en los niveles de los metales de transición ha sido reportado como uno de los principales factores que contribuyen a la degeneración de las neuronas dopaminérgicas en la PD. Específicamente, se ha descripto que la sobrecarga de hierro (Fe) y la desregulación de los niveles de cobre (Cu) estarían involucradas en el daño de las neuronas dopaminérgicas en esta patología. En la primera parte de este trabajo de tesis, nuestro objetivo fue caracterizar los mecanismos de reparación de membrana mediante el estudio de las reacciones de acilación y deacilación y su rol en la injuria oxidativa en la neuronas dopaminérgicas N27 expuestas a sobrecarga de Fe y suplementación con Cu. Las neuronas N27 incubadas en presencia de Fe2+ (1 mM) por 24 hs mostraron elevados niveles de especies reactivas de oxígeno (ROS), peroxidación lipídica y aumentada permeabilidad de membrana plasmática. Por otro lado, en las neuronas que fueron suplementadas con Cu2+ (10,50 μM) no se observaron alteraciones en los marcadores de OS. Se observó un perfil de acilación diferencial en las neuronas N27 premarcadas con [3H]ácido araquidónico (AA) o [3H]ácido oleico (OA). En las neuronas expuestas a Fe2+, la incorporación de AA aumentó en la fracción de triacilglicéridos (TAG), mientras que su incorporación en la fracción de fosfolípidos (PL) se vio disminuida. El contenido de TAG resultó más elevado (40 %) en las neuronas expuestas a Fe2+ que en los controles. Este aumento fue acompañado por la aparición de cuerpos lipídicos Nile Red positivos. En contraposición, la incorporación de OA se vio incrementada en la fracción de PL y no mostró cambios en los TAG. El perfil de acilación lipídica en las neuronas que fueron suplementadas con Cu mostró una mayor acumulación de AA en el PL fosfatidilserina y ningún cambio con respecto a su incorporación en TAG. La inhibición de las reacciones de acilación/deacilación desencadenaron un aumento en los niveles de los marcadores de OS y disfuncionalidad mitocondrial en las neuronas expuestas a sobrecarga de Fe2+. Estos hallazgos brindan evidencia acerca de la participación de los mecanismos de acilación frente a la injuria oxidativa inducida por Fe2+ y postulan que las neuronas dopaminérgicas preservan, inteligentemente, el AA en los TAG en respuesta al OS. Como se mencionó anteriormente, la sobreexpresión patológica de la α-sin está involucrada en la muerte de las neuronas dopaminérgicas en la PD. En la segunda parte de este trabajo, caracterizamos el rol de dos variantes de la α-sin, WT (en su forma nativa) y A53T (una mutación que se encuentra en la PD familiar de aparición temprana), durante el OS inducido por Fe2+ y estudiamos como el metabolismo lipídico estaría involucrado en el destino neuronal. Para ello, utilizamos la línea celular neuronal dopaminérgica N27 sin transfectar (UT) y dos líneas celulares N27 transfectadas de forma estable con WT-α-sin (WT) o A53T-α-sin (A53T). Estas células fueron expuestas a daño inducido por Fe2+ y luego, se analizaron los marcadores de OS y el estado del metabolismo lipídico. Dependiendo del tipo de α-sin expresado, se obtuvieron distintas respuestas neuronales a la sobrecarga de Fe2+. Las células A53T expuestas a injuria inducida por Fe2+ mostraron menores niveles de ROS y menor alteración en la permeabilidad de la membrana plasmática respecto a las neuronas WT. La presencia de A53T-α-sin provocó un aumento en el contenido de TAG, el cual fue aún mayor luego de la exposición de las neuronas a sobrecarga de Fe2+. Por otro lado, las neuronas WT no mostraron alteraciones en el contenido de TAG, respecto a las células UT. Las neuronas A53T también presentaron un aumento en la expresión de la sintasa de ácidos grasos (FAS), junto con una mayor resistencia a la cerulenina, un potente inhibidor de la FAS. El contenido de PL y colesterol (Chol) fue similar en las neuronas UT, WT y A53T. La inhibición farmacológica de la síntesis de novo de los TAG provocó un aumento en la muerte celular de las células A53T durante el daño inducido por Fe2+ mientras que la inhibición de los mecanismos de acilación/deacilación no afectaron ni el contenido de TAG ni la viabilidad celular en la medida en que se afectaron estos parámetros en las células UT. Nuestros resultados brindan nueva evidencia acerca del rol diferencial de las variantes de α-sin en el metabolismo lipídico neuronal, que está relacionado a la respuesta neuronal a la sobrecarga de Fe2+. En conclusión, hemos demostrado que la respuesta neuronal al daño oxidativo y a la sobreexpresión de A53T-α-sin, es dependiente de los mecanismos de acilación/deacilación lipídica e involucra acumulación de TAG. Aunque la inhibición de la síntesis de TAG en las neuronas A53T promueva la muerte celular, nuestros resultados sugieren que la aparición de TAG, algo inusual para el fenotipo neuronal, podría constituir un marcador temprano de daño neuronal. / Parkinson’s disease (PD) is a progressive movement disorder and is the second most common age-related neurodegenerative illness after Alzheimer’s disease. PD is a multifactorial and complex disorder including epidemiological, genetic and toxicological factors whose main characteristic is the progressive loss of dopaminergic neurons. Despite all the effort to understand the molecular basis of this pathology, the exact molecular mechanism that triggers the degeneration of dopaminergic neurons remains still unknown. Cumulative evidence highlights two common facts that occur in the substantia nigra pars compacta lesions in the brain of PD patients: i) alterations in transition metal content and, in consequence, increased oxidative stress (OS) and ii) overexpression and pathological aggregation of the protein α-synuclein (α-syn). Metal-imbalance has been reported as one of the main contributing factor for the degeneration of dopaminergic neurons in PD. Specifically, iron (Fe) overload and copper (Cu) mis-compartmentalization have been reported to be involved in the injury of dopaminergic neurons in this pathology. In the first part of this work, our aim was to characterize the mechanisms of membrane repair by studying lipid acylation and deacylation reactions and their role in oxidative injury in N27 dopaminergic neurons exposed to Fe-overload and Cu-supplementation. N27 dopaminergic neurons incubated with Fe2+ (1 mM) for 24 hs displayed increased levels of reactive oxygen species (ROS), lipid peroxidation and elevated plasma membrane permeability. Cu2+-supplemented neurons (10, 50 μM) showed no evidence of OS markers. A different lipid acylation profile was observed in N27 neurons pre-labeled with [3H]arachidonic acid (AA) or [3H]oleic acid (OA). In Fe-exposed neurons, AA uptake was increased in triacylglycerols (TAG) whereas its incorporation into the phospholipid (PL) fraction was diminished. TAG content was 40 % higher in Feexposed neurons than in controls. This increase was accompanied by the appearance of Nile red positive lipid bodies. Contrariwise, OA incorporation increased in the PL fractions and showed no changes in TAG. Lipid acylation profile in Cu-supplemented neurons showed AA accumulation into phosphatidylserine and no changes in TAG. The inhibition of deacylation/acylation reactions prompted an increase in OS markers and mitochondrial dysfunction in Fe-overloaded neurons. These findings provide evidence about the participation of lipid acylation mechanisms against Fe-induced oxidative injury and postulate that dopaminergic neurons cleverly preserve AA in TAG in response to OS. As previously mentioned, pathological α-syn overexpression is involved in the death of dopaminergic neurons in PD. In the second part of this work, we characterized the role of α-syn variants, Wild Type (WT) and A53T (a dominant mutation found in familial early onset PD) during Fe-induced OS and investigated whether lipid metabolism has implications for neuronal fate. To this end, we used the N27 dopaminergic neuronal cell line non-transfected (UT) and two stably transfected N27 cell lines with WT α-syn (WT) or mutated A53T α-syn (A53T). Cells were exposed to Fe-induced injury and OS markers and the status of lipid metabolism were analyzed. Neuronal response to Fe-induced overload is dependent on the type of α-syn expressed. A53T cells exposed to Fe-induced injury showed lower ROS levels and diminished plasma membrane permeability alteration than WT neurons. The presence of A53T α-syn promoted an increase in TAG content that was enhanced during Fe-induced OS. On the contrary, WT neurons did not display changes in TAG levels with respect to UT cells. A53T neurons also exhibited an increase in fatty acid synthase (FAS) expression, and higher resistance to the potent FAS inhibitor cerulenin. PL and cholesterol (Chol) content were similar in UT, WT and A53T neurons. Pharmacological inhibition of de novo synthesis of TAG increased A53T cell death during Fe-induced injury whereas the blockage of PL and Chol acylation/deacylation affected neither TAG content nor cell viability to the same extent as that observed in UT neurons. Our results bring new evidence about a differential role of α-syn variants on neuronal lipid metabolism that is related to the neuronal response to Fe-overload. In conclusion, we have demonstrated that the neuronal response to OS injury and A53T α-syn overexpression is dependent on lipid acylation and deacylation mechanisms and also involves TAG accumulation. Even though the inhibition of TAG synthesis in A53T neurons promoted cell death, our findings suggest that TAG appearance, rather unusual for the neuronal phenotype, could constitute an early marker of neuronal injury.

Research was conducted to investigate the effect of phenolic compounds derived from inherently rich antioxidant grape extracts (GE) on α-glucosidase inhibitory activity in vitro and in vivo blood glucose control, oxidative stress, and inflammation associated with obesity-induced type 2 diabetes. Because intestinal α-glucosidase plays a key role in the digestion and absorption of complex carbohydrates, the inhibition of this enzyme is a metabolic target for managing diabetes by improving post-prandial blood glucose control. Initially, red Norton wine grape (Vitis aestivalis) and pomace extracts were evaluated and determined to have notable phenolic content and antioxidant properties. Next, grape skin (GSE) and pomace extract (GPE) were tested and both had in vitro yeast and mammalian α-glucosidase inhibitory activity. The GSE was 32-times more potent at inhibiting yeast α-glucosidase than acarbose, a commercial oral hypoglycemic agent. From HPLC and LC-MS analysis, three phenolics from the GSE (resveratrol, ellagic acid, and catechin) were identified as active inhibitory compounds. The acute administration of GPE (400 mg/kg bw) to mice reduced postprandial blood glucose level by 35% following an oral glucose tolerance test compared to the control. The daily supplementation (250 mg/kg bw) of GSE and GPE for 12-weeks to mice affected fasting blood glucose levels, oxidative stress, and inflammatory biomarkers associated with obesity and type 2 diabetes. At the end of the study, the GSE group gained significantly (P < 0.05) more weight (24.6 g) than the control, high fat, or GPE groups (11.2, 20.2, 19.6 g, respectively). Both GSE and GPE groups had lower fasting blood glucose levels (119.3 and 134.2 mg/dL, respectively) compared to the high fat group (144.6 mg/dL). The 12-week supplementation of GSE was associated with a higher plasma oxygen radical absorbance capacity (ORAC), lower liver lipid peroxidation as measure by TBARS, and lower levels of inflammation as measured by plasma C-reactive protein compared to the high fat group. In conclusion, our collective observations from these studies provide insight into the potential effects of antioxidant rich grape extracts on diabetes-related biomarkers through a dual mechanism of antioxidant protection and specific inhibition of intestinal α-glucosidases. / Ph. D.