Oral Supplementation with Benzylamine Delays the Onset of Diabetes in Obese and Diabetic db-/- Mice

Porphyrinoid-Functionalized ZnO Nanoflowers for Visible Light-Enhanced and Selective Benzylamine Detection at Room Temperature

Functionalization of hybrid organic molecules as layers on ZnO nanoflowers (NFs) gives an excellent combination of sensing toward visible light and vapors of various volatile organic compounds (VOCs). In this work, hybrid organic molecules functionalized ZnO NFs were utilized for the photoinduced detection of benzylamine at room temperature. The ZnO NFs were synthesized via a facile solution route and functionalized with four different porphyrin-conjugated molecules namely (i) pyrene-porphyrin (PP), (ii) pyrene- porphyrinato zinc (ZnPP), (iii) triphenylamine- porphyrin (TP) and (iv) triphenylamine- porphyrinato zinc (ZnTP). The diameter of the flower-like structure was found to be ∼3.2 μm with the thickness of petals being ∼24.1 nm. The gas adsorption performance of the functionalized ZnO NFs on light activation at room temperature was studied by using a scanning Kelvin probe (SKP) system. The improved adsorption properties of the samples can be attributed to the heterojunctions and light activation. In particular, an enhanced response of ZnTP functionalized ZnO (ZnTPZ) toward benzylamine was observed. Further, static gas sensing experiments using ZnTPZ under various concentrations (1, 3, 5, 10, 15, and 25 ppm) of benzylamine vapors both in dark and visible light conditions have exhibited a linear increase in the response. The selectively enhanced response of ZnTPZ compared to that of pristine ZnO was thus confirmed at 1 ppm of benzylamine. The sensitivity and limit of detection of the ZnTPZ sensor were calculated to be 0.0292 ppm-1 and 197 ppb, respectively. The coordination metal (Zn) has helped in effective charge transfer between benzylamine and ZnTPZ by providing additional active sites for interactions. Also, density functional theory calculations demonstrated the role of the hybrid organic molecules on the sensor surface in improving gas adsorption. Further, fresh cabbage was utilized for real sample analysis with the proposed sensor under visible light illumination conditions, and a linear response was obtained for low ppm evaluation at room temperature. Overall, the obtained results suggest the development of novel ZnTPZ-based light-activated gas sensors for low ppm benzylamine detection at room temperature. These kinds of sensors can be used to track the freshness of vegetables as they are transported from farms to commercial outlets.

Effects of Chemical Structures Interacting with Amine Oxidases on Glucose, Lipid and Hydrogen Peroxide Handling by Human Adipocytes

Benzylamine is a natural molecule present in food and edible plants, capable of activating hexose uptake and inhibiting lipolysis in human fat cells. These effects are dependent on its oxidation by amine oxidases present in adipocytes, and on the subsequent hydrogen peroxide production, known to exhibit insulin-like actions. Virtually, other substrates interacting with such hydrogen peroxide-releasing enzymes potentially can modulate lipid accumulation in adipose tissue. Inhibition of such enzymes has also been reported to influence lipid deposition. We have therefore studied in human adipocytes the lipolytic and lipogenic activities of pharmacological entities designed to interact with amine oxidases highly expressed in this cell type: the semicarbazide-sensitive amine oxidase (SSAO also known as PrAO or VAP-1) and the monoamine oxidases (MAO). The results showed that SZV-2016 and SZV-2017 behaved as better substrates than benzylamine, releasing hydrogen peroxide once oxidized, and reproduced or even exceeded its insulin-like metabolic effects in fat cells. Additionally, several novel SSAO inhibitors, such as SZV-2007 and SZV-1398, have been evidenced and shown to inhibit benzylamine metabolic actions. Taken as a whole, our findings reinforce the list of molecules that influence the regulation of triacylglycerol assembly/breakdown, at least in vitro in human adipocytes. The novel compounds deserve deeper investigation of their mechanisms of interaction with SSAO or MAO, and constitute potential candidates for therapeutic use in obesity and diabetes.

Hyperglycemia and reduced adiposity of streptozotocin-induced diabetic mice are not alleviated by oral benzylamine supplementation

BACKGROUND

Benzylamine (Bza) oral administration delays the onset of hyperglycemia in insulin-resistant db^-/- mice; a genetic model of obesity and type 2 diabetes.

AIM

To extend the antihyperglycemic properties of oral benzylamine to a model of insulin-deficient type 1 diabetes.

METHODS

Male Swiss mice were rendered diabetic by streptozotocin treatment (STZ) and divided in two groups: one received 0.5% Bza as drinking solution for 24 d (STZ Bza-drinking) while the other was drinking water ad libitum. Similar groups were constituted in age-matched, nondiabetic mice. Food intake, liquid intake, body weight gain and nonfasting blood glucose levels were followed during treatment. At the end of treatment, fasted glycemia, liver and white adipose tissue (WAT) mass were measured, while glucose uptake assays were performed in adipocytes.

RESULTS

STZ diabetic mice presented typical features of insulin-deficient diabetes: reduced body mass and increased blood glucose levels. These altered parameters were not normalized in the Bza-drinking group in spite of restored food and water intake. Bza consumption could not reverse the severe fat depot atrophy of STZ diabetic mice. In the nondiabetic mice, no difference was found between control and Bza-drinking mice for any parameter. In isolated adipocytes, hexose uptake was partially activated by 0.1 mmol/L Bza in a manner that was obliterated in vitro by the amine oxidase inhibitor phenelzine and that remained unchanged after Bza supplementation. Oxidation of 0.1 mmol/L Bza in WAT was lower in STZ diabetic than in normoglycemic mice.

CONCLUSION

Bza supplementation could not normalize the altered glucose handling of STZ diabetic mice with severe WAT atrophy. Consequently, its antidiabetic potential in obese and diabetic rodents does not apply to lipoatrophic type 1 diabetic mice.