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Intracellular Maturation of Acute Phase Proteins
Published in Andrzej Mackiewicz, Irving Kushner, Heinz Baumann, Acute Phase Proteins, 2020
Erik Fries, E. Mathilda Sjöberg
The formation of N-linked carbohydrates can be inhibited by the addition of the antibiotic tunicamycin.68 Use of this compound has made it possible to study the role of N-linked carbohydrates in secretion. When Hep G2 cells or hepatocytes are treated with tunicamycin, the secretion of some, but not all, proteins is impaired.66,67,69,70 In another type of cell, it has been shown that a protein’s sensitivity to tunicamycin treatment is correlated to its binding to BiP,30 suggesting an effect of the glycan moiety on the conformation of the polypeptide. A number of compounds have been discovered which inhibit specific hydrolases of the N-glycosylation pathway.68 Thus, for example, deoxynojirimycin inhibits the ER enzymes which remove the glucoses. When Hep G2 cells are incubated with this compound, the secretion of some proteins is inhibited.69,71 The mechanism of this differential retention of proteins with incompletely processed oligosaccharides is unknown. Deoxymannojirimycin, on the other hand, inhibits the Golgi enzymes that reduce the number of mannose residues down to five; in the presence of this compound, the transport rates are unaffected.72,73
Biocatalyzed Synthesis of Antidiabetic Drugs
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Some examples of each kind are shown in Fig. 11.39: Thus, polyhydroxylated piperidine 1-deoxynojirimycin (DNJ) 108, isolated from the roots of mulberry trees, or pyrrolidine 2,5-dideoxy-2,5-imino-D-mannitol 109, commonly known as DMDP, found in many plants and microorganisms, have been both studied for their antihyperglycemic properties (Horne et al., 2011). Indolizidine 110 is the toxic alkaloid castanospermine, a potent inhibitor of lysosomal α-glucosidase (Lahiri et al., 2013). DNJ, DMDP and castanospermine also inhibit glycoprotein processing enzymes to varying degrees (Asano et al., 2000). Casuarine 111 is an example of a pyrrolizidine, which was also isolated from plants and have been used in the treatment of breast cancer, diabetes, and bacterial infections (Wardrop and Waidyarachchi, 2010). Finally, Calystegine A3112 belongs to nortropane-type alkaloids possessing glycosidase inhibitory activity (Asano et al., 2000).
Functional Foods Continued
Published in Robert Fried, Richard M. Carlton, Type 2 Diabetes, 2018
Robert Fried, Richard M. Carlton
One study published in the journal Molecule reported developing laboratory procedures to identify polyhydroxylated alkaloids with potent glucosidase inhibitor activity in mulberry leaf. Numerous such compounds were identified including 1-deoxynojirimycin (DNJ) (see below).
Competitive α-glucosidase inhibitors, dihydrobenzoxanthones, from the barks of Artocarpus elasticus
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2019
Janar Jenis, Aizhamal Baiseitova, Sang Hwa Yoon, Chanin Park, Jeong Yoon Kim, Zuo Peng Li, Keun Woo Lee, Ki Hun Park
The inhibitory activity of α-glucosidase (EC3.2.1.20) was carried out with a few changes from literature reported method, using p-nitrophenyl-α-D-glucopyranoside at optimal pH of 6.8 (50 mM phosphate buffer)3. Inhibitors were dissolved and diluted to a needed concentration in DMSO. Concisely, in 96-well plates to 10 μL of inhibitor or deoxynojirimycin (DNJ) as a control and 40 μL substrate (p-NPG, 1.0 mM) in the aforesaid buffer (130 μL) were added 20 μL of the enzyme (0.1 unit/mL). The absorbance of formed p-nitrophenol immediately measured with a wavelength of 405 nm at 37 °C. Compound activity was expressed in the concentration when 50% of enzyme activity was inhibited (IC50). Calculation of the % of inhibition was as follows:
Role of ethanolic extract of Morus alba leaves on some biochemical and hematological alterations in irradiated male rats
Published in International Journal of Radiation Biology, 2018
Naglaa Elshahat Mohamed, Saleh E. Ashour
Mulberry leaves contain compounds such as 1,4-dideoxy-onstituents, 1,4-imino-d-arabinitol, 1-deoxynojirimycin and 1,4-dideoxy-1,4-imino-dribitol may possess its antidiabetic effect (Andallu and Varadacharyulu 2007). This hypoglycemic effect of mulberry leaves extract may be attributed to the insulin mimic effect, inhibition of intestinal α-amylase activity (Gad et al. 2006), enhancement of hepatic glucokinase and hexokinase enzymes activities and activation of insulin signaling pathway in adipocytes and liver cells. Mulberry leaves contain 1-deoxynojirimycin (DNJ), which inhibits hyperglycemia (Asano et al. 2001) by inhibiting α-glucosidase in the small intestine and its intake was not associate with abnormalities (Kimura et al. 2007). Also, this compound aid in reducing glucose level by decreasing the rate of digestion and absorption of carbohydrates from intestines and inhibit α-galactosidases (Wild et al. 2004). Also, the hypoglycemic effect may be attributed to its activation of macrophages the main source of interlukine-1 (IL-1) in the body, which increases insulin production resulting in lowering of blood glucose level (Lang and Dobrescu 1989). However, the major function of insulin to maintain blood glucose level and enhancing glycogen synthesis (Murray et al. 2003).
A decade of nutraceutical patents: where are we now in 2018?
Published in Expert Opinion on Therapeutic Patents, 2018
Patricia Daliu, Antonello Santini, Ettore Novellino
A study by Barrios et al. (2017) put in evidence the beneficial effect of a nutraceutical containing a combination of red yeast rice, berberine, polycosanol, astaxanthin, and coenzyme Q10 [61]. The component present in the proposed nutraceutical formulation, 1-deoxynojirimycin, has been studied for cholesterol-reducing effect [62] and also for its antioxidant and antidiabetic activity of ethanol extracts in vitro, as evidenced by a recent study of 2018; however no clinical studies have been till today performed to substantiate its use as cholesterol-lowering substance [63]. Liu et al. (2016) evaluated the effect of this molecule on liver injury and hepatic glucose metabolism in mice revealing a positive effect on lipid homeostasis and beneficial impact on hepatic steatosis [64].