Effect of an amino group at carbon 2 of 1-deoxyglucose analogues on anorexia in the rat

Discovery of a tetrazolyl β-carboline with in vitro and in vivo osteoprotective activity under estrogen-deficient conditions

β-Carbolines have been assessed for osteoclastogenesis. However, their effect on osteoblasts during estrogen deficiency is still unclear. Here, a series of novel piperazine and tetrazole tag β-carbolines have been synthesized and examined for osteoblast differentiation in vitro. In vitro data suggest that compound 8g is the most promising osteoblast differentiating agent that was evaluated for in vivo studies. Compound 8g promoted osteoblast mineralization, stimulated Runx2, BMP-2 and OCN expression levels, increased BrdU incorporation and inhibited generation of free radicals as well as nitric oxide. Since a piperazine group is involved in bone repair activity and β-carboline in IκB kinase (IKK) inhibition, compound 8g inhibited tumor necrosis factor α (TNFα) directed IκBα phosphorylation, preventing nuclear translocation of NF-κB thereby alleviating osteoblast apoptosis. In vivo studies show that compound 8g was able to restore estrogen deficiency-induced bone loss in ovariectomized rats without any toxicity, thus signifying its potential in bone-protection chemotherapy under postmenopausal conditions.

1,5-Anhydro-D-fructose; a versatile chiral building block: biochemistry and chemistry

There is a steadily increasing need to expand sustainable resources, and carbohydrates are anticipated to play an important role in this respect, both for bulk and fine chemical preparation. The enzyme alpha-(1-->4)-glucan lyase degrades starch to 1,5-anhydro-D-fructose. This compound, which has three different functional properties, a prochiral center together with a permanent pyran ring, renders it a potential chiral building block for the synthesis of valuable and potentially biologically active compounds. 1,5-Anhydro-D-fructose is found in natural materials as a degradation product of alpha-(1-->4)-glucans. The occurrence of lyases and the metabolism of 1,5-anhydro-D-fructose are reviewed in the biological part of this article. In the chemical part, the elucidated structure of 1,5-anhydro-D-fructose will be presented together with simple stereoselective conversions into hydroxy/amino 1,5-anhydro hexitols and a nojirimycin analogue. Synthesis of 6-O-acylated derivatives of 1,5-anhydro-D-fructose substituted with long fatty acid residues is carried out using commercially available enzymes. Those reactions lead to compounds with potential emulsifying properties. The use of protected derivatives of 1,5-anhydro-D-fructose for the synthesis of natural products is likewise reviewed. The potential utilization of this chemical building block is far from being exhausted. Since 1,5-anhydro-D-fructose now is accessible in larger amounts through a simple-enzyme catalyzed degradation of starch by alpha-(1-->4)-glucan lyase, the application of 1,5-anhydro-D-fructose may be considered a valuable contribution to the utilization of carbohydrates as the most abundant resource of sustainable raw materials.

Serum 1,5-anhydroglucitol (1,5 AG): new clinical marker for glycemic control

We review the use of 1,5-anhydroglucitol (1,5 AG) in diagnosing and monitoring patients with diabetes. This six-carbon chain monosaccharide is one of the major polyols present in humans. Its concentration in serum is normally about 12 to 40 micrograms/ml. This substance is derived mainly from food, is well absorbed in the intestine, and is distributed to all organs and tissues. It is metabolically stable, being excreted in the urine when its level exceeds the renal threshold. It is reabsorbed in the renal tubules, and is competitively inhibited by glucosuria, which leads to a reduction in its level in serum. The correlation between this reduction and the amount of glucose present in urine is so close that 1,5 AG can be used as a sensitive, day-to-day, real-time marker of glycemic control. It provides useful information on current glycemic control and is superior to both HbA1c and fructosamine in detecting near-normoglycemia.

2,5-Anhydro-D-mannitol: its unique central action on food intake and blood glucose in rats

Peripheral administration of D-fructose has been reported to decrease food intake, and its 2-deoxy analogue, 2,5-anhydro-D-mannitol (2,5-AM), increased food intake and decreased blood glucose in rats. In the present study, 2,5-AM was selected for comparison with well-known 2-deoxy analogues of glucose. Infusion of 2,5-AM into the rat third cerebroventricle at 11.00 h induced feeding dose dependently (Y = 0.63 logX-1.20, r = 0.95, P less than 0.05). Rats treated with 2,5-AM at a maximal effective dose of 24 mumol/rat ate meals most persistently (P less than 0.05). No periprandial drinking was observed. Ambulatory activity increased concomitantly with feeding, but did not exceed the activity normally associated with a meal. Infusion of 24 mumol 2,5-AM into the third cerebroventricle induced no substantial change in plasma glucose or insulin in any 60-min experimental period. Unilateral microinfusion of 1.2 mumol 2,5-AM induced feeding in all 6 rats (P less than 0.01) when a cannula tip was located in the ventromedial hypothalamic nucleus (VMH), but not in the lateral hypothalamic area (LHA). These findings indicate that feeding elicitation may be due to disinhibition by 2,5-AM through the VMH. This is quite unique compared to the action mechanisms of hexose, pentose and their analogues, except 2,5-AM.