Aldose

About: Aldose is a research topic. Over the lifetime, 1270 publications have been published within this topic receiving 27197 citations. The topic is also known as: aldoses.

Palladium(II) complexes of the reducing sugars D-arabinose, D-ribose, rac-mannose, and D-galactose.

Abstract: The cellulose solvent Pd-en, an aqueous solution of [(en)PdII(OH)2] (en=ethylenediamine), reacts with the monosaccharides D-arabinose (D-Ara), D-ribose (D-Rib), rac-mannose (rac-Man), and D-galactose (D-Gal) under formation of dimetalated aldose complexes, if the molar ratio of Pd and sugar is 2:1 or larger. In the Pd2 complexes, the aldoses are tetra-deprotonated and act as bisdiolato ligands. Two crystalline pentose complexes were isolated: [(en)2Pd2(β-D-Arap1,2,3,4 H−4)]⋅5 H2O (1) and [(en)2Pd2(β-D-Ribp1,2,3,4 H−4)]⋅6.5 H2O (2), along with two hexose complexes. With rac-Man, the major solution species is crystallized as the 9.4-hydrate [(en)2Pd2(β-rac-Manp1,2,3,4 H−4)]⋅9.4 H2O (3). From the respective D-Gal solutions, [(en)2Pd2(β-D-Galf1,3,5,6 H−4)]⋅5 H2O⋅C2H5OH (4), with the sugar tetraanion in its furanose form, is crystallized though it is not the major species, rather the second most abundant in purely aqueous solutions. The Galf species is enriched in the mother liquors to the extent of 25 % of total sugar content. Substitution of the en ligand by two molecules of ammonia, methylamine, or isopropylamine, respectively, results in the formation of different solution species. With the bulkiest ligand, isopropylamine, monometalation of the aldoses in the 1,2-position is exclusively observed.

α-Glucosidase and aldose reductase inhibitory activities from the fruiting body of Phellinus merrillii.

Abstract: The inhibitory activity from the isolated component of the fruiting body Phellinus merrillii (PM) was evaluated against α-glucosidase and lens aldose reductase from Sprague-Dawley male rats and compared to the quercetin as an aldose reductase inhibitor and acarbose as an α-glucosidase inhibitor. The ethanol extracts of PM (EPM) showed the strong α-glucosidase and aldose reductase activities. α-Glucosidase and aldose reductase inhibitors were identified as hispidin (A), hispolon (B), and inotilone (C), which were isolated from EtOAc-soluble fractions of EPM. The above structures were elucidated by their spectra and comparison with the literatures. Among them, hispidin, hispolon, and inotilone exhibited potent against α-glucosidase inhibitor activity with IC(50) values of 297.06 ± 2.06, 12.38 ± 0.13, and 18.62 ± 0.23 μg/mL, respectively, and aldose reductase inhibitor activity with IC(50) values of 48.26 ± 2.48, 9.47 ± 0.52, and 15.37 ± 0.32 μg/mL, respectively. These findings demonstrated that PM may be a good source for lead compounds as alternatives for antidiabetic agents currently used. The importance of finding effective antidiabetic therapeutics led us to further investigate natural compounds.

The synthesis of aldose sugars from half-protected dialdehydes using rabbit muscle aldolase

Abstract: t'\"0:'\":\" group at C2 rather than an aldehyde group at C I . Conversion of a ketose to an aldose is not straightforward.T Here we descr ibe a new st ra tegy for us ing RAMA ( the \" inver ted\" s t ra teg) . Scheme I ) that increases the usefu lness of th is enzyme as a cata lys t in the synthes is o f sugars . We a lso demonst ra te the va lue of r id i to l dehydrogenase ( lDH) as a catalyst for the diastereospecif ic reduction of the ketone in this class of carbohydrates to an alcohol.8'e RAMA-catalyzed aldol condensation between DHAP and a half-protected dialdehyde, OCHR'(CHg;n, generates a protected aldose having a ketone (that derived from DHAP) at Cn-,. Dephosphorylat ion. reduction. or other transformation of the ketone and deprotect ion o f the a ldehyde prov ide the a ldose. Both the structure of this aldose and the location of the vicinal diol formed in the aldol reaction can be control led through the structure of R'. The ketone group derived from the DHAP offers control of the chemistry at the end of the sugar distal to the aldehyde. Scheme II i l lustrates this * inverted\" approach to the synthesis of sugars us ing RAMA wi th syntheses of t -xy lose (4) and 2deoxy-o-ar abi no-hexose (9). RAMA-cata lyzed (50 un i ts ) condensat ion o f d ie thoxyacet a ldehyde ( l ) r0 ( l mmol . added in f ive por t ions over 5 days) and of ructose 1,6-d iphosphate (1 mmol) in the presence of t r iosephosphate isomerase (EC 5.3.1 .1 , ca. 200 un i ts ) , fo l lowed by treatment in situ with acid phosphatase (AP, 20 units), afforded 2 in 60Vo overal l yield. 'r Conversion of ketone 2 (1 mmol) to alcohol 3 with L stereochemistry was accomplished in 69Vo yield, using IDH (from Condida utilis,l0 units),e coupled with formate dehydrogenase (FDH, 10 units) and sodium formate (3 mmol)