Screening and evaluation of fungal resources for loratadine metabolites.

Loratadine is a selective inverse agonist of peripheral histamine H1-receptors. Microbial biotransformation gained a lot of attention for its ability to convert molecules to valuable medicinally active substances. The main objective of the present research was to investigate the ability of different fungi to biotransform the drug loratadine to its active metabolite desloratadine, because desloratadine is four times more potent, possess longer duration of action than loratadine and is effective at low doses. The screening studies were performed with selected fungi using their respective broth media and sterile incubation conditions. The drug and metabolites formed (if any) were extracted and analysed using HPLC analysis. Structural elucidation and confirmation of metabolites were by mass and proton NMR spectroscopy. Among the six fungi selected, Cunninghamella elegans, Cunninghamella echinulata and Aspergillus niger cultures showed extra peaks at 3.8, 3.6 and 4.1 min, respectively, in HPLC when compared with their controls, which indicated the formation of metabolites. The metabolites thus formed were isolated and their structures were confirmed as dihydroxy desloratadine, desethoxy loratadine and 3-hydroxy desloratadine by Cunninghamella elegans, Cunninghamella echinulata and Aspergillus niger cultures, respectively, by mass spectrometry and NMR spectroscopy. Three fungi were identified to have the ability to biotransform loratadine to its active metabolite and other different metabolites.

A novel mutation (F71L) in alphaA-crystallin with defective chaperone-like function associated with age-related cataract.

Age-related cataract (ARC) is a multifactorial disease and the leading cause of blindness worldwide. Genetic predisposition in association with other etiological factors may contribute to ARC. However, gene mutation studies on ARC are scanty. In the present work, we identified a genetic variation (F71L) in the exon-2 of CRYAA (alphaA-crystallin) gene in three unrelated female sporadic cases among 711 ARC patients but not in 265 normal non-cataractous controls by SSCP and RFLP analysis. By comparing human recombinant wild-type and F71L-alphaA-crystallin, we characterized the functional significance of this missense mutation. Chromatography, fluorescence and far- and near-UV CD studies indicated that F71L missense mutation did not significantly affect the apparent molecular mass, secondary and tertiary structures and hydrophobicity of alphaA-crystallin. While the mutant alphaA-crystallin displayed significant (35-90%) loss of chaperone-like activity (CLA) in thermal aggregation of carbonic anhydrase, betaL- and gamma-crystallins, it showed moderate (10-50%) loss in CLA in DTT-induced aggregation of insulin and lysozyme. This is the first report of an alphaA-F71L mutation being associated with ARC and suggests that ARC in individuals carrying this mutation (F71L) might be due to the overall loss of in vivo chaperone activity due to interaction with other environmental factors.

Haptoglobin phenotypes in diabetes mellitus and diabetic retinopathy.

An analysis of haptoglobin (HP) phenotypes in 81 cases of diabetes mellitus (DM) without retinopathy and 122 cases with diabetic retinopathy (DR) were studied in relation to 180 normal and healthy controls matched for age and sex. A significant decrease in HP 2-1 frequency was found, suggesting protection for heterozygotes in both DM and DR (with a relative risk of about 0.31). As an acute-phase reactant HP may be functionally involved in the etiology of DM and DR, which are associated with immunologic and inflammatory processes, respectively. No significant differences were found with respect to sex, age at onset, duration of DR, types of DM and DR, and family history.