A. S. Kamalanathan

Bio: A. S. Kamalanathan is an academic researcher from VIT University. The author has contributed to research in topics: Affinity chromatography & Glycan. The author has an hindex of 7, co-authored 14 publications receiving 97 citations.

A dipyrrole derivative from Aloe vera inhibits an anti-diabetic drug target Dipeptidyl Peptidase (DPP)-IV in vitro.

Abstract: Aloe vera, a succulent herb, has a long history of use in traditional medicine, including diabetes. Earlier studies from our laboratory demonstrated that the Aloe vera extract has the ability to inhibit the diabetic drug target dipeptidyl peptidase (DPP) IV in vitro. This current study focuses on the isolation of small water soluble active molecule(s) involved in DPP-IV inhibition from Aloe vera extract, and further to characterize its structure and to elucidate the mode of inhibition of the DPP-IV enzyme. Aloe vera gel ethanolic extract was subjected to preparative reverse-phase high-pressure liquid chromatography (RP-HPLC), LH-20 Sephadex gel filtration chromatography, followed by analytical RP-HPLC, to isolate the active molecule involved in DPP-IV inhibition. Based on the spectroscopic studies, the structure of the isolated DPP-IV inhibitor was predicted to be 3, 6-dioxo-3, 3a, 6, 6 a-tetrahydropyrrolo [3, 4-c] pyrrole-1, 4-dicarboxamide with the chemical formula C8H6N4O4, having the molecular weight of 225.175 Da. This molecule inhibited the DPP-IV enzyme in a noncompetitive manner with an IC50 value of 8.59 ± 2.61 µM, with a Ki of 4.7 ± 0.038 µM. Thus, the mechanism of DPP-IV inhibition and the inhibitory constants were determined. The results of our studies suggested that the inhibition of the DPP-IV enzyme as one of the pathways by which the Aloe vera extract may restore the pancreatic islets cell mass in diabetic animal model.

Development of L-histidine immobilized CIM(®) monolithic disks for purification of immunoglobulin G.

Abstract: The pseudobiospecific affinity ligand l-histidine was immobilized on epoxy, carbonyldiimidazole (CDI), and ethylenediamine (EDA) convective interaction media (BIA Separations, Slovenia) monolithic disks to obtain the histidyl affinity column for purification of immunoglobulin G (IgG) The kinetics and the mass transfer properties of the affinity columns were studied to determine the optimum buffer condition, flow rate, and concentration of IgG for maximum IgG adsorption The binding capacities of all the three affinity columns were higher with zwitterionic buffer morpholinopropanesulfonic acid than with charged buffers such as tris-HCl and phosphate buffers, and the optimum pH was 65 The interaction of IgG with histidine immobilized CDI and epoxy disks was found to be predominantly driven by ionic interaction, while the interaction with EDA-histidine disk could be partially governed by multiple non-covalent forces of interaction The maximum binding capacity (Qm ) of l-histidine immobilized on EDA-, CDI-, and epoxy-activated convective interaction media disks were 1983 ± 025, 1585 ± 018 and 1211 ± 017 mg/ml of support, respectively, and the dissociation constant (Kd ) were calculated to be in the micromolar range for all the three histidyl monolithic columns Purification of IgG from untreated human serum was also attempted, and the results indicate the high potential of this method for purification of total IgG from complex biological sources and also for separation of IgG1 from other subclasses

Overview of the Structure–Function Relationships of Mannose-Specific Lectins from Plants, Algae and Fungi

Abstract: To date, a number of mannose-binding lectins have been isolated and characterized from plants and fungi. These proteins are composed of different structural scaffold structures which harbor a single or multiple carbohydrate-binding sites involved in the specific recognition of mannose-containing glycans. Generally, the mannose-binding site consists of a small, central, carbohydrate-binding pocket responsible for the "broad sugar-binding specificity" toward a single mannose molecule, surrounded by a more extended binding area responsible for the specific recognition of larger mannose-containing N-glycan chains. Accordingly, the mannose-binding specificity of the so-called mannose-binding lectins towards complex mannose-containing N-glycans depends largely on the topography of their mannose-binding site(s). This structure⁻function relationship introduces a high degree of specificity in the apparently homogeneous group of mannose-binding lectins, with respect to the specific recognition of high-mannose and complex N-glycans. Because of the high specificity towards mannose these lectins are valuable tools for deciphering and characterizing the complex mannose-containing glycans that decorate both normal and transformed cells, e.g., the altered high-mannose N-glycans that often occur at the surface of various cancer cells.

Chemical diversity and activity profiles of HIV-1 reverse transcriptase inhibitors from plants

Abstract: Current challenges to antiretroviral therapy have opened new vistas in the search for novel drugs from natural products. This review focusses on plants as sources of inhibitors for human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. Based on a systematic search of the literature, anti-HIV-1 reverse transcriptase activity was recorded for 132 plant species in 100 genera and 51 families. Seven families comprise 52.6% of plant species with anti-reverse transcriptase activity: Lamiaceae (13.7%), Fabaceae (10.7%), Euphorbiaceae (9.9%), Clusiaceae (6.1%), Asteraceae (4.6%), Combretaceae (4.6%), and Moraceae (3.0%). The repertoire of anti-reverse transcriptase active compounds includes (-)-catechin, 1,8-cineole, 3,4-di-O-caffeoylquinic acid, 5,7-dimethoxy-6-methylflavone, apigenin, baicalein, betulinic acid, caffeic acid, cis-3-hexene-1-ol, eugenol, euscaphic acid, gallic acid, hoslunddiol, limonene, naringenin, oleanolic acid, p-cymene, pomolic acid, quinic acid, rosmarinic acid, stigmasterol, thymol, ursolic acid, α-bergamotene, α-pinene, and γ-terpinene. Among the IC50 values are 0.10 μg/ml (Uvaria angolensis), 3 μg/ml (Hemidesmus indicus), 2. 3μg/ml (Adansonia digitata), 6.24 μg/ml (Caesalpinia coriaria), 7.2 μg/ml (Terminalia sericea), 17.4 μg/ml (Hypoxis hemerocallidea), and 79 μg/ml (Moringa oleifera). The chemical diversity and activity profiles of HIV-1 reverse transcriptase inhibitors from plants reveal two recurring motifs: the structure of several active anti-reverse transcriptase compounds mimics nucleoside analogues, and numerous anti-reverse transcriptase phytochemicals have pleiotropic effects and heterogenous pharmacological benefits during infection and disease. To accelerate drug discovery and development, this review recommends the urgent need to tap into the rich vein of indigenous knowledge of putative anti-HIV/AIDS medicinal plants (reverse pharmacology), determine pan-assay interference compounds, analyze structure-activity relationships, and conduct more clinical trials.