ABSTRACT
Three chalcone derivatives with amine groups (4a–c) were synthesized and evaluated for their antimalarial activity.Three aminoalkylated chalcone derivatives (4a–c) have been prepared through Claisen–Schmidt condensation reactionfrom vanillin and chloroacetophenone, followed by the Mannich reaction to add amine group. The structure of thecompounds was confirmed by the spectrophotometric analysis using mass spectrometers (MS) and proton and carbonnuclear magnetic resonance (1H- and 13C-NMR) spectroscopy. Antimalarial activity of 4a–c was evaluated againstPlasmodium falciparum (3D7) strain, and the molecular docking of 4b was performed to understand the interactionagainst Pf DHFR-TS protein (1J3I.pdb). The prepared aminoalkylated chalcone (4a–c) was obtained in a yield of 80%,75%, and 70%. The addition of morpholine (4a), piperidine (4b), and diethylamine (4c) as amine groups significantlycould improve the antimalarial activity with IC50 of 0.62, 0.54, and 1.12 µM, respectively (strong activity), comparedwith the chalcone without amine group (3) with IC50 of 25.84 µM (moderate activity). The molecular docking ofcompound 4b exhibited strong hydrogen bond interaction with ILE112, ILE64, SER111, SER108, ASP54, TYR170,and PRO113 residues with CDOCKER interaction energy of −48.84 kcal/mol. Thus, aminoalkylated chalcone couldbe proposed for further studies and developed into antimalarial drug candidates
ABSTRACT
In this work, a novel conjugate of ractopamine and bovine serum albumin (RAC-BSA) has been developed via the Mannich reaction, with a mole coupling ratio for RAC-BSA of 9:1. The proposed conjugation method provides a simple and one-step method with the use of fewer reagents compared with other conjugation methods for competitive immunoassays. RAC-BSA conjugation was used to fabricate a competitive lateral flow strip test for RAC detection in animal feed. For sample preparation, RAC was spiked in swine feed purchased from the local markets in Thailand, and methanol and running buffer at a volume ratio of 10:90 was used as extraction buffer. The procedures for sample preparation were completed within 25 min. Under optimal conditions, the limit of detection (LOD), assessed by the naked eye within 5 min, was found to be 1 ng/g. A semi-quantitative analysis was also conducted using a smart phone and computer software, with a linearity of 0.075-0.750 ng/g, calculated LOD of 0.10 ng/g, calculated limit of quantitation of 0.33 ng/g, and good correlation of 0.992. The recoveries were found in the range of 96.4%-103.7% with a relative standard deviation of 2.5%-3.6% for intra- and inter-assays. Comparison of the results obtained by the strip test with those obtained by enzyme-linked immunosorbent assay had a good agreement in terms of accuracy. Furthermore, this strip test exhibited highly specific RAC detection without cross reactivity with related compounds. Therefore, the RAC-BSA conjugation via the Mannich reaction can be accepted as a one-step and easy conjugation method and applied to the competitive lateral flow strip test.
Subject(s)
Animals , Animal Feed/analysis , Cross Reactions , Enzyme-Linked Immunosorbent Assay/methods , Limit of Detection , Phenethylamines/chemistry , Reagent Strips , Serum Albumin, Bovine/chemistry , SwineABSTRACT
In this work, a novel conjugate of ractopamine and bovine serum albumin (RAC–BSA) has been developed via the Mannich reaction, with a mole coupling ratio for RAC–BSA of 9:1. The proposed conjugation method provides a simple and one-step method with the use of fewer reagents compared with other conjugation methods for competitive immunoassays. RAC–BSA conjugation was used to fabricate a competitive lateral flow strip test for RAC detection in animal feed. For sample preparation, RAC was spiked in swine feed purchased from the local markets in Thailand, and methanol and running buffer at a volume ratio of 10:90 was used as extraction buffer. The procedures for sample preparation were completed within 25 min. Under optimal conditions, the limit of detection (LOD), assessed by the naked eye within 5 min, was found to be 1 ng/g. A semi-quantitative analysis was also conducted using a smart phone and computer software, with a linearity of 0.075–0.750 ng/g, calculated LOD of 0.10 ng/g, calculated limit of quantitation of 0.33 ng/g, and good correlation of 0.992. The recoveries were found in the range of 96.4%–103.7% with a relative standard deviation of 2.5%–3.6% for intra- and inter-assays. Comparison of the results obtained by the strip test with those obtained by enzyme-linked immunosorbent assay had a good agreement in terms of accuracy. Furthermore, this strip test exhibited highly specific RAC detection without cross reactivity with related compounds. Therefore, the RAC–BSA conjugation via the Mannich reaction can be accepted as a one-step and easy conjugation method and applied to the competitive lateral flow strip test.
ABSTRACT
Two novel Mannich base derivatives of silybin, SLB-DEA and DHSLB-PIP, were designed and synthesized. All the structures of new Mannich base derivatives of silybin were characterized by 1H NMR and HR-MS. Their protective action against CCl4-induced liver injury in mice were investigated. The changes of alanine aminotransferase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH), total cholesterol (TC) and triglyceride (TG) were determined and the histopathological changes in liver tissues were examined. Pretreatment with a higher dosage of DHSLB-PIP (40 mg·kg-1) prevented CCl4-induced liver injury as indicated by the reduced levels of ALT, AST, LDH and TG. Meanwhile, liver histopathological improvement was observed in the model groups. The pharmacokinetics study in rats showed that the relative bioavailability of SLB-DEA and DHSLB-PIP were 172.5% and 259.8% compared with silybin. All the results suggest that SLB-DEA and DHSLB-PIP may protect liver against injury by CCl4 and the relative bioavailability was significantly increased, which is worth of further investigation for their druggability.
ABSTRACT
A series of new [1-(N,N-disubstituted)aminomethyl-2-(2,4-dinitrophenyl)sulphanyl]-6-substituted- 1H-benzimidazoles (16a-19f) were synthesized by the Mannich reaction on 2-[(2,4-dinitrophenyl)sulphanyl]-5(6)- substituted-1H-benzimidazoles with appropriate secondary amine and paraformaldehyde in presence of concentrated hydrochloric acid in ethanol. The synthesized compounds have been evaluated for analgesic and antiinflammatory activities. Considerable numbers of them were found to exhibit good activity. 2-(2,4- Dinitrophenylsulphanyl)-6-methoxy-1-pyrrolidin-4-ylmethyl-1H-benzimidazole (18e) was found to be more potent analgesic than standard pentazocine and almost equivalent in its anti-inflammatory activity in comparison with the working standard diclofenac.