Chemotaxonomic significance of sesquiterpenes and amide derivatives from Chloranthus angustifolius Oliv.

Phytochemical investigation of the aerial parts of Chloranthus angustifolius Oliv. (Chloranthaceae) resulted in the isolation and characterization of seven sesquiterpenes (1–7) and six amide derivatives (8–13). All structures were established based on analysis of their spectroscopic data. This is the first report of compounds 2 and 8–13 from the family Chloranthaceae, and the first report of compounds 3–5 from C. angustifolius. Moreover, the chemotaxonomic significance of these compounds was summarized.     

Design and synthesis of para-fluorophenylalanine amide derivatives as thrombin receptor antagonists.

An antagonist specific for the thrombin receptor is expected to be a remedy for thrombosis. Structure-activity studies of thrombin receptor-tethered ligand SFLLRNP have revealed the importance of the Phe-2-phenyl group in receptor recognition and the replacement of the Phe-2 by para-fluorophenylalanine [(p-F)Phe] was found to enhance its activity [Nose, T. et al. (1993) Biochem. Biophys. Res. Commun. 193, 694-699]. In order to obtain a small sized antagonist, a series of (p-F)Phe derivatives was designed and synthesized novel structural elements essential for receptor interactions being introduced at both the N and C-termini. beta-Mercaptopropionyl (betaMp) or its derivative activated by S-3-nitro-2-pyridinesulphenyl (Npys) was introduced at the N-terminus, and phenylmethyl amines were coupled to the C-terminus. All compounds were inactive when assayed for human platelet aggregation, indicating that they are not agonists. beta-Mercaptopropionyl derivatives were also inactive as antagonists. However, Npys-containing analogs were found to inhibit the agonist activity of SFLLRNP. In particular, SNpys-betaMp-(p-F)Phe-NH-R [R = -CH(C6H5)2 and -CH2-CH-(C6H5)2] potently suppressed platelet aggregation. The results suggested that (p-F)Phe can be used as a structural core to construct an effective antagonist conformation.     

Synthesis and biological activity of amide derivatives of nimbolide

Nimbolide (1), a limonoid isolated from Azadirachta indica, is the chief cytotoxic principle in Neem leaves extract. Using nimbolide as a lead compound for anti-cancer analogue design, a series of nimbolide derivatives have been synthesized and evaluated for in vitro cytotoxic activity against a panel of human cancer cell lines. Out of 10 compounds screened 2g, 2h and 2i showed potent activity.     

Comparison of pH-sensitive degradability of maleic acid amide derivatives

We synthesized five maleic acid amide derivatives (maleic, citraconic, cis-aconitic, 2-(2′-carboxyethyl) maleic, 1-methyl-2-(2′-carboxyethyl) maleic acid amide), and compared their degradability for the future development of pH-sensitive biomaterials with tailored kinetics of the release of drugs, the change of charge density, and the degradation of scaffolds. The degradation kinetics was highly dependent upon the substituents on the cis-double bond. Among the maleic acid amide derivatives, 2-(2′-carboxyethyl) maleic acid amide with one carboxyethyl and one hydrogen substituent showed appropriate degradability at weakly acidic pH, and the additional carboxyl group can be used as a pH-sensitive linker.     

Chroman amide and nicotinyl amide derivatives: inhibition of lipid peroxidation and protection against head trauma

A series of chroman amide and nicotinyl amide derivatives was designed and synthesized for the treatment of traumatic and ischemic CNS injury. Five compounds were significantly more potent inhibitors of lipid peroxidation in vitro than the reference antioxidant, trolox (p < 0.01). Quantitative structure activity studies demonstrated that the inhibitory action was related to the ability to donate electrons, charge on hydroxy group and E(LUMO), to scavenging radicals and to the lipophilicity log P, which determines penetration of membrane lipids. ESR study indicated the ability of 12 to scavenge the hydroxyl radicals. The most promising compound, [(3,4-dihydro-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-2yl)ca rbonyl]-3'-(aminoethyl) indole (12), inhibited ex vivo lipid peroxidation in a head injury model and showed potent in vivo neuroprotective efficacy. Improvement of neurological recovery within 1 h of injury (grip test score) by as much as 200% was observed together with significant anti-anoxia activity. Compound 12 was a potent antagonist of methamphetamine-induced hypermotility resulting from dopamine release in the mouse brain. These results support the importance of cerebroprotective radical-scavenging agents for the treatment of traumatic injury and anoxia as well as provide additional evidence for the role of oxygen radicals and dopamine in brain damage.     

Chroman amide and nicotinyl amide derivatives: Inhibition of lipid peroxidation and protection against head trauma

A series of chroman amide and nicotinyl amide derivatives was designed and synthesized for the treatment of traumatic and ischemic CNS injury. Five compounds were significantly more potent inhibitors of lipid peroxidation in vitro than the reference antioxidant, trolox (p < 0.01). Quantitative structure activity studies demonstrated that the inhibitory action was related to the ability to donate electrons, charge on hydroxy group and E_LUMO, to scavenging radicals and to the lipophilicity log P, which determines penetration of membrane lipids. ESR study indicated the ability of 12 to scavenge the hydroxyl radicals. The most promising compound, [(3,4-dihydro-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-2yl)carbonyl]-3′-(aminoethyl) indole (12), inhibited ex vivo lipid peroxidation in a head injury model and showed potent in vivo neuroprotective efficacy. Improvement of neurological recovery within 1 h of injury (grip test score) by as much as 200% was observed together with significant anti-anoxia activity. Compound 12 was a potent antagonist of methamphetamine-induced hypermotility resulting from dopamine release in the mouse brain. These results support the importance of cerebroprotective radical-scavenging agents for the treatment of traumatic injury and anoxia as well as provide additional evidence for the role of oxygen radicals and dopamine in brain damage.     

Synthesis and evaluation of anti-thrombotic activity of benzocoumarin amide derivatives

A series of novel benzocoumarin amide derivatives have been synthesized and evaluated for their anti-thrombotic activity. Amongst these, compounds 5, 7 and 8 exhibited promising anti-thrombotic profile in an established model of mouse thrombosis. Hence, comprehensive profiling on platelet aggregation and coagulation parameters was carried out to assess its potential as a lead candidate. In vitro treatment of these compounds in mice plasma resulted into significant reduction in ADP (p<0.01) and collagen (p<0.001) induced platelet aggregation. Moreover, Compounds 5, 7 and 8 also significantly increased thrombin time (p<0.05). Thus, in the present study, these benzocoumarin amide derivatives exhibited anti-thrombotic profile via both anti-platelet as well as anti-coagulant action.     

Synthesis and antimicrobial activity of amide derivatives of polyether antibiotic-salinomycin

For the first time a direct and practical approach to the synthesis of eight amide derivatives of polyether antibiotic-salinomycin is described. The structure of allyl amide (3a) has been determined using X-ray diffraction. Salinomycin and its amide derivatives have been screened for their in vitro antimicrobial activity against the typical gram-positive cocci, gram-negative rods and yeast-like organisms, as well as against a series of clinical isolates of methicillin-resistant Staphylococcus aureus and methicillin-sensitive S. aureus. Amides of salinomycin have been found to show a wide range of activities, from inactive at 256 μg/mL to active with MIC of 2 μg/mL, comparable with salinomycin. As a result, phenyl amide (3b) was found to be the most active salinomycin derivative against gram-positive bacteria, MRSA and MSSA.     

Multidrug resistance reversal activity of permethyl ningalin B amide derivatives

A series of amide derivatives of permethyl ningalin B were prepared and examined as multidrug resistance (MDR) reversal agents illustrating that the C5 carboxylate is widely tolerant of such derivatization.     

Synthesis and anticancer activity of novel amide derivatives of non-acetal deoxoartemisinin

Novel amide derivatives of C-12 non-acetal deoxoartemisinin were synthesized. Some of the derivatives had potent in vitro anticancer activity against major human cancer cell lines. The deoxoartemisinin amide trimer had potent in vivo antiangiogenic activity, according to the mouse matrigel plug assay.     

New indole amide derivatives as potent CRTH2 receptor antagonists

A new series of indole amide acting as hCRTH2 receptor ligands had been explored and are described herein. Several amide derivatives displaying low nanomolar activity in hCRTH2 binding and whole blood assays were identified. They were found to behave as a full antagonists, exhibiting good selectivity over related prostaglandin receptors. Also, prototypical compounds in this novel series which displayed acceptable CYP profiles and were orally bioavailable in rats were identified.     

Chymotrypsin catalysed synthesis of fluorescent amino acid amide and peptide derivatives

Chymotrypsin catalyses a condensation reaction between 1-methyl-3,4-dihydro-beta-carboline-3-methyl carboxylate and amino acid amides or peptides, yielding fluorescent derivatives. During the peptide bond formation, the enzyme ensures the reaction's steric control of both carboxyl and amino components.