ABSTRACT
Peptide nucleic acid (PNA) is a nucleic acid mimic in which the deoxyribose-phosphate was replaced by a peptide-like backbone. The absence of negative charge in the PNA backbone leads to several unique behaviors including a stronger binding and salt independency of the PNA-DNA duplex stability. However, PNA possesses poor aqueous solubility and cannot directly penetrate cell membranes. These are major obstacles that limit in vivo applications of PNA. In previous strategies, the PNA can be conjugated to macromolecular carriers or modified with positively charged side chains such as guanidinium groups to improve the aqueous solubility and cell permeability. In general, a preformed modified PNA monomer was required. In this study, a new approach for post-synthetic modification of PNA backbone with one or more hydrophilic groups was proposed. The PNA used in this study was the conformationally constrained pyrrolidinyl PNA with prolyl-2-aminocyclopentanecarboxylic acid dipeptide backbone (acpcPNA) that shows several advantages over the conventional PNA. The aldehyde modifiers carrying different linkers (alkylene and oligo(ethylene glycol)) and end groups (-OH, -NH2, and guanidinium) were synthesized and attached to the backbone of modified acpcPNA by reductive alkylation. The hybrids between the modified acpcPNAs and DNA exhibited comparable or superior thermal stability with base-pairing specificity similar to those of unmodified acpcPNA. Moreover, the modified apcPNAs also showed the improvement of aqueous solubility (10-20 folds compared to unmodified PNA) and readily penetrate cell membranes without requiring any special delivery agents. This study not only demonstrates the practicality of the proposed post-synthetic modification approach for PNA modification, which could be readily applied to other systems, but also opens up opportunities for using pyrrolidinyl PNA in various applications such as intracellular RNA sensing, specific gene detection, and antisense and antigene therapy.
Subject(s)
Cycloleucine/analogs & derivatives , Dipeptides/chemistry , Peptide Nucleic Acids/chemistry , Pyrrolidines/chemistry , Cell Membrane Permeability , Cycloleucine/chemical synthesis , Cycloleucine/metabolism , Dipeptides/chemical synthesis , Dipeptides/metabolism , HEK293 Cells , Humans , Hydrophobic and Hydrophilic Interactions , Peptide Nucleic Acids/chemical synthesis , Peptide Nucleic Acids/metabolism , Permeability , Pyrrolidines/chemical synthesis , Pyrrolidines/metabolism , Solubility , TemperatureABSTRACT
Gardenia plants have long been used as traditional medicines in various countries including Thailand. In this study, two new 3,4-seco-cycloartane triterpenes, sootependial (1) and sootepenoic acid (2), were isolated from bud exudate of G. sootepensis, together with five known compounds. Their structures were elucidated on the basis of spectroscopic data. Sootependial (1) showed potent cytotoxicity selective to Hep-G2 cell lines and anti-angiogenic activity in ex vivo model (a rat aortic ring sprouting) assay. Furthermore, its angiogenic effect was found to occur mainly by suppressing endothelial cell proliferation and tubule formation, suggesting the potential of 1 as a lead compound for cancer treatment.
Subject(s)
Angiogenesis Inhibitors/pharmacology , Antineoplastic Agents, Phytogenic/pharmacology , Aorta/drug effects , Gardenia/chemistry , Plant Exudates/pharmacology , Triterpenes/pharmacology , Angiogenesis Inhibitors/chemistry , Angiogenesis Inhibitors/isolation & purification , Animals , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/isolation & purification , Aorta/cytology , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Hep G2 Cells , Human Umbilical Vein Endothelial Cells/cytology , Human Umbilical Vein Endothelial Cells/drug effects , Humans , Male , Plant Exudates/chemistry , Plant Exudates/isolation & purification , Plant Shoots/chemistry , Rats , Rats, Wistar , Structure-Activity Relationship , Triterpenes/chemistry , Triterpenes/isolation & purificationABSTRACT
Twelve naturally occurring 3,4-seco-cycloartane triterpenes (1-12) isolated from Gardenia sootepensis and Gardenia obtusifolia, and eight semi-synthetic derivatives (13-20) were evaluated for their antiangiogenic activity on a rat aortic sprouting assay, an ex vivo model of angiogenesis. Among these compounds, sootepin B (1) displayed the most potent activity in terms of the inhibition of microvessel sprouting from rat aortic rings in a dose-dependent manner with IC(50) value of 4.46 µM. Its angiogenic effect was found to occur via suppression of endothelial cell proliferation and tubular formation, and was likely mediated by regulation (inhibition) of the Erk1/2 signaling pathway.
Subject(s)
Angiogenesis Inhibitors/pharmacology , Neovascularization, Pathologic , Plant Extracts/pharmacology , Triterpenes/chemical synthesis , Triterpenes/pharmacology , Animals , Aorta/drug effects , Cell Proliferation , Chemistry, Pharmaceutical/methods , Dose-Response Relationship, Drug , Endothelial Cells/cytology , Gardenia , Human Umbilical Vein Endothelial Cells , Humans , Inhibitory Concentration 50 , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , Models, Biological , Rats , Signal Transduction , Structure-Activity RelationshipABSTRACT
Four new cycloartane triterpenes, named gardenoins E-H (1-4), were isolated from the apical buds of Gardenia obtusifolia, together with five known cycloartanes. Only compound 1 displayed cytotoxicity against colon, hepatic and lung cancer cell lines.
Subject(s)
Gardenia/chemistry , Triterpenes/chemistry , Cell Line, Tumor , Humans , Magnetic Resonance Spectroscopy , Molecular Conformation , Triterpenes/isolation & purification , Triterpenes/toxicityABSTRACT
Four new mexicanolide limonoids, named xylorumphiins A-D (1-4), were isolated from the seed kernels of Xylocarpus rumphii, together with three known limonoids. Their structures and configurations were established on the basis of spectroscopic data.
Subject(s)
Limonins/isolation & purification , Meliaceae/chemistry , Limonins/chemistry , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Seeds/chemistry , ThailandABSTRACT
Four new 3,4-seco-cycloartanes, gardenoins A-D (1-4), together with the known compound secaubryenol (5), were isolated from the exudate of Gardenia tubifera. The structures of 1-4 were elucidated on the basis of spectroscopic analysis. The cytotoxic activity of compounds 1-4 was evaluated against five human tumor cell lines.
Subject(s)
Antineoplastic Agents, Phytogenic/isolation & purification , Antineoplastic Agents, Phytogenic/pharmacology , Gardenia/chemistry , Triterpenes/isolation & purification , Triterpenes/pharmacology , Antineoplastic Agents, Phytogenic/chemistry , Drug Screening Assays, Antitumor , Humans , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Thailand , Triterpenes/chemistryABSTRACT
Five new 3,4-seco-cycloartanes, sootepins A-E (1-5), along with four known triterpenes (6-9), were isolated from the apical buds of Gardenia sootepensis. Their structures were elucidated on the basis of spectroscopic methods (1D and 2D NMR, HRESIMS, and X-ray crystallography), and the compounds were tested for in vitro cytotoxic activity against human breast (BT474), lung (CHAGO), liver (Hep-G2), gastric (KATO-3), and colon (SW-620) cancer cell lines. Generally, the compounds possessing an exomethylene gamma-lactone ring showed broad cytotoxicity for all cell lines tested.
