ABSTRACT
Three new substituted bithiophenes (1â»3), and one new sulf-polyacetylene ester, ritroyne A (16) were isolated from the whole plant of Echinops ritro together with twelve known substituted thiophenes. The structures were elucidated on the basis of extensive spectroscopic analysis including 1D and 2D NMR as well as MS. Furthermore, the absolute configuration of ritroyne A (16) was established by computational methods. In bioscreening experiments, four compounds (2, 4, 12, 14) showed similar antibacterial activity against Staphylococcus aureus ATCC 2592 with levofloxacin (8 µg/mL). Five compounds (2, 4, 9, 12, 14) exhibited antibacterial activities against Escherichia coli ATCC 25922, with minimum inhibitory concentration (MIC) values of 32â»64 µg/mL. Three compounds (2, 4, 12) exhibited antifungal activities against Candida albicans ATCC 2002 with MIC values of 32â»64 µg/mL. However, compound 16 did not exhibit antimicrobial activities against three microorganisms.
Subject(s)
Echinops Plant/chemistry , Polyacetylene Polymer/chemistry , Polyacetylene Polymer/pharmacology , Thiophenes/chemistry , Thiophenes/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Antifungal Agents/chemistry , Antifungal Agents/pharmacology , Candida albicans/drug effects , Escherichia coli/drug effects , Microbial Sensitivity Tests , Molecular Structure , Plant Extracts/chemistry , Staphylococcus aureus/drug effectsABSTRACT
Four new triterpenoids, kadlongilactones C-F (2-5), containing a consecutive hexacyclic [7,7,5,6,6,6] ring system, were isolated from the leaves and stems of Kadsura longipedunculata. In comparison with the NMR data of kadlongilactones A (1) and D (3), a significant phenomena was discovered that ring D of 3 inverted from a half-chair in 1 to a half-boat conformation when the HO-16 group changed from alpha- to beta-orientation. The structures of 2-5 were established on the basis of detailed spectroscopic analysis, and DFT computational methods were applied in the structural validation of compounds 3 and 5. Compounds 1-4 showed significant cytotoxicity against A549, HT-29, and K562 cell lines with IC50 values of 0.49-3.61 microM in vitro.
Subject(s)
Antineoplastic Agents, Phytogenic/isolation & purification , Drugs, Chinese Herbal/isolation & purification , Kadsura/chemistry , Plants, Medicinal/chemistry , Triterpenes/isolation & purification , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Drug Screening Assays, Antitumor , Drugs, Chinese Herbal/chemistry , Drugs, Chinese Herbal/pharmacology , Inhibitory Concentration 50 , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Plant Leaves/chemistry , Plant Stems/chemistry , Triterpenes/chemistry , Triterpenes/pharmacologyABSTRACT
[structure: see text]. A new hexacyclic alkaloid, calydaphninone (1), containing a 4-azatricyclo[5.2.2.0(1,4)]undecan ring system, has been isolated from the leaves and twigs of Daphniphyllum calycillum (Daphniphyllaceae). Its structure was elucidated by spectral and crystallographic means. Furthermore, conformations of calydaphninone (1) in solution are discussed on the basis of NMR spectral analysis and computational (B3LYP/6-31G*) results.