Antiplasmodial Chromanes and Chromenes from the Monotypic Plant Species Koeberlinia spinosa

Abstract

Nine new compounds containing either a chromane or chromene ring moiety were isolated from the monotypic plant Koeberlinia spinosa. Compounds 1-4 are chromanes with all possible E and Z isomers of the isoprenoid side chain, with compound 5 a methylated derivative of 1. Compounds 6 and 7 were assigned as diastereomeric cyclized derivatives of 2 and were probably artifacts formed during the extraction or the isolation processes. Compounds 8 and 9 were characterized as new chromenes. Structure elucidation of 1-9 was conducted via 1D and 2D NMR spectroscopic data interpretation, and absolute configurations were determined by ECD spectroscopic analysis. Compounds 2, 5, 6, and 7 had weak antiplasmodial activity, while none of the compounds exhibited antiproliferative activity. The isolation, structure elucidation, and biological evaluation of these compounds are presented.

Synthesis and Evaluation of Thiochroman-4-One Derivatives as Potential Leishmanicidal Agents

“…Chromones (1,4-benzopyrone) are known as privileged scaffolds [ 6 , 7 , 8 ] in medicinal chemistry due to their wide range of biological activities, displayed, among others, as antiprotozoal [ 9 , 10 ], antioxidants [ 11 ] or anticancer agents [ 12 , 13 , 14 ]. The S-containing heterocyclic compounds, benzothiopyrans or thiochromones, have been significantly less exploited, most certainly because they are not naturally occurring compounds; from a bioisoterically point of view, thiochromones could serve as a rational modification for the optimization of chromone bioactivity.…”

Dual High-Resolution α-Glucosidase and PTP1B Inhibition Profiling Combined with HPLC-PDA-HRMS-SPE-NMR Analysis for the Identification of Potentially Antidiabetic Chromene Meroterpenoids from Rhododendron capitatum

“…The absolute configuration at C-2 of 6 was established by the empirical chromane helicity rule, which has been used widely to determine absolute stereochemistry of a large number of chromane/chromene derivatives in recent years. ,,− According to this rule, 1 L b excitation of the chromane/chromene chromophore, characterized by an ECD band at around 270–290 nm, is correlated with the helicity of this chromophore , Compound 6 showed a negative Cotton effect at 280–310 nm for the 1 L b ECD band (Figure A), suggesting P -helicity (Figure C), corresponding to the R absolute configuration at C-2.…”

Raistrickiones A−E from a Highly Productive Strain of Penicillium raistrickii Generated through Thermo Change

“…Detailed comparison of the spectroscopic data revealed that the 1 H and 13 C NMR spectra of the isolated diastereoisomers assembled those of their precursor mixture ( Figure S5 , Figure S12 , and Figure S15 , 1 H spectra for 1 , 2 , and the precursor mixture, respectively; Figure S6 , Figure S13 , and Figure S16 , 13 C spectra for 1 , 2 , and the precursor mixture, respectively). Unlike enantiomers, most diastereomers are easy to be separated by reverse phase HPLC or normal preparative thin layer chromatography (TLC) [ 23 , 24 , 25 , 26 , 27 , 28 ], due to their different physical properties. Only a few diastereomers need to use chiral HPLC to isolate [ 29 , 30 ].…”