Teraryl-based alpha-helix mimetics have resulted in efficient inhibitors of protein-protein interactions (PPIs). Extending the concept to even longer oligoarene systems would allow for the mimicking of even larger interaction sites. We present a highly efficient synthetic modular access to quateraryl alpha-helix mimetics, in which, at first, two phenols undergo electrooxidative dehydrogenative cross-coupling. The resulting 4,4 -biphenol is then activated by conversion to nonaflates, which serve as leaving groups for iterative Pd-catalyzed Suzuki-cross-coupling reactions with suitably substituted pyridine boronic acids. This work, for the first time, demonstrates the synthetic efficiency of using both electroorganic as well as transition-metal catalyzed cross-coupling in the assembly of oligoarene structures.
A new cafestol-type diterpenoid, 5β-hydroxy-2-oxocafestol named coffecanepholide C (1) along with three known diterpenoids including cafestol (2), tricalysiolide A (3) and atractyligenin (4) were identified from the Coffea canephora trunks collected at Lam Dong province, Vietnam. Their structures were elucidated by HRESIMS and NMR spectroscopic analysis ( 1 H, 13 C, COSY, HSQC, HMBC, and NOESY NMR) as well as compared with data in the literature. Upon evaluation of the a-glucosidase inhibitory activity, compound 1 (IC50 = 142.0 ± 0.2 µM) and compound 3 (IC50 = 286.2 ± 1.2 µM) exhibited activity against aglucosidase, while structures 2 and 4 showed no activity. Furthermore, the docking simulations revealed that the carbonyl groups of compounds 1 and 3 formed hydrogen bonds with Lys506 residue at the enzyme pocket, which may induce the a-glucosidase inhibitory activity.
Hylocereus polyrhizus, known as red dragon fruit provides a betacyanin pigment source, which is not only concentrated in the flesh but also present in the peel with high content. Betacyanins are beautiful red-violet pigments used as food additives and stable in a wide pH range from 3 to 6. However, the stability of betacyanins is affected by heat, which causes discoloration. The aim of this work was to report the extraction of betacyanins from red dragon fruit peels by an aqueous two-phase system (ATPS) to overcome the drawback. By applying the aqueous two-phase extraction (ATPE) method on Hylocereus polyrhizus peels, the highest betacyanin yield of 85.07% was obtained in the optimal conditions of ammonium sulfate (12.75%, w/w); ethanol (30.00%, w/w); dragon fruit peel (8%, w/w), and pH 5.0 at 30 oC.
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