Ambidalmines A–E and ambidimerine F: Bioactive dihydrobenzophenanthridine alkaloids from Corydalis ambigua var. amurensis

Research Progress on Natural Benzophenanthridine Alkaloids and their Pharmacological Functions: A Review

“…If 8-H was substituted with a methoxyl group, the chemical shift of N-Me and H-14 would appeared ata lower field of 0.1-1.0 ppm; in the case that C-6, and C-8 formed an oxygen bridge, H-6 and H-14 would shift to a higher field with 0.4 ppm and the most typical characteristic is that H-8 would shift to δ 5.25-5.30; if it were either oxidized or sulfated, H-8 would exhibit a major shift to a lower field (Table 2). In 13 Yang et al reported that a strong negative Cotton effect at 219 nm and a mild negative effect at 269 nm were found for the 8S configuration and the opposite corresponded to the enantiomeric arrangement, which has also been confirmed by X-ray single crystal diffraction [55].…”

Rapid Access to Polyfunctionalized 3,4‐Dihydroquinazolinones through a Sequential N‐Acyliminium Ion Mannich Reaction Cascade

“…The formation of 8 could result from the poor Mannich donor character of acetone at the lower temperature, which allows for competition from ketone 2 . As this C 2 ‐symmetric ketone moiety is present in several natural products that have interesting biological properties,61–63 we sought to optimize this reaction. Therefore, N ‐acyliminium ion I was treated with 0.5 equiv.…”

Natural Enantiomers: Occurrence, Biogenesis and Biological Properties

“…Compared with their respective antipodal enantiomers, indole alkaloids (−)-129b and (+)-130a also increased the cell viability by about 20% in an OKA-induced PC12 cell damage assay [83]. The isoquinoline alkaloids (−)-165a, (−)-166a and (+)-173b exhibited slightly better protective effects (51%−55% cell viability) than the positive control on hypoxic H9C2 cells, while (+)-166b were less active (45% cell viability) and (+)-165b and (−)-173a were considered inactive [103]. Two pairs of acetophenone enantiomers 423a/423b and 426a/426b exerted excellent protection on human vein endothelial cells (HUVEC) against extreme glucose-induced oxidative stress at 1 µM [200], with both dextrorotary enantiomers being much more active than their levorotary counterparts and showing complete cell protection.…”

“…Three same type of enantiomer pairs 165, 166 and 173 were isolated and characterized from Corydalis ambigua var. amurensis by Han and coworkers, and three racemic mixtures 167−169 were also acquired and analyzed by chiral chromatography but without further separation due to their limited amount [103]. As for structure elucidation, single-crystal X-ray diffraction analysis was applied to determine the abs.…”