Alkaloid Enantiomers from Isatis tinctoria with Neuroprotective Effects against H2O2-Induced SH-SY5Y Cell Injury

Abstract

Six pairs of alkaloid enantiomers including 11 new alkaloids (1a/1b–5a/5b, 6a) were isolated from the leaves of Isatis tinctoria. Their structures were established by extensive spectroscopic analyses. Enantiomers were separated successfully by chiral chromatographic column and the absolute configurations of all isolates were determined by comparison of experimental and calculated electronic circular dichroism spectra. The isolated alkaloids were evaluated for their neuroprotective activities against H2O2-induced cell injury in human neuroblastoma SH-SY5Y cells. The results showed that 5a/5b and 6a/6b exhibited potent neuroprotective activities at 50 µM compared with the H2O2-treated group.

Hydroalcoholic Leaf Extract of Isatis tinctoria L. via Antioxidative and Anti-Inflammatory Effects Reduces Stress-Induced Behavioral and Cellular Disorders in Mice

“…Isatis tinctoria is a plant with great therapeutic potential and extracts obtained from it possess the ability to inhibit the formation/activity of nitric oxide, anti-inflammatory, antioxidant, and neuroprotective properties [ 16 , 39 , 40 ]. Therefore, considering the above activities, preliminary pharmacological studies were performed to investigate the effect of polar extract from I. tinctoria leaves (IT) on stress-associated behaviors, as well as for the reduction of anxiety-like or depression-like behaviors.…”

Natural Enantiomers: Occurrence, Biogenesis and Biological Properties

“…The structures of indole alkaloid enantiomers reported in this period are depicted in Figure 8 and the names summarized in Table S8 in Supplementary Materials. Song and coworkers reported two pairs of oxindole enantiomers 127a/127b and 128a/128b from Isatis tinctoria in 2019 [81], while 128b had been previously reported in optically pure form from Isatis indigotica in 2012 [82]. In 2017, Zhang and colleagues discovered two pairs of enantiomers bearing two prenyl groups (129a/129b and 130a/130b) from Clausena lansium and assigned the rel.…”

“…Compounds 241a/241b and 242a/242b are flavonoid alkaloid enantiomers reported from Scutellaria moniliorrhiza in 2018 [129], while 243a/243b represent a pair of 9,10-dihydrophenanthrene alkaloid enantiomers from Bletilla striata [130]. The enantiomer pairs 244a/244b and 245a/245b featuring a spiro[benzofuranone-benzazepine] skeleton from Juglans mandshurica [131], as well as 246a/246b incorporating a benzo[f ] [1,3,5]triazocine backbone from Isatis tinctoria [81], were all reported by the research team of Song and Huang. Compounds 247a/247b are a pair of enantiomers formed by an oxyneolignan and a phenethylamine units from Lycium chinense [132], while 248a/248b and 249a/249b are rearranged nor-lignan amide enantiomers featuring a unique benzo-angular triquinane skeleton from Cannabis sativa [133].…”

“…Compounds 147a/147b, featuring a furoquinoline core hybridized with a phenylpropanoid unit via a 1,4-dioxane ring, were separated and characterized from Zanthoxylum nitidum in 2018 [97]. Three 2-quinolinone enantiomer pairs 148−150 were reported from Isatis tinctoria by Song and coworkers in 2019 [81], and in the same year, Zhang et al discovered the same type of alkaloid enantiomers 151a/151b from the roots of Isatis indigotica [86]. The last example of quinolinone enantiomer pair is compound 152 also from I. indigotica, and it incorporates an additional anthranilic acid residue [98].…”

Research progress on antiviral constituents in traditional Chinese medicines and their mechanisms of action

“…More than 100 alkaloids have been found in Banlangen by now, such as quinazolone alkaloids, indole alkaloids, quinoline alkaloids, and so on (Xi et al. 2019 ; Zhang et al. 2020b ).…”