Isatindigoside A and B (1 − 2), two new indole alkaloid glycosides along with five known ones (3 − 7) were obtained from the roots of I. tinctoria. Their structures were determined as isatindigoside A (1), isatindigoside B (2), isatindosulfonicacid A 3-O-β-D-glucopyranoside (3), indole-3-acetonitrile 6-O-β-D-glucopyranoside (4), isatindigobisindoloside A (5), isatindigobisindoloside B (6) isatindigobisindoloside F (7),
Abstract:Two new furostanol saponins 1-2 and a new spirostanol saponin 3 were isolated together with two known furostanol saponins 4-5 from the roots and rhizomes of Tupistra chinensis. Their structures were characterized as 1β,2β,3β,4β,5β,26-hexahydroxyfurost-20(22), 25(27)-dien-5,26-O-β-D-glucopyranoside (1), 1β,2β,3β,4β,5β,6β,7α,23ξ,26-nona-hydroxyfurost-20(22) ).
Five pairs of alkaloid enantiomers (1a/1b–5a/5b) were obtained from Isatis indigotica (I. indigotica) roots. Among them, 1a/1b, 2a/2b and 3a/3b were determined as three pairs of new alkaloid enantiomers. Their structures were elucidated by physicochemical properties and spectroscopic methods. The absolute configurations were deduced by comparison of their experimental circular dichroism (CD) and calculated electronic circular dichroism (ECD) spectra, as well as by single-crystal X-ray crystallography using anomalous scattering of Cu Kα radiation. Alkaloids 1a and 1b possess an unpresented carbon skeleton and their putative biosynthetic pathways are discussed. Moreover, all of the alkaloids were tested for their nitric oxide (NO) inhibitory effects in RAW 264.7 cells, and 4a and 4b showed inhibitory effects with IC50 values of 76.97 μM and 65.88 μM, respectively.
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