دانلود رایگان مقاله انگلیسی گلیکوئیدات رامنتین از جنس اسپیره - اشپرینگر 2018

Rhamnetin (7-O-methylquercetin, 1) and its glycosides were found for the first time in the genus Spiraea (Rosaceae) during chromatographic studies of representatives from the subgenus Protospiraea. Leaves of S. salicifolia yielded 1, rhamnetin-3-O--D-glucopyranoside (2), and two new flavonoids 3 and 4 that were identified by UV, IR, and NMR spectroscopy and mass spectrometry as rhamnetin-3-O-(6-O-p-coumaroyl)- -D-glucopyranoside (spiraearhamnin A, 3) and rhamnetin-3-O-(6-O-caffeoyl)--D-glucopyranoside (spiraearhamnin B, 4). Leaves of S. betulifolia and S. betulifolia var. aemiliana afforded 1 and 2 and glycosides of kaempferol, quercetin, and isorhamnetin. Species of the subgenus Metaspiraea (S. alpina, S. chamaedryfolia, S. dahurica, S. hypericifolia, and S. media) did not contain 1 or its derivatives.

The genus Spiraea (Rosaceae) is an interesting subject for chemotaxonomic studies because of the broad distribution and various opinions about the number of species, which are complicated by hybridization and polymorphism. Flavonoids of various structural types are considered marker compounds for this genus and the family as a whole [1]. Characteristic flavonoids of the genus Spiraea are the flavonols kaempferol and quercetin and their glycosides [1], which were detected in S. canescens D. Don [2], S. cantoniensis Lour. [3], S. chamaedryfolia L. [4], S. formosana Hayata [5], S. hypericifolia L., S. media Schmidt [4], and S. salicifolia L. [6]. Methoxylated quercetin derivatives including rhamnazin and the dimeric flavonols sparin A and B, which were atypical of the genus, were relatively recently isolated from S. brahuica Boiss. [7]. Isorhamnetin was also observed in several Siberian Spiraea species [8]. This suggested that methoxylated flavonols were more broadly distributed within this genus.