Phytochemical investigation of compounds, obtained from Calendula officinalis L., growing in Samara region

The pot marigold flowers (Calendula officinalis L.) are widely used in worldwide medical practice. The extensive spectrum of pharmacological activity of Calendula flowers (anti-inflammatory, regenerating, antimicrobial, cholagogue, expectorant properties) is based on the presence of various classes of biologically active substances, namely carotenoids, flavonoids (glycosides of kaempferol, quercetin and isorhamnetin), saponins. This factor makes Calendula a highly promising resource of new herbal medicines. Nevertheless, in the literature there are conflicting data on the chemical composition of medicinal marigolds, which require an additional study of the chemical composition of pot marigold flowers. The aim of this study is thephytochemical study of compounds isolated from flowers of pot marigold, cultivated in the Samara region. Materials and methods. The object of the study was the flowers of marigolds, cultivated on the pharmacopoeial site of the Botanical Garden of Samara University. The chemical structure of the substances was established using the data of 1H-NMR, 13C-NMR-spectroscopy, UV spectroscopy and mass spectrometry. Results.Calenduloside K, which is a new natural compound and having the structure: 3-O - [(1 → 4) -ß-D-glucopyranosyl- (1→ 6)-ß-D-glucuronopyranosyl] -ß-D-glucopyranoside of oleanolic acid, was isolated using column chromatography from the Сalendula flowers sort «Kalta» cultivated in the Samara region), as well as 3-O-ß-D-glucopyranoside of isorhamnetin, 3-O-a-L-rhamnopyranoside of isorhaminein and 3-O-p-coumaroylquinic acid. In addition, a diagnostically significant and dominant flavonoid narcissin was isolated from the Сalendula flowers. As a result of the carried out researches, saponin (calenduloside K), flavonoids (narcissin, 3-O-ß-D-glucopyranoside of isorhaminein, 3-O-a-L-rhamnopyranoside of isorhamnetin) and phenylpropanoids (3-O-p-coumaroylquinic acid). It was determined that flavonoid narcissin (3-O-rutinoside of isorhamnetin) is the dominant and diagnostically significant flavonoid of Calendula flowers. In our opinion, it is advisable to determine the authenticity of flowers of Calendula officinalis by detection by TLC of narcissin, rather than rutin, as provided by the current regulatory documentation. Conclusion. As a result of the carried out researches, saponin (calenduloside K), flavonoids (narcissin, 3-O-ß-D-glucopyranoside of isorhaminein, 3-O-a-L-rhamnopyranoside of isorhamnetin) and phenylpropanoids (3-O-p-coumaroylquinic acid). It was determined that the analysis of the raw material «Calendula officinalis flowers» is expedient to be carried out by TLC method by detection of narcissin, taking into account its specificity, and also the fact that this flavonoid is the dominant one in this plant.

Calendula officinalis L, Calendula officinalis L, Pot marigold, flowers, flavonoids, narcissin, p-coumaroylquinic acid, saponins