Flavonoid Glycosides in Leaves of Plants of the Genus Nigella L.

Abstract

Phenolic compounds in plants of the genus Nigella are represented by various groups of flavonoids, gallocatechins, and derivatives of cinnamic and caffeic acids. The content of flavonoid glycosides in the leaves of Nigella damascena L., N. sativa L., and N. orientalis L. was established by the HPLC-MS method. Species-specific dependence of accumulation of flavonoid glycosides has been established. It was shown that the main flavonoids in the leaves of the studied objects were glycosides of quercetin and kaempferol, while quercetin glycosides were 1.40–1.97 times more than kaempferol in the studied extracts. N. sativa leaves had an increased composition of flavonoid glycosides compared to other studied species. The qualitative composition of N. damascena flavonoid glycosides was like N. sativa, whereas it is close to N. orientalis in terms of the total content of this group of compounds. Total amount of flavonoid glycosides in N. sativa leaf extracts was four times higher than in extracts of other types of Nigella. It is worth noting that the types N. sativa and N. damascena have the greatest phenotypic similarity and are more resistant to growing conditions in Belarus, while the species N. orientalis is different in appearance and more demanding on cultivation conditions. It was found that the variety of flavonoids glycosides in N. orientalis leaves is less in the absence of high molecular weight and acylated forms. The possible absence of acylated derivatives and less variety of flavonoids glycosides affects the low stability N. orientalis to abiotic factors and reduces its adaptive potential.