The members of Gentiana genus are widely distributed in the Caucasus region where they are used as phytoremedies, but they still have not been studied for their chemical composition and bioactivity. High-performance liquid chromatography with diode array and electrospray triple quadrupole mass detection (HPLC-DAD-ESI-QQQ-MS) was used to investigate metabolites of herb and roots of six gentians (Gentiana asclepiadea, G. cruciata, G. gelida, G. paradoxa, G. pneumonanthe, G. septemfida) grown in the Caucasus. In total, 137 compounds were found including three carbohydrates, 71 iridoid glycosides (mostly loganic acid), loganin, swertiamarin, gentiopicroside and sweroside derivatives, 40 flavones C-, O-, C,O-glycosides (such as luteolin, apigenin, chrysoeriol, and acacetin derivatives), two phenolic O-glycosides, five hydroxycinnamates, eight xanthones, and seven triterpene glycosides. Most of these compounds were identified in gentian samples for the first time. Quantitative differences were found in levels of seven iridoid glycosides, nine glycosylflavones, and two xanthones obtained by HPLC-DAD assay. The gentian extracts were evaluated for their radical-scavenging properties against DPPH and superoxide anion radicals, lipid peroxidation inhibition, and α-amylase/α-glycosidase inhibition. The herb extracts showed higher activity than root extracts. Positive correlations were found between the content of quantified phenolics and antioxidant and digestive enzymes inhibiting activity. The findings presented in our work suggest that the Caucasian gentians are a good source of bioactive phytocompounds with antioxidant and antidiabetic potential.

Fringed sagewort (Artemisia frigida Willd., Compositae family) is a well-known medicinal plant in Asian medical systems. Fifty-nine hydroxycinnamates and flavonoids have been found in A. frigida herbs of Siberian origin by high-performance liquid chromatography with diode array and electrospray triple quadrupole mass detection (HPLC-DAD-ESI-QQQ-MS). Their structures were determined after mass fragmentation analysis as caffeoylquinic acids, flavone O-/C-glycosides, flavones, and flavonol aglycones. Most of the discovered components were described in A. frigida for the first time. It was shown that flavonoids with different types of substitution have chemotaxonomic significance for species of Artemisia subsection Frigidae (section Absinthium). After HPLC-DAD quantification of 16 major phenolics in 21 Siberian populations of A. frigida and subsequent principal component analysis, we found substantial variation in the selected compounds, suggesting the existence of two geographical groups of A. frigida. The antioxidant activity of A. frigida herbal tea was determined using 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH•) and hydrophilic/lipophilic oxygen radical absorbance capacity (ORAC) assays and DPPH•-HPLC profiling, revealing it to be high. The effect of digestive media on the phenolic profile and antioxidant capacity of A. frigida herbal tea was assessed under simulated gastrointestinal digestion. We found a minor reduction in caffeoylquinic acid content and ORAC values, but remaining levels were satisfactory for antioxidant protection. These results suggest that A. frigida and its food derivate herbal tea could be recommended as new plant antioxidants rich in phenolics.

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