Phenolic Compounds and Cinnamamide from Scutellaria scordiifolia

Phytochemical investigation of Scutellaria scordiifolia and its trypanocidal activity

Scutellaria scordiifolia Fisch. ex Schrank is used to treat various inflammatory diseases and other ailments in traditional and contemporary medicine. In this study, 10 undescribed compounds, including a flavanone (1), four chrysin C-glycosides (2-5), a phenanthrene glucoside (6), four iridoid glucosides (7-10) and 31 known compounds were identified from an extract of the aerial parts of S. scordiifolia. The absolute configurations of sugars in C-glycosides were determined by comparing electric circular dichroism spectra with calculated data. The flavanones (1 and 17), flavonols (11-13), flavone (14), and some of the flavone glucuronides (15, 16) exhibited trypanocidal activities against Trypanosoma congolense. The activity data and quantitative HPLC analysis of flavonoids from the aerial parts of S. scordiifolia suggest that they may effectively treat diseases caused by the aforementioned trypanosomes. Other compounds such as novel iridoids and phenanthrene glycosides, which may be useful for chemophenetic and chemoecological discussions, were also identified.

Bioactive Phenolics of the Genus Artemisia (Asteraceae): HPLC-DAD-ESI-TQ-MS/MS Profile of the Siberian Species and Their Inhibitory Potential Against α-Amylase and α-Glucosidase

Artemisia genus of Asteraceae family is a source of medicinal plants known worldwide and used as ethnopharmacological remedies for the treatment of diabetes in Northern Asia (Siberia). The aim of this study was to determine the phenolic profile of 12 Siberian Artemisia species (A. anethifolia, A. commutata, A. desertorum, A. integrifolia, A. latifolia, A. leucophylla, A. macrocephala, A. messerschmidtiana, A. palustris, A. sericea, A. tanacetifolia, A. umbrosa) and to test the efficacy of plant extracts and pure compounds for antidiabetic potential. Finally, by HPLC-DAD-ESI-TQ-MS/MS technique, 112 individual phenolic compounds were detected in Artemisia extracts in a wide range of concentrations. Some species accumulated rare plant phenolics, such as coumarin-hemiterpene ethers (lacarol derivatives) from A. latifolia and A. tanacetifolia; melilotoside from A. tanacetifolia; dihydrochalcones (davidigenin analogs) from A. palustris; chrysoeriol glucosides from A. anethifolia, A. sericea, and A. umbrosa; eriodictyol glycosides from A. messerschmidtiana; and some uncommon flavones and flavonols. The predominant phenolic group from Artemisia species herb was caffeoylquinic acid (CQAs), and in all species, the major CQAs were 5-O-CQA (20.28-127.99 μg/g) and 3,5-di-O-CQA (7.35-243.61 μg/g). In a series of in vitro bioassays, all studied Artemisia extracts showed inhibitory activity against principal enzymes of carbohydrate metabolism, such as α-amylase (IC₅₀ = 150.24-384.14 μg/mL) and α-glucosidase (IC₅₀ = 214.42-754.12 μg/mL). Although many phenolic compounds can be inhibitors, experimental evidence suggests that the CQAs were key to the biological response of Artemisia extracts. Mono-, di- and tri-substituted CQAs were assayed and showed inhibition of α-amylase and α-glucosidase, with IC₅₀ values of 40.57-172.47 μM and 61.08-1240.35 μM, respectively, and they were more effective than acarbose, a well-known enzyme inhibitor. The results obtained in this study reveal that Siberian Artemisia species and CQAs possess a pronounced inhibitory activity against α-amylase and α-glucosidase and could become a complement to synthetic antidiabetic drugs for controlling blood glucose level.

A novel HPLC-assisted method for investigation of the Fe2+-chelating activity of flavonoids and plant extracts

Flavonoids are a class of natural phenolic compounds that show antioxidant properties. Besides the known mechanisms of action of flavonoids (binding/inactivation of free radicals and other reactive oxygen species) that determine this effect, an important factor is their ability to bind transition metal ions. In this paper, we used a HPLC method with a prechromatographic reaction of a sample with Fe2+ ions (FeCA-HPLC) to characterize the Fe2+-chelating properties of individual compounds, their mixtures, and plant extracts. Using two classes of flavonoids (flavones, flavonols) the ability of compounds to bind Fe2+ ions due to a number of structural features of the compounds was shown. If the compounds possessed Fe2+-chelating properties, the decrease in the area of the chromatographic peaks on the chromatogram was marked. By comparing the resulting chromatogram with that of the untreated sample, it was possible to estimate the value of the effect. Application of this method for the analysis of plant extracts representing a mixture of substances allows determination of the compounds that have the greatest influence on the Fe2+-chelating activity.