Chemical composition of Rhododendron aureum (gold rosebay) essential oil from Pribaikal’e (Russian Federation)

The essential oils from five samples of leaves of Rhododendron aureum from the Irkutsk region, Pribaikal’e, Russian Federation, were isolated by hydrodistillation and analyzed by a combination of GC and GC/MS. Compounds representing 70.5–78.3 % of the oils were identified. Twenty-seven compounds were identified according to their chromatographic retention indices and mass spectra. The major components of the oils were calarene (10.4––66.4 %), b-bourbonene (0.5–27.4 %), a-selinene (2.1–8.0 %) and kaur-16-ene (2.0–6.3 %). It was found that the chemical composition of Rh. aureum essential oil depends on the altitude of the growing plants

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

Synanthropic Plants as an Underestimated Source of Bioactive Phytochemicals: A Case of Galeopsis bifida (Lamiaceae)

Hemp nettle (Galeopsis bifida Boenn.) is a synanthropic species of the Lamiaceae family that is widely distributed across Europe, Asia, and Siberia. Galeopsis bifida is deeply embedded in the ethnomedical tradition of Asian healers; however, this plant is still poorly characterized, both chemically and pharmacologically. To study Siberian populations of G. bifida, we used high-performance liquid chromatography with photodiode array and electrospray triple quadrupole mass detection for metabolic profiling. Ninety compounds were identified, including iridoid glycosides, phenylethanoid glycosides, hydroxycinnamates, and flavone glycosides, most of which were identified in G. bifida for the first time, while some phenolics were found to have potential chemotaxonomic significance in the Lamiaceae family and Galeopsis genus. An unequal quantitative distribution of the selected metabolites was observed within separate organs of the G. bifida plant, characterized by high accumulation of most compounds within the aerial part of the plant (leaves, flowers). Analysis of the content of specific chosen compounds within the leaves of different populations of G. bifida from Eastern Siberia revealed the existence of two chemical types based on metabolic specifics: the southern type accumulates flavone glucuronides, while the northern type tends to accumulate high levels of phenylpropanoids and acylated flavone glucosides. The first study of the bioactivity of G. bifida extract demonstrated that the herb has low toxicity in acute experiments and expresses antioxidant potential against free radicals in the form of DPPH˙, ABTS˙+, and superoxide radical, as well as high ferric reducing antioxidant power, oxygen radical absorbance capacity, and protective action in the carotene bleaching assay. In general, our results suggest the herb of G. bifida as a new, prospective synanthropic plant for medical application

Separation, Characterization and Mammal Pancreatic Lipase Inhibitory Potential of Cucumber Flower Flavonoids

Edible flowers are a new “old” trend in modern gastronomy and healthy nutrition aimed at increasing food attractiveness and improving the consumption of beneficial phytocompounds that have valuable properties. Cucumber (Cucumis sativus L., Cucurbitaceae family) is a well-known agricultural product; it is an important crop that is commonly used across the globe. Despite sufficient knowledge of nutrients and secondary metabolites in cucumber fruits, the use of cucumber flowers for food purposes is still understudied. In this study, the total flavonoid fraction of cucumber flowers was isolated and purified after liquid–liquid and solid-phase extraction and polyamide and Amberlite XAD-2 separation followed by high-performance liquid chromatography with photodiode array detection and electrospray ionization triple quadrupole mass spectrometric detection (HPLC–PDA–ESI–tQ–MS/MS), resulting in the detection of 47 compounds. Identified flavonoids included luteolin, apigenin, and chrysoeriol-based flavones such as C-, O-, and C,O-glycosides, most of which were detected for the first time in C. sativus. Flower extracts from ten cucumber cultivars were quantified, and isoorientin, isoorientin-4′-O-glucoside, and cucumerins B and D were predominant. The use of in vitro assay potential to inhibit mammalian pancreatic lipases was demonstrated for the C. sativus extracts. The dominant compounds were studied separately, and luteolin derivatives were determined to be responsible for the bioactivity. To the best of our knowledge, this is the first study on cucumber flowers that has shown their wide potential for use as a beneficial dietary supplement

Metabolites of Serratula L. and Klasea Cass. (Asteraceae): Diversity, Separation Methods, and Bioactivity

Serratula L. and Klasea Cass. are two systematically related genera of the family Asteraceae, which are distributed in most of the Eurasia area and are used as food and colorants and in traditional medicines as a drug. Since 1967, 261 metabolites have been isolated and identified from five Serratula species and 21 Klasea species. This review provides information on the chemodiversity of the terpenes, penolics, lipids, and other compounds found in both genera and their occurrence in individual species. Among the studied species, the most studied are S. coronata subsp. coronata, K. centauroides, and K. centauroides subsp. centauroides. This review also provides information on the methods of extraction, isolation, and analysis of ecdysteroids and flavonoids as the most valuable metabolites. For the first time, we provide general information about the biological activity of these extracts and individual compounds. The data presented in this review demonstrate the prospects of Serratula and Klasea species as sources of bioactive metabolites

The Ethnopharmacological Uses, Metabolite Diversity, and Bioactivity of Rhaponticum uniflorum (Leuzea uniflora): A Comprehensive Review

Rhaponticum uniflorum (L.) DC. (syn. Leuzea uniflora (L.) Holub) is a plant species of the Compositae (Asteraceae) family that is widely used in Asian traditional medicines in China, Siberia, and Mongolia as an anti-inflammatory and stimulant remedy. Currently, R. uniflorum is of scientific interest to chemists, biologists, and pharmacologists, and this review includes information from the scientific literature from 1991 to 2022. The study of the chemodiversity of R. uniflorum revealed the presence of 225 compounds, including sesquiterpenes, ecdysteroids, triterpenes, sterols, thiophenes, hydroxycinnamates, flavonoids, lignans, nucleosides and vitamins, alkanes, fatty acids, and carbohydrates. The most studied groups of substances are phenolics (76 compounds) and triterpenoids (69 compounds). Information on the methods of chromatographic analysis of selected compounds, as well as on the quantitative content of some components in various organs of R. uniflorum, is summarized in this work. It has been shown that the extracts and some compounds of R. uniflorum have a wide range of biological activities, including anti-inflammatory, antitumor, immunostimulatory, anxiolytic, stress-protective, actoprotective, antihypoxic, anabolic, hepatoprotective, inhibition of PPARγ receptors, anti-atherosclerotic, and hypolipidemic. Published research on the metabolites and bioactivity of R. uniflorum does not include clinical studies of extracts and pure compounds; therefore, an accurate study of this traditional medicinal plant is needed

Coumarins of Lovage Roots (<i>Levisticum officinale</i> W.D.J.Koch): LC-MS Profile, Quantification, and Stability during Postharvest Storage

Lovage (Levisticum officinale W.D.J. Koch) is a known aromatic apiaceous species that is widely used as a culinary and medicinal plant. Traditionally, more scientific attention has been paid to lovage volatiles, while other groups of compounds have been underutilized. In this study, metabolites of fresh lovage roots were investigated by liquid chromatography–mass spectrometry, and 25 compounds were identified, including coumarins as basic components and minor hydroxycinnamates; most were detected for the first time in the plant. Four major coumarins (including apterin, xanthotoxin, isopimpinellin, and pimpinellin) were successfully separated by a validated HPLC–PDA method, and the fresh roots of seven lovage cultivars as well as the dry roots of commercial lovage were quantified. The coumarin content deviation was 1.7–2.9 mg/g in the fresh roots and 15–24 mg/g in the dry roots. A variation in the coumarin level was found during storage of the fresh lovage roots at chill and room temperatures, while storage of the dried roots at room temperature showed the lowest loss of target compounds. This new information about the metabolites of lovage indicates the prospects of the plant roots as a source of dietary coumarins

Green Waste from Cucumber (<i>Cucumis sativus</i> L.) Cultivation as a Source of Bioactive Flavonoids with Hypolipidemic Potential

Cucumber is an important agricultural crop that is cultivated under greenhouse conditions. Cucumber cultivation generates substantial quantities of green waste that require proper disposal. The lack of data on the chemical composition of cucumber greens and their biological activity emphasizes the necessity for research on useful products resulting from this widely available waste. Our examination of the flavonoid contents in the leaves and stems of 30 cucumber cultivars revealed 6 cultivars with high flavonoid contents. In addition, the cutting time did not cause negative effects, and we observed a positive effect with 0.05–0.10% organomineral fertilizer application on the flavonoid levels in the greens. Liquid chromatography–mass spectrometry detected 38 apigenin derivatives, including acylated and non-acylated cucumerins and C-, O-, and C,O-glycosides. Among these, 12 known flavonoids and 18 novel compounds were identified. The concentrations of these compounds in the six flavonoid extracts varied at 39.85–181.53 mg/g for the non-acylated flavones, 14.67–293.31 mg/g for the cucumerins, and 401.73–892.17 mg/g for the acylated flavones. Oral administration of the total flavonoid extracts (at a dosage of 100 g/kg/day) resulted in a hypolipidemic effect in hyperlipidemic hamsters, with subsequent normalization of their serum lipid profiles, malondialdehyde levels, and liver antioxidative enzyme activities. These results substantiate the lipid-lowering potential of cucumber waste extracts. Our investigation of the selected flavonoid activity showed that isovitexin-2′′-O-glucoside-6′′-O-p-coumarate (administered at 50 g/kg/day) had the highest hypolipidemic potency. These results can contribute to the practical use of cucumber green waste and the development of novel supplements for diseases linked to high-fat consumption

Componential Profile and Amylase Inhibiting Activity of Phenolic Compounds from Calendula officinalis L. Leaves

An ethanolic extract and its ethyl acetate-soluble fraction from leaves of Calendula officinalis L. (Asteraceae) were found to show an inhibitory effect on amylase. From the crude extract fractions, one new phenolic acid glucoside, 6′-O-vanilloyl-β-D-glucopyranose, was isolated, together with twenty-four known compounds including five phenolic acid glucosides, five phenylpropanoids, five coumarins, and nine flavonoids. Their structures were elucidated based on chemical and spectral data. The main components, isoquercitrin, isorhamnetin-3-O-β-D-glucopyranoside, 3,5-di-O-caffeoylquinic acid, and quercetin-3-O-(6′′-acetyl)-β-D-glucopyranoside, exhibited potent inhibitory effects on amylase