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

Leucosceptosides A and B: Two Phenyl-Ethanoid Glycosides with Important Occurrence and Biological Activities

In this review paper, the occurrence in the plant kingdom, the chemophenetic value and the biological activities associated with two specific phenyl-ethanoid glycosides, i.e., leucosceptoside A and leucosceptoside B, were reported. This is the first work ever conducted on such a subject. Analysis of the literature data clearly led to three important conclusions: leucosceptoside A is much more common in plants than leucosceptoside B; leucosceptoside A exerts more biological activities than leucosceptoside B even if nothing can be generally concluded about which one is actually the most potent; neither of these compounds can be used as a chemophenetic marker. These three aspects and more are discussed in more depth in this work.

Metabolites of Prickly Rose: Chemodiversity and Digestive-Enzyme-Inhibiting Potential of Rosa acicularis and the Main Ellagitannin Rugosin D

Prickly rose (Rosaacicularis Lindl.) is the most distributed rose species in the Northern Hemisphere, used by indigenous people for various food purposes. The lack of detailed information about the chemical composition of R. acicularis has led us to study the phytochemical composition and metabolic profile of prickly rose extracts using chromatographic techniques. Many groups of phenolic and non-phenolic compounds were quantified in the leaves, flowers, roots and fruits of R. acicularis. Phenolic compounds were the dominant phytochemicals in the aerial parts and roots of R. acicularis. A precise study by high-performance liquid chromatography with photodiode array detection and electrospray ionization triple quadrupole mass spectrometric detection showed the presence of 123 compounds, among which ellagic acid derivatives, ellagitannins, gallotannins, catechins, catechin oligomers, hydroxycinnamates and flavonoid glycosides of kaempferol, quercetin and dihydroquercetin were all identified for the first time. The most abundant phenolic compounds were ellagitannins and flavonoid glycosides, with a maximal content of 70.04 mg/g in leaves and 66.72 mg/g in flowers, respectively, indicating the great ability of R. acicularis organs to accumulate phenolic compounds. By applying a standardized static, simulated gastrointestinal digestion method, we found the inhibitory potential of the leaf extract against digestive α-amylases. A pancreatic α-amylase activity-inhibiting assay coupled with HPLC microfractionation demonstrated high inhibition of enzyme activity by ellagitannin rugosin D, which was later confirmed by a microplate reaction with mammalian α-amylases and the simulated digestion method. This study clearly demonstrates that R. acicularis leaf extract and its main component, ellagitannin rugosin D, strongly inhibit digestive α-amylase, and may be a prospective antidiabetic agent.

Water-Soluble Melanoidin Pigment as a New Antioxidant Component of Fermented Willowherb Leaves (Epilobium angustifolium)

Willowherb (Epilobium angustifolium L., family Onagraceae) is a well-known food and medicinal plant used after fermentation as a source of beverages with high antioxidant potential. Despite this long history of use, only a few papers have described the chemical profile and bioactivity of fermented willowherb tea in general. To understand the basic metabolic differences of non-fermented and fermented E. angustifolium leaves, we used general chemical analysis, high-performance liquid chromatography with photodiode array detection and electrospray ionization triple quadrupole mass spectrometric detection assay, and an isolation technique. As a result, the content of 14 chemical groups of compounds was compared in the two plant materials; 59 compounds were detected, including 36 new metabolites; and a new water-soluble phenolic polymer of melanoidin nature was isolated and characterized. The fundamental chemical shifts in fermented E. angustifolium leaves relate mainly to the decrease of ellagitannin content, while there is an increase of melanoidin percentage and saving of the antioxidant potential, despite the significant changes detected. The strong antioxidative properties of the new melanoidin were revealed in a series of in vitro bioassays, and a simulated gastrointestinal and colonic digestion model demonstrated the stability of melanoidin and its antioxidant activity. Finally, we concluded that the new melanoidin is a basic antioxidant of the fermented leaves of E. angustifolium, and it can be recommended for additional study as a promising food and medicinal antioxidant agent.

Sagan Dalya Tea, a New "Old" Probable Adaptogenic Drug: Metabolic Characterization and Bioactivity Potentials of Rhododendron adamsii Leaves

Adams' rhododendron (Rhododendron adamsii Rehder) or Sagan Dalya tea is a famous Siberian evergreen medical plant of the Ericaceae family used in traditional medicines of Buryats, Yakuts, and Mongols as a tonic, stimulant, and adaptogenic drug. The high popularity of R. adamsii coupled with poor scientific knowledge prompted the addressing of gaps related to metabolic and biomedical data of Sagan Dalya tea. The application of solid-phase extraction and liquid chromatography-mass spectrometric techniques for the metabolomic study of R. adamsii leaf extracts resulted in the identification of more than 170 compounds, including carbohydrates, organic acids, simple phenol glycosides, triterpene glycosides, flavonoids, prenylated phenols, benzoic acid derivatives, hydroxycinnamates, dihydrochalcones, catechins, and procyanidins, most of which were identified for the first time in the plant. Extended surveys of the seasonal content of all detected compounds prove that specific metabolite variations reflect the bioactivity of R. adamsii extracts. Regarding in vitro methods, the expressed antioxidant potential of R. adamsii extracts was investigated via radical-scavenging, nitric oxide scavenging, and ferrous (II) ion chelating assays. The animal-based swimming to exhaustion test demonstrates the stimulating influence of R. adamsii extract on physical performance and endurance, concluding that the drug could act as an adaptogen. Thus, Sagan Dalya tea (R. adamsii) has confirmed its "old" application as a tonic remedy and requires further precise study as a novel adaptogenic plant.