Structure Elucidation of Two New Norlignans from Anemone vitifolia and Their Anti‐Inflammatory Activities

Vitifolignans, 3,4-dibenzyltetrahydrofuran lignans from Anemone vitifolia Buch.-Ham

Anemone vitifolia is a small herb found in Asia that is used to treat a range of diseases in Chinese traditional medicine. GNPS-based molecular networking of an Anemone vitifolia specimen revealed the presence of a network containing numerous ions indicating the presence of lignans, several of which suggested that there might be previously undescribed compounds in the extract. Fractionation of the organic extract yielded five undescribed lignans, the vitifolignans, together with one known. The structures were identified based on extensive spectroscopic data analysis (NMR, HR-ESI-MS, and UV), coupling constant calculation and comparison with reported data. Their absolute configurations were determined by comparison of experimental ECD spectra with calculated spectra. Compounds 4/5 showed weak inhibition of LPS-induced NO production in mouse mononuclear macrophages.

Copper-Catalyzed Umpolung Reactivity of Propargylic Carbonates in the Presence of Diboronates: One Stone Four Birds

Allylation and propargylation are two powerful synthetic strategies for making new substances that have been of significant importance in chemistry, medicine, and material fields. Conventional tactics employ various preformed allylation and propargylation reagents. In this study, a conceptually novel copper-catalyzed and B2pin2-mediated Umpolung reactivity of propargylic carbonates has been achieved for the first time, realizing both allylation and propargylation of aldehydes and ketones without additional reductants. Three types of allylation products and one type of propargylation product are generated efficiently, and all allylation products are formed with syn-configurations predominantly. The choice of ligands plays a vital role in modulating the Umpolung modes. The synthetic applications have been demonstrated in a myriad of further transformations including natural product synthesis, and systematic mechanistic studies have been conducted to reveal detailed insights into the Umpolung processes.

Review of lignans from 2019 to 2021: Newly reported compounds, diverse activities, structure-activity relationships and clinical applications

Lignans, with various biological activities, such as antitumor, antioxidant, antibacterial, and antiviral activities, are widely distributed in nature and mainly exist in the xylem of plants. In this paper, we summarized the structures and bioactivities of lignans reported in recent years (2019-2021) from five parts, including (1) a summary and classification of newly reported compounds; (2) the pharmacological activities of lignans; (3) molecular resources and activity distribution; (4) the structure-activity relationships; and (5) the clinical application of lignans. This review covers all undescribed compounds that were reported within the covered period of time and all bioactivity data about previously isolated lignans. The distribution of lignans in different plants and families is visualized, which improves the efficiency of searching for specific molecules. The diverse activities of different types of lignans provide an important reference for the rapid screening of these compounds. Discussion about the structure-activity relationships of lignans provides a direction for the structural modification of skeleton molecules. Combined with the clinical application of such molecules, this work will provide a valuable reference for pharmaceutical chemists.

Antiviral and Antioxidant Components from the Fruits of Illicium verum Hook.f. (Chinese Star Anise)

Illicium verum Hook.f. (Chinese star anise), a known Chinese traditional spice, is commonly applied in Chinese cuisine and cooking in Southeast Asia. As a kind of medicinal and edible resource, the fruit of I. verum has attracted great attention for its chemical constituents and physiological activities. In this work, the phytochemical study of the fruits of I. verum led to the isolation and identification of 20 compounds, including 6 new lignans and phenylpropanoids (1-6) and 14 known ones (7-20). Their structures were characterized by extensive analysis of spectroscopic data (IR, UV, high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), one-dimensional (1D) and two-dimensional (1D) NMR), electronic circular dichroism (ECD) calculation, and by comparison with literature data. Meanwhile, all compounds (1-20) were evaluated for their antiviral and antioxidant activities. Especially, compound 7 [(-)-bornyl p-coumarate] showed strong antiviral activities against influenza virus A/Puerto Rico/8/34 H1N1 (PR8) with an IC₅₀ value of 1.74 ± 0.47 μM, which is much better than those of Tamiflu (IC₅₀ = 10.01 ± 0.92 μM) and ribavirin (IC₅₀ = 10.76 ± 1.60 μM). The antiviral activity against PR8 of compound 7 was reported for the first time, which was sufficiently confirmed by cell counting kit 8 (CCK-8), cytopathic effect (CPE) reduction, and immunofluorescence assays. In this study, the discovery of antiviral and antioxidant components from the fruits of I. verum could benefit the further development and utilization of this plant.

(+/-)-Alashanoid N, Two Enantiomeric Sesquiterpenes from Syringa pinnatifolia

Two enantiomeric humulane sesquiterpenes, namely (+)-alashanoid N (1a) and (-)-alashanoid N (1b), along with two known analogs ((2R,3R,5R)-2,3-epoxy-6,9-humuladien-5-ol-8-one (2) and (2R,3S,5R)-2,3-epoxy-6,9-humuladien-5-ol-8-one (3)), were described from the peeled stems of a folk Mongolian herbal medicine Syringa pinnatifolia. Their structures were characterized based on UV, IR, NMR, and HR-ESI-MS data analyses, and the absolute configurations were determined by data analysis of X-ray diffraction and quantum chemical calculations. (+/-)-Alashanoid N showed inhibition against NO production in RAW 264.7 macrophage cells with IC₅₀ values of 90.1 μM and 71.7 μM, and protective effect against oxygen-glucose deprivation injury to H9c2 cells at a concentration of 20 μM and 5 μM, respectively.