Seven undescribed phenylpropanoid constituents, including three new bibenzyl derivatives (1–3) along with four new benzofuran stilbene derivatives (4–7), were isolated from the aerial parts of Dioscorea polystachya. The structures of these compounds were elucidated using a combination of spectroscopic analyses, including UV, IR, HRESIMS, 1D, and 2D NMR. Further, all the compounds were evaluated on the anti-inflammatory activity for their inhibition of nitric oxide (NO) production by RAW 264.7 macrophages cells, and some of them (1–3 and 6) displayed inhibitory activity with IC₅₀ values in the range of 9.3–32.3 μM. Moreover, compound 3 decreased the expression of iNOS in Western blot analysis, suggesting compound 3 is mediated via the suppression of an LPS-induced NF-κB inflammasome pathway.

Two new phenolic compounds Fusagunolics A (1) and B (2) were isolated from the plant endophytic fungus Fusarium guttiforme, in addition to the previously known metabolites (3-6). The structures of these compounds was elucidated using a combination of spectroscopic analyses, including UV, HRESIMS, 1 D, and 2 D NMR, as well as electronic circular dichroism (ECD) and the optical rotatory dispersion (ORD). Further, the anti-inflammatory activity of all the compounds was evaluated to assess their capability to inhibit nitric oxide (NO) production by RAW 264.7 macrophages. The bioactive screening revealed that compounds 2 and 6 exhibited moderate inhibitory effects against NO production with the IC₅₀ values 28.6 and 37.6 μM, respectively. Graphical Abstract

Three undescribed phenylpropanoid derivatives, including two new bibenzyl constituents (1–2), one new stilbene constituent (3), together with five known compounds stilbostemin F (4), dihydropinosylvin (5), 2-(4-hydroxyphenyl)ethyl benzoate (6), 1-(4-hydroxybenzoyl)ethanone (7), and 4-hydroxy-3-prenylbenzoic acid (8), were isolated from the tuber of Asparagus cochinchinensis. The structures of 1–8 were elucidated according to UV, IR, HRMS, 1D and 2D-NMR methods together with the published literature. All of the isolated compounds were assessed for anti-inflammatory activity by acting on lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells in vitro. The results showed that compounds 2 and 5 were found to inhibit the production of nitric oxide (NO) with the IC₅₀ value of 21.7 and 35.8 µM, respectively. In addition, further studies found that compound 2 demonstrated concentration-dependent suppression of the protein expression of iNOS and exerted anti-inflammatory activity via the NF-κB signalling pathway. The present data suggest that phenylpropanoid derivatives from the tuber of A. cochinchinensis might be used as a potential source of natural anti-inflammatory agents.

Phytochemical analysis of Populus euphratica resins has resulted in the isolation and identification of two undescribed terpenoids, including a new triterpene (1), a new sesquiterpene (2), and nine additional terpenoid (3-11) compounds. The structures of these novel compounds were determined using HR-ESI-MS and NMR (1D and 2D) spectroscopic analyses, combined with ECD calculations. The inhibitory activity of these terpenoids against α-glucosidase was also evaluated, and the results revealed that none of the compounds exhibited significant α-glucosidase inhibitory activity at a concentration of 50 μM. Only compound 1 displayed weak inhibitory activity (1.84 ± 8.96%) compared to the positive control.

Chemical investigations of Platycodon grandiflorus have resulted in the isolation and identification of seven 8,4'-oxyneolignans, including four undescribed compounds (1-4). The structures of these novel compounds were determined using HR-ESI-MS and NMR (1D and 2D) spectroscopic analyses, combined with ECD calculations. The inhibitory activity of these terpenoids against α-glucosidase was also evaluated, and the results revealed that none of the compounds exhibited significant α-glucosidase inhibitory activity at a concentration of 50 μM. Compared with the positive control, all the compounds displayed weak inhibitory activity, with inhibition rates ranging from 1.06% to 7.31%.

A phytochemical investigation of the stems of Dendrobium nobile Lindl. led to the isolation of six nitrogen-containing compounds, including one previously undescribed quinoline–aspartic acid hybrid alkaloid, dendronobiline A (1), together with five known alkaloid-related constituents (2–6). The structure of compound 1 was elucidated by comprehensive spectroscopic analyses, including HRESIMS, 1D and 2D NMR experiments, and its absolute configuration was assigned by comparison of experimental and calculated ECD spectra. Structurally, compound 1 features a quinoline-derived unit connected to a dimethyl aspartate moiety through an amide linkage. All isolated compounds were evaluated for their inhibitory effects on LPS-induced nitric oxide production in RAW264.7 macrophages. Among them, compound 1 displayed the most potent anti-inflammatory activity, with an IC50 value of 9.05 ± 1.60 μM, comparable to that of the positive control dexamethasone. These findings enrich the chemical diversity of D. nobile alkaloids and suggest that its stems are a promising source of anti-inflammatory natural products.