Urtica dioica is a perennial herb from the family of Urticaceae that is commonly known as stinging nettle. This plant is widespread in Europe, Africa, America, and a part of Asia, as it adapts to different environments and climatic conditions. The leaves, stalk, and bark of U. dioica found applications in the field of nutrition, cosmetics, textile, pest control and pharmacology. In this connection, bioactive chemical constituents such as flavonoids, phenolic acids, amino acids, carotenoids, and fatty acids have been isolated from the plant. With this review, we aim at providing an updated and comprehensive overview of the contributions in literature reporting computational, in vitro, pre-clinical and clinical data supporting the therapeutic applications of U. dioica. Experimental evidence shows that U. dioica constituents and extracts can provide neuroprotective effects by acting through a combination of different molecular mechanisms, that are discussed in the review. These findings could lay the basis for the identification and design of more effective tools against neurodegenerative diseases.

Two novel compounds including a cyclohelminthol type polyketide (namely oxaleimide K,1) and a maleimide derivative (namely peniroquefortine A,2), and a new natural product (namely 2-(acetylamino)-N-[(1E)-2-phenylethenyl]-acetamide,3), together with four known compounds (4-7), were isolated and identified from fungus Penicillium roqueforti, which was separated from the root soil of Hypericum beanii N. Robson collected from the Shennongjia Forestry District, Hubei Province. Their structures including absolute configurations were mainly established by the NMR spectroscopy analyses and single-crystal X-ray diffraction experiment. Compound1 represents the second example of a cyclohelminthol type polyketide, which features a rare 6/6/5/5 tetracyclic system and a branched aliphatic chain containing a terminal olefin (oct-1-en-3-yl) moiety, and compound2 possesses an unprecedented carbon skeleton that is uniquely defined by a maleimide moiety linked to the respective 4-methylene-2-(3-methylbut-2-en-1-yl)-phenol and para-substituted aromatic moieties via the carbon-carbon bonds. Remarkably, the absolute configuration of a cyclohelminthol type polyketide as exemplified by compound1 is determined by the single-crystal diffraction analysis for the first time, highlighting an E-configuration for the linkage of a succinimide moiety and a tetrahydrofuran moiety for1 rather than a Z-configuration as previously reported in the biosynthesis study, which gives a new insight into the structural elucidation of this category of polyketides. Additionally, compound1 exhibited significant cytotoxic activity against multiple tumor cells, especially against the Farage and SU-DHL-2 cells (IC₅₀<20 μM, 48 h). Further mechanism study revealed that compound1 significantly induced cell cycle arrest in Farage and SU-DHL-2 cells by causing abnormal ROS level and triggering oxidative stress.

Four polysaccharides (MCPa, MCPb, MCPc, MCPd) were obtained from Lepidium meyenii Walp. Their structures were characterized by chemical and instrumental methods including total sugar, uronic acid and protein content determination, UV, IR and NMR spectroscopy, as well as monosaccharide composition determination and methylation analyses. Four polysaccharides were a group of glucans with different molecular weights ranging from 3.12 to 14.4 kDa, and shared a similar backbone chain consisting of (1→4)-glucose linkages with branches attached to C-3 and C-6. Furthermore, bioactivity assay showed that MCPs had concentration-dependent inhibitory activity on α-glucosidase. MCPb (Mw=10.1 kDa) and MCPc (Mw=5.62 kDa) with moderate molecular weights exhibited higher inhibitory activity compared with MCPa and MCPd.

This study investigates the potential of cannabidiol (CBD), one major cannabinoid of the plant Cannabis sativa, alone and in combination with a terpene-enriched extract from Humulus lupulus (“Hops 1”), on the LPS-response of RAW 264.7 macrophages as an established in vitro model of inflammation. With the present study, we could support earlier findings of the anti-inflammatory potential of CBD, which showed a dose-dependent [0-5 μM] reduction in nitric oxide and tumor necrosis factor-alpha (TNF-α) released by LPS-stimulated RAW 264.7 macrophages. Moreover, we observed an additive anti-inflammatory effect after combined CBD [5 μM] and hops extract [40 μg/mL] treatment. The combination of CBD and Hops 1 showed effects in LPS-stimulated RAW 264.7 cells superior to the single substance treatments and akin to the control hydrocortisone. Furthermore, cellular CBD uptake increased dose-dependently in the presence of terpenes from Hops 1 extract. The anti-inflammatory effect of CBD and its cellular uptake positively correlated with terpene concentration, as indicated by comparison with a hemp extract containing both CBD and terpenes. These findings may contribute to the postulations for the so-called “entourage effect” between cannabinoids and terpenes and support the potential of CBD combined with phytomolecules from a non-cannabinoid source, such as hops, for the treatment of inflammatory diseases.

Bone marrow mesenchymal stem cells (BMSCs) are non-hematopoietic multipotent stem cells capable of differentiating into mature cells. Isoquercetin, an extract from natural sources, has shown promise as a potential treatment for osteoporosis. To investigate the therapeutic effects of isoquercetin on osteoporosis, bone marrow mesenchymal stem cells (BMSCs) were cultured in vitro, and osteogenesis or adipogenesis was induced in the presence of isoquercetin for 14 days. We evaluated cell viability, osteogenic and adipogenic differentiation, as well as mRNA expression levels of Runx2, Alpl, and OCN in osteoblasts, and mRNA expression levels of Pparγ, Fabp4, and Cebpα in adipocytes. The results showed that isoquercetin dose-dependently increased cell viability and promoted osteogenic differentiation, as evidenced by Alizarin Red and alkaline phosphatase staining and mRNA expression levels of Runx2, Alpl, and OCN in osteoblasts (P<0.05). In contrast, isoquercetin inhibited adipogenic differentiation and decreased the mRNA expression levels of Pparγ, Fabp4, and Cebpα in adipocytes (P<0.05). In vivo, isoquercetin treatment increased bone quantity and density in an osteoporosis model mice group, as determined by μCT scanning and immunohistochemistry (P<0.05). These findings suggest that isoquercetin may have therapeutic potential for osteoporosis by promoting the proliferation and differentiation of BMSCs towards osteoblasts while inhibiting adipogenic differentiation.

Three new halimane furanoditerpenoids (1-3) and three new clerodane furanoditerpenoids (4-6), along with seven known terpenoids including four pimarane diterpenoids (7-10) and three norisoprenoids (11-13) were isolated from the 95% EtOH extracts of the plants of Croton cnidophyllus. The 2D structures including absolute configuration of new furanoditerpenoids (1-6) were elucidated by analysis of their HRMS and NMR data as well as comparison of experimental and calculated ECD curves. Bioassay revealed that two compounds (8 and9) possessed certain inhibitory effects against NO production stimulated by LPS, with IC₅₀ values of 19.00±1.76 and 21.61±1.11 μM, respectively.

Four undescribed pyrethrins C-F (1-4) as well as four known pyrethrins (5-8) were isolated from seeds of Pyrethrum cinerariifolium Trev. The structures of compounds1-4 were elucidated by UV, HRESIMS, and NMR (¹H and ¹³C NMR, ¹H-¹H COSY, HSQC, HMBC and ROESY), among which the stereostructure of compound4 was determined by calculated ECD. Furthermore, compounds1-4 were evaluated for their aphidicidal activities. The insecticidal assay results showed that1-4 exhibited moderate aphidicidal activities at the concentration of 0.1 mg/mL with the 24 h mortality rates ranging from 10.58 to 52.98%. Among them, pyrethrin D (2) showed the highest aphidicidal activity, with the 24 h mortality rate of 52.98%, which was slightly lower than the positive control (pyrethrin II, 83.52%).