Diversity-oriented synthesis of diterpenoid alkaloids yields a potent anti-inflammatory agent.

BACKGROUND: The diterpenoid alkaloids belong to a highly esteemed group of natural compounds, which display significant biological activities. It is a productive strategy to expand the chemical space of these intriguing natural compounds for drug discovery. METHODS: We prepared a series of new derivatives bearing diverse skeletons and functionalities from the diterpenoid alkaloids deltaline and talatisamine based on a diversity-oriented synthesis strategy. The anti-inflammatory activity of these derivatives was initially screened and evaluated by the release of nitric oxide (NO), tumor necrosis factor (TNF-α), and interleukin-6 (IL-6) in lipopolysaccharide (LPS)-activated RAW264.7 cells. Futhermore, the anti-inflammatory activity of the representative derivative 31a was validated in various inflammatory animal models, including phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mice ear edema, LPS-stimulated acute kidney injury, and collagen-induced arthritis (CIA). RESULTS: It was found that several derivatives were able to suppress the secretion of NO, TNF-α, and IL-6 in LPS-activated RAW264.7 cells. Compound 31a, one of the representative derivatives named as deltanaline, demonstrated the strongest anti-inflammatory effects in LPS-activated macrophages and three different animal models of inflammatory diseases by inhibiting nuclear factor kappa-B (NF-κB)/mitogen-activated protein kinase (MAPK) signaling and inducing autophagy. CONCLUSION: Deltanaline is a new structural compound derived from natural diterpenoid alkaloids, which may serve as a new lead compound for the treatment of inflammatory diseases.

Exploring the Mechanism of Curcumin on Retinoblastoma Based on Network Pharmacology and Molecular Docking.

Background: Curcumin shows great effects of inhibiting tumor cell proliferation, inducing apoptosis, inhibiting tumor metastasis, and inhibiting angiogenesis on a variety of tumors. However, the biological activity and possible mechanisms of curcumin in the treatment of retinoblastoma have not been fully elucidated. This study explored the potential therapeutic targets and pharmacological mechanisms of curcumin against retinoblastoma based on network pharmacology and molecular docking. Methods: The genes corresponding to curcumin targets were screened from the HERB, PharmMapper, and SwissTargetPrediction databases. Protein-protein interaction (PPI) networks were constructed for the intersecting targets in the STRING database. Cytoscape 3.7.0 was used for network topology analysis and screening of important targets. R 4.1.0 software was used for Gene Ontology (GO) function enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of intersection targets. The molecular structures of curcumin and core target proteins were obtained from PubChem and PDB databases, and the two were preprocessed and molecularly docked using AutoDockTools and PyMOL software. Results: Through network data mining, we obtained 504 curcumin targets and 966 retinoblastoma disease targets, and 44 potential targets for curcumin treatment of retinoblastoma were obtained by mapping. Three core targets were obtained from network topology analysis. 462 biological processes, 21 cellular compositions, and 34 molecular functions were obtained by GO enrichment analysis. KEGG pathway analysis revealed 94 signaling pathways, mainly involving chemical carcinogenesis-receptor activation, chemical carcinogenesis-reactive oxygen species, viral carcinogenesis, Th17 cell differentiation, etc. The molecular docking results indicated that the binding energy of curcumin to the core targets was less than 0 kJ mol-1, among which the binding energy of RB1 and CDKN2A to curcumin was less than -5 kJ mol-1 with significant binding activity. Conclusion: Based on molecular docking technology and network pharmacology, we initially revealed that curcumin exerts its therapeutic effects on retinoblastoma with multitarget, multipathway, and multibiological functions, providing a theoretical basis for subsequent studies.

Identification and optimization of 3-bromo-N'-(4-hydroxybenzylidene)-4-methylbenzohydrazide derivatives as mTOR inhibitors that induce autophagic cell death and apoptosis in triple-negative breast cancer.

Triple negative breast cancer (TNBC) has a worse prognosis than other types of breast cancer due to its special biological behavior and clinicopathological characteristics. TNBC cell proliferation and progression to metastasis can be suppressed by inducing cytostatic autophagy. mTOR is closely related to autophagy and is involved in protein synthesis, nutrient metabolism and activating mTOR promotes tumor growth and metastasis. In this paper, we adopted the strategy of structure simplification, aimed to look for novel small-molecule inhibitors of mTOR by pharmacophore-based virtual screening and biological activity determination. We found a lead compound with 3-bromo-N'-(4-hydroxybenzylidene)-4-methylbenzohydrazide for rational drug design and structural modification, then studied its structure-activity relationship. After that, compound 7c with the best TNBC cells inhibitory activities and superior mTOR enzyme inhibitory activity was obtained. In addition, we found that compound 7c could induce autophagic cell death and apoptosis in MDA-MB-231 and MDA-MB-468 cell lines. In conclusion, these findings provide new clues for our 3-bromo-N'-(4-hydroxybenzylidene)-4-methylbenzohydrazide derivatives, which are expected to become drug candidates for the treatment of TNBC in the future.

Four new C20-diterpenoid alkaloids from Aconitum rotundifolium.

Four new C20-diterpenoid alkaloids, rotundifosines D-G (1-4), along with eight known ones (5-12) were isolated from the whole plant of Aconitum rotundifolium Kar. & Kir. The structures of the compounds were elucidated on the basis of spectroscopic analyses, including HR-ESI-MS and 1D, 2D NMR. Rotundifosine F (3) is a rare C20-diterpenoid alkaloid with quaternary ammonium salt. Alkaloids 1-4, 5, 6, 9, and 12 were evaluated for cytotoxicity against MCF-7, HCT-116 and HepG2 human cancer cell lines.

Four New Diterpenoid Alkaloids from the Roots of Aconitum carmichaelii.

Aconitum carmichaelii Debeaux is a widely used traditional Chinese medicine and an important source of clinical drugs, of which the parent and lateral roots are known as 'Chuanwu' and 'Fuzi', respectively. Four new C19 -diterpenoid alkaloids, carmichasines A - D (1 - 4), were isolated from the roots of Aconitum carmichaelii, together with twelve known compounds (5 - 16). Their structures were elucidated via spectroscopic analyses, including HR-ESI-MS, IR, and NMR. Carmichasine A (1) is the first natural C19 -diterpenoid alkaloid possessing a cyano group. Most of the diterpenoid alkaloids isolated were C19 -category, which might provide further clues for understanding the chemotaxonomic significance of this plant. The cytotoxicity of the new compounds was also investigated against several human cancer cell lines, including MCF-7, HCT116, A549, and 786-0, and none of them showed considerable cytotoxic activity.

Diterpenoid Alkaloids from Two Aconitum Species with Antifeedant Activity against Spodoptera exigua.

Twenty-five diterpenoid alkaloids were isolated from the roots of two Aconitum species. The structures of seven new C19-diterpenoid alkaloids, apetaldines A-G (1-7), and 10 known alkaloids (8-17) from Aconitum apetalum and eight known alkaloids (18-25) from Aconitum franchetii var. villosulum were elucidated via HRESIMS, IR, and NMR data. Alkaloids 1-10, 15, 16, and 18-25 were screened for their antifeedant activity. Among the compounds tested, chasmanthinine (19) showed highly potent antifeedant activity with an effective concentration for 50% feeding reduction (EC50) at 0.07 mg/cm2. The antifeedant structure-activity relationship of the diterpenoid alkaloids is also discussed.

Cyanogenetic glycosides and simple glycosides from the linseed meal.

Three new cyanogenetic triglycosides linustatins A-C (1-3), and two new simple glycosides linustatins D and E (4 and 5) were isolated from the 70% ethanol extract of flaxseed meal (Linum usitatissimum L.). Their structures were elucidated on the basis of spectroscopic analysis and chemical evidence. All of the isolates showed moderate activities against aldose reductase and weak activities against α-glucosidase, DPP-IV, and FBPase at the same concentrations as the positive control drugs.

Diterpenoid Alkaloids from Aconitum soongaricum var. pubescens.

One new diterpenoid alkaloid, pubescensine (1), along with nine known diterpenoid alkaloids (2-10) were isolated from the roots of Aconitum soongaricum var. pubescens. Their structures were elucidated by spectroscopic analyses and comparison with previously reported data. All the compounds were evaluated for their antifeedant activities. The aconitine-type diterpenoid alkaloids (1-6) showed considerably potent antifeedant activity (EC50 < 1 mg/cm2), while the activities of napelline-type diterpenoid alkaloids (compds. 7, 9 and 10) were not significant (EC50 > 50 mg/cm2).

Two New C18-Diterpenoid Alkaloids from Delphinium anthriscifolium.

Two new C18-diterpenoid alkaloids, anthriscifoltine A (1) and anthriscifoltine B (2), along with three known diterpenoid alkaloids, deoxydelcorine (3), anthriscifolcine A (4) and anthriscifolcine G (5), were isolated from the whole herbs of Delphinium anthriscifolium var. majus. Their structures were elucidated by spectroscopic methods, including 1D, 2D NMR, and HR-ESI-MS.

Antifungal and cytotoxic activities of the secondary metabolites from endophytic fungus Massrison sp.

Three novel compounds with spiro-5, 6-lactone ring skeleton has been isolated from the fermentation broth of Massrison sp. which could be isolated repeatedly from wild Rehmannia glutinosa. Psetariae oryza P-2b was applied to guide fractionation of bioactive compounds produced by Massrison sp. The molecular structures were established by a variety of one- and two-dimensional NMR experiments and the compounds with similar skeleton were reported for the first time from endophytic fungi of terraneous plant. Antifungal and cytotoxic activities of the compounds were tested, compounds 2 and 3 displayed stronger antifungal and cytotoxic activities. The compounds have the potential to be antibiotic against fungal pathogens and tumor cells.