Search Results (5)

Clinical reports have shown that administration of Nauclea officinalis (Danmu in Chinese, DM) preparations may cause significant gastrointestinal discomfort. This study aimed to systematically evaluate the adverse effects of DM and its primary active constituent, strictosamide, on gastrointestinal motility, intestinal barrier integrity, and gut microbiota homeostasis. Furthermore, we sought to investigate the potential role of the bitter taste receptor (T2R) signaling pathway in mediating these effects. In vitro cell cultures and ex vivo intestinal tissues were employed to assess cell viability and molecular alterations. In vivo studies involved short-term (2 weeks) gavage of DM (0.54 and 1.08 g/kg) and long-term (16 weeks) intervention (0.4, 0.8, and 1.2 g/kg) in rodents. Evaluations included histopathological examination, serum levels of cytokines and oxidative stress markers (ELISA), expression of tight junction proteins (Western blot and qPCR), and 16S rDNA sequencing of cecal microbiota. Mechanistic analyses focused on α-defensin secretion and T2R-associated gene and protein expression. Administration of DM resulted in significant gastrointestinal dysfunction, characterized by delayed intestinal propulsion and increased gastric retention. Dose-dependent histopathological damage, disruption of the intestinal barrier (reduced occludin and claudin-1 expression), and elevated levels of pro-inflammatory cytokines (IL-6, TNF-α, and IL-1β), oxidative stress markers (MDA, SOD, and GSH-Px), and immune mediators (IFN-γ) were observed. Gut microbiota analysis revealed dysbiosis, marked by a decline in beneficial genera (e.g., Mucispirillum, Butyricicoccus, Roseburia) and an increase in potentially pathogenic bacteria (e.g., Citrobacter, Helicobacter). Mechanistically, DM suppressed α-defensin secretion and downregulated the expression of TAS2R108, TAS2R138, and Gα-gustducin both in vitro and in vivo. DM and strictosamide disrupt gut microbiota composition and compromise intestinal barrier function, likely through inhibition of the T2R/α-defensin pathway. These findings provide important mechanistic insights into drug-induced gastrointestinal toxicity and underscore the potential risks associated with prolonged use of DM-containing preparations. Full article

Comprehensive phytochemical examination from different perspectives using preparative and analytical chromatographic techniques combined with spectroscopic/spectrometric methods of the so-called “yellow twig” Nauclea orientalis (L.) L. (Rubiaceae) led to the identification of 13 tryptamine-derived (=monoterpene-indole) alkaloids. The identified alkaloids comprise strictosamide and four of its glucosidic derivatives, three oxindole derivatives, and five yellow-colored angustine-type aglycones. Qualitative and quantitative HPLC analyses showed the enrichment of strictosamide in all studied organs. Based on these results, we performed metabolomic analyses of monoterpene-indole alkaloids and made a ¹H NMR in vitro monitoring of enzymatic deglucosylation of strictosamide. A comparison of the stability of strictosamide and its enantiomer vincoside lactam by theoretical calculations was also performed revealing a slightly higher stability of vincoside lactam. Additionally, we conducted two different anti-feedant assays of strictosamide using larvae of the polyphageous moth Spodoptera littoralis Boisduval. The obtained results indicate that generally two different biosynthetic pathways are most likely responsible for the overall alkaloid composition in this plant. Strictosamide is the key compound in the broader pathway and most likely the source of the identified angustine-type aglycones, which may contribute significantly to the yellow color of the wood. Its cross-organ accumulation makes it likely that strictosamide is not only important as a reservoir for the further biosynthesis, but also acts in the plants’ defense strategy. Full article

As an important source of cholinesterase inhibitors, alkaloids in natural products have high potential value in terms of exerting pharmacological activities. In this study, a strategy for targeted preparation of cholinesterase inhibitors in Uncaria rhynchophlly (Miq.) Miq. ex Havil (UR) by high-speed counter-current chromatography was provided. In the method, a two-phase polar solvent system composed of ethyl acetate/n-butanol/water (1:4:5, v/v/v) was used, which isolated five alkaloids from the UR extract for the first time. All alkaloids were identified by HR-ESI-MS and NMR as 7-epi-javaniside (1), vincosamide (2), strictosamide (3), cadambine (4), and 3α-dihydrocadambine (5). The poorly resolved compounds 2 and 3 were separated by preparative HPLC (prep-HPLC). Among them, compounds 1, 4, and 5 were firstly obtained from UR. The purity of these plant isolates was 98.8%, 98.7%, 99.2%, 95.7%, and 98.5%, respectively. Compounds 1–5 exhibited an inhibitory effect on acetyl-cholinesterase and butyryl-cholinesterase with an IC₅₀ from 1.47 to 23.24 µg/mL and 1.01 to 18.24 µg/mL. Molecular docking and inhibitory activities indicated that compound 1 showed stronger inhibitory activity on acetyl-cholinesterase and butyryl-cholinesterase. Full article

A phytochemical study of leaves and twigs of Psychotria nuda resulted in 19 compounds, including five indole alkaloids, N,N,N-trimethyltryptamine, lyaloside, strictosamide, strictosidine, and 5α-carboxystrictosidine; two flavonolignans, cinchonain Ia and cinchonain Ib; an iridoid, roseoside; a sugar, lawsofructose; a coumarin, scopoletin; a diterpene, phytol; three triterpenes, pomolic acid, spinosic acid, and rotungenic acid; and five steroids, sitosterol, stigmasterol, campesterol, β-sitosterol-3-O-β-d-glucoside, and β-stigmasterol-3-O-β-d-glucoside. Some compounds were evaluated for their in vitro activity against Mycobacterium tuberculosis and their ability to inhibit NO production by macrophages stimulated by lipopolysaccharide (LPS). The compounds pomolic acid, spinosic acid, strictosidine, and 5α-carboxystrictosidine displayed antimycobacterial activity with minimum inhibitory concentrations ranging from 7.1 to 19.2 µg/mL. These compounds showed promising inhibitory activity against NO production (IC₅₀ 3.22 to 25.5 μg/mL). 5α-carboxystrictosidine did not show cytotoxicity against macrophages RAW264.7 up to a concentration of 100 µg/mL. With the exception of strictosamide, this is the first report of the occurrence of these substances in P. nuda. Full article

Camptothecin (CPT) has strong antitumor activity and is used as an anticancer therapeutic agent. To better understand and decipher the pathway of CPT biosynthesis in Camptotheca acuminata, the main purpose here was focused on creating an effective extraction strategy for a rich intermediate metabolite profile. In the present study, a 70% aqueous acetonitrile was verified as an optimal extraction solvent for microwave-assisted extraction (MAE) of metabolites by spiking experiments. Based on multi-objective optimization, the best extraction conditions of a solid-liquid ratio of 1:20, microwave power of 230 W, and a time of 4 min were achieved using a full factorial 3⁴ experimental design. Crude extracts obtained from the shoot apex of C. acuminata using MAE have been qualitatively profiled by high-performance liquid chromatography coupled with linear ion trap quadrupole-orbitrap mass spectrometry (HPLC-LTQ-Orbitrap-MS/MS) and a HPLC triple quadrupole-MS (HPLC-TSQ-MS) analysis was conducted for their metabolite content in different tissues. CPT, and ten related metabolites and their isomers, including tryptamine, loganic acid, secologanic acid, strictosidinic acid, strictosamide, strictosamide epoxide, strictosamide diol, strictosamide ketolactam, pumiloside, and deoxypumiloside, were detected and tentatively identified. Scanning electron microscopy (SEM) imaging of the shoot apex demonstrated that severe cell disruption was evident after intensified extraction processes. The study showed the difference of metabolite profiles and the enhancement of metabolite content after microwave-pretreated techniques, and the established MAE procedure is an effective methodology to preserve valuable metabolite compounds for analysis. Full article