Two new neolignans and an indole alkaloid from the stems of Nauclea officinalis and their biological activities

Protective Effects of Danmu Extract Syrup on Acute Lung Injury Induced by Lipopolysaccharide in Mice through Endothelial Barrier Repair

OBJECTIVE

To investigate the effects of Danmu Extract Syrup (DMS) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice and explore the mechanism.

METHODS

Seventy-two male Balb/C mice were randomly divided into 6 groups according to a random number table (n=12), including control (normal saline), LPS (5 mg/kg), LPS+DMS 2.5 mL/kg, LPS+DMS 5 mL/kg, LPS+DMS 10 mL/kg, and LPS+Dexamethasone (DXM, 5 mg/kg) groups. After pretreatment with DMS and DXM, the ALI mice model was induced by LPS, and the bronchoalveolar lavage fluid (BALF) were collected to determine protein concentration, cell counts and inflammatory cytokines. The lung tissues of mice were stained with hematoxylin-eosin, and the wet/dry weight ratio (W/D) of lung tissue was calculated. The levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1 β in BALF of mice were detected by enzyme linked immunosorbent assay. The expression levels of Claudin-5, vascular endothelial (VE)-cadherin, vascular endothelial growth factor (VEGF), phospho-protein kinase B (p-Akt) and Akt were detected by Western blot analysis.

RESULTS

DMS pre-treatment significantly ameliorated lung histopathological changes. Compared with the LPS group, the W/D ratio and protein contents in BALF were obviously reduced after DMS pretreatment (P<0.05 or P<0.01). The number of cells in BALF and myeloperoxidase (MPO) activity decreased significantly after DMS pretreatment (P<0.05 or P<0.01). DMS pre-treatment decreased the levels of TNF-α, IL-6 and IL-1 β (P<0.01). Meanwhile, DMS activated the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) pathway and reversed the expressions of Claudin-5, VE-cadherin and VEGF (P<0.01).

CONCLUSIONS

DMS attenuated LPS-induced ALI in mice through repairing endothelial barrier. It might be a potential therapeutic drug for LPS-induced lung injury.

Monoterpenoid indole alkaloid dimers from the Melodinus axillaris induce G2/M phase arrest and apoptosis via p38 MAPK activation in HCT116 cells

Four monoterpenoid indole alkaloid dimers (MIADs), axidimins A-D (1-4), which possesses unprecedented apidosperma-aspidosperma-type skeletons, along with twelve known MIAs were isolated from Melodinus axillaris. Their structures were established by comprehensive analysis of the HRESIMS, NMR, ECD calculation and DP4 + analysis. A possible biosynthetic pathway for axidimins A-D was proposed. In vitro, axidimins C and D exhibited significant cytotoxicities against HCT116 cells with IC50 values of 5.3 μM and 3.9 μM, respectively. The results obtained from flow cytometry and Western blot analysis clearly demonstrated that axidimins C and D significantly induced a reverse G2/M phase arrest and apoptosis of HCT116 cells. The potential mechanism of axidimins C and D on HCT116 cells were thoroughly discussed through the utilization of network pharmacology and molecular docking research. Subsequently, the selected targets were validated using Western blot and CETSA analysis, confirming that axidimins C and D exert its cytotoxic effects through the activation of the p38 MAPK pathway, ultimately leading to HCT116 cells death. This study provides evidence indicating that axidimins C and D have the potential to induce cell cycle arrest and apoptosis in HCT116 cells by modulating the p38 MAPK signaling pathway. These findings offer a novel perspective for the development of anti-colorectal cancer drugs.

Spirooxindole: A Versatile Biologically Active Heterocyclic Scaffold

Spirooxindoles occupy an important place in heterocyclic chemistry. Many natural spirooxindole-containing compounds have been identified as bio-promising agents. Synthetic analogs have also been synthesized utilizing different pathways. The present article summarizes the recent development of both natural and synthetic spirooxindole-containing compounds prepared from isatin or its derivatives reported in the last five years. The spirooxindoles are categorized based on their mentioned biological properties.

Measurement of Pharmacokinetics and Tissue Distribution of Four Compounds from Nauclea officinalis in Rat Plasma and Tissues through HPLC-MS/MS

A rapid, sensitive, selective, and accurate HPLC-MS/MS method was developed and validated for the simultaneous determination of chlorogenic acid, naucleactonin C, khaephuoside A 3,4-dimethoxyphenyl-1-O-β-apiofuroseyl(1 ⟶ 2)-β-D-glucopyranoside in rat plasma and tissues after oral administration of Nauclea officinalis extracts. Chloramphenicol was used as an internal standard (IS). The plasma and tissue samples were extracted by protein precipitation with methanol-ethyl acetate (1 : 1, v/v) including 0.1% (v/v) formic acid. The chromatographic separation was achieved by using an C18 column with gradient elution using mobile phase, which consisted of 0.1% formic acid water (A) and acetonitrile (B) and the flow rate of 0.8 mL/min. Mass spectrometric detection was performed in multiple reaction monitoring (MRM) mode utilizing electrospray ionization (ESI) in negative mode. The developed method exhibited good linearity (determination coefficients, R ² ≥ 0.9849), and the lower limits of quantification were 2, 5, 5, and 25 ng/mL for chlorogenic acid, naucleactonin C, khaephuoside A, and 3,4-dimethoxyphenyl-1-O-β-apiofuroseyl(1 ⟶ 2)-β-D-glucopyranoside. The intraday and interday precisions (relative standard deviation, RSD) were less than 12.65%, while the accuracy was ranged from 86.31 to 114.17%. The recovery rate were 51.85-97.06%, 75.99-106.68%, 77.46-105.35%, and 68.36-103.75% for chlorogenic acid, naucleactonin C, khaephuoside A, and 3,4-dimethoxyphenyl-1-O-β-apiofuroseyl(1 ⟶ 2)-β-D-glucopyranoside the matrix effects were 50.17-116.62%, 86.75-115.99%, 45.79-87.44%, and 51.60-92.34% for chlorogenic acid, naucleactonin C, khaephuoside A, and 3,4-dimethoxyphenyl-1-O-β-apiofuroseyl(1 ⟶ 2)-β-D-glucopyranoside in different matrix. The developed method was successfully applied to a pharmacokinetic study and tissue distribution of four compounds in rats after oral administration of Nauclea officinalis extracts.

Yellow Twig (Nauclea orientalis) from Thailand: Strictosamide as the Key Alkaloid of This Plant Species

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.