Anthraquinone metabolites isolated from the rhizosphere soil Streptomyces of Panax notoginseng (Burk.) F. H. Chen target MMP2 to inhibit cancer cell migration.

ETHNOPHARMACOLOGICAL RELEVANCE: Panax notoginseng (Burk.) F. H. Chen belongs to the Araliaceae family. It has been used by traditional Chinese people in Northeast Asia for centuries as an antidiabetic, antioxidant, antitumor agent, etc. Endophytic or rhizospheric microorganisms play key roles in plant defense mechanisms, and they are essential in the discovery of pharmaceuticals and valuable new secondary metabolites. In particular, endophytic or rhizospheric microorganisms of traditional medicinal plants. AIM OF THE STUDY: To discover valuable new secondary metabolites from rhizosphere soil Streptomyces sp. SYP-A7185 of P. notoginseng, and to explore potential bioactivities and targets of metabolites protrusive function. MATERIALS AND METHODS: The metabolites were obtained via column chromatography and identified by multiple spectroscopic analyses. The antitumor, antioxidant, antibacterial, and antiglycosidases effects of isolated metabolites were tested using 3-[4,5-dimethythiazol-2-yl]-2,5-diphenyltetazolium bromide (MTT), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 96-well turbidimetric, and α-glucosidase inhibitory assays. The potential antitumor targets were predicted through network pharmacological approaches. The interactions between metabolites and target were verified by molecular docking and biolayer interferometry (BLI) assay. The effects of cancer cells migration were detected through wound healing assays in A549 and MCF-7. Other cellular validation experiments including reverse transcription-quantitative PCR (RT‒qPCR) and western blotting (WB) were used to confirm the hypothesis of network pharmacology. RESULTS: Five different chemotypes of anthraquinone derivatives (1-10), including six new compounds (3, 6-10), were identified from Streptomyces sp. SYP-A7185. Compounds 1-6 and 9 displayed moderate to strong cytotoxicity on five human cancer cell lines (A549, HepG2, MCF-7, MDA-MD-231, and MGC-803). Moreover, matrix metalloproteinase-2 (MMP2) were predicted as a potential antitumor target of metabolites 1-6 and 9 by comprehensive network pharmacology analysis. Later, BLI assays revealed strong intermolecular interactions between MMP2 and antitumor metabolites, and molecular docking results showed the interaction of metabolites 1-6 and 9 with MMP2 was dependent on the crucial amino acid residues of LEU-83, ALA-84, LEU-117, HIS-131, PRO-135, GLY-136, ALA-140, PRO-141, TYR-143, and THR-144. These results implied that metabolites (1-6 and 9) might inhibit cancer cell migration besides cancer cell proliferation. After that, the cell wound healing assay showed that the cell migration processes were also inhibited after the treatments of compounds 1 and 3 in A549 and MCF-7 cells. In addition, the RT‒qPCR and WB results demonstrated that the gene expression levels of MMP2 were decreased after the treatment with compounds 1 and 3 in A549 and MCF-7 cells. Besides, compound 2 displayed moderate antioxidant activity (EC50, 27.43 µM), compounds 3 and 6 exhibited moderate antibacterial activity, and compound 3 inhibited α-glucosidase with an IC50 value of 13.10 µM. CONCLUSIONS: Anthraquinone metabolites, from rhizosphere soil Streptomyces sp. of P. notoginseng, possess antitumor, antioxidant, antibacterial, and antiglycosidase activities. Moreover, metabolites 1 and 3 inhibit cancer cells migration through downregulating MMP2.

A new indole alkaloid from the traditional Chinese medicine Chansu.

A new indole alkaloid N'-formylserotonin (1), along with five known indole alkaloids N'-methylserotonin (2), 5-hydroxy-1H-indole-3-carbaldehyde (3), N-acetylserotonin (4), 6-hydroxy-1-oxo-3,4-dihydro-ß-carboline (5), and bufoserotoin C (6), were isolated from the water extract of traditional Chinese medicine Chansu. Their structures were elucidated on the basis of spectral analyses. The cytotoxicities of 1-6 against human lung adenocarcinoma epithelial cells A549 were tested using the MTT method. Compound 6 exhibited stronger cytotoxic effect than 5-FU, and 1-5 showed no cytotoxic effects. Bufoserotonin C is one of the cytotoxic components in water-soluble extract of Chansu.

Beta-eudesmol suppresses tumour growth through inhibition of tumour neovascularisation and tumour cell proliferation.

In the present study, we investigated the potential anti-angiogenic mechanism and anti-tumour activity of beta-eudesmol using in vitro and in vivo experimental models. Proliferation of human umbilical vein endothelial cells (HUVEC) stimulated with vascular endothelial growth factor (VEGF, 30 ng/ml) and basic fibroblast growth factor (bFGF, 30 ng/ml) was significantly inhibited by beta-eudesmol (50-100 microM). Beta-eudesmol (100 microM) also blocked the phosphorylation of cAMP response element binding protein (CREB) induced by VEGF (30 ng/ml) in HUVEC. Beta-eudesmol (10-100 microM) inhibited proliferation of HeLa, SGC-7901, and BEL-7402 tumour cells in a time- and dose-dependent manner. Moreover, beta-eudesmol treatment (2.5-5 mg/kg) significantly inhibited growth of H(22) and S(180) mouse tumour in vivo. These results indicated that beta-eudesmol inhibited angiogenesis by suppressing CREB activation in growth factor signalling pathway. This is the first study to demonstrate that beta-eudesmol is an inhibitor of tumour growth.

[Mechanism of dracorhodin perchlorate-induced Hela cell apoptosis].

AIM: To study the mechanism of dracorhodin perchlorate-induced Hela cell apoptosis. METHODS: Cell viability was measured by MTT method. Morphological changes were observed by phase contrast microscopy and Hoechst 33258 staining. DNA fragmentation was assayed by agarose gel electrophoresis. Protein expression was detected by Western blot analysis. RESULTS: Dracorhodin perchlorate induced Hela cell apoptosis. The apoptosis was partially reversed by caspase-1, -3, -8, -9 and caspase family inhibitors. Treatment of Hela cells with dracorhodin perchlorate for 12 h increased the protein expression ratio of Bax/Bcl-XL; procaspase-3, -8, ICAD and PARP were cleaved to smaller molecules. CONCLUSION: Dracorhodin perchlorate induced Hela cell death via alteration of Bax/Bcl-XL ratio and activation of caspases.