Polyprenylated polycyclic acylphloroglucinol: Angiogenesis inhibitor from Garcinia multiflora

Garciyunnanones A-R: Caged polycyclic polyprenylated acylphloroglucinols decorated with a lavandulyl substituent from Garcinia yunnanensis

Garciyunnanones A-R (1-18), eighteen undescribed caged polycyclic polyprenylated acylphloroglucinols, two undescribed biogenetic congeners (19-20), and nineteen known analogues (21-39), were isolated from the stem barks of Garcinia yunnanensis Hu. All of these isolates are decorated with a C-5 lavandulyl substituent. Their structures and absolute configurations were confirmed by HRESIMS, 1D & 2D NMR spectroscopic analysis, quantum chemical calculations of electronic circular dichroism data, and single-crystal X-ray diffraction analysis. The X-ray crystallographic data of ten isolated caged compounds ascertained the absolute configuration of C-23 in the lavandulyl as S. The cytotoxicity on three cancer cell lines and the anti-nonalcoholic steatohepatitis activity of the isolates were tested. In a free fatty acid-induced L02 cell model, compounds 33 and 39 decreased intracellular lipid accumulation significantly.

Antiproliferative polycyclic polyprenylated acylphloroglucinols from Garcinia paucinervis

Bioassay-guided isolation of the stems of Garcinia paucinervis led to one new adamantane-type polycyclic polyprenylated acylphloroglucinols (PPAPs), (-)-garpauvinin A (1), and four known analogues (2-5). The structure and absolute configuration of 1 was established via spectroscopic techniques and ECD method. All the isolates displayed moderate antiproliferative activity against HL-60, PC-3 and Caco-2 human cancer cell lines with IC50 values ranging from 0.81 to 19.92 μM, and exhibited low toxicity on WPMY-1 normal human cells, showing selectivity between normal and malignant prostate cells. The biosynthetic pathways of the isolated PPAPs were proposed.

Polyprenylated Benzophenones and Tocotrienol Derivatives from the Edible Fruits of Garcinia oblongifolia Champ. ex Benth. and Their Cytotoxicity Activity

The fruits of Garcinia oblongifolia Champ. ex Benth. were famous as an edible fruit in tropical regions of China. Because of its unique taste and great nutritional value, the ripe fresh fruits of G. oblongifolia could be eaten directly or used as raw materials for natural beverages and food supplements. In this work, six new polyprenylated benzophenones (1-6) and one new dimeric tocotrienol derivative (7), together with 18 known ones (8-25), were isolated from the fruits of G. oblongifolia. Compounds 1-4 were peculiar polycyclic polyprenylated acylphloroglucinols (PPAPs) featuring the rare carbon skeleton of a bicyclo[3.4.1]decane-1,3-diketone. Moreover, all isolates (1-25) were evaluated for their cytotoxicity activities against nasopharyngeal carcinoma (NPC) cell lines (CNE1 and CNE2). Among these isolates, compound 6 exhibited the strongest cytotoxicity activity on CNE1 and CNE2 cells with the IC₅₀ values of 7.8 ± 0.2 and 9.1 ± 0.3 μM, respectively. Further mechanistic investigation demonstrated that 6 could induce mitophagy to promote Caspase-9/GSDME-mediated pyroptosis through triggering ROS in NPC cells.

Polyprenylated Acylphloroglucinols With Different Carbon Skeletons From the Fruits of Garcinia multiflora

Eleven new polycyclic polyprenylated acylphloroglucinols (PPAPs, 1-11) and three new monocyclic polyprenylated acylphloroglucinols (MPAPs, 12-14), together with ten known analogues were isolated from the fruits of Garcinia multiflora. These PPAPs belong to three types including the bicyclic polyprenylated acylphloroglucinols (BPAPs), the caged PPAPs, and the complicated PPAPs. Their structures and absolute configurations were determined through HRESIMS, NMR spectroscopy data, electronic circular dichroism (ECD) calculations, and gauge-independent atomic orbital (GIAO) NMR calculations with DP4+ analyses. Moreover, compounds 2 and 7 exhibited moderate cytotoxicity against three human cancer lines (MCF-7, T98, and HepG2) with IC50 values ranging from 9.81 ± 1.56 to 17.00 ± 2.75 μM.

Stereodivergent Strategy in Structural Determination: Asymmetric Total Synthesis of Garcinol, Cambogin, and Related Analogues

The asymmetric total synthesis of five biologically significant polycyclic polyprenylated acylphloroglucinols (PPAPs), including garcinol and cambogin, was achieved through a highly diastereoselective and stereodivergent strategy. Along the way, an efficient cascade Dieckmann cyclization was employed to construct the bicyclo[3.3.1]nonane core in one step. The synthesis provided a general approach toward the chiral endo-type B PPAPs and their C-30 diastereomers in a single sequence, which resolved the challenges of the absolute configuration determination/structural revision of PPAPs bearing exocyclic stereocenters.

Garcimultiflorone K from Garcinia multiflora attenuates hepatocellular carcinoma metastasis by suppressing transforming growth factor-β signaling

BACKGROUND

Transforming growth factor‑β (TGF-β) signaling is a crucial inducer of tissue fibrosis and extracellular matrix accumulation and a vital suppressor of epithelial cell proliferation and cancer metastasis. The nature of this multifunctional cytokine has prompted the development of TGF-β signaling inhibitors as therapeutic agents. Our research group has recently isolated the polyprenylated polycyclic acylphloroglucinol garcimultiflorone K (GMK) from the stems of Garcinia multiflora; GMK exhibits antiangiogenic activity in endothelial cells.

PURPOSE

In the current study, we aimed to explore the antitumor effect and detailed mechanisms of Garcimultiflorone K in hepatocellular carcinoma cells.

METHODS

Cell proliferation and viability were evaluated using the MTT assay. The migratory ability of HepG2 cells was measured using wound healing assays. The inhibitory effect of GMK against the nuclear translocation of Smad by TGF-β was assessed through immunofluorescence staining and Western blotting. To investigate TGF-β-dependent gene expression profiles upon GMK stimulation, RNA transcript levels were determined using reverse transcription polymerase chain reaction. The effects of GMK in Smad2-driven transcriptomic activities were studied using a reporter gene assay. Protein levels were detected using Western blotting.

RESULTS

Our data revealed that GMK inhibited TGF-β-induced cellular responses, including Smad protein phosphorylation, cell migration, and extracellular matrix production, during epithelial-mesenchymal transition (EMT). Mechanistic studies further demonstrated that GMK suppressed TGF-β signaling by downregulating TGF-β receptor II (TβRII).

CONCLUSION

These findings elucidate that TβRII expression in hepatic cells can be specifically suppressed by GMK to attenuate metastasis and the disease-promoting effects of EMT, representing a therapeutic approach.

Recent progress in TGF-β inhibitors for cancer therapy

Transforming growth factor-β (TGF-β) is a multifunctional cytokine that is involved in proliferation, metastasis, and many other important processes in malignancy. Inhibitors targeting TGF-β have been considered by pharmaceutical companies for cancer therapy, and some of them are in clinical trial now. Unfortunately, several of these programs have recently been relinquished, and most companies that remain in the contest are progressing slowly and cautiously. This review summarizes the TGF-β signal transduction pathway, its roles in oncogenesis and fibrotic diseases, and advancements in antibodies and small-molecule inhibitors of TGF-β.

Picrorhizones A-H, Polyprenylated Benzoylphloroglucinols from the Stem Bark of Garcinia picrorhiza

Eight new polyprenylated benzoylphloroglucinol derivatives (1-8) and four known analogues (9-12) were isolated from the stem bark of Garcinia picrorhiza. Their structures were determined by spectroscopic data analysis (1D and 2D NMR and HRESIMS), and the absolute configurations were established by single-crystal X-ray diffraction combined with experimental and calculated ECD data. The new metabolites represent rare examples of benzoylphloroglucinols bearing a cyclobutyl-containing side chain. The isolated compounds were evaluated for their cytotoxic properties against five types of human cancer cells (KB, HeLa S3, MCF-7, Hep G2, and HT-29 cells) and their inhibitory activities against COX-1 and COX-2 enzymes. The cytotoxicity results showed that compound 6 was active against KB, HeLa S3, MCF-7, and Hep G2 cancer cells, with IC₅₀ values ranging from 5.9 to 9.4 μM. Among the compounds tested for cyclooxygenase inhibition, compound 8 possessed the highest inhibitory effect toward COX-1 (35.2 ± 9.6% inhibition at 20 μM).

Garcimultiflorone K inhibits angiogenesis through Akt/eNOS- and mTOR-dependent pathways in human endothelial progenitor cells

Background Garcimultiflorone K is a novel polyprenylated polycyclic acylphloroglucinol isolated from the stems of Garcinia multiflora that exhibits promising anti-angiogenic activity in human endothelial progenitor cells (EPCs). Purpose This study sought to determine the underlying anti-angiogenic mechanisms and pharmacological properties of garcimultiflorone K. Methods We examined the anti-angiogenic effects of garcimultiflorone K and its mechanisms of action using in vitro EPC models and in vivo zebrafish embryos. Results EPCs proliferation, migration, differentiation and capillary-like tube formation were effectively and concentration-dependently inhibited by garcimultiflorone K without any signs of cytotoxicity. Our investigations revealed that garcimultiflorone K suppressed EPCs angiogenesis through Akt, mTOR, p70S6K, and eNOS signaling cascades. Notably, garcimultiflorone K dose-dependently impeded angiogenesis in zebrafish embryos. Conclusion Our data demonstrate the anti-angiogneic effects of garcimultiflorone K in both in vitro and in vivo models. Garcimultiflorone K appears to have potential in the treatment of angiogenesis-related diseases.