Anti-angiogenic effects and mechanisms of zerumin A from Alpinia caerulea

Labdane-type diterpenoids and sesquiterpenes from Curcuma aromatica and their nitric oxide inhibitory activity in lipopolysaccharide-stimulated RAW264.7 macrophages

One new labdane-type diterpenoid, 3β,15-dihydroxylabda-8(17),12E-dien-16,15-olide (1) named curcumatin and twelve known compounds, coronarin D (2), isocoronarin D (3), (E)-labda-8(17),12-diene-15,16-dial (4), zerumin A (5), (E)-labda-8(17),12-dien-15,16-dioic acid (6), furanodiene (7), linderazulene (8), zedoarol (9), zedoarondiol (10), germacrone-1,10-epoxide (11), germacrone-4,5-epoxide (12), and zingiberenol (13) were isolated from the ethanol extract of the roots of Curcuma aromatica Salisb. Their structures were elucidated by 1D-, 2D-NMR spectroscopic analysis, HR-ESI-MS, and comparing with the NMR data reported in the literature. Compounds 2, 5, and 13 significantly inhibited the nitric oxide production effect in LPS-stimulated RAW 264.7 macrophages with IC50 values of 8.8 ± 1.7, 4.0 ± 0.9, and 6.2 ± 0.4 µM, respectively.

Zerumin A attenuates the inflammatory responses in LPS-stimulated H9c2 cardiomyoblasts

Zerumin A (ZA) is one of the potential components of Curcuma amada rhizomes, and it has been shown to possess a variety of pharmacological activities. This study deals with the beneficial activity of ZA in lipopolysaccharide (LPS)-stimulated inflammation in H9c2 cardiomyoblasts. Herein, H9c2 cells were preincubated with ZA for 1 h and stimulated with LPS for 24 h. The cells were analyzed for the expression of various pro-inflammatory mediators and signaling molecules. Results showed that the cell viability was significantly improved and reactive oxygen species production was alleviated remarkably with ZA pretreatment. We also found that ZA pretreatment significantly suppressed the upregulation of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) protein levels, and nitric oxide (NO) release in LPS-stimulated cells. In addition, ZA significantly ameliorated LPS-elicited overexpression of pro-inflammatory chemokines and cytokines such as monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor α (TNF- α), interferon-γ (IFN-γ), and interleukin-1 (IL-1) in H9c2 cells, and it upregulated the synthesis of the anti-inflammatory cytokine interleukin-10 (IL-10). Moreover, pretreatment with ZA and the mitogen-activated protein kinases (MAPK) pathway inhibitors also reduced the phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinases (JNK), and p38. ZA significantly inhibited IkB-a phosphorylation and nuclear factor (NF)-kB p65 subunit translocation into nuclei. Overall data demonstrated that ZA protects cardiomyocytes against LPS injury by inhibiting NF-kB p65 activation via the MAPK signaling pathway in vitro. These findings suggest that ZA may be a promising agent for a detailed study for the prevention or treatment of myocardial dysfunction in sepsis.

Ptehoosines A and B: Two new sesamin-type sesquilignans with antiangiogenic activity from Pterocephalus hookeri (C.B. Clarke) Höeck

Two undescribed sesamin-type sesquilignans ptehoosines A (1) and B (2), together with 4 known lignans (3-6), were isolated from Pterocephalus hookeri (C.B. Clarke) Höeck which was widely used as traditional Tibetan medicine for treatment of rheumatoid arthritis. Their structures were determined by HR-ESI-MS, NMR analysis and CD experiment. The in vitro antiangiogenic effect of all isolated compounds against human umbilical vein endothelial cells (HUVECs) were evaluated by CCK-8 assay. Among them, compound 1 exhibited significant proliferative inhibition on HUVECs with IC₅₀ value of 32.82 ± 0.99 μM. Further in vitro study indicated 1 could arrest cell cycle at G0/G1 phase and reduce the migration of HUVECs. In vivo experiment exhibited 1 could inhibit tail vessels plexus in zebrafish. The above finding suggested that 1 was a promising lead compound against RA by inhibiting of angiogenesis.

Protective effect of Ziziphora clinopodioides flavonoids against H2O2-induced oxidative stress in HUVEC cells

The present study was designed to study the protective effect of Ziziphora clinopodioides flavonoids (ZCF) against H₂O₂-induced oxidative stress in HUVEC cells. MTT assay was carried out to determine the cell viability of HUVEC cells following pretreatment with ZCF. Fluorescent microscopy measurements were performed to evaluate apoptosis of HUVEC cells. Furthermore, the effects of ZCF on the activities of antioxidants superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), malondialdehyde production (MDA) and lactic dehydrogenase (LDH) levels were analyzed. Apoptosis was observed by Hoechst33258 staining and AO staining. Real-time fluorescence quantitative polymerase chain reaction (Real-time PCR) was used to detect the expression of B-cell lymphoma/leukemia-2 (Bcl-2), Bcl-2-associated X protein (Bax) and aspartate proteolytic enzyme-3 (Caspase-3) mRNA. The expression of vascular endothelial growth factor receptor 2 (VEGFR2), protein kinase B (Akt), phosphorylated protein kinase B (p-Akt), Bax, Bcl-2 and Caspase-3 were detected by western blot. ZCF attenuated H₂O₂-induced cell death, as determined by the MTT assay. ZCF decreased malondialdehyde and lactic dehydrogenase levels, increased superoxide dismutase, glutathione peroxidase, catalase activities and inhibited apoptosis. Moreover, pretreatment with ZCF decreased the expression of Bax and Caspase-3 at mRNA level, increased the expression of Bcl-2 mRNA level, decreased the levels of VEGFR2, Bax and Caspase-3 protein, and increased the level of p-Akt / Akt and Bcl-2 protein in HUVEC cells. These results suggested that ZCF protected against H₂O₂-induced injury in HUVEC cells. The mechanism for this effect is related to the enhancement of antioxidant capacity, suppression of angiogenesis and apoptosis.

Mechanistic Study of the In Vitro and In Vivo Inhibitory Effects of Protocatechuic Acid and Syringic Acid on VEGF-Induced Angiogenesis

The antiangiogenic activities of two structurally similar phenolics, protocatechuic acid (PA) and syringic acid (SA), were investigated. In vitro study using HUVECs demonstrated that both PA and SA (at 25 μM) significantly ( p < 0.05) inhibited VEGF-induced cell proliferation by 22.68 ± 5.6% and 21.93 ± 2.0%, respectively; cell migration by 50.04 ± 3.3% and 39.72 ± 4.7%, respectively; cell invasion by 44.16 ± 4.23% and 51.90 ± 2.73%, respectively; and cellular ROS generation by 11.48 ± 6.32% and 21.17 ± 9.10%, respectively. Our mechanistic study revealed that PA and SA blocked the VEGFR2-dependent Akt/ MMP2 and ERK pathways in HUVECs. These inhibitory effects were further confirmed by a decrease of endogenous alkaline phosphatase activity for PA and SA (21.47 ± 1.77% and 10.37 ± 1.27%, respectively) and the suppression of subintestinal vessel plexus formation in Tg (fli1a:EGFP) y1-type transgenic zebrafish embryos. PA and SA down-regulated the angiogenesis-related signal transduction pathway of VEGFα-VEGFR2 or Ang2- Tie2 in zebrafish. Moreover, it was also found that PA demonstrated a better inhibition on VEGF-induced migration of HUVEC and zebrafish vasculature. This might be due to the different number of hydroxyl and methoxy substituents possessed by PA and SA. Taken together, these findings indicate that phenolics PA and SA have potent antiangiogenic activities and are potential targets for the design and development of anticancer agents.

Chemical Compositions and Tyrosinase Activity of the Essential Oils of Alpinia aquatica

The essential oils obtained from the fresh rhizome, leaf, and pseudostem of Alpinia aquatica Roscoe. were hydrodistillated and analyzed using capillary gas chromatography (GC) and gas chromatography-mass spectroscopy (GC-MS). β-Pinene (11.7%), α-humulene (8.9%), aromadendrene (8.7%), and sabinene (7.7%) were the major components in the rhizome oil. The most abundant components of the leaf oil were germacrene D (21.3%), β-pinene (15.6%) and sabinene (12.1%), while α-humulene (19.8%), germacrene D (15.2%) and β-caryophyllene (8.7%) were the main constituents in the pseudostem oil. Antityrosinase assay revealed that all the three essential oils exhibited weak tyrosinase inhibition activities. The rhizome oil showed the highest inhibition activity with the value of 9.5% for the L-DOPA oxidation.

Anti-Vasculogenic Activity of a Polysaccharide Derived from Brittle Star via Inhibition of VEGF, Paxillin and MMP-9

Background: Bioactive compounds such as terpenoids, chondroitin sulfate, and polysaccharides with added value can be found in prestine marine creatures. These compounds often do have highly valuable therapeutic applications such as being antioxidant, antitumorogenic, anti-inflammatory and anti-angiogenic. For the latter, varieties of angiogenesis factors can suppress this issue within the bodily tissues. Objectives: The anti-angiogenic and anti-metastatic capacity of a polysaccharide derived from brittle star was investigated. Material and Methods: The anti-proliferative effect of derived polysaccharide on umbilical vein endothelial cells (HUVEC) was measured using MTT (dimethyl thiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay. The anti-angiogenic effect of the isolated polysaccharide was examined by Chorioallantoic membrane (CAM) assay. The transcriptional expression of VEGF (Vascular Endothelial Growth Factor) was evaluated by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). The anti-metastatic activity was investigated via scratch-wound healing assay. The levels of Paxillin and Matrix Metalloproteinase-9 (MMP-9) expression were analyzed by RT-PCR. Statistical analysis and mean comparisons (p< 0.05) were carried out by SPSS 16. Results: Our results elucidated that the brittle star isolated polysaccharide exerted a dose dependent cytotoxic effect on the HUVEC endothelial cells. The CAM assay exhibited potent anti-angiogenic activity in vivo. The RT-PCR analysis showed that the extracted polysaccharide (40, 60 µg.mL^-1) down-regulated the VEGF expression. Further, the diminished attachment of endothelial cells demonstrated that the anti-invasiveness of the derived polysaccharide (25, 50 µg.mL^-1) was administrated via down-regulation of paxillin and MMP-9 mRNA expression. Conclusions: Taken together, these results indicated that the polysaccharide extracted from brittle star was able to decrease the viability of the HUVEC cells, to suppress angiogenesis, and possibly act as a natural anti-angiogenic and anti-metastatic marine organic compound against angiogenesis related pathologies.

Proanthocyanidins, Isolated from Choerospondias axillaris Fruit Peels, Exhibit Potent Antioxidant Activities in Vitro and a Novel Anti-angiogenic Property in Vitro and in Vivo

The production of new blood vessels (angiogenesis) is an important stage in the growth and spread of cancerous tumors. Anti-angiogenesis is one strategy for controlling tumor progression. This study evaluated the antioxidant and anti-angiogenic activities of a proanthocyanidins (PAs) extract from Choerospondias axillaris peels. HPLC-MS analysis revealed that numerous oligomeric forms of the PAs were detected in the PAs extract, including dimers, trimers, tetramers, and flavan-3-ol monomers. The PAs extract possessed appreciable free radical scavenging activity (IC50/DPPH = 164 ± 7 μg/mL, IC50/ABTS = 154 ± 6 μg/mL), potent reducing power (0.930 ± 0.030 g AAE/g), and strong cellular antioxidant activity (EC50 = 10.2 ± 1.4 and 38.9 ± 2.1 μg/mL without or with PBS-wash, respectively). It could also retard various stages of angiogenesis, such as the migration of endothelial cells and the creation of tubes, without causing toxicity to the cells. With regard to intracellular signal transduction, the PAs extract attenuated the phosphorylation of Akt, ERK, and p38MAPK dose-dependently in endothelial cells from human umbilical veins. In transgenic zebrafish embryo, new blood vessel formation was suppressed by PAs extract in a concentration-dependent manner at 72 h post fertilization. Thus, these results suggest that PAs from C. axillaris peels could be a good source of natural inhibitors to target angiogenesis.

Anti-angiogenic activity and mechanism of kaurane diterpenoids from Wedelia chinensis

BACKGROUND

Wedelia chinensis is a traditional medicinal herb used in Asia and it has been reported to possess various bioactivities including anti-inflammatory and anticancer effects. However, its anti-angiogenic activity has never been reported.

PURPOSE

To determine the most potent anti-angiogenic component in W. chinensis and its molecular mechanism of action.

STUDY DESIGN

Initially, the active fraction of the plant was studied. Then, we determined the active components of the fraction and explored the mechanism of the most active compound.

METHODS

The ethanol extract of W. chinensis and its four fractions with different polarities were evaluated for their anti-angiogenic activity in the Zebrafish model using quantitative endogenous alkaline phosphatase (EAP) assay. The molecular mechanism of the most active compound from the active fraction was studied using the real-time polymerase chain reaction (PCR) assay on Zebrafish embryos. The inhibitory effect of the most active compound on the proliferation, invasion and tube formation steps of angiogenesis was evaluated using the vascular endothelial growth factor (VEGF)-induced human umbilical vein endothelial cells (HUVECs) model, and the influences of the active compound on tyrosine phosphorylation of VEGF receptor (VEGFR-2) and its downstream signal pathway were evaluated by western blotting assay. Moreover, its anti-angiogenic effect was further evaluated by the VEGF-induced sprouts formation on aortic ring assay and the VEGF-induced vessel formation of mice on matrigel plug assay, respectively.

RESULTS

Petroleum ether (PE) fraction of the plant displayed potent anti-angiogenic activity. Twelve kaurane diterpenoids (1-12) isolated from this fraction showed quite different effects. Compounds 9-12 could dose-dependently inhibit vessel formation in the Zebrafish embryos while the others showed little inhibitory effect. Among the active diterpenoids, compound 10, 3α-cinnamoyloxy-9ß-hydroxy-ent-kaura-16-en-19-oic acid (CHKA), possessed the strongest effect, and it affected multiple molecular targets related to angiogenesis including VEGF and angiopoietin in Zerbrafish. Moreover, CHKA significantly inhibited a series of VEGF-induced angiogenesis processes including proliferation, invasion, and tube formation of endothelial cells. Besides, it directly inhibited VEGFR-2 tyrosine kinase activity and its downstream signaling pathways in HUVECs. CHKA also obviously inhibited sprouts formation of aortic ring, and block vessel formation in mice.

CONCLUSION

Our findings demonstrate that kaurane diterpenoids is one of anti-angiogenic components in W. chinensis, and CHKA may become a promising candidate for the development of anti-angiogenic agent.

Diterpenoids from the roots of Croton crassifolius and their anti-angiogenic activity

Six diterpenoids [crassifolin J, K, L, M, N and O] along with eleven known ones were isolated from the supercritical fluid extract (SFE) of the roots of Croton crassifolius (Euphorbiaceae). Their structures were elucidated using spectroscopic methods (IR, UV, HRESIMS, 1D and 2D NMR). The structure and stereochemistry of crassifolin J was confirmed by single-crystal X-ray diffraction analysis, and the absolute configurations of crassifolin K-M were determined by CD spectra. Twenty-three diterpenoids from this plant were screened for their anti-angiogenic activity using a wild-type zebrafish in vivo model. Four of the known compounds were active, of which penduliflaworosin possessed the best activity relative to the positive control (SU5416). Further study demonstrated that penduliflaworosin could inhibit vessel formation on Tg(fli1a:EGFP)y1-type zebrafish embryos.

Antioxidant and antiangiogenic properties of phenolic extract from Pleurotus tuber-regium

Pleurotus tuber-regium (Fries) Singer (PTR), both an edible and a medicinal mushroom also known as tiger milk mushroom, has experienced growing popularity and economic importance due to its flavor, nutritive value, and medicinal effects. In this study, the antioxidant and antiangiogenic activities of a 60% ethanol extract (EE) obtained from the sclerotium of PTR were investigated. Typical phenolic compounds including protocatechuic, chlorogenic, syringic, ferulic, and folic acid were identified and quantified in EE by the HPLC-UV-ESI/MS analyses. EE possessed strong antioxidant activity and could dose-dependently inhibit vascular endothelial growth factor (VEGF)-induced human umbilical vein endothelial cells (HUVEC) migration and tube formation. qPCR results showed that VEGF-induced FGF, ANG-Tie, and MMP gene expression as well as VEGFR were down-regulated at the mRNA level after treated with EE, suggesting that multiple molecular targets related to angiogenesis was involved. Furthermore, EE also inhibited the formation of subintestinal vessel plexus (SIVs) in zebrafish embryos in vivo. All of these suggested that EE of PTR could be the source of potential inhibitors to target angiogenesis.