Anti-Hyperlipidemic Components of the Leaves of Synsepalum dulcificum (Miracle Fruit).

Synsepalum dulcificum (Miracle fruit) is a tropical plant in West and Central Africa, which has been historically used for treating diarrhea in humans and animals. Pharmacological research has shown that the leaves of the plant possess anti-hyperlipidemia activity. However, its anti-hyperlipidemic components have not been reported. In this study, the leaves of S. dulcificum were extracted using 95% ethanol and the extract was fractionated using different polar solvents. The anti-hyperlipidemia activity of the extract and fractions were evaluated using the zebrafish model. The results showed that the ethyl acetate (EA) fraction displayed the best anti-hyperlipidemic effect. A comparison of the high-performance liquid chromatography equipped with diode array detector (HPLC-DAD) profiles of the ethanol extract and different fractions at 350 nm indicated that a peak at 37.4 min has the highest intensity in the EA part, relatively. Then the chemical constituents of the extract and the active fraction were extensively identified using UPLC-Q-Exactive-Orbitrap-MS/MS, showing the main peak was quercitrin and other components in the EA part mainly included quercitrin analogs. Furthermore, the quercitrin was isolated from the plant and its contents in the extract and fractions were determined using high-performance liquid chromatography with ultraviolet detector (HPLC-UV) method. The quantitative results showed that the content of quercitrin in the EA fraction was 10.04% (w/w). Further pharmacological study indicated that quercitrin also possessed potent anti-hyperlipidemia activity (improvement rates of liver fat and total cholesterol were 75.6% and 92.5% at 40 µg/mL, respectively). Besides, quercitrin showed little toxicity to zebrafish embryos.

Tunable Toxicity of Bufadienolides is Regulated through a Configuration Inversion Catalyzed by a Short-Chain Dehydrogenase/Reductase.

Bufadienolides are toxic components widely found in amphibious toads that exhibit a wide range of biological activities. Guided by UPLC-QTOF-MS analysis, several 3-epi-bufadienolides with unique structures were isolated from the bile of the Asiatic toad, Bufo gargarizans. However, the enzymatic machinery of this epimerization in toads and its significance in chemical ecology remains poorly understood. Herein, we firstly compared the toxicities of two typical bufadienolides, bufalin (featuring a 14ß-hydroxyl) and resibufogenin (containing a 14, 15-epoxy group), with their corresponding 3-epi isomers in a zebrafish model. The results of the toxicology assays showed that the ratio of maximum non-toxic concentrations of these two pairs of compounds are 256 and 96 times, respectively, thereby indicating that 3-hydroxyl epimerization leads to a significant decrease in toxicity. Aiming to investigate the biotransformation of 3-epi bufadienolides in toads, we applied liver lysate to transform bufalin and found that it could stereoselectively catalyze the conversion of bufalin into its 3α-hydroxyl epimer. Following this, we cloned and characterized a short-chain dehydrogenase/reductase, HSE-1, from the toad liver cDNA library and verified its 3(ß→α)-hydroxysteroid epimerization activity. To the best of our knowledge, this is the first hydroxyl epimerase identified from amphibians that regulates the toxicity of animal-derived natural products.

Penduliflaworosin, a Diterpenoid from Croton crassifolius, Exerts Anti-Angiogenic Effect via VEGF Receptor-2 Signaling Pathway.

Anti-angiogenesis targeting vascular endothelial growth factor receptor-2 (VEGFR-2) has been considered as an important strategy for cancer therapy. Penduliflaworosin is a diterpenoid isolated from the plant Croton crassifolius. Our previous study showed that this diterpenoid possesses strong anti-angiogenic activity by inhibiting vessel formation in zebrafish. This study was conducted to further investigate the anti-angiogenic activity and mechanism of penduliflaworosin. Results revealed that penduliflaworosin significantly inhibited VEGF-induced angiogenesis processes including proliferation, invasion, migration, and tube formation of human umbilical vein endothelial cells (HUVECs). Moreover, it notably inhibited VEGF-induced sprout formation of aortic rings and blocked VEGF-induced vessel formation in mice. Western blotting studies showed that penduliflaworosin inhibited phosphorylation of the VEGF receptor-2 and its downstream signaling mediators in HUVECs, suggesting that the anti-angiogenic activity was due to an interference with the VEGF/VEGF receptor-2 pathway. In addition, molecular docking simulation indicated that penduliflaworosin could form hydrogen bonds within the ATP-binding region of the VEGF receptor-2 kinase unit. Finally, cytotoxicity assay showed that penduliflaworosin possessed little toxicity toward both cancer and normal cells. Taken together, our findings demonstrate that penduliflaworosin exerts its anti-angiogenic effect via the VEGF receptor-2 signaling pathway. The anti-angiogenic property and low cytotoxicity of penduliflaworosin suggest that it may be useful in cancer treatments.

Potent anti-angiogenic component in Kaempferia galanga L. and its mechanism of action.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditionally, the roots of Kaempferia galanga has been used to treat high blood pressure, chest pain, headache, toothache, rheumatism, indigestion, cough, inflammation and cancer in Asia. Nevertheless, most of its pharmacological studies were focused on ethanolic extracts and volatile oils. The exact active chemical constituents and their underlying mechanisms are still poorly understood, especially towards its anti-cancer treatment. Inhibition of angiogenesis is an important atrategy to inhibit tumor growth. It has been reported that the low polar component of the plant possessed anti-angiogenic activity. Yet, the potent compound which is responsible for the effect and its molecular mechanism has not been reported. AIM OF THE STUDY: To determine the potent anti-angiogenic component in K.galanga and its mechanism of action. MATERIAL AND METHODS: The low polar components of the plant were concentrated using the methods of supercritical fluid extraction (SFE), subcritical extraction (SCE) and steam distillation (SD). The anti-angiogenic activity of the three extracts was evaluated using a zebrafish model. The content of the active compound in those extracts was determined with HPLC analysis. The in-vitro and in-vivo activity of the isolated compound was evaluated using human umbilical vein endothelial cells (HUVECs) model, the aortic ring assay and the matrigel plug assay, respectively. Its molecular mechanism was further studied by the western blotting assay and computer-docking experiments. Besides, its cytotoxicity on cancer and normal cell lines was evaluated using the cell-counting kit. RESULTS: HPLC results showed that trans-ethyl p-methoxycinnamate (TEM) was the major component of the extracts. The extract of SFE showed the best effect as it has the highest content of TEM. TEM could inhibit vascular endothelial growth factor (VEGF)-induced viability, migration, invasion and tube formation in human umbilical vein endothelial cells (HUVECs) in vitro. Moreover, it inhibited VEGF-induced sprout formation ex vivo and vessel formation in vivo. Mechanistic study showed that it could suppress tyrosine kinase activity of the receptor of VEGF (VEGFR2) and alter its downstream signaling pathways. In addition, the molecular docking showed that the binding of TEM and VEGFR2 is stable, which mainly attributed to the non-covalent binding interaction. Beside, TEM possessed little toxicity to both cancer and normal cells. CONCLUSION: TEM is the major anti-angiogenic component present in K. galanga and its anti-angiogenic property rather than toxicity provides scientific basis for the traditional use of K. galanga in cancer treatment.

Bufadienolide-Fatty Acid Conjugates from the Fertilized Eggs of Toad Bufo gargarizans: Isolation, Characterization, Toxicity, and Antiproliferative Evaluation.

Bufadienolides (BDs) are a class of naturally occurring toxins present in amphibian toads. Serving as the chemical weapons, they exist not only in the adult toads but also in toad eggs. Guided by mass spectrometry (MS)-based component analysis and feature-based molecular networking (FBMN), 30 bufadienolide-fatty acid conjugates (BDFs) were isolated from the fertilized eggs of toad Bufo gargrizans, including 25 previously undescribed compounds (1-25). Their chemical structures were elucidated by extensive spectroscopic analysis, chemical methods, and GC-MS. The toxicities of all BDFs and their corresponding free BDs were assessed using the zebrafish model. The structure-toxicity relationship analysis showed that the modification of BDs by hydroxy fatty acids can cause a significant increase of the toxicity. Furthermore, all the isolated compounds were evaluated for their antiproliferative activities in pancreatic cancer cell lines ASPC-1 and PANC10.05. The structure-activity relationship (SAR) analysis revealed that BDFs with hellebrigenin as the bufogenin moiety (6 and 7) exhibited the most potent antiproliferative effect. Further investigation into their functional mechanism demonstrated that 6 and 7 induced apoptosis in pancreatic cancer cells PANC10.05 and significantly suppressed the expression of the apoptosis-related gene c-MYC. In addition, 6 and 7 effectively inhibited the expression of the PI3K/Akt/mTOR pathway in PANC10.05. Moreover, we assessed the efficacy of 6 and 7 on cancer cells from various tissues and observed their broad-spectrum antiproliferative activity.

Erxian decoction, a traditional chinese herbal formula, inhibits angiogenesis in human umbilical vein endothelial cells.

Our previous study demonstrated that Erxian Decoction (EXD), a traditional Chinese herbal formula, inhibited angiogenesis in zebrafish embryos. To further investigate the anti-angiogenic activity and mechanism of EXD, we evaluated its inhibitory effect on angiogenesis in mammalian endothelial cells in vitro. Cell based assays included proliferation, apoptosis, migration, tube formation and cell cycle analysis. Real-time quantitative polymerase chain reaction (qPCR) and Western blotting were carried out to evaluate the molecular targets and signaling pathways of EXD in human umbilical vein endothelial cells (HUVECs). EXD inhibited proliferation, migration and tube formation in HUVECs. EXD also caused HUVEC apoptosis and cell increase in G0/G1 phase in cell cycle analysis. Furthermore, it decreased the mRNA expressions of vascular endothelial growth factor A (VEGF-A), VEGFR-1 and VEGFR-2 in HUVECs. It also inhibited extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt activation, suggesting the involvement of these signaling pathways in the anti-angiogenic action of EXD in HUVECs. The anti-angiogenic activity of EXD provides new insights to its clinical application and may lead to potential drug development for treating various cancers, especially in menopausal period in the future.

A new biflavonoid with antiviral activity from the roots of Wikstroemia indica.

A new biflavonoid, 4'-methoxydaphnodorin E, was isolated from the antiviral fraction of Wikstroemia indica against respiratory syncytial virus (RSV). Its structure was determined on the basis of extensive spectroscopic data including HR-ESI-MS and 2D NMR. The biflavonoid was tested for its in vitro anti-RSV activity with cytopathic effect (CPE) reduction assay, and displayed potent effect with 50% inhibitory concentration (IC50) value of 2.8 µM and selective index (SI) value of 5.4.

Cassaine diterpenoid glycosides from the seeds of Erythrophleum fordii Oliv. and their antiviral and anti-inflammatory activities.

Seven new cassaine diterpenoids (1-7) along with four known ones (8-11) were isolated from the seeds of Erythrophleum fordii Oliv. (Leguminosae). Their chemical structures were elucidated by extensive spectroscopic data interpretation and chemical methods. Compound 1 is a rare unsymmetrical dimer, which is formed by the linking of another cassaine diterpenoid acid glycoside to the 6-hydroxyl group of the sugar unit in a cassaine amide glycoside through an ester bond. Compound 2 is a cassaine diterpenoid acid derivative featuring an unusual Z double bond at C-13 and C-15. The in vitro antiviral and anti-inflammatory activities of 1-11 were evaluated. The results showed that compounds 1, 2 and 3 showed significant antiviral activities against human respiratory syncytial virus (RSV) with IC50s of 6.3, 7.8, and 9.4 µM, respectively. Compound 9 significantly suppressed the expression of nuclear factor-kappa B (NF-κB) with an IC50 value of 2.6 µM.

Cassaine diterpenoids from the seeds of Erythrophleum fordii Oliv. and their antiangiogenic activity.

Fourteen undescribed cassaine diterpenoids along with nine known ones were isolated from the seeds of Erythrophleum fordii Oliv. (Leguminosae). In addition, subsequent structural modification yielded ten derivatives. Their chemical structures were established by extensive spectroscopic methods and acid hydrolysis. All the diterpenoids were screened for their antiangiogenic activity using the human umbilical vein endothelial cell (HUVEC) model. Five compounds were active, of which three possessed excellent activity as their effect was better than that of the positive control (SU5416). The structure-activity relationship analysis revealed that the side chain at C-13 was the key part affecting the inhibitory effect. Further study demonstrated that 3ß-hydroxynorerythrosuamine-3-O-ß-D-glucopyranoside and the formate of 3ß-hydroxynorerythrosuamine-3-O-ß-D-glucopyranoside significantly inhibited a series of angiogenic processes including proliferation, migration and capillary-like structure formation of endothelial cells. These findings may provide a new type of antiangiogenic agent for future cancer drug development.

Microphase separation of block copolymer thin films.

Today, high-ordered micro- and nano-patterned surfaces are widely used in many areas, such as in the preparation of super-thin dielectric films, photonic crystals, antireflective films, super-non-wetting surfaces, bio-compatible surfaces and microelectric devices. Considering the critical fabrication conditions and the irreducible high cost of the photolithography technique in patterning nano-scale structures (<100 nm), the development of other micro- and nano-patterning techniques that can be used to fabricate long-range ordered features - especially nanoscale arrays - is a promising subject in surface science. In contrast to the traditional photolithography patterning technique, block copolymers can spontaneously phase separate into arrays of periodic patterns with length-scales of 10-50 nm, which provides an efficient pathway to pattern nanoscale features. Today, preparing long-range ordered arrays by block copolymer microphase separation is one of the most promising techniques for the fabrication of nanoscale arrays, not only being a simple process but also having a lower cost than traditional methods. In this feature article, we first summarize the many techniques developed to induce ordering in the microphase separation of the block copolymer thin films. Then, evolution, order-order transitions and reversible switching microdomains are considered, since they are very important in the ordered engineering of microphase separation of the block copolymer thin films. Finally, the outlook of this research area will be given.

Cyperenoic acid, a sesquiterpene derivative from Croton crassifolius, inhibits tumor growth through anti-angiogenesis by attenuating VEGFR2 signal pathway in breast cancer.

BACKGROUND: Cyperenoic acid, one of the main chemical constituents of the root of Croton crassifolius, exhibited potent anti-angiogenic property on the zebrafish embryo model with little cytotoxicity. Nevertheless, its anti-angiogenic mechanism and anti-tumor effect have not been investigated. PURPOSE: To investigate the anti-angiogenic mechanisms of cyperenoic acid and evaluate it whether could exert anti-tumor effect by inhibiting angiogenesis. STUDY DESIGN: Targeting vascular endothelial growth factor receptor-2 (VEGFR2) pathway to inhibit tumor angiogenesis is a significant strategy for cancer treatment. Initially, the anti-angiogenic effect of cyperenoic acid as well as the mechanisms of the action was studied using both in-vitro and in-vivo methodologies. Then, its anti-tumor effect through anti-angiogenesis by attenuating VEGFR2 signaling pathway was evaluated. METHODS: The in-vitro inhibitory effect of cyperenoic acid on the vascular endothelial growth factor (VEGF)-induced angiogenesis was evaluated using human umbilical vein endothelial cells (HUVECs) model. Moreover, its ex-vivo and in-vivo effects were evaluated using the aortic ring assay and the matrigel plug assay. The influence of the cyperenoic acid on tyrosine phosphorylation of VEGFR2 was studied by western blotting assay and the influence on downstream signaling pathway of VEGFR2 also be detected. Computer-docking simulations were carried out to study the interaction between cyperenoic acid and VEGFR2. Finally, its inhibitory effect on tumor growth was studied using breast cancer xenograft model. RESULTS: Cyperenoic acid possessed little toxicity to HUVECs, but it significantly inhibited VEGF-induced proliferation, invasion, migration and tube formation of HUVECs. Moreover, it inhibited VEGF-induced sprout formation ex vivo and vessel formation in vivo. Further mechanistic study showed that cyperenoic acid could suppress VEGFR2 tyrosine kinase activity and alter its downstream signaling pathways in VEGF-induced HUVECs. In addition, it could form two hydrogen bonds with the ATP binding pocket of the VEGFR2 kinase domain by docking. For breast cancer xenograft model, cyperenoic acid suppressed tumor growth, but no obvious toxic pathologic changes were observed in mice. Besides, it suppressed the phosphorylation of VEGFR2 in tumor, demonstrating its anti-angiogenic ability in vivo partly targeting the VEGFR2. CONLUSION: Cyperenoic acid could exert anti-tumor effect in breast cancer by inhibiting angiogenesis via VEGFR2 signaling pathway.

The cholesterol-lowering activity of miracle fruit (Synsepalum dulcificum).

Miracle fruit (Synsepalum dulcificum) is famous for its uniqueness of modifying sour taste to sweetness. However, its cholesterol-lowering activity has not been reported. This study investigated the effect of S. dulcificum on the compositional changes of plasma lipids in hamsters fed a high-cholesterol control diet. Six groups of hamsters were fed either a control diet or one of the five experimental diets containing 2% ethanol extract of leaves, 2% water extract of leaves, 2% ethanolic extract of seeds (ES), 2% water extract of seeds, or 2% dry pulp. Results showed that ES decreased the plasma total cholesterol (TC). Two triterpenoids (lupeol acetate and ß-amyrin acetate) were isolated from the ES and they added to a diet could decrease TC by 15%-20% in hamsters. It was concluded that ES showed potent TC-lowering activity and triterpenoid was one of the active components of ES. PRACTICAL APPLICATIONS: In recent years, people are more interested in phytochemicals from functional foods treated for hyperlipidemia because they possessed fewer side effects than the synthetic drugs. The triterpenoids isolated from the miracle fruit may be promising candidates for the development of cholesterol-lowering agent, especially for patients whose blood cholesterol level and body weight are high. Meanwhile, the miracle fruit have a good potential as cholesterol-lowering functional food or a natural source of cholesterol-lowering agent.

Formation of Two Kinds of Hexagonally Arranged Structures in ABC Triblock Copolymer Thin Films Induced by a Strongly Selective Solvent Vapor.

An order-order transition (OOT) in the sequence of a hexagonally arranged core-shell cylinder to a double-hexagonally arranged dot in polystyrene-block-poly(butadiene)-block-poly(2-vinylpyridine) (SBV) triblock copolymer thin films is reported to be induced upon exposure to a solvent vapor that is strongly selective for the two end blocks. These two kinds of hexagonally arranged structures could form when the film thickness is 44, 123, and 223 nm. When the film thickness is decreased to 13 nm, the ordered structure is absent. The sizes of the core-shell cylinder structures formed with the same annealing time in films of different thickness are compared to address the effects of film thickness on the phase structure. The mechanism is analyzed from the total surface area of the blocks and the effective interaction parameter in the solvent vapor.

[Studies on the chemical constituents of Blumea laciniata].

OBJECTIVE: To study the chemical constituents of Blumea laciniata. METHODS: The chemical constituents of the ethyl acetate fraction of ethanol extract from Blumea laciniata were isolated with column chromatographic techniques. The structures of the isolated compounds were elucidated by spectroscopic analysis and comparison with their published datas. RESULTS: Five compounds were isolated and identified as: protocatechuic acid (1), chrysoeriol (2), apigenin (3), 4-hydroxy-3,5-dimethoxbenzoic acid (4), scopolet (5). CONCLUSION: Compounds 1 - 5 are isolated from this plant for the first time, and also obtained from this genus for the first time.

[Studies on the chemical comstituents of Pithecellobium clypearia].

OBJECTIVE: To study the chemical constituents of Pithecellobium clypearia. METHODS: The compounds were isolated from Pithecellobium clypearia with column chromatography. Their structures were characterized on the basis of their physical and chemical preperties, as well as chromatographic and spectroscopic evidences. RESULTS: A pair of isomeric flavans consisting of 7, 3'-O-di-gallyoltricetiflavan (I) and 7,4'-O-di-gallyoltricetiflavan (II), along with a catechin compound (-)-epigallocatechin-7-O-gallate (III) were isolated from the leaves and twigs of Pithecellobium clypearia. CONCLUSION: Compound I is a new flavan. Compound III is isolated from Pithecellobium genus for the first time, and its 13C-NMR data is firstly given in the present study.

PHMH, a diarylheptanoid from Alpinia officinarum attenuates VEGF-induced angiogenesis via inhibition of the VEGFR-2 signaling pathway.

The rhizome of Alpinia officinarum Hance, a popular spice used as a condiment in China and Europe, has various reported bioactivities, including anticancer, anti-inflammatory and antioxidant effects. However, its anti-angiogenic activity has not previously been reported. In this study, a diarylheptanoid was isolated from Alpinia officinarum and identified as 1-phenyl-7-(4-hydroxy-3-methoxyphenyl)-4E-en-3-heptanone (PHMH). We demonstrated that PHMH exerts anti-angiogenic activity both in vitro and in vivo. PHMH inhibited vascular endothelial growth factor (VEGF)-induced viability, migration, invasion and tube formation in human umbilical vein endothelial cells (HUVECs) in vitro, and also suppressed VEGF-induced sprout formation of rat aorta ex vivo. Furthermore, PHMH was found to block VEGF-induced vessel formation in mice and suppress angiogenesis in both zebrafish and chorioallantoic membrane models. Mechanistic studies indicated that PHMH inhibited VEGF-induced VEGF receptor-2 (VEGFR-2) auto-phosphorylation and resulted in the blockage of VEGFR-2-mediated signaling cascades in HUVECs, including the Akt/mTOR, ERK1/2, and FAK pathways. Our findings provide new insights into the potential application of PHMH as a therapeutic agent for anti-angiogenesis.

Heart regeneration in adult Xenopus tropicalis after apical resection.

BACKGROUND: Myocardium regeneration in adult mammals is very limited, but has enormous therapeutic potentials. However, we are far from complete understanding the cellular and molecular mechanisms by which heart tissue can regenerate. The full functional ability of amphibians to regenerate makes them powerful animal models for elucidating how damaged mature organs are naturally reconstituted in an adult organism. Like other amphibians, such as newts and axolotls, adult Xenopus displays high regenerative capacity such as retina. So far, whether the adult frog heart processes regenerative capacity after injury has not been well delineated. RESULTS: We examined the regeneration of adult cardiac tissues of Xenopus tropicalis after resection of heart apex. We showed, for the first time, that the adult X. tropicalis heart can regenerate perfectly in a nearly scar-free manner approximately 30 days after injury via apical resection. We observed that the injured heart was sealed through coagulation immediately after resection, which was followed by transient fibrous tissue production. Finally, the amputated area was regenerated by cardiomyocytes. During the regeneration process, the cardiomyocytes in the border area of the myocardium adjacent to the wound exhibited high proliferation after injury, thus contribute the newly formed heart tissue. CONCLUSIONS: Establishing a cardiac regeneration model in adult X. tropicalis provides a powerful tool for recapitulating a perfect regeneration phenomenon and elucidating the underlying molecular mechanisms of cardiac regeneration in an adult heart, and findings from this model may be applicable in mammals.

Pyran-2-one Derivatives from the Roots of Croton crassifolius.

One new pyran-2-one derivative [crotonpyrone C (1)] and two known ones (2-3) were isolated from the supercritical fluid extract (SFE) of the roots of Croton crassifolius. Their structures were elucidated using spectroscopic (IR, UV, 1D and 2D NMR) and HRESIMS methods. The isolated compounds were evaluated for their anti-angiogenic activity using a zebrafish model, but showed little activity.

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.

Anti-angiogenic Activity and Mechanism of Sesquiterpene Lactones from Centipeda minima.

Centipeda minima is a Chinese herbal medicine used in the treatment of various diseases including cancer. An ethanol extract of the herb, its four fractions with different polarities, and two volatile oils prepared by steam distillation (SD) and supercritical fluid extraction (SFE) were investigated for their anti-angiogenic activity in a wild-type zebrafish model using a quantitative endogenous alkaline phosphatase (EAP) assay. The SFE oil displayed potent anti-angiogenic activity. Fifteen sesquiterpene lactones (SLs; compounds 1-15) isolated from the SFE oil were evaluated for their anti-angiogenic effect. Results revealed that pseudoguaianolide type SLs (1-8) inhibited vessel formation in the zebrafish embryos while guaianolide type SLs (9-15) showed little effect. Among the active ones, 6-O-angeloylenolin (1), a major component of SFE oil, possessed the strongest effect by reducing vessel formation in zebrafish embryos to 40% of the control value at 29.7 µM. Further study using the Tg (fli1a:EGFP) y1-type zebrafish model revealed that it blocked both intersegmental blood vessels (ISVs) and subintestinal vessels plexus (SIVs) formation in zebrafish embryos. Real-time polymerase chain reaction assay on the wild-type zebrafish embryos suggested that 6-O-angeloylenolin affected multiple molecular targets related to angiogenesis including VEGF receptor, angiopoietin, and its receptors. Taken together, our findings demonstrate that C. minima possesses anti-angiogenic activity, and 6-O-angeloylenolin is a promising candidate for the development of an anti-angiogenic agent.