Isolation and Anticancer Progression Evaluation of the Chemical Constituents from Bridelia balansae Tutcher.

The dichloromethane extract of the roots of Bridelia balansae Tutcher (Phyllanthaceae) was found to show potential anticancer activity against HCT116 colorectal cancer cell. Our bioassay-guided phytochemical investigation of the roots of B. balansae led to the identification of 14 compounds including seven lignans (1-7), three phenylbenzene derivatives (8-10), two flavanone (11-12), and two triterpenoids (13-14). Among them, 4'-demethyl-4-deoxypodophyllotoxin (1) is the first aryltetralin lignan compound identified from this plant species. In addition, the stereochemistry of 1 was validated by X-ray crystallography for the first time, and its distinguished cytotoxic effect on HCT116 cells with an IC50 value at 20 nM was induced via an apoptosis induction mechanism. Compound 1 could also significantly decrease the migration rate of HCT116 cells, indicating its potential application against cancer metastasis. The western blot analysis showed that 1 has the potential to inhibit cell proliferation and metastasis. Treatment of 1 resulted in the downregulation of matrix metalloproteinases 2 (MMP2) and p-Akt, while p21 was upregulated. Collectively, the present study on the phytochemical and biological profile of B. balansae has determined the plant as a useful source to produce promising anticancer lead compounds.

Stable Axially Chiral Isomers of Arylnaphthalene Lignan Glycosides with Antiviral Potential Discovered from Justicia procumbens.

Arylnaphthalene lignans (ANLs) were known to have axial chirality due to the biphenyl skeleton with hindered rotation at the single bond. However, the stable ANL atropisomers have not been isolated from nature until the present study. Phytochemical separation of the methanol extract of the stems and barks of Justicia procumbens led to the isolation of 11 ANL glycosides including four pairs of new atropisomers with stable confirmations at room temperature. Their structures were deduced from elucidation of the extensive spectral data, and their absolute configurations were determined by the circular dichroism, electronic circular dichroism, and X-ray methods as well as the total synthesis of one pair of the atropisomers. The ANL compounds were evaluated for their antiviral potential, and it was found that they displayed great antiviral activity discrepancy between a pair of atropisomers due to the geometric orientation. The 1'P-oriented atropisomers showed much more significant antiviral potency than their corresponding 1'M-oriented counterparts. The biological activity discrepancy caused by the axial chirality will not only inspire synthetic design of novel ANL atropisomers to enrich the structural diversity, but also provide important hints to direct the synthetic approaches toward the antiviral drug development of ANL compounds.

Lappaol F, an anticancer agent, inhibits YAP via transcriptional and post-translational regulation.

CONTEXT: Lappaol F (LAF), a natural lignan from Arctium lappa Linné (Asteraceae), inhibits tumour cell growth by inducing cell cycle arrest. However, its underlying anticancer mechanism remains unclear. OBJECTIVE: The effects of LAF on the Hippo-Yes-associated protein (YAP) signalling pathway, which plays an important role in cancer progression, were explored in this study. MATERIALS AND METHODS: Cervical (HeLa), colorectal (SW480), breast (MDA-MB-231) and prostate (PC3) cancer cell lines were treated with LAF at different concentrations and different durations. BALB/c nude mice bearing colon xenografts were intravenously injected with vehicle, LAF (10 or 20 mg/kg) or paclitaxel (10 mg/kg) for 15 days. The expression and nuclear localisation of YAP were analysed using transcriptome sequencing, quantitative PCR, western blotting and immunofluorescence. RESULTS: LAF suppressed the proliferation of HeLa, MDA-MB-231, SW480 and PC3 cells (IC50 values of 41.5, 26.0, 45.3 and 42.9 µmol/L, respectively, at 72 h), and this was accompanied by significant downregulation in the expression of YAP and its downstream target genes at both the mRNA and protein levels. The expression of 14-3-3σ, a protein that causes YAP cytoplasmic retention and degradation, was remarkably increased, resulting in a decrease in YAP nuclear localisation. Knockdown of 14-3-3σ with small interfering RNA partially blocked LAF-induced YAP inhibition and anti-proliferation effects. In colon xenografts, treatment with LAF led to reduced YAP expression, increased tumour cell apoptosis and tumour growth inhibition. CONCLUSION: LAF was shown to be an inhibitor of YAP. It exerts anticancer activity by inhibiting YAP at the transcriptional and post-translational levels.

Flexicaulin A, An ent-Kaurane Diterpenoid, Activates p21 and Inhibits the Proliferation of Colorectal Carcinoma Cells through a Non-Apoptotic Mechanism.

Natural products, explicitly medicinal plants, are an important source of inspiration of antitumor drugs, because they contain astounding amounts of small molecules that possess diversifying chemical entities. For instance, Isodon (formerly Rabdosia), a genus of the Lamiaceae (formerly Labiatae) family, has been reported as a rich source of natural diterpenes. In the current study, we evaluated the in vitro anti-proliferative property of flexicaulin A (FA), an Isodon diterpenoid with an ent-kaurane structure, in human carcinoma cells, by means of cell viability assay, flow cytometric assessment, quantitative polymerase chain reaction array, Western blotting analysis, and staining experiments. Subsequently, we validated the in vivo antitumor efficacy of FA in a xenograft mouse model of colorectal carcinoma. From our experimental results, FA appears to be a potent antitumor molecule, since it significantly attenuated the proliferation of human colorectal carcinoma cells in vitro and restricted the growth of corresponsive xenograft tumors in vivo without causing any adverse effects. Regarding its molecular mechanism, FA considerably elevated the expression level of p21 and induced cell cycle arrest in the human colorectal carcinoma cells. While executing a non-apoptotic mechanism, we believe the antitumor potential of FA opens up new horizons for the therapy of colorectal malignancy.

Dual-Functional Liposomes with Carbonic Anhydrase IX Antibody and BR2 Peptide Modification Effectively Improve Intracellular Delivery of Cantharidin to Treat Orthotopic Hepatocellular Carcinoma Mice.

Liposomal nanotechnology has a great potential to overcome the current major problems of chemotherapy. However, the lack of penetrability and targetability retards the successful delivery of liposomal carriers. Previously, we showed that BR2 peptide modification endowed cantharidin-loaded liposomes with intracellular penetration that enhanced the drug cytotoxic effects. Here, we aimed to improve the targeting delivery of drugs into cancer cells via highly expressed carbonic anhydrase IX (CA IX) receptors by modifying our previous catharidin-loaded BR2-liposomes with anti-CA IX antibody. A higher cellular uptake of dual-functional liposomes (DF-Lp) than other treatments was observed. Induction of CA IX over-expressing resulted in a higher cellular binding of DF-Lp; subsequently, blocking with excess antibodies resulted in a decreased cancer-cell association, indicating a specific targeting property of our liposomes towards CA IX expressed cells. After 3h tracking, most of the liposomes were located around the nucleus which confirmed the involvement of targeting intracellular delivery. Cantharidin loaded DF-Lp exhibited enhanced cytotoxicity in vitro and was most effective in controlling tumor growth in vivo in an orthotopic hepatocellular carcinoma model compared to other groups. Collectively, our results presented the advantage of the BR2 peptide and CA IX antibody combination to elevate the therapeutic potential of cantharidin loaded DF-liposomes.

Potent Inhibitor of Drug-Resistant HIV-1 Strains Identified from the Medicinal Plant Justicia gendarussa.

Justicia gendarussa, a medicinal plant collected in Vietnam, was identified as a potent anti-HIV-1 active lead from the evaluation of over 4500 plant extracts. Bioassay-guided separation of the extracts of the stems and roots of this plant led to the isolation of an anti-HIV arylnaphthalene lignan (ANL) glycoside, patentiflorin A (1). Evaluation of the compound against both the M- and T-tropic HIV-1 isolates showed it to possess a significantly higher inhibition effect than the clinically used anti-HIV drug AZT. Patentiflorin A and two congeners were synthesized, de novo, as an efficient strategy for resupply as well as for further structural modification of the anti-HIV ANL glycosides in the search for drug leads. Subsequently, it was determined that the presence of a quinovopyranosyloxy group in the structure is likely essential to retain the high degree of anti-HIV activity of this type of compounds. Patentiflorin A was further investigated against the HIV-1 gene expression of the R/U5 and U5/gag transcripts, and the data showed that the compound acts as a potential inhibitor of HIV-1 reverse transcription. Importantly, the compound displayed potent inhibitory activity against drug-resistant HIV-1 isolates of both the nucleotide analogue (AZT) and non-nucleotide analogue (nevaripine). Thus, the ANL glycosides have the potential to be developed as novel anti-HIV drugs.

Augmented Anticancer Effects of Cantharidin with Liposomal Encapsulation: In Vitro and In Vivo Evaluation.

PEGylated liposomes have received much attention as pharmaceutical carriers to deliver chemotherapeutic agents for therapeutic purpose. The aim of this study was to prepare and characterize PEGylated liposome of cantharidin and investigate its therapeutic effect on human hepatocellular carcinoma treatment in vitro and in vivo. Liposomal cantharidin was evaluated for their anticancer effects in vitro using human hepatocellular carcinoma HepG2 cells and in vivo using HepG2-bearing nude mice compared to free drug. PEGylated liposome of cantharidin had a particle size of 129.9 nm and a high encapsulation efficacy of approximately 88.9%. The liposomal cantharidin had a higher anti-proliferative effect vis-à-vis free cantharidin in inducing G2/M cell cycle arrest and apoptosis. Liposomal cantharidin killed more HepG2 cancer cells at the same concentration equivalent to free cantharidin. Further study in vivo also showed that liposomal cantharidin achieved a higher tumor growth inhibition efficacy than free drug on hepatocellular carcinoma. As our study exhibited enhanced cytotoxicity against HepG2 cells and augmented tumor inhibitory effects in vivo, the results validate the potential value of cantharidin-liposome in improving the therapeutic efficacy of cantharidin for liver cancer.

Bioactive compounds from Vitex leptobotrys.

A new lignan, vitexkarinol (1), as well as a known lignan, neopaulownin (2), a known chalcone, 3-(4-hydroxyphenyl)-1-(2,4,6-trimethoxyphenyl)-2-propen-1-one (3), two known dehydroflavones, tsugafolin (4) and alpinetin (5), two known dipeptides, aurantiamide and aurantiamide acetate, a known sesquiterpene, vemopolyanthofuran, and five known carotenoid metabolites, vomifoliol, dihydrovomifoliol, dehydrovomifoliol, loliolide, and isololiolide, were isolated from the leaves and twigs of Vitex leptobotrys through bioassay-guided fractionation. The chalcone (3) was found to inhibit HIV-1 replication by 77% at 15.9 µM, and the two dehydroflavones (4 and 5) showed weak anti-HIV activity with IC50 values of 118 and 130 µM, respectively, while being devoid of cytotoxicity at 150 µM. A chlorophyll-enriched fraction of V. leptobotrys, containing pheophorbide a, was found to inhibit the replication of HIV-1 by 80% at a concentration of 10 µg/mL. Compounds 1 and 3 were further selected to be evaluated against 21 viral targets available at NIAID (National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA).

Dihydro-Resveratrol Attenuates Oxidative Stress, Adipogenesis and Insulin Resistance in In Vitro Models and High-Fat Diet-Induced Mouse Model via AMPK Activation.

Management of obesity has become a prevalent strategy for preventing the diseases closely integrated with excess body weight such as diabetes over the last half century. Searching for therapeutic agents acting on oxidative stress, adipogenesis and insulin resistance is considered as an efficient approach to control obesity-related diseases. The present study was designed to examine the in vitro and in vivo effects of dihydro-resveratrol (DR2), a naturally occurring compound from Dendrobium medicinal plants, on oxidative stress aggravation, adipogenesis, lipogenesis and insulin sensitivity. We utilized an in vitro 3T3-L1 adipocyte differentiation model to show that DR2 could reduce pre-adipocyte maturation by activation of AMPK/SIRT1 signaling proteins to inhibit p38MAPK proteins. With the use of in vitro oxidative-stress-induced hepatocytes and myoblasts models, DR2 was also shown to be able to reduce oxidative stress aggravation through mediation of Nrf2-related antioxidative cascade, reduce intracellular lipid accumulation through phosphorylation of ACC protein, reduce lipid peroxidation in hepatocytes and promote insulin sensitivity via activation of AKT protein in the insulin-resistant HepG2 cells and C2C12 cells. The effects of DR2 on adipogenesis, lipid accumulation, insulin resistance and blood glucose clearance were further demonstrated in the high-fat diet-induced obesity mouse model. Our in vitro and in vivo studies determined that DR2 could contain therapeutic potential for the treatment of obesity and type 2 diabetes.

Two new triterpenoids from Lysimachia heterogenea Klatt and evaluation of their cytotoxicity.

Two new 13,28-epoxy oleanane-type triterpenoids, namely heterogenoside E and F, were isolated from Lysimachia heterogenea Klatt, together with the eight known compounds: palmitic acid, ß-stigmasterol, kaempferol, quercetin, hyperin, isorhamnetin, isorhamnetin-3-O-galactopyranoside and anagallisin C. Heterogenoside F possesses acetoxyl groups at the unusual C-21 and C-22 positions of its oleanane skeleton. The cytotoxic activities of anagallisin C, heterogenoside E and F were weak.

[Determination of longistylin A and longistylin C in Cajanus cajan].

OBJECTIVE: To establish quality control criteria for medicinal herb Cajanus cajan based on the determination of longistylin A and longistylin C, two bioactive and specific stilbenes of the plant. METHOD: Longistylin A and longistylin C were obtained from the leaves of C. cajan by silica gel column chromatography and identified as marker compounds of this plant by spectroscopic analysis. A RP-HPLC method was established to determine the two compounds. RESULT: Longistylin A and longistylin C were well separated on a Thermo BDS Hypersil C18 column (4.6 mm x 250 mm, 5 microm) with a mobile phase methanol-water (8:2), and showed good linearity in the range of 0.00288 - 0.0576 microg and 0.0112 - 0.224 microg, respectively. The average recoveries were 98.9% and 97.2% with RSD of 2.4% and 2.2% for these two compounds, respectively. CONCLUSION: The established analysis method is simple and accurate, whicn can be used for quality control of C. cajan.

Anti-HIV lignans from Justicia procumbens.

Twenty-one lignans including three new ones (1, 2 and 13) were isolated from Justicia procumbens. The chemical structures of the new lignans were determined by spectroscopic means including 1D and 2D NMR analysis. These compounds were evaluated for their cytotoxic and anti-HIV activities. The new secoisolariciresinol dimethyl ether acetate (13) exhibited anti-HIV-1 activity with an IC50 value of 5.27 µmol·L-1 and a selective index (SI) value of 2.2. The known arylnaphthalene lignan procumbenoside A (3) and diphyllin (8) demonstrated inhibitory activity against HIV-1 with IC50 values of 4.95 (SI > 6.2) and 0.38 µmol·L-1 (SI = 5.3), respectively.

In Vitro and in Vivo Antitumor Effects of Plant-Derived Miliusanes and Their Induction of Cellular Senescence.

Our earliest phytochemical separation of Miliusa sinensis aided us in the isolation of a class of unique miliusanes, which were demonstrated as anticancer lead molecules. In the present study, we isolated 19 miliusanes (1-19), including 11 novel ones (5 and 10-19) from another Miliusa plant ( M. balansae), and synthesized additional derivatives to elucidate the structure-activity relationship of miliusanes. When extrapolated to various carcinoma xenograft mouse models, miliusol (1) and its derivatives 20, 26, and 27 (7.5-40 mg/kg) were demonstrated with tumor inhibitory efficacy comparable or even superior to the mainstay chemotherapeutics paclitaxel or fluorouracil. To gain a molecular insight into their anticancer mechanism, 1-3 (GI50 0.03-4.79) were administered to a wide spectrum of human cancer cell lines, including those with specific drug resistance. We further revealed that the antiproliferative properties of miliusanes in carcinoma cells were highly associated with the p21-dependent induction of cellular senescence.

Resveratrol Ameliorates the Severity of Fibrogenesis in Mice with Experimental Chronic Pancreatitis.

SCOPE: Resveratrol is generally considered beneficial to health-span and longevity since this dietary stilbenoid has been scrutinized for its activating property on the "rescue gene" sirtuin-1 that promotes cellular survival under stress. In addition to its antiaging property, our previous in vitro studies revealed that resveratrol notably inhibits the production of extracellular matrix (ECM) proteins in pancreatic stellate cells (PSCs), the classic effector cells against pancreatic injury. OBJECTIVE: We aim to extrapolate resveratrol intervention to the management of fibrogenesis in mice with chronic pancreatitis. METHODS AND RESULTS: C57/BL6 mice are given repetitive injections of cerulein (50 µg kg-1  h-1 ) for 6 weeks for the induction of chronic pancreatitis. We demonstrate that the oral administration of resveratrol (20 mg kg-1  d-1 ) effectively attenuated PSC activation, ECM deposition, fibrogenesis, and acinar atrophy in the pancreatitic parenchyma of cerulein-induced mice, as the damage index score was improved by 45.5%. The enhanced cell survival and preserved acinar integrity by resveratrol plausibly involves a perpetuated nuclear accumulation of Mist1 and a negative modulation of the Akt and p38 MAPK pathways. CONCLUSION: We suggest that resveratrol is potentially a nutraceutical for the mitigations of pancreatic fibrosis in chronic pancreatitis for which no effective therapeutic measure is currently available.

Efficient Semisynthesis of (-)-Pseudoirroratin A from (-)-Flexicaulin A and Assessment of Their Antitumor Activities.

Accumulating evidence indicates that natural ent-kaurane diterpenoids show great potential for medical treatment of different pathological conditions including cytotoxicity, antibacterial, and anti-inflammatory activity. Among a variety of diterpenoids tested, (-)-pseudoirroratin A displayed a promising antitumor property in vitro and in vivo. However, this diterpenoid could merely be isolated in a limited amount from a rare source of Isodon pseudoirrorata. To overcome such scanty source, we developed a novel, facile, and efficient semisynthetic strategy to prepare (-)-pseudoirroratin A from natural (-)-flexicaulin A, which can be expediently obtained from I. flexicaulis in a great quantity. The three-dimensional structure and the absolute configuration of our synthetic diterpenoid have been determined and confirmed with the X-ray crystallographic analysis. More importantly, we demonstrated for the first time that pseudoirroratin A exerted significant cytotoxicity against human colorectal carcinoma cells via an induction of apoptosis, as well as a remarkable suppression on tumor growth in a colon cancer xenograft mouse model.

Anti-HIV diphyllin glycosides from Justicia gendarussa.

In a search for new anti-HIV active leads from over several thousands of plant extracts, we have identified a potent plant lead. The active plant is determined as Justicia gendarussa (Acanthaceae), a medicinal plant that has been used for the treatment of injury, arthritis and rheumatism in Asia including China. Our bioassay-guided fractionation of the methanol extract of the stems and barks of the plant led to the isolation of two anti-HIV compounds, justiprocumins A and B. The compounds are identified as new arylnaphthalide lignans (ANL) glycosides. We further determined that the ANL glycosides are the chemical constituents that contribute to the anti-HIV activity of this plant. Justiprocumin B displayed potent activity against a broad spectrum of HIV strains with IC50 values in the range of 15-21 nM (AZT, IC50 77-95 nM). The compound also displayed potent inhibitory activity against the NRTI (nucleoside reverse transcriptase inhibitor)-resistant isolate (HIV-11617-1) of the analogue (AZT) as well as the NNRTI (non-nucleoside reverse transcriptase inhibitor)-resistant isolate (HIV-1N119) of the analogue (nevaripine).

Lappaol F, a novel anticancer agent isolated from plant arctium Lappa L.

In an effort to search for new cancer-fighting therapeutics, we identified a novel anticancer constituent, Lappaol F, from plant Arctium Lappa L. Lappaol F suppressed cancer cell growth in a time- and dose-dependent manner in human cancer cell lines of various tissue types. We found that Lappaol F induced G(1) and G(2) cell-cycle arrest, which was associated with strong induction of p21 and p27 and reduction of cyclin B1 and cyclin-dependent kinase 1 (CDK1). Depletion of p21 via genetic knockout or short hairpin RNA (shRNA) approaches significantly abrogated Lappaol F-mediated G(2) arrest and CDK1 and cyclin B1 suppression. These results suggest that p21 seems to play a crucial role in Lappaol F-mediated regulation of CDK1 and cyclin B1 and G(2) arrest. Lappaol F-mediated p21 induction was found to occur at the mRNA level and involved p21 promoter activation. Lappaol F was also found to induce cell death in several cancer cell lines and to activate caspases. In contrast with its strong growth inhibitory effects on tumor cells, Lappaol F had minimal cytotoxic effects on nontumorigenic epithelial cells tested. Importantly, our data also demonstrate that Lappaol F exhibited strong growth inhibition of xenograft tumors in nude mice. Lappaol F was well tolerated in treated animals without significant toxicity. Taken together, our results, for the first time, demonstrate that Lappaol F exhibits antitumor activity in vitro and in vivo and has strong potential to be developed as an anticancer therapeutic.