Anti-Cancer Effects of Glaucarubinone in the Hepatocellular Carcinoma Cell Line Huh7 via Regulation of the Epithelial-To-Mesenchymal Transition-Associated Transcription Factor Twist1.

Hepatocellular carcinoma (HCC), the most common type of liver cancer, is a leading cause of cancer-related deaths. As HCC has a high mortality rate and its incidence is increasing worldwide, understanding and treating HCC are crucial for resolving major public health concerns. In the present study, wound healing screening assays were performed using natural product libraries to identify natural chemicals that can inhibit cancer cell migration. Glaucarubinone (GCB) showed a high potential for inhibiting cell migration. The anti-cancer effects of GCB were evaluated using the HCC cell line, Huh7. GCB showed anti-cancer effects, as verified by wound healing, cell migration, invasion, colony formation, and three-dimensional spheroid invasion assays. In addition, cells treated with GCB showed suppressed matrix metalloproteinase activities. Immunoblotting analyses of intracellular signaling pathways revealed that GCB regulated the levels of Twist1, a crucial transcription factor associated with epithelial-to-mesenchymal transition, and mitogen-activated protein kinase. The invasive ability of cancer cells was found to be decreased by the regulation of Twist1 protein levels. Furthermore, GCB downregulated phosphorylation of extracellular signal-regulated kinase. These results indicate that GCB exhibits anti-metastatic properties in Huh7 cells, suggesting that it could be used to treat HCC.

The anti-biofilm and anti-virulence activities of trans-resveratrol and oxyresveratrol against uropathogenic Escherichia coli.

Uropathogenic Escherichia coli (UPEC) is the primary causative agent of urinary tract infections, which are one of the most common infectious disease types in humans. UPEC infections involve bacterial cell adhesion to bladder epithelial cells, and UPEC can also form biofilms on indwelling catheters that are often tolerant to common antibiotics. In this study, the anti-biofilm activities of t-stilbene, stilbestrol, t-resveratrol, oxyresveratrol, ε-viniferin, suffruticosol A, and vitisin A were investigated against UPEC. t-Resveratrol, oxyresveratrol, and ε-viniferin, suffruticosol A, and vitisin A significantly inhibited UPEC biofilm formation at subinhibitory concentrations (10-50 µg ml-1). These findings were supported by observations that t-resveratrol and oxyresveratrol reduced fimbriae production and the swarming motility in UPEC. Furthermore, t-resveratrol and oxyresveratrol markedly diminished the hemagglutinating ability of UPEC, and enhanced UPEC killing by human whole blood. The findings show that t-resveratrol, oxyresveratrol, and resveratrol oligomers warrant further attention as antivirulence strategies against persistent UPEC infections.

Upregulation of Death Receptor 5 and Production of Reactive Oxygen Species Mediate Sensitization of PC-3 Prostate Cancer Cells to TRAIL Induced Apoptosis by Vitisin A.

BACKGROUND/AIMS: Although Vitisin A, derived from wine grapes, is known to have cytotoxic, anti-adipogenic, anti-inflammatory and antioxidant effects, the underlying antitumor mechanism has not been investigated in prostate cancer cells to date. In the present study, the apoptotic mechanism of Vitisin A plus TNF-related apoptosis-inducing ligand (TRAIL) in prostate cancer cells was elucidated. METHODS: The cytotoxicity of Vitisin A and/or TRAIL against PC-3, DU145 and LNCaP prostate cancer cells was measured by MTT colorimetric assay. Annexin V-FITC Apoptosis Detection kit was used to detect apoptotic cells by flow cytometry. Intracellular levels of ROS were measured by flow cytometry using 2070-diacetyl dichlorofluorescein (DCFDA). RESULTS: Combined treatment with Vitisin A and TRAIL enhanced cytotoxicity and also increased sub-G1 population in PC-3 cells better than DU145 or LNCap prostate cancer cells. Similarly, Annexin V and PI staining revealed that combination increased early and late apoptosis in PC-3 cells compared to untreated control. Consistently, combination attenuated the expression of pro-caspases 7/8, DcR1, Bcl-XL or Bcl-2 and activated caspase 3, FADD, DR5 and DR4 in PC-3 cells. Also, combination increased DR5 promoter activity compared to untreated control. Furthermore, combination increased the production of reactive oxygen species (ROS) and DR5 cell surface expression. The ROS inhibitor NAC and silencing of DR5 by siRNA transfection inhibited the ability of combination to induce PARP cleavage and generate ROS. CONCLUSION: These findings provide evidence that Vitisin A can be used in conjunction with TRAIL as a potent TRAIL sensitizer for synergistic apoptosis induction via upregulation of DR5 and production of ROS in prostate cancer cells.

Identification of a novel 11ß-HSD1 inhibitor from a high-throughput screen of natural product extracts.

Selective inhibitors of 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) have considerable potential as a treatment for metabolic syndrome including type 2 diabetes mellitus and obesity. To identify 11ß-HSD1 inhibitors, we conducted high-throughput screening (HTS) of active natural product extracts from the Korea Chemical Bank, including Tanshinone I, Tanshinone IIA, and flavanone derivatives, and 2- and 3-phenyl-4H-chromen-4-one. Then Tanshinone IIA and its derivatives were targeted for the development of a lead compound according to the HTS results. However, the mechanism for anti-adipogenic effect through 11ß-HSD1 enzyme inhibition by Tanshinone IIA is not clear. Tanshinone IIA (2a) concentration-dependently inhibited 11ß-HSD1 activity in human and mouse 11ß-HSD1 overexpressed cells and 3T3-L1 adipocytes. Tanshinone IIA (2a) also inhibited 11ß-HSD1 enzyme activities in murine liver and fats. Furthermore, Tanshinone IIA (2a)-suppressed adipocyte differentiation of cortisone-induced adipogenesis in 3T3-L1 cells was associated with the suppression of the cortisone-induced adipogenesis-specific markers mRNA and protein expression. In 3T3-L1 preadipocytes, Tanshinone IIA (2a)-inhibited cortisone induced reactive oxygen species formation in a concentration-dependent manner. Thus, these results support the therapeutic potential of Tanshinone IIA (2a) as a 11ß-HSD1 inhibitor in metabolic syndrome patients.

In vitro and in vivo Bone-Forming Activity of Saururus chinensis Extract.

Bone is maintained by osteoclast-mediated resorption and osteoblast-mediated formation. Recently, anti-osteoporotic activity of Saururus chinensis extract (SCE) and anti-osteoclastogenic activity of its components have been reported, but the effect of SCE on bone formation has not been studied well. Therefore, in this study, we investigated whether Saururus chinensis SCE exhibits in vitro osteogenic and in vivo bone-forming activity. extract strongly enhanced the bone morphogenetic protein (BMP)-2-stimulated induction of alkaline phosphatase, an early phase biomarker of osteoblast differentiation, in bi-potential mesenchymal progenitor C2C12 cells. In vitro osteogenic activity of SCE was accompanied by enhanced expression of BMP-2, BMP-4, BMP-7 and BMP-9 mRNA. In addition, a pharmacological inhibition study suggested the involvement of p38 activation in the osteogenic action of SCE. Moreover, the BMP dependency and the involvement of p38 activation in the osteogenic action of SCE were confirmed by the treatment of noggin, an antagonist of BMP. Saururus chinensis extract also exhibited to induce runt-related transcription factor 2 activation at the high concentration. Furthermore, the in vivo osteogenic activity of SCE was confirmed in zebrafish and mouse calvarial bone formation models, suggesting the possibility of its use for bone formation. In conclusion, we suggested that in vivo anti-osteoporotic activity of SCE could be because of its dual action in bone, anti-osteoclastogenic and anabolic activity.

Biological evaluation of tanshindiols as EZH2 histone methyltransferase inhibitors.

EZH2 is the core subunit of Polycomb repressive complex 2 catalyzing the methylation of histone H3 lysine-27 and closely involved in tumorigenesis. To discover small molecule inhibitors for EZH2 methyltransferase activity, we performed an inhibitor screen with catalytically active EZH2 protein complex and identified tanshindiols as EZH2 inhibitors. Tanshindiol B and C potently inhibited the methyltransferase activity in in vitro enzymatic assay with IC50 values of 0.52µM and 0.55µM, respectively. Tanshindiol C exhibited growth inhibition of several cancer cells including Pfeiffer cell line, a diffuse large B cell lymphoma harboring EZH2 A677G activating mutation. Tanshindiol treatment in Pfeiffer cells significantly decreased the tri-methylated form of histone H3 lysine-27, a substrate of EZH2, as revealed by Western blot analysis and histone methylation ELISA. Based on enzyme kinetics and docking studies, we propose that tanshindiol-mediated inhibition of EZH2 activity is competitive for the substrate S-adenosylmethionine. Taken together, our findings strongly suggest that tanshindiols possess a unique anti-cancer activity whose mechanism involves the inhibition of EZH2 activity and would provide chemically valuable information for designing a new class of potent EZH2 inhibitors.

Resveratrol oligomers inhibit biofilm formation of Escherichia coli O157:H7 and Pseudomonas aeruginosa.

Biofilm formation is closely related to bacterial infection and is also a mechanism of antimicrobial resistance. Hence, the antibiofilm approach provides an alternative to an antibiotic strategy. In this study, the antibiofilm activities of resveratrol (1) and five of its oligomers, namely, ε-viniferin (2), suffruticosol A (3), suffruticosol B (4), vitisin A (5), and vitisin B (6), were investigated against enterohemorrhagic Escherichia coli O157:H7 and Pseudomonas aeruginosa PA14. Vitisin B (6), a stilbenoid tetramer, was found to inhibit biofilm formation by the two bacteria the most effectively and at 5 µg/mL inhibited E. coli O157:H7 biofilm formation by more than 90%.

Stilbenes reduce Staphylococcus aureus hemolysis, biofilm formation, and virulence.

Stilbenoids have a broad range of beneficial health effects. On the other hand, the emergence of antibiotic-resistant Staphylococcus aureus presents a worldwide problem that requires new antibiotics or nonantibiotic strategies. S. aureus produces α-hemolysin (a pore-forming cytotoxin) that has been implicated in the pathogenesis of sepsis and pneumonia. Furthermore, the biofilms formed by S. aureus constitute a mechanism of antimicrobial resistance. In this study, we investigated the hemolytic and antibiofilm activities of 10 stilbene-related compounds against S. aureus. trans-Stilbene and resveratrol at 10 µg/mL were found to markedly inhibit human blood hemolysis by S. aureus, and trans-stilbene also inhibited S. aureus biofilm formation without affecting its bacterial growth. Furthermore, trans-stilbene and resveratrol attenuated S. aureus virulence in vivo in the nematode Caenorhabditis elegans, which is normally killed by S. aureus. Transcriptional analysis showed that trans-stilbene repressed the α-hemolysin hla gene and the intercellular adhesion locus (icaA and icaD) in S. aureus, and this finding was in line with observed reductions in virulence and biofilm formation. In addition, vitisin B, a stilbenoid tetramer, at 1 µg/mL was observed to significantly inhibit human blood hemolysis by S. aureus.

Kamolonol suppresses angiotensin II-induced stress fiber formation and cellular hypertrophy through inhibition of Rho-associated kinase 2 activity.

Kamolonol (7-[[(1R,2R,4R,4aS,5R,8aS)-4-hydroxy-1,2,4a,5-tetramethyl-6-oxo-3,4,5,7,8,8a-hexahydro-2H-naphthalen-1-yl]methoxy]chromen-2-one) is a sesquiterpene coumarin and an active component of gum extracts from Ferulaassafoetida. The aim of this study was to investigate the anti-fibrotic and anti-cellular hypertrophic effects of kamolonol, and further to explore its possible mechanism. Kamolonol (3-30µM) significantly inhibited stress fiber formation induced by angiotensin II (Ang II) in rat heart-derived H9c2 cells. Furthermore, kamolonol (3-30µM) showed a potent inhibitory effect on Ang II-induced cellular hypertrophy in H9c2 cells. Next, a Rho-associated kinase (ROCK) activity was measured because actin stress fiber formation and/or cellular hypertrophy are usually induced by the activation of ROCK. Rho-associated kinase 2 (ROCK2) studies using a time-resolved fluorescence resonance energy transfer (TR-FRET) showed that kamolonol possesses a potent ROCK2 inhibitory activity with IC50 values of 2.27µM, and has an ATP-competitive inhibitory mode. In validation study, pretreatment of kamolonol (3-30µM) for 2h decreased the Ang II-induced phosphorylation of myosin phosphatase 1 (MYPT1) and myosin light chain 2 (MLC2). Taken together, these results indicate that kamolonol suppresses Ang II-induced stress fiber formation and cellular hypertrophy, and propose that one mechanism underlying these anti-fibrotic and anti-cellular hypertrophic effects involves inhibition of the ROCK-MLC pathway.

Diverse plant extracts and trans-resveratrol inhibit biofilm formation and swarming of Escherichia coli O157:H7.

Infection with enterohemorrhagic Escherichia coli O157:H7 (EHEC) is a worldwide problem. Of the 498 plant extracts screened against EHEC, 16 inhibited the formation of biofilm of EHEC by >85% without inhibiting the growth of planktonic cells, and 14 plant extracts reduced the swarming motility of EHEC. The most active extract, Carex dimorpholepis, decreased swimming and swarming motilities and curli formation. Transcriptional analyses showed that the extract of C. dimorpholepis repressed curli genes, various motility genes, and AI-2 quorum sensing genes, which was corroborated by reduction in the production of fimbria, motility, and biofilm by EHEC. Trans-resveratrol at 10 µg ml(-1) in the extract of C. dimorpholepis was found to be a new anti-biofilm compound against EHEC, but importantly, the extract of C. dimorpholepis and trans-resveratrol did not inhibit the fomation of biofilm in four commensal E. coli strains. Furthermore, the extract of C. dimorpholepis decreased the adhesion of EHEC cells to human epithelial cells without affecting the viability of these cells.

Anti-inflammatory effects of the Zingiber officinale roscoe constituent 12-dehydrogingerdione in lipopolysaccharide-stimulated Raw 264.7 cells.

Ginger has long been used worldwide as a spice, seasoning, and wine and is also used as a traditional medicine. There have been no previous studies of the potential beneficial effects of the ginger constituent 12-dehydrogingerdione (12-DHGD). We investigated the anti-inflammatory effect of 12-DHGD on lipopolysaccharide (LPS)-stimulated Raw 264.7 cells. The cytotoxicity of 12-DHGD was measured using the MTT assay, and production of prostaglandin E2 (PGE2 ) and the inflammatory cytokines interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α was measured by ELISA. Production of nitric oxide (NO) was measured using Griess reagent and expression of cyclooxygenase-2 (COX-2) and inducible NO (iNOS) enzymes was assessed by reverse transcriptase-polymerase chain reaction. Treatment of Raw 264.7 cells with 12-DHGD significantly inhibited LPS-stimulated production of NO (at 12-DHGD concentrations of 150 and 200 ng/ml), IL-6 (at 50, 100, 150, and 200 ng/ml), and PGE2 (at 200 ng/ml). Consistent with the effects on NO and PGE2 production, 12-DHGD treatment also inhibited the LPS-stimulated increase in iNOS and COX-2 mRNA levels. However, 12-DHGD did not affect production of IL-1ß or TNF-α in response to LPS. 12-DHGD, a constituent of ginger, is a potent inhibitor of proinflammatory mediator production in Raw 264.7 macrophage cells.

Elicitation of induced resistance against Pectobacterium carotovorum and Pseudomonas syringae by specific individual compounds derived from native Korean plant species.

Plants have developed general and specific defense mechanisms for protection against various enemies. Among the general defenses, induced resistance has distinct characteristics, such as broad-spectrum resistance and long-lasting effectiveness. This study evaluated over 500 specific chemical compounds derived from native Korean plant species to determine whether they triggered induced resistance against Pectobacterium carotovorum supsp. carotovorum (Pcc) in tobacco (Nicotiana tabacum) and Pseudomonas syringae pv. tomato (Pst) in Arabidopsis thaliana. To select target compound(s) with direct and indirect (volatile) effects, a new Petri-dish-based in vitro disease assay system with four compartments was developed. The screening assay showed that capsaicin, fisetin hydrate, jaceosidin, and farnesiferol A reduced the disease severity significantly in tobacco. Of these four compounds, capsaicin and jaceosidin induced resistance against Pcc and Pst, which depended on both salicylic acid (SA) and jasmonic acid (JA) signaling, using Arabidopsis transgenic and mutant lines, including npr1 and NahG for SA signaling and jar1 for JA signaling. The upregulation of the PR2 and PDF1.2 genes after Pst challenge with capsaicin pre-treatment indicated that SA and JA signaling were primed. These results demonstrate that capsaicin and jaceosidin can be effective triggers of strong induced resistance against both necrotrophic and biotrophic plant pathogens.

Inhibition of LPS binding to MD-2 co-receptor for suppressing TLR4-mediated expression of inflammatory cytokine by 1-dehydro-10-gingerdione from dietary ginger.

Myeloid differentiation protein 2 (MD-2) is a co-receptor of toll-like receptor 4 (TLR4) for innate immunity. Here, we delineated a new mechanism of 1-dehydro-10-gingerdione (1D10G), one of pungent isolates from ginger (Zingiber officinale), in the suppression of lipopolysaccharide (LPS)-induced gene expression of inflammatory cytokines. 1D10G inhibited LPS binding to MD-2 with higher affinity than gingerol and shogaol from dietary ginger. Moreover, 1D10G down-regulated TLR4-mediated expression of nuclear factor-κB (NF-κB) or activating protein 1 (AP1)-target genes such as tumor necrosis factor α (TNF-α) and interleukin-1ß, as well as those of interferon (IFN) regulatory factor 3 (IRF3)-target IFN-ß gene and IFN-γ inducible protein 10 (IP-10) in LPS-activated macrophages. Taken together, MD-2 is a molecular target in the anti-inflammatory action of 1D10G.

Platyconic acid, a saponin from Platycodi radix, improves glucose homeostasis by enhancing insulin sensitivity in vitro and in vivo.

BACKGROUND: Previous research demonstrated that the crude saponins of Platycodi radix improve glucose metabolism by enhancing insulin sensitivity in type 2 diabetic animals; however, which individual saponins are the most potent insulin sensitizers is unknown. OBJECTIVES: This study investigated which saponin(s) have anti-diabetic action in vitro and in vivo. METHODS: The insulin-stimulated glucose uptake and PPAR-γ agonistic actions of six saponins from Platycodi radix were investigated in 3T3-L1 adipocytes, and glucose-stimulated insulin secretion was determined in Min6 cells. Four individual saponins (20 mg/kg body weight) were orally administered to low-dose streptozotocin-injected diabetic mice fed a high-fat diet for 8 weeks to evaluate glucose tolerance by oral glucose tolerance testing (OGTT), insulin sensitivity by insulin tolerance testing, and insulin signaling in the liver and adipose tissues. RESULTS: Platyconic acid (PA) most effectively increased insulin-stimulated glucose uptake in 3T3-L1 adipocytes, possibly in part by working as a peroxisome proliferator-activated receptors (PPAR)-γ activator; however, none of the saponins improved glucose-stimulated insulin secretion in insulinoma cells. PA-treated diabetic mice exhibited the lowest peak serum glucose levels and highest serum insulin levels during the first part of OGTT. PA also improved insulin sensitivity: PA increased glycogen accumulation and decreased triacylglycerol storage in liver, which was associated with enhanced hepatic insulin signaling, while PA potentiated the expression of adiponectin and PPAR-γ in adipose tissue, and improved insulin signaling and increased GLUT4 translocation into the membranes. CONCLUSIONS: PA improves glucose homeostasis in type 2 diabetic mice, partly by enhancing hepatic and adipocyte insulin sensitivity, possibly by activating PPAR-γ.

Antiosteoporotic activity of Saururus chinensis extract in ovariectomized rats.

Recent studies suggest that phytoestrogens may exert a protective effect against osteoporosis. This study examined whether treatment with phytoestrogen extracts from Saururus chinensis (SC) exerted a preventive effect on estrogen-deficiency-induced osteoporosis. Six- to seven-month-old female Sprague-Dawley rats were randomly assigned into either a sham-operated group or one of three ovariectomy (OVX) subgroups: OVX treated with vehicle, OVX with alendronate, and OVX with SC extract (SC). Rats began receiving treatment 4 weeks before the OVX treatment and continued receiving treatment for an additional 10 weeks after OVX (for a combined total of 14 weeks). The results showed that the SC treatment prevented loss of femur bone mineral density after OVX, as determined by a significant decrease in the levels of serum bone turnover markers osteocalcin and alkaline phosphatase as well as urinary deoxypyridinoline. Micro-computed tomography analysis showed that the SC treatment significantly prevented decreases in bone volume/tissue volume, trabecular number and trabecular thickness, while also preventing an increase in trabecular separation. It was concluded that SC treatment could prevent OVX-induced loss of bone mass and deterioration in trabecular microarchitecture by suppressing bone turnover, thereby maintaining bone structural integrity. Further, no stimulation of proliferation of uterine tissue was noted. Therefore, it is suggested that treatment with S. chinensis extracts might be a potential alternative therapy for treating postmenopausal osteoporosis.

Decursin, an active compound isolated from Angelica gigas, inhibits fat accumulation, reduces adipocytokine secretion and improves glucose tolerance in mice fed a high-fat diet.

Decursin (De), an active component of Angelica gigas, is known to exert anticancer and neuroprotective effects. However, its antiobesity and antidiabetic potential has not yet been investigated. This study evaluated the antiobesity effect of decursin, particularly focusing on its ability to inhibit adipocyte differentiation in 3T3-L1 cells. Decursin treatment resulted in the inhibition of adipocyte differentiation and the expression of fatty acid synthase. The study further investigated these antiobesity effects using mice fed a normal diet (ND), a high-fat diet (HFD) and a HFD plus decursin 200 mg/kg diet (HFD + De) for 7 weeks. Mice administered HFD plus decursin showed a drastic decrease in weight gain, triglyceride content, total cholesterol content and fat size compared with those that received the HFD alone; this was observed despite similar quantities of total food intake. Furthermore, decursin improved glucose tolerance in mice fed a HFD. Finally, administration of decursin along with the HFD significantly reduced the secretion of HFD-induced adipocytokines such as leptin, resistin, IL-6 and MCP-1. These results suggest that decursin might be useful for the treatment of obesity and diabetes.

Galbanic acid isolated from Ferula assafoetida exerts in vivo anti-tumor activity in association with anti-angiogenesis and anti-proliferation.

PURPOSE: To investigate whether galbanic acid (GBA) exerts anti-angiogenic and anti-cancer activities. METHODS: Using human umbilical vein endothelial cell (HUVEC) model, we analyzed effects of GBA on cellular and molecular events related to angiogenesis. We tested its direct anti-proliferative action on mouse Lewis lung cancer (LLC) cells and established its in vivo anti-angiogenic and anti-tumor efficacy using LLC model. RESULTS: GBA significantly decreased vascular endothelial growth factor (VEGF)-induced proliferation and inhibited VEGF-induced migration and tube formation of HUVECs. These effects were accompanied by decreased phosphorylation of p38-mitogen-activated protein kinase (MAPK), c-jun N-terminal kinase (JNK), and AKT, and decreased expression of VEGFR targets endothelial nitric oxide synthase (eNOS) and cyclin D1 in VEGF-treated HUVECs. GBA also decreased LLC proliferation with an apparent G2/M arrest, but did not induce apoptosis. In vivo, inclusion of GBA in Matrigel plugs reduced VEGF-induced angiogenesis in mice. Galbanic acid given by daily i.p. injection (1 mg/kg) inhibited LLC-induced angiogenesis in an intradermal inoculation model and inhibited the growth of s.c. inoculated LLC allograft in syngenic mice. Immunohistochemistry revealed decreased CD34 microvessel density index and Ki-67 proliferative index in GBA-treated tumors. CONCLUSIONS: GBA exerts anti-cancer activity in association with anti-angiogenic and anti-proliferative actions.

New guaiane sesquiterpene lactones from Ixeris dentata.

Three new guaiane-type sesquiterpene lactones (1-3), together with nine related sesquiterpenes (4-12), were isolated from the whole extract of Ixeris dentata (Asteraceae). The chemical structures of isolates 1-12 were established by spectroscopic analyses as 3 ß,8 ß-dihydroxy-guaia-10(14)-en-1 α,4 α,5 α,6 ß,7 α,11 ßH-12,6 α-olide (1), ixerin N 6'- O-acetate (2), ixerisoside A 6'- O-acetate (3), ixerin N ( 4), ixerisoside A (5), ixerin M (6), tectroside (7), 8-epidesacylcynaropicrin glucoside (8), 8-epiisolipidiol (9), 11 ßH-11,13-dihydrointegrifolin (10) 8 ß-hydroxy-4 ß,15-dihydrozaluzanin C (11), and integrifolin (12). Compounds 1-12 were evaluated for their inhibitory effect on the proliferation of the cultured human tumor cell lines MES-SA, MES-SA/DX5, HCT-15, and HCT15/CL02 in vitro.

In vitro BACE-1 inhibitory activity of resveratrol oligomers from the seed extract of Paeonia lactiflora.

A new resveratrol oligomer (1) together with eight related components (2- 9) were isolated from the seed extract of Paeonia lactiflora (Paeoniaceae) as active principles responsible for the inhibition of beta-site APP-cleaving enzyme 1 (BACE-1) in vitro. The chemical structure of 1 was established as (-)-7a,8a- CIS- ε-viniferin with the aid of spectroscopic analyses including NOESY experiments. All isolated resveratrol oligomers (1- 9) demonstrated significant inhibition on baculovirus-expressed BACE-1 in a dose-dependent manner, which was assessed by the FRET assay using Rh-EVNLDAEFK as a substrate in vitro.

Galbanic acid, a cytotoxic sesquiterpene from the gum resin of Ferula asafoetida, blocks protein farnesyltransferase.

Farnesylation of the activated RAS oncogene product by protein farnesyltransferase (FTase) is a critical step for its oncogenic function. Bioassay-guided purification of Ferula asafoetida (Umbelliferae) extract led to the isolation of the coumarin-derived sesquiterpene galbanic acid (1) as an active principal for FTase inhibitory activity, together with the four structurally related sesquiterpenes karatavicinol (2), umbelliprenin (3), farnesiferol B (4), and farnesiferol C (5). The 50 % inhibitory concentration (IC (50)) of 1 against FTase in an enzyme-based assay was calculated as 2.5 µM. Compound 1 also demonstrated potent inhibition of the proliferation of oncogenic RAS-transformed NIH3T3/Hras-F in a dose-dependent manner. The IC (50) value of 1 on the proliferation of oncogenic RAS-transformed NIH3T3/Hras-F cells was calculated as 16.2 µM, whereas its IC (50) value on control vector-transfected normal RAS-containing NIH3T3/ZIPneo cells was 58.5 µM.