Effect of methoxyflavones contained in Kaempferia parviflora on CRE-mediated transcription in PC12D cells.

The cAMP-response element (CRE) is critical in the formation of long-term memory. To prove the pharmacological effects of the methoxyflavones-rich residue (MRR) and its constituent methoxyflavones (1-9) extracted from the rhizomes of Kaempferia parviflora on the nervous system, we examined the effects of the MRR and methoxyflavones (1-9) on CRE-mediated transcription in PC12D cells. The MRR increased CRE-mediated transcription in PC12D cells. In addition, among methoxyflavones (1-9) isolated from MRR, compounds 1-4 increased CRE-mediated transcription. These results suggest that K. parviflora and methoxyflavone might be very useful materials for preventing and recovering from cognitive decline.

Imidacloprid, a neonicotinoid insecticide, facilitates tyrosine hydroxylase transcription and phenylethanolamine N-methyltransferase mRNA expression to enhance catecholamine synthesis and its nicotine-evoked elevation in PC12D cells.

Imidacloprid is a neonicotinoid insecticide acting as an agonist of nicotinic acetylcholine receptors (nAChRs) in the target insects. However, questions about the safety to mammals, including human have emerged. Overactivation of mammalian peripheral catecholaminergic systems leads to onset of tachycardia, hypertension, vomiting, etc., which have been observed in acutely imidacloprid-poisoned patients as well. Physiological activation of the nAChRs is known to drive catecholamine biosynthesis and secretion in mammalian adrenal chromaffin cells. Yet, the impacts of imidacloprid on the catecholaminergic function of the chromaffin cells remain to be evaluated. In this study using PC12D cells, a catecholaminergic cell line derived from the medulla chromaffin-cell tumors of rat adrenal gland, we examined whether imidacloprid itself could impact the catecholamine-synthesizing ability. Imidacloprid alone did facilitate tyrosine hydroxylase (TH) transcription via activation of α3ß4 nAChR and the α7 subunit-comprising receptor. The insecticide showed the TH transcription-facilitating ability at the concentrations of 3 and 30 µM, at which acetylcholine is known to produce physiological responses, including catecholamine secretion through the nAChRs in adrenal chromaffin cells. The insecticide-facilitated TH transcription was also dependent on PKA- and RhoA-mediated signaling pathways. The insecticide coincidentally raised levels of TH and phenylethanolamine N-methyltransferase (PNMT) mRNA, and as a consequence, increased catecholamine production, although the efficacy of the neonicotinoid was lesser than that of nicotine, indicating its partial agonist-like action. Intriguingly, in cultured rat adrenal chromaffin cells, imidacloprid did increase levels of TH and PNMT protein. When the chromaffin cells were treated with nicotine in the presence of the insecticide, nicotine-elevated adrenaline production was enhanced due to facilitation of nicotine-increased TH and PNMT protein expression, and simultaneous enhancement of nicotine-elevated adrenaline secretion also took place. These findings thus suggest that imidacloprid may facilitate the physiological functions of adrenal glands in mammals.

Tyrosine hydroxylase gene expression is facilitated by alcohol followed by the degradation of the protein by ubiquitin proteasome system.

OBJECTIVES: Alcohol intake induces brief periods of euphoria; however, its continuous consumption can lead the development of alcohol tolerance. The euphoria, an intense feeling of wellbeing, is deeply associated with dopamine. Dopamine biosynthesis is strictly regulated by tyrosine hydroxylase (TH), a rate-limiting enzyme of dopamine. The aim of this study was to examine the transient or chronic effects of ethanol treatment on TH protein level in vitro. METHODS: Cultured primary mesencephalic neurons were prepared and exposed to 100 mM ethanol for 48 hours or 168 hours. TH and cAMP-responsive element (CRE)-mediated transcriptional activity was measured by reporter gene assay using pTH9.0kb-Luc and pCRE-Luc reporter plasmid. TH protein expression and TH phosphorylation was analyzed by Western blot analysis. Dopamine content was measured by high-performance liquid chromatography (HPLC). RESULTS: Ethanol treatment for 48 hours facilitates TH transcriptional activity and TH protein expression in a cAMP-dependent protein kinase A (PKA) and MAPK/Erk kinase (MEK)-dependent manner in cultured mesencephalic neurons. Ethanol also facilitated TH phosphorylation, which resulted in the elevation of dopamine content. On the other hand, treatment with ethanol for 168 hours did not show significant elevation of TH gene expression and dopamine biosynthesis. Intriguingly, simultaneous treatment with MG-132, a 26S proteasomal inhibitor, recovered the ethanol-induced increase of TH protein expression and dopamine biosynthesis. CONCLUSION: Transient ethanol-treatment facilitates TH gene expression and its phosphorylation in a PKA- and MEK-dependent manner to elevate dopamine biosynthesis, whereas continuous exposure to ethanol abolishes its potent effects on the dopaminergic function to reduce dopamine content. This reduction seems to originate from the decrease of TH protein level by degradation of the protein. Our current data may contribute to the better understanding of alcohol tolerance associated with degradation of TH protein to reduce total-TH level and dopamine biosynthesis.

Dopamine or biopterin deficiency potentiates phosphorylation at (40)Ser and ubiquitination of tyrosine hydroxylase to be degraded by the ubiquitin proteasome system.

The protein amount of tyrosine hydroxylase (TH), that is the rate-limiting enzyme for the biosynthesis of dopamine (DA), should be tightly regulated, whereas its degradation pathway is largely unknown. In this study, we analyzed how the TH protein is chemically modified and subsequently degraded under deficiencies of DA and tetrahydrobiopterin (BH4), a cofactor for TH, by using pharmacological agents in PC12D cells and cultured mesencephalic neurons. When inhibition of DA- or BH4-synthesizing enzymes greatly reduced the DA contents in PC12D cells, a marked and persistent increase in phosphorylated TH at (40)Ser (p40-TH) was concomitantly observed. This phosphorylation was mediated by D2 dopamine auto-receptor and cAMP-dependent protein kinase (PKA). Our immunoprecipitation experiments showed that the increase in the p40-TH level was accompanied with its poly-ubiquitination. Treatment of PC12D cells with cycloheximide showed that total-TH protein level was reduced by the DA- or BH4-depletion. Notably, this reduction in the total-TH protein level was sensitive not only to a 26S proteasomal inhibitor, MG-132, but also to a PKA inhibitor, H-89. These data demonstrated that DA deficiency should induce compensatory activation of TH via phosphorylation at (40)Ser through D2-autoreceptor and PKA-mediated pathways, which in turn give a rise to its degradation through an ubiquitin-proteasome pathway, resulting in a negative spiral of DA production when DA deficiency persists.

Potent activity of nobiletin-rich Citrus reticulata peel extract to facilitate cAMP/PKA/ERK/CREB signaling associated with learning and memory in cultured hippocampal neurons: identification of the substances responsible for the pharmacological action.

cAMP/PKA/ERK/CREB signaling linked to CRE-mediated transcription is crucial for learning and memory. We originally found nobiletin as a natural compound that stimulates this intracellular signaling and exhibits anti-dementia action in animals. Citrus reticulata or C. unshiu peels are employed as "chinpi" and include a small amount of nobiletin. We here provide the first evidence for beneficial pharmacological actions on the cAMP/PKA/ERK/CREB cascade of extracts from nobiletin-rich C.reticulata peels designated as Nchinpi, the nobiletin content of which was 0.83 ± 0.13% of the dry weight or 16-fold higher than that of standard chinpi extracts. Nchinpi extracts potently facilitated CRE-mediated transcription in cultured hippocampal neurons, whereas the standard chinpi extracts showed no such activity. Also, the Nchinpi extract, but not the standard chinpi extract, stimulated PKA/ERK/CREB signaling. Interestingly, treatment with the Nchinpi extract at the concentration corresponding to approximately 5 µM nobiletin more potently facilitated CRE-mediated transcriptional activity than did 30 µM nobiletin alone. Consistently, sinensetin, tangeretin, 6-demethoxynobiletin, and 6-demethoxytangeretin were also identified as bioactive substances in Nchinpi that facilitated the CRE-mediated transcription. Purified sinensetin enhanced the transcription to a greater degree than nobiletin. Furthermore, samples reconstituted with the four purified compounds and nobiletin in the ratio of each constituent's content in the extract showed activity almost equal to that of the Nchinpi extract to stimulate CRE-mediated transcription. These findings suggest that above four compounds and nobiletin in the Nchinpi extract mainly cooperated to facilitate potently CRE-mediated transcription linked to the upstream cAMP/PKA/ERK/CREB pathway in hippocampal neurons.

Nobiletin induces inhibitions of Ras activity and mitogen-activated protein kinase kinase/extracellular signal-regulated kinase signaling to suppress cell proliferation in C6 rat glioma cells.

Ras, a small G-protein, physiologically directs cell proliferation and cell cycle via regulation of mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling cascade. Dysregulation of Ras/MEK/ERK signaling has been reported to cause tumorigenesis and gliomas. Nobiletin, a citrus flavonoid, has been shown to have anti-tumor cells action. However, it remains elusive whether nobiletin could affect Ras activity. In this study, we provide the first evidence that nobiletin suppresses the proliferation by inhibiting Ras activity in C6 glioma cells, a rat glioma cell line. First, Ras pull-down assay showed that nobiletin inhibits Ras activity in a concentration-dependent manner in C6 cells. Second, farnesyltransferase inhibitor I, a Ras inhibitor, and U0126, a MEK inhibitor, induced an inhibition of the cell proliferation in C6 cells, while the cell proliferation was inhibited by nobiletin as well. Third, western blotting revealed that nobiletin showed inhibitory effects on MEK and ERK phopsphorylation levels in a concentration-dependent manner. Finally, such an inhibitory effect on the level of ERK phosphorylation by nobiletin was appreciably prevented by Gö6976, a selective inhibitor of conventional protein kinase Cs (PKCs) showing Ca(2+)-sensitivity, while GF109203X, a general inhibitor for PKCs, and BAPTA, a cell-permeable Ca(2+) chelator, to a lesser extent, suppressed a reduction of the phosphorylation. These findings suggest that the proliferation of C6 cells is Ras- and MEK/ERK signaling-dependent, and that nobiletin suppresses the cell proliferation by inhibiting Ras activity and MEK/ERK signaling cascade probably via a Ca(2+)-sensitive PKC-dependent mechanism. Thus, the natural compound has potential to be a therapeutic agent for glioma.

Repeated treatment with nicotine induces phosphorylation of NMDA receptor NR2B subunit in the brain regions involved in behavioral sensitization.

Protein phosphorylation is an important mechanism for the post-translational modulation of N-methyl-d-aspartate (NMDA) receptor functions. In the present study, we investigated the levels of NR2B phosphorylation at Tyr1472 and Ser1303 in the nucleus accumbens, striatum, frontal cortex, and hippocampus of rats that exhibit behavioral sensitization to nicotine. Repeated treatment of rats with nicotine (0.6mg/kg, s.c., for 7 days) produced locomotor sensitization accompanied by increased NR2B phosphorylation at Tyr1472 in the nucleus accumbens and striatum, brain regions involved in behavioral sensitization. In contrast, no changes in NR2B phosphorylation were observed after a single treatment with nicotine in these brain regions. In addition, no changes in NR2B phosphorylation at Ser1303 were observed after repeated treatment with nicotine in any examined brain regions. These results suggest that repeated treatment with nicotine induces NR2B phosphorylation at Tyr1472 in the nucleus accumbens and striatum, which might contribute to the development of synaptic and behavioral plasticity in response to nicotine.

Isolation, structural elucidation, and neuroprotective effects of iridoids from Valeriana jatamansi.

Two new iridoids, jatadoids A (1) and B (2), and two known compounds (3 and 4) were isolated from Valeriana jatamansi. Their structures were elucidated on the basis of extensive spectroscopic analyses (IR, ESI-MS, HR-ESI-MS, 1D and 2D NMR). Compound 1 possessed an isovaleroxy group at the C-3 position that has previously been unreported in the class of iridoids. Four compounds were evaluated and compounds 1 and 3 showed moderate neuroprotective effects against MPP+-induced neuronal cell death in human dopaminergic neuroblastoma SH-SY5Y cells.

Neuroprotective Kaurane Diterpenes from Fritillaria ebeiensis.

The new kaurane diterpene, ent-3ß-butanoyloxykaur-15-en-17-ol, and four known kaurane diterpenes were isolated from the bulbs of Fritillaria ebeiensis. Their structures were elucidated on the basis of extensive spectroscopic analyses (IR, ESI-MS, HR-ESI-MS, 1-D and 2-D NMR). All the isolates showed neuroprotective effects against MPP(+)-induced neuronal cell death in human dopaminergic neuroblastoma SH-SY5Y cells.

Honeybee royal jelly and nobiletin stimulate CRE-mediated transcription in ERK-independent and -dependent fashions, respectively, in PC12D cells.

To prove the pharmacological actions of honeybee royal jelly (RJ) on the nervous system, we examined the effects of RJ on CRE-mediated transcription. RJ increased CRE-mediated transcription in PC12D cells. Moreover, CRE-mediated transcriptional activity by RJ was enhanced by nobiletin. U0126, a MEK inhibitor, inhibited CRE-mediated transcription by combining RJ plus nobiletin without affecting transcription by RJ alone. These results suggest that RJ stimulates CRE-mediated transcription via an ERK-independent cascade, whereas the increasing CRE-mediated transcriptional effect by nobiletin is dependent on ERK phosphorylation. Combining RJ plus nobiletin may activate effectively neuronal functions via enhancement of CRE-mediated transcription.

Two distinct mechanisms for actin capping protein regulation--steric and allosteric inhibition.

The actin capping protein (CP) tightly binds to the barbed end of actin filaments, thus playing a key role in actin-based lamellipodial dynamics. V-1 and CARMIL proteins directly bind to CP and inhibit the filament capping activity of CP. V-1 completely inhibits CP from interacting with the barbed end, whereas CARMIL proteins act on the barbed end-bound CP and facilitate its dissociation from the filament (called uncapping activity). Previous studies have revealed the striking functional differences between the two regulators. However, the molecular mechanisms describing how these proteins inhibit CP remains poorly understood. Here we present the crystal structures of CP complexed with V-1 and with peptides derived from the CP-binding motif of CARMIL proteins (CARMIL, CD2AP, and CKIP-1). V-1 directly interacts with the primary actin binding surface of CP, the C-terminal region of the alpha-subunit. Unexpectedly, the structures clearly revealed the conformational flexibility of CP, which can be attributed to a twisting movement between the two domains. CARMIL peptides in an extended conformation interact simultaneously with the two CP domains. In contrast to V-1, the peptides do not directly compete with the barbed end for the binding surface on CP. Biochemical assays revealed that the peptides suppress the interaction between CP and V-1, despite the two inhibitors not competing for the same binding site on CP. Furthermore, a computational analysis using the elastic network model indicates that the interaction of the peptides alters the intrinsic fluctuations of CP. Our results demonstrate that V-1 completely sequesters CP from the barbed end by simple steric hindrance. By contrast, CARMIL proteins allosterically inhibit CP, which appears to be a prerequisite for the uncapping activity. Our data suggest that CARMIL proteins down-regulate CP by affecting its conformational dynamics. This conceptually new mechanism of CP inhibition provides a structural basis for the regulation of the barbed end elongation in cells.

4'-Demethylnobiletin, a bioactive metabolite of nobiletin enhancing PKA/ERK/CREB signaling, rescues learning impairment associated with NMDA receptor antagonism via stimulation of the ERK cascade.

The biochemical and pharmacological activities of nobiletin, including neurotrophic and memory-enhancing action, in both in vitro and in vivo systems are well established. However, whether its metabolites do have such beneficial effects like nobiletin remains to be examined. Here we, for the first time, report that 2-(4-hydroxy-3-methoxyphenyl)-5,6,7,8-tetramethoxychromen-4-one (4'-demethylnobiletin), a major metabolite of nobiletin identified in the urine of rats and mice, stimulates the phosphorylation of ERK and CREB and enhances CRE-mediated transcription by activating a PKA/MEK/ERK pathway, like nobiletin, in cultured hippocampal neurons. Since NMDA receptor-mediated ERK signaling is involved in memory processing, including associative memories, we also examined whether 4'-demethylnobiletin, by activating ERK signaling, could restore learning impairment. Chronic intraperitoneal (ip) treatment of the mice with 10 or 50 mg of 4'-demethylnobiletin/kg rescued the NMDA receptor antagonist MK-801-induced learning impairment, accompanied by improvement of the MK-801-induced decrease in the level of ERK phosphorylation in the hippocampus of the animals. Consistently, 4'-demethylnobiletin also restored MK-801-induced inhibition of NMDA-stimulated phosphorylation of not only ERK but also PKA substrates in cultured rat hippocampal neurons. Moreover, we actually detected 4'-demethylnobiletin in the brain of mice following acute ip administration, demonstrating that the metabolite can cross the blood-brain barrier to reach the brain and thereby exert its effects to reverse learning impairment. Therefore, these results suggest that 4'-demethylnobiletin, a bioactive metabolite of nobiletin, may serve as a potential therapeutic agent, at least, for memory disorders associated with a dysregulated NMDA receptor ERK signaling, like nobiletin.

A novel diol-derivative of chalcone produced by bioconversion, 3-(2,3-dihydroxyphenyl)-1-phenylpropan-1-one, activates PKA/MEK/ERK signaling and antagonizes Abeta-inhibition of the cascade in cultured rat CNS neurons.

Chalcone compounds have been widely studied for their anti-inflammatory, anti-pyretic, anti-invasive and anti-proliferative activities in various cell lines. However, their effects on the central nervous system (CNS) are still largely unexplored. We have recently developed a bioconversion system using a recombinant Escherichia coli that enables us to produce chemical compounds that are naturally rare and usually difficult to chemically synthesize. One such compound is 3-(2,3-dihydroxyphenyl)-1-phenylpropan-1-one, a novel chalcone-diol. Here we show, for the first time, that the chalcone-diol enhanced the phosphorylation of extracellular signal-regulated kinase (ERK) in a time- and concentration-dependent manner in cultured cortical neurons. Also, this chalcone-diol increased intracellular cyclic AMP (cAMP) concentration, thereby enhancing phosphorylation of ERK and cAMP-response element-binding protein (CREB), and CRE-mediated transcription via the cAMP-dependent protein kinase (PKA)/mitogen-activated protein kinase/ERK kinase (MEK) pathway in cultured rat hippocampal neurons. Recent studies have demonstrated that PKA/CREB-dependent signaling, which is required for long-term potentiation, is inhibited by sublethal concentrations of amyloid beta-peptide (Abeta) in cultured hippocampal neurons. After treatment with the chalcone-diol at 50 muM prior to treatment with a sublethal concentration of Abeta(1-42), the Abeta(1-42)-induced inhibition of phosphorylation of PKA substrates and CREB was prevented in cultured hippocampal neurons, indicating the potential for protection against the Abeta-induced impairment of PKA/CREB signaling observed in Alzheimer's disease. Therefore, these results suggest that our present study provides a new approach for discovering novel lead compounds for the treatment of neurodegenerative CNS diseases associated with impaired PKA/CREB signaling, including Alzheimer's disease.

Nobiletin, a citrus flavonoid with neurotrophic action, augments protein kinase A-mediated phosphorylation of the AMPA receptor subunit, GluR1, and the postsynaptic receptor response to glutamate in murine hippocampus.

Nobiletin isolated from citrus peels prevents bulbectomy- and amyloid-beta protein-induced memory impairment in rodents. In the present study, using combined methods of biochemistry and electrophysiology, we examined the effects of nobiletin on phosphorylation of GluR1 receptor, the subunit of alpha-amino-3-hydroxy-5-methyl-D-aspartate (AMPA) receptors, and the receptor-mediated synaptic transmission in the hippocampus, a region implicated in memory formation, in culture and/or in slices. Western blot analysis showed that nobiletin-stimulated phosphorylation of multiple protein kinase A (PKA) substrates at 10 min following the treatment in cultured hippocampal neurons. In the cultured neurons, this natural compound also increased not only PKA activity, but also phosphorylation of GluR1 receptor at a PKA phosphorylation site, Ser 845, which has been demonstrated to be critical for synaptic plasticity, including enhancement of postsynaptic glutamate response, and important for spatial memory in vivo. The increased phosphorylation of GluR1 receptor at Ser 845 was abolished by H89 (N-(2-[p-bromocinnamylamino]ethyl)-5-isoquinolinesulfonamide hydrochloride), the PKA inhibitor, but not U0126 (1,4-diamino-2,3-dicyano-1,4-bis (2-aminophenylthio) butadiene), the mitogen-activated protein kinase/ERK kinase (MEK) inhibitor, in the cultured neurons. An increment of the phosphorylation of GluR1 receptor at Ser 845 was induced by nobiletin in the hippocampal slices as well. Furthermore, our electrophysiological analysis showed that nobiletin potentiated the AMPA receptor-mediated synaptic transmission at Schaffer collateral-CA1 pyramidal cell synapses in the hippocampal slices. This potentiation induced by the natural compound was not accompanied by the changes in paired-pulse ratio, and partially occluded the long-term potentiation, indicating the possible involvement of the postsynaptic mechanism. These findings suggest that nobiletin probably up-regulates synaptic transmission via the postsynaptic AMPA receptors at least partially by stimulation of PKA-mediated phosphorylation of GluR1 receptor in the hippocampus.

Clerodane diterpenoids and flavonoids with NGF-potentiating activity from the aerial parts of Baccharis gaudichaudiana.

A new clerodane diterpene, 15-hydroxy-16-acetoxy-ent-clerod-3-en-18-oic acid (1), together with three known clerodane diterpenes (2-4) and three known flavones (5-7), were isolated from the aerial parts of Baccharis gaudichaudiana. Their structures were elucidated on the basis of spectroscopic analysis. Compounds 2, 3, and 5 showed enhancing activity of nerve growth factor (NGF)-induced neurite outgrowth in PC 12D cells.

Nobiletin, a citrus flavonoid, reverses learning impairment associated with N-methyl-D-aspartate receptor antagonism by activation of extracellular signal-regulated kinase signaling.

Recent studies have indicated that learning-induced activation of extracellular signal-regulated kinase (ERK) signaling via N-methyl-D-aspartate (NMDA) receptors is required for consolidation of the resultant learning. These findings raise an idea that control of ERK signaling may be a potential target for treatment of cognitive dysfunction. Our recent studies have demonstrated that nobiletin, a polymethoxylated flavone from Citrus depressa, enhances cAMP/protein kinase A/ERK signaling in cultured rat hippocampal neurons and PC12D cells. Here, we, for the first time, present the evidence that this natural compound reverses learning impairment associated with NMDA receptor antagonism by activation of ERK in the hippocampus. Treatment with 50 mg/kg nobiletin reversed the NMDA receptor antagonist MK-801 (dizocilpine maleate)-induced learning impairment in mice. Western blot analysis also showed that nobiletin reversed MK-801-induced inhibition of learning-associated ERK activation in the hippocampus of the animals. Furthermore, consistent with these results, in cultured rat hippocampal neurons, nobiletin restored MK-801-induced impairment of NMDA-stimulated phosphorylation of ERK in a concentration-dependent manner. Taken together, the present study suggests that compounds that activate ERK signaling improve cognitive deficits associated with NMDA receptor hypofunction and that nobiletin may give us a new insight into therapeutic drug development for neurological disorders exhibiting cognitive impairment accompanied by a hypofunction of NMDA receptor-ERK signaling.

Metronomic scheduling of a cyclic hexapeptide Ra-VII for anti-angiogenesis, tumor vessel maturation and anti-tumor activity.

RA-VII, a cyclic hexapeptide isolated from Rubiae radix, binds to actin, causing a conformational change in the actin molecule and inducing G2 arrest by inhibiting cytokinesis. Here we examined the effect of RA-VII, its water-soluble derivative, and related RA-III and RA-V on endothelial cells. Among the four compounds tested, RA-VII most potently inhibited angiogenesis-related properties of endothelial cells (i.e. migration and proliferation) in vitro. We confirmed the anti-angiogenic activity of RA-VII in vivo by using a mouse corneal model. We then applied RA-VII for the treatment of tumors in mice. Daily intraperitoneal injection of RA-VII (1.5 or 3 mg/kg/day) exhibited no toxic effect on the animals, but significantly and dose dependently inhibited the growth of Lewis lung carcinoma cells previously inoculated into the mice. Interestingly, although two doses of RA-VII decreased the tumor vascular area to a similar extent, a higher dose of RA-VII led to tumor vessel maturation together with a significant increase in tumor cell apoptosis. Also, RA-VII showed a cytotoxic effect on Lewis lung carcinoma cells. These results indicate that metronomic scheduling of RA-VII is efficient for cancer treatment. A careful dose setting of RA-VII is crucial to obtain therapeutic superiority, possibly through tumor vessel maturation and a better distribution of the compound in the tumor tissue.

Three-membered ring sesquiterpenoids with NGF-potentiating activity from the roots of Valeriana fauriei.

Three novel three-membered ring sesquiterpenoids, named kissoone A (1), kissoone B (2), and its acetylated product, kissoone C (3), were isolated from the roots of Valeriana fauriei. Their structures were elucidated on the basis of spectroscopic analysis. Compounds 2 and 3 showed enhancing activity on nerve growth factor (NGF)-mediated neurite outgrowth in PC 12D cells.

Bioactive ent-clerodane diterpenoids from the aerial parts of Baccharis gaudichaudiana.

Three new ent-clerodane diterpenes (1-3) were isolated from the aerial parts of Baccharis gaudichaudiana, and their structures were elucidated as 15,16-epoxy-15alpha-methoxy-ent-clerod-3-en-18-oic acid (1), 13-epi-15,16-epoxy-15alpha-methoxy-ent-clerod-3-en-18-oic acid (2), and 7-oxo-16-hydroxy-ent-clerod-3-en-15-oic acid methyl ester-18,19-olide (3), on the basis of spectroscopic data analysis. A known compound, 7-oxo-ent-clerod-3-en-15,16:18,19-diolide, was also identified. Compounds 1 and 2 showed enhancing activity of nerve growth factor (NGF)-induced neurite outgrowth in PC 12D cells.

Iridoids and sesquiterpenoids with NGF-potentiating activity from the rhizomes and roots of Valeriana fauriei.

A new iridoid glycoside, 10-isovaleryl kanokoside C (1), and a new sesquiterpene (2) together with two known compounds (3, 4) were isolated from the rhizomes and roots of Valeriana fauriei. Their structures were elucidated on the basis of spectroscopic analysis. Compounds 2 and 4 showed enhancing activity of nerve growth factor (NGF)-induced neurite outgrowth in PC 12D cells.