tCFA15, a trimethyl cyclohexenonic long-chain fatty alcohol, affects neural stem fate and differentiation by modulating Notch1 activity.

We have investigated the effects of tCFA15, a non-peptidic compound, on the differentiation of neural stem cell-derived neurospheres, and have found that tCFA15 promotes their differentiation into neurons and reduces their differentiation into astrocytes, in a dose-dependent manner. This response is reminiscent of that resulting from the loss-of-function of Notch signaling after inactivation of the Delta-like 1 (Dll1) gene. Further analysis of the expression of genes from the Notch pathway by reverse transcriptase-PCR revealed that tCFA15 treatment results in a consistent decrease in the level of Notch1 mRNA. We have confirmed this result in other cell lines and propose that it reflects a general effect of the tCFA15 molecule. We discuss the implications of this finding with respect to regulation of Notch activity in neural stem cells, and the possible use of tCFA15 as a therapeutic tool for various pathologies that result from impairment of Notch signaling.

Induction of neuronal differentiation in neurosphere stem cells by ellagic acid derivatives.

A bioassay-guided fractionation of methanol extracts of stem barks, combined with screening based on Epidermal Growth Factor (EGF)-responsive neural stem cells (erNSCs) differentiation assay, has been used. This study resulted in the isolation of 3,3'-di-O-methylellagic acid 1, 3,3'-di-O-methyl ellagic acid-4-O-beta-D-xylopyranoside 2, ellagic acid 3, and arjunolic acid 4. Among them, compounds 1 and 2 exhibit potent induction of neuronal differentiation in neurosphere stem cells with no cytotoxic effect. These results indicate that compounds 1 and 2 may be useful as pharmacological agents for the treatment of neurodegenerative diseases. These compounds may account, for the use of T. superba in folk medicine for nervous system and mental disorders.

Antimicrobial pentacyclic triterpenoids from Terminalia superba.

Antibacterial bioassay-guided fractionation of the methanol extract of the stem bark of Terminalia superba led to the isolation of four new triterpene glucosides (1-4) which were characterized as 2 alpha,3 beta-dihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (1), 2 alpha,3 beta, 21 beta-trihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (2), 2 alpha,3 beta, 29-trihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (3) and 2 alpha,3 beta,23,27-tetrahydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (4) together with the known triterpene 2 alpha,3 beta,23-trihydroxyolean-12-en-28-oic acid (5). Structures were established by spectroscopic methods including one- and two-dimensional NMR, EI-MS and HR-EI-MS. The antibacterial activity of 1-5 was also investigated against two gram-positive (Bacillus subtilis, Staphylococcus aureus), and four gram-negative (Escherichia coli, Shigella flexenari, Pseudomonas aeruginosa, Salmonella typhi) bacterial strains.

Alpha-glucosidase inhibitors ellagic acid derivatives with immunoinhibitory properties from Terminalia superba.

Fractionation of stem barks of Terminalia superba yielded two new ellagic acid derivatives, 3,4'-di-O-methylellagic acid 3'-O-beta-D-xylopyranoside (1) and 4'-O-galloy-3,3'-di-O-methylellagic acid 4-O-beta-D-xylopyranoside (2) together with known 3,3'-di-O-methylellagic acid, ellagic acid and 3,3'-di-O-methylellagic acid 4'-O-beta-D-xylopyranoside. Compounds (1) and (2) showed significant alpha-glucosidase inhibition activity and possessed significant immunoinhibitory activities with no cytotoxic effects.

Bioactive aristolactams from Piper umbellatum.

Four alkaloids named piperumbellactams A-D (1-4) were isolated from branches of Piper umbellatum together with known N-hydroxyaristolam II (5), N-p-coumaroyl tyramine (6), 4-nerolidylcatechol (7), N-trans-feruloyltyramine, E-3-(3,4-dihydroxyphenyl)-N-2-[4-hydroxyphenylethyl]-2-propenamide, beta-amyrin, friedelin, apigenin 8-C-neohesperidoside, acacetin 6-C-beta-d-glucopyranoside, beta-sitosterol, its 3-O-beta-d-glucopyranoside and its 3-O-beta-d-[6'-dodecanoyl]-glucopyranoside. Glycosidase inhibition, antioxidant and antifungal activities of these compounds were evaluated. Compounds 1-3 showed moderate alpha-glucosidase enzyme inhibition with IC50 values 98.07+/-0.44, 43.80+/-0.56 and 29.64+/-0.46, respectively. In DPPH radical scavenging assay, compounds 2, 3 and 6 showed potent inhibitory activity while compounds 4, 5 and 7 showed potent antifungal activity.

Further cytotoxic sesquiterpene lactones from Elephantopus mollis KUNTH.

Three new sesquiterpene lactones, (4betaH)-5alpha-hydroxy-8alpha-(2-methylbut-2-enoyloxy)-2-oxo-1(10),11(13)-guaiadien-12,6alpha-olide (1), (4betaH)-8alpha-(2-methylbut-2-enoyloxy)-2-oxo-1(5),10(14),11(13)-guaiatrien-12,6alpha-olide (2) and 2,5-epoxy-2beta-hydroxy-4alpha-methoxy-8alpha-(2-methylbut-2-enoyloxy)-4(15),10(14),11(13)-germacratrien-12,6alpha-olide (3), have been isolated from roots and stems of Elephantopus mollis together with two known sesquiterpene lactones (4, 5). The identification of the isolates was accomplished by spectroscopic methods. Compounds (1-5) exhibited significant cytotoxic activities against mouse neuroblastoma B104 cells.

Panaxadiol glycosides that induce neuronal differentiation in neurosphere stem cells.

Bioassay-guided fractionation, combined with screening based on EGF-responsive neural stem cells (NSCs) differentiation assay, has been used to search for active molecules from Panax notoginseng. Ginsenosides Rg3 (1), Rk1 (2), and Rg5 (3) were identified as potential neurogenic molecules. The degrees of their neurogenic effects were found to be 3 > 2 > 1. The neurogenic effect of 3 represents a biphasic dose- and time-dependent regulation. Transient exposure of NSCs to 8 microM 3 for 24 h followed by 1 microM and 72 h incubation was the optimal procedure for the induction of neurons in NSCs, and compound 3 resulted in an approximately 3-fold increase in neurogenesis at the expense of astrogliogenesis. The neurogenic effect of 3 was completely eliminated by the Ca2+ channel antagonist nifedipine. These findings imply that 3 may be utilized as a pharmacological agent in studying the molecular regulation of neurogenesis of brain stem cells and, subsequently, for treatment of neurodegenerative diseases.

Dual bioactivity of resveratrol fatty alcohols: differentiation of neural stem cells and modulation of neuroinflammation.

The synthesis of resveratrol fatty alcohols (RFAs), a new class of small molecules presenting strong potential for the treatment of neurological diseases, is described. RFAs, hybrid compounds combining the resveratrol nucleus and omega-alkanol side chains, are able to modulate neuroinflammation and to induce differentiation of neural stem cells into mature neurons. Acting on neuroprotection and neuroregeneration, RFAs represent an innovative approach for the treatment or cure of neuropathies.

Cytotoxic triterpene and sesquiterpene lactones from Elephantopus mollis and induction of apoptosis in neuroblastoma cells.

Activity-guided fractionation of root and leaf extracts from Elephantopus mollis led to the isolation of a new triterpene (1) and a new sesquiterpene lactone (2) together with five known sesquiterpene lactones (3-7). The structures of compounds 1 and 2 were determined based on their spectroscopic data. The cytotoxic activity of the isolated compounds was evaluated against neuroblastoma B104 cells. The sesquiterpene lactone-type compounds 2-7 were highly cytotoxic. Among these, compound (5) was the most cytotoxic and induced apoptosis of neuroblastoma B104 cells in a dose- and time-dependent manner. No significant difference was observed for cytotoxicity of compound 5 towards all 3 cell lines tested.

Solid-phase synthesis of quinol fatty alcohols, design of N/O-substituted quinol fatty alcohols and comparative activities on axonal growth.

Following the promising activity of Q2FA15 on axonal growth, two new series of N/O-substituted QFAs were synthesized, based on a SN2-type reaction. O-alkylated QFA bearing 14 carbon atoms on the side chain (n=14) shows a very potent activity on axonal growth though lowered when compared to Q2FA15. While O-alkylation allows good retention of the biological activity, N-alkylation abolishes it nonetheless. A solid-phase-supported synthesis of Q2FA15 allowing the conception of new hybrid compounds is also described.

Quinol fatty alcohols as promoters of axonal growth.

The synthesis of three series of quinol fatty alcohols (QFAs) and their biological activities on the promotion of axonal growth are described. Interestingly, the 15-(2,5-dimethoxyphenyl)pentadecan-1-ol, the QFA bearing 15 carbon atoms on the side chain (n=15), shows the most potent promotion of axonal growth in the presence of both permissive and non-permissive naturally occurring substrates such as Sema3A and myelin proteins.

Effect of a cyclohexenonic long-chain fatty alcohol on calcium mobilization.

Cyclohexenonic long-chain fatty alcohols constitute a family of synthetic compounds with trophic, secretagogue and antioxidant properties. Despite their multiple biological actions in neuronal and non-neuronal tissues, the intracellular mechanisms underlying CFA activity remain unknown. In the present study, we show that 3-(15-hydroxypentadecyl)-2,4,4-trimethyl-2-cyclohexen-1-one (tCFA15) directly mobilizes Ca(2+) in the pituitary neural lobe synaptosomes and in primary sensory neurons from dorsal root ganglia. This effect is dependent on the presence of extracellular Ca(2+), but does not involve transmembrane voltage-operated calcium channels. Using a combination of pharmacological agents that block or deplete intracellular Ca(2+) stores, our results suggest the implication of a calcium induced-calcium release mechanism evoked by tCFA15-induced Ca(2+) influx. To our knowledge, these findings constitute the first attempt towards the comprehension of the biological actions of cyclohexenonic long-chain fatty alcohols at a molecular level.

Ginsenoside-Rd from Panax notoginseng enhances astrocyte differentiation from neural stem cells.

Neural stem cells cultured as neurospheres were used to assess the effects of P. notoginseng on the production of neurons and glia. The crude saponins (PNS) and ginsenoside-Rd promote the differentiation of neurospheres into astrocytes. Ginsenoside-Rd increases the production of astrocytes in a dose-dependent manner. On the other hand, both PNS and ginsenoside-Rd induce a weak but significant effect by decreasing the number of neurons. The other ginsenosides do not induce any differentiation on both neurons and astrocytes.

Tocopherol long chain fatty alcohols decrease the production of TNF-alpha and NO radicals by activated microglial cells.

The synthesis of a series of Tocopherol long chain Fatty Alcohols (TFA) and their biological activities on the modulation of microglial activation are described. Specifically, the 2-(12-hydroxy-dodecyl)-2,5,7,8-tetramethyl-chroman-6-ol, the TFA bearing 12 carbon atoms on the side chain (n=12), shows the most potent inhibition of secretion on nitric oxide (NO) and tumour necrosis factor-alpha (TNF-alpha) by lipopolysaccharide (LPS)-activated microglia.

Effects of indole fatty alcohols on the differentiation of neural stem cell derived neurospheres.

In a search for inducers of neuronal differentiation to treat neurodegenerative diseases such as Alzheimer's disease, a series of indole fatty alcohols (IFAs) were prepared. 13c (n = 18) was able to promote the differentiation of neural stem cell derived neurospheres into neurons at a concentration of 10 nM. Analysis of the expression of the Notch pathway genes in neurospheres treated during the differentiation phase with 13c (n = 18) revealed a significant decrease in the transcription of the Notch 4 receptor.

Counteraction of axonal growth inhibitory properties of Semaphorin 3A and myelin-associated proteins by a synthetic neurotrophic compound.

One of the reasons for the lack of nerve regeneration in the CNS is the formation of a glial scar over-expressing multiple inhibitory factors including myelin-associated proteins and members of the Semaphorin family. Innovative therapeutic strategies must stimulate axon extension across the lesion site despite this inhibitory molecular barrier. We recently developed a synthetic neurotrophic compound combining an omega-alkanol with a retinol-like cycle (3-(15-hydroxy-pentadecyl)-2,4,4,-trimethyl-cyclohexen-2-one (tCFA15)). Here, we demonstrate that tCFA15 is able to promote cortical axon outgrowth in vitro even in the presence of the inhibitory Semaphorin 3A and myelin extracts. This growth-promoting effect is selectively observed in axons and requires multiple growth-associated intracellular pathways. Our results illustrate the potential use of synthetic neurotrophic compounds to promote nerve regeneration by counteracting the axonal growth inhibition triggered by glial scar-associated inhibitory factors.

Effects of combinations of 7beta-hydroxycholesterol and anticancer drugs or ionizing radiation on the proliferation of cultured tumor cells.

Oxysterols compose a large class of natural substances endowed in a number of cases with marked antiproliferative and cytotoxic activities. The consequences of treatments combining 7beta-hydroxycholesterol (7beta-OHC) or XG-142 (a galactose-linked hydrosoluble derivative of 7beta-OHC) with drugs used in cancer chemotherapy or gamma radiation has been evaluated upon a variety of tumor cell lines: Hep-G2, U937, K562 cells, its adriamycin-resistant variant K562 Adr+ and RDM4. Proliferation was assessed by the Uptiblue assay and the [3H]Thymidine incorporation test. Results indicated that 7beta-OHC increased the sensitivity of tumor cells to adriamycin, VP-16, 5-FU and bleomycin to various degrees. 7beta-OHC was found to reinforce the susceptibility of K562 adriamycin-resistant cells to this drug. In RDM4 cells, an enhanced radiosensitivity by 7beta-OHC was also obtained, whereas XG-142 was less efficient in provoking such an effect.