The naturally occurring steroid solasodine induces neurogenesis in vitro and in vivo

From Plant to Chemistry: Sources of Antinociceptive Non-Opioid Active Principles for Medicinal Chemistry and Drug Design

Pain is associated with many health problems and a reduced quality of life and has been a common reason for seeking medical attention. Several therapeutics are available on the market, although side effects, physical dependence, and abuse limit their use. As the process of pain transmission and modulation is regulated by different peripheral and central mechanisms and neurotransmitters, medicinal chemistry continues to study novel ligands and innovative approaches. Among them, natural products are known to be a rich source of lead compounds for drug discovery due to their chemical structural variety and different analgesic mechanisms. Numerous studies suggested that some chemicals from medicinal plants could be alternative options for pain relief and management. Previously, we conducted a literature search aimed at identifying natural products interacting either directly or indirectly with opioid receptors. In this review, instead, we have made an excursus including active ingredients derived from plants whose mechanism of action appears from the literature to be other than the modulation of the opioid system. These substances could, either by themselves or through synthetic and/or semi-synthetic derivatives, be investigated in order to improve their pharmacokinetic characteristics and could represent a valid alternative to the opioid approach to pain therapy. They could also be the basis for the study of new mechanisms of action in the approach to this complex and disabling pathology.

Solasodine Containing Solanum torvum L. Fruit Extract Prevents Chronic Constriction Injury-Induced Neuropathic Pain in Rats: In Silico and In Vivo Evidence of TRPV1 Receptor and Cytokine Inhibition

This study aimed to assess the efficacy of ethanolic extract of Solanum torvum L. fruit (EESTF) containing solasodine in treating chronic constriction injury (CCI)-induced neuropathic pain in rats. Three-dimensional (3D) simulation studies of solasodine binding were conducted on the TRPV1 receptor, IL-6, and TNF-α structures. For in vivo justification, an assessment of behavioral, biochemical, and histological changes was designed after a CCI-induced neuropathic pain model in rats. On days 7, 14, and 21, CCI significantly increased mechanical, thermal, and cold allodynia while producing a functional deficit. IL-6, TNF-α, TBARS, and MPO levels also increased. SOD levels of catalase and reduced glutathione levels also decreased. Administration of pregabalin (30 mg/kg, oral), solasodine (25 mg/kg, oral), and EESTF (100 and 300 mg/kg, oral) significantly reduced CCI-induced behavioral and biochemical changes (P < 0.05). The protective nature of EESTF was also confirmed by histological analysis. Capsaicin, a TRPV1 receptor agonist, abolished the antinociceptive effects of EESTF when used previously. From the observations of the docking studies, solasodine acted as an antagonist at TRPV1, whereas the docking scores of solasodine against TNF-α and IL-6 were reported to be -11.2 and -6.04 kcal/mol, respectively. The attenuating effect of EESTF might be related to its antagonistic effects on TRPV1, suppression of cytokines, and anti-inflammatory and antioxidant properties.

Orally administered solasodine, a steroidal glycoalkaloid, suppresses ovalbumin-induced exaggerated Th2-immune response in rat model of bronchial asthma

Bronchial asthma is a chronic lung disorder, that affects an estimated 262 million people worldwide, thereby, causing a large socio-economic burden. Drug molecules from natural sources have exhibited a good promise in providing an alternative therapy in many chronic ailments. Solasodine, a glycoalkaloid has received an immense interest due to its large pharmacological and industrial value, however, its usefulness in asthma control has not been investigated till date. In this work, solasodine was tested for its ability to reverse several characteristics of bronchial asthma induced by intraperitoneal injection of ovalbumin (OVA) and aluminium hydroxide in experimental rats. Treating asthmatic animals with solasodine (1 mg/kg b.w. or 10 mg/kg b.w.) or dexamethasone (2.5 mg/kg b.w.) reversed OVA-induced airway hyperresponsiveness, infiltration of inflammatory cells and histamine levels in the airways. Furthermore, as compared to OVA-control rats, allergen-induced elevated levels of IgE, nitrites, nitric oxide, and pro-inflammatory mediators, including TNF-α, IL-1β, LTD-4, and Th2-cytokines, particularly, IL-4, IL-5 were remarkably reduced in both bronchoalveolar lavage fluid and blood. These findings are supported by significant protection offered by various treatments against OVA-induced airway inflammation and mast cell degranulation in mesenteric tissues. Further, In-silico molecular docking studies performed to determine inhibitory potential of solasodine at IL-4 and IL-5, demonstrated strong affinity of phytocompound for these receptors than observed with antagonists previously reported. Results of current study imply that solasodine has therapeutic promise in allergic asthma, presumably due to its ability to prevent mast cell degranulation and consequent generation of histamine and Th2-associated cytokines in airways.

Validated LC-MS/MS method for quantitation of solasodine in rat urine and feces: Blocking nonspecific adsorption

Solasodine, a steroidal alkaloid, is distributed extensively in Solanaceae plants with multiple biological activities such as neuroprotection, antineoplastic and anticonvulsant activities. However, there is little information about the excretion of intact solasodine in vivo. To investigate its excretion, a reliable LC-MS/MS method for quantitation solasodine in rat urine and feces was established and validated. Sample preparation was carried out by liquid-liquid extraction using MTBE as extractant. Moreover, rat urine was preconditioned with BSA, an anti-adsorptive additive, to prevent the nonspecific binding of solasodine to containers and tubes. The method was validated over the range of 4–2000 ng mL−1. The correlation coefficient (r 2) were all above 0.999. The intra- and inter-day precision and accuracy were within 16.9% and between −11.0 and 8.9%, respectively. The recovery of solasodine in urine and feces was in the range of 72.5–80.3 and 75.7–80.2%, respectively. IS-normalized matrix factor ranged from 0.94 to 1.12 with RSD% ≤4.02%. This method was successfully applied to the excretion study of solasodine following oral and intravenous administration.

Solasonine relieves sevoflurane-induced neurotoxicity via activating the AMP-activated protein kinase/FoxO3a pathway

BACKGROUND

Solasonine (SS), the main active ingredient of Solanumnigrum L, has been reported to boast extensive anti-tumor, anti-oxidant, and anti-inflammatory properties. This study is committed to exploring whether solasonine can alleviate neurotoxicity resulting from sevoflurane.

MATERIALS AND METHODS

The mouse hippocampal neuron cell line HT22 was treated with sevoflurane and/or solasonine of different doses. The proliferation, inflammation, oxidative stress response, and apoptosis of HT22 cells were examined. The AMP-activated protein kinase (AMPK)/FoxO3a signaling pathway was ascertained through Western blot and cellular immunofluorescence. In in-vivo experiments, Morris water maze figured out the changes in learning and memory abilities of mice treated with 8 mg/kg solasonine and exposed to SEV.

RESULTS

Sevoflurane induced apoptosis and hampered proliferation in HT22 cells. It also aggravated the release of inflammatory factors and oxidative stress mediators. Solasonine weakened neuron damage mediated by sevoflurane in a concentration-dependent pattern. Mechanically, sevoflurane clogged AMPK/FoxO3a signaling pathway activation, which was strengthened by solasonine. AMPK inhibition greatly influenced solasonine's protective effect on HT22 cells. Invivo, solasonine prominently ameliorated learning and memory disorders and nerve damage in mice exposed to sevoflurane.

CONCLUSIONS

Solasonine alleviates sevoflurane-induced neurotoxicity through activating the AMPK/FoxO3a signaling pathway.

Pharmacokinetics, oral bioavailability and metabolic analysis of solasodine in mice by dried blood spot LC-MS/MS and UHPLC-Q-Exactive MS

Solasodine, a major ingredient in Solanaceae family, has various biological functions such as inducing neurogenesis, anticonvulsant and anti-tumor. Its risk assessment has also drawn public attention. However, little is known about its oral bioavailability and metabolic process. In this study, an liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of solasodine in mice dried blood spot (DBS) samples. To block nonspecific adsorption, DBS samples were pretreated with bovine serum albumin (BSA) and then extracted with ethyl acetate. This method was applied to a pharmacokinetic and bioavailability study of solasodine. The absolute bioavailability was only 1.28%. Thereafter, its metabolites in mice were characterized using an ultra-performance liquid chromatography Q-Exactive high-resolution mass spectrometer (UHPLC-QE-HRMS). Several isomeric metabolites were well separated and differentiated using their retention time, fragmentation pathways and correspondingly fragmentation rules of solasodine. As a result, 21 metabolites were characterized including 16 phase I and 5 phase II metabolites. The proposed metabolic pathways showed that solasodine mainly experienced oxidation, dehydration, dehydrogenation and sulfation. These results could help us to better understand the efficacy and safety of solasodine.

Solasodine, Isolated from Solanum sisymbriifolium Fruits, Has a Potent Anti-Tumor Activity Against Pancreatic Cancer

BACKGROUND

Increasing evidences have revealed that solasodine, isolated from Solanum sisymbriifolium fruits, has multiple functions such as anti-oxidant, anti-tumor and anti-infection. However, its role in pancreatic cancer has not been well studied.

METHODS

To explore the role of solasodine in pancreatic cancer, human pancreatic cell lines including SW1990 and PANC1 were treated with different concentrations of solasodine for 48 h, and cell viability was evaluated by MTT assay, cell invasion and migration were evaluated by Transwell assay. The effect of solasodine on the apoptosis of SW1990 and PANC1 cells was detected by flow cytometry. To further explore the antitumor effect of solasodine in vivo, an SW1990 tumor-bearing mouse model was constructed. The effects of solasodine on cytokines in the serum of SW1990 tumor-bearing mice were also evaluated by ELISA assay.

RESULTS

Specifically, in vitro, solasodine could significantly inhibit the proliferation of pancreatic cancer cell lines SW1990 and PANC1 cells. Flow cytometric analysis indicated that solasodine could induce apoptosis of SW1990 and PANC1 cells. Western blot assay indicated that solasodine could significantly inhibit the activation of Cox-2/Akt/GSK3β signal pathway. Meanwhile, the release of Cytochrome c from mitochondria to cytoplasm which can raise the caspases cascade (C-caspase 3 and C-caspase 9) was significantly enhanced by solasodine. In vivo, the results showed that solasodine had potent anti-tumor activities with a lower cytotoxicity. In addition, the serum TNF-α, IL-2 and IFN-γ levels in SW1990 tumor-bearing mice after the treatment of solasodine was significantly increased.

CONCLUSION

Taken together, our results suggested that the solasodine could prevent the progression of pancreatic cancer by inhibiting proliferation and promoting apoptosis, as well as stimulating immunity, suggesting that solasodine might be a potential therapeutic strategy for pancreatic cancer.

Effect of habitat variations on the chemical composition, antioxidant, and antimicrobial activities of Achillea fragrantissima (Forssk) Sch. Bip

Achilea fragmentisma plant is widely distributed along northern regions of Saudi Arabia with various traditional medical uses. The plant was collected from Tabuk and Arar regions to study the effect of the variation in habitat on the chemical compositions, antimicrobial and antioxidant activities of the plant. The results showed significant differences between the two studied region regarding the parameters of the weather in years from 2010-2016.The antioxidant and antimicrobial of the plant showed significant variation in two habitats. Plant collected from Arar showed high antioxidant activity with IC50 (0.21 ± 0.01 g/L) by DPPH radical scavenging methods, and good antibacterial activity with gram-positive bacteria (Staphylococcus epidermidis, Bacillus cereus and Staphylococccus aureus clinical isolate), antibacterial activity ranging between high to no activity (between 14.5 ± 0.5-6.0 ± 0.0 mm zone of inhibition), On the other side the tested plant extracts showed no effect on, all gram-negative bacteria. GC/MS data showed marked variation in chemical compositions of both phenolic and alkaloid compounds in plants collected from both regions. Phenolic compounds were accumulated with higher amounts(Ferulic acid, Eugenol and Salicylic acid ester) in Arar region, while the alkaloid fractions (Ethyl isoallocholate, Pterin 6-carboxylic-acid and kadain) showed higher concentrations in plants collected from Tabuk region. The results reflect the variation in of weather parameter, affect on chemical compositions and biological activities of the plant in two studied regions.

Solasonine promotes ferroptosis of hepatoma carcinoma cells via glutathione peroxidase 4-induced destruction of the glutathione redox system

Solasonine is a compound isolated from Solanum melongena that has anti-infection properties, and promotes neurogenesis. However, the use of solasonine for the treatment of hepatocellular carcinoma (HCC) has not yet been reported. So, the aim of this study was to assess the efficacy of solasonine for the treatment of HCC. The effects of solasonine were tested using the HCC cell lines HepG2 and HepRG. Metabolomics analysis was conducted to assess the effects of solasonine on tumor growth of nude mice xenografts using HepG2 cells. The data demonstrated that solasonine significantly suppressed proliferation of HepG2 and HepRG cells. A mouse xenograft model of HepG2 tumor formation confirmed that solasonine suppressed tumor volume and weight, and inhibited HCC cell migration and invasion, as determined with the Transwell and scratch wound assays. To further reveal the underlying regulatory mechanism, metabolomics analysis was performed. The results revealed the effects of solasonine on glutathione metabolism, including glutathione peroxidase 4 (GPX4) and glutathione synthetase (GSS). The glutathione-dependent lipid hydroperoxidase GPX4 prevents ferroptosis by converting lipid hydroperoxides into non-toxic lipid alcohols. Ferroptosis has previously been implicated in the cell death that underlies several degenerative conditions, and induction of ferroptosis by the inhibition of GPX4 has emerged as a therapeutic strategy to trigger cancer cell death. Solasonine increased lipid ROS levels in HepG2 cells by suppression of GPX4 and GSS. However, the use of a ferroptosis inhibitor reversed solasonine-induced ROS production and cell apoptosis. Taken together, these results demonstrate that solasonine promotes ferroptosis of HCC cells via GPX4-induced destruction of the glutathione redox system.

Effect of ethanolic extract of Solanum virginianum Linn. on neuropathic pain using chronic constriction injury rat model and molecular docking studies

The present research work was designed to examine the neuroprotective effect of ethanolic extract of Solanum virginianum Linn. (SV) in chronic construction injury (CCI) of sciatic nerve-induced neuropathic pain in rats. The extract was initially standardized by high-performance thin-layer chromatography using solasodine as a biomarker and was then subjected to assess the degree of mechanical allodynia, thermal allodynia, mechanical hyperalgesia, thermal hyperalgesia and biochemical evaluations. Administration of SV (100 and 200 mg/kg; p.o.) and pregabalin (10 mg/kg; p.o.) as a reference standard significantly debilitated hyperalgesia and allodynia and notably restored the altered antioxidant level and pro-inflammatory cytokine (IL-1β and TNF-α) expression in a dose-dependent manner. Further, to appraise the mechanistic approach of solasodine, docking simulation studies were done on the 3D structure of the voltage-gated N-type calcium channel (Cav 2.2), R-type calcium channel (Cav 2.3) and sodium channel (Nav 1.7), and the results revealed that solasodine properly positioned into Phe 19, Leu 32, Met 51 and Met 71 (FLMM pocket) of Cav 2.2 and Cav 2.3 and being a competitor of Ca²⁺/N-lobe it may inactivate these calcium channels but did not bind into the desired binding pocket of Nav 1.7. Thus, the study confirmed the role of solasodine as a major biomarker for the observed neuroprotective nature of Solanum virginianum.

Two-step Synthesis of Solasodine Pivalate from Diosgenin Pivalate

A two-step synthesis of solasodine pivalate from diosgenin pivalate is described. The key transformation involves the reaction of diosgenin pivalate with benzyl carbamate (CbzNH₂) promoted by TMSOTf. During the reaction the F-ring of the spiroketal moiety opens up with a simultaneous introduction of a Cbz-protected amino group in position 26. A one-pot deprotection of 26-amine with AcBr/BuOH followed by the N-cyclization affords solasodine pivalate in 45% overall yield.

Physical state of the culture medium triggers shift in morphogenetic pattern from shoot bud formation to somatic embryo in Solanum khasianum

Solanum khasianum is a rich source of steroidal alkaloids that are important secondary metabolites with enormous pharmaceutical uses. Development of plantlets from somatic tissues, under in vitro conditions, takes place both through adventitious shoot bud differentiation or somatic embryogenesis (SE) pathway. We observed that the physical state of medium, solid or liquid, determined the regenerant differentiation patterns from root segment explants in S. khasianum. In the solidified medium, the root segments developed adventitious shoot buds whereas somatic embryos were regenerated in the liquid medium. Varying gradients from liquid to solid medium were further used to confirm the effect of solidified condition on regeneration pathway. Histological analysis of developing shoot buds and somatic embryos was also performed to confirm their development and differentiation patterns. In order to further confirm the developmental pathways, qRT-PCR analysis of the marker genes of SE and shoot regeneration was also performed. While SOMATIC EMBRYOGENESIS RECEPTOR KINASE1 (SkSERK1) expression was significantly up-regulated during the early embryogenic stage, the LATE EMBRYOGENESIS ABUNDANT (SkLEA) protein was found to be highly expressed in the mature embryos. Expression of the HISTONE DEACETYLASE (HDA6), a repressor of SE related genes, was highly decreased during embryogenesis in the liquid culture. Furthermore, expression of the ENHANCER OF SHOOT REGENERATION  (ESR) gene was comparatively increased during shoot regeneration in the culture using solid medium. Our results point out that the physical state of the medium in S. khasianum plays a decisive role in differentiation pattern which was independent of hormonal supplements.

Solasodine reverses stemness and epithelial-mesenchymal transition in human colorectal cancer

Adverse side effects of conventional chemotherapy, acquired resistance and fatal tumor metastasis of human colorectal cancer (CRC) are propelling the exploration for novel selective anticarcinogens. Solasodine is a main active component isolated from Solanum incanum L that exhibited a potent stemness and invasion inhibitory effect on human colorectal cancer HCT116 cells. Colony Spheroid formation assay showed that solasodine dose-dependently prohibited HCT116 cell stemness. CD133, CD44, Nanog, Oct-4 and Sox-2 were inhibited by solasodine to reverse stemness and similar mechanism was stimulated in vivo. Transwell and scratch wound assays revealed that solasodine impeded HCT116 cell invasion and migration potential strengthened by TGF-β1. Moreover, solasodine attenuated TGF-β1-induced EMT and decreased MMPs while in vivo study showed the same trend. The results of this study implied that solasodine may be a novel therapeutic drug for CRC treatment.

Solasodine inhibits human colorectal cancer cells through suppression of the AKT/glycogen synthase kinase-3β/β-catenin pathway

Solasodine is a main active component isolated from Solanum incanum L. that performs a wide range of functions containing anti‐oxidant, anti‐infection, and neurogenesis promotion. In this study, we explored the influence of solasodine on three types of human colorectal cancer (CRC) cell lines. The results show that solasodine prohibited CRC cell proliferation dose‐ and time‐dependently and impeded CRC cell motility by downregulating MMPs. Solasodine was also found to fuel caspase‐cascade reaction and increase the ratio between Bax and Bcl‐2 so as to induce CRC cell apoptosis. When cells were pretreated with AKT activator (insulin‐like growth factor‐1) followed by solasodine, the solasodine‐induced apoptosis was partially abrogated by insulin‐like growth factor‐1. Moreover, solasodine hindered tumor development and stimulated similar mechanisms in vivo. In general, our study provides the first evidence that solasodine has a suppressive effect on CRC cells and that this agent may be a novel therapeutic drug for CRC treatment.

Semi-synthetic sapogenin exerts neuroprotective effects by skewing the brain ischemia reperfusion transcriptome towards inflammatory resolution

Stroke represents one of the first causes of mortality and morbidity worldwide. We evaluated the therapeutic potential of a novel semi-synthetic spirosteroid sapogenin derivative "S15" in a transient middle cerebral artery occlusion (tMCAO) focal ischemia model in rat. S15-treated rats had significantly reduced infarct volumes and improved neurological functions at 24h post-reperfusion, compared with ischemia. Corresponding gene expression changes in brain were characterized by mRNA sequencing and qPCR approaches. Next, we applied geneset, pathway and transcription factor motif enrichment analysis to identify relevant signaling networks responsible for neuronal damage upon ischemia-reperfusion or neuroprotection upon pretreatment with S15. As expected, ischemia-reperfusion brain damage strongly modulates transcriptional programs associated with immune responses, increased differentiation of immune cells as well as reduced (cat)ion transport and synaptic activity. Interestingly, S15-dependent neuroprotection regulates inflammation-associated genes involved in phagosome specific resolution of tissue damage, chemotaxis and anti-inflammatory alternative activation of microglia. Altogether our transcriptome wide RNA sequencing and integrated pathway analysis provides new clues in the neuroprotective properties of a novel spirosteroid S15 or neuronal damage in rat brains subjected to ischemia, which opens new perspectives for successful treatment of stroke.

Divergent Synthesis of Solanidine and 22-epi-Solanidine

A divergent synthesis of solanidine and 22-epi-solanidine, two 25S natural steroidal alkaloids, from 25R-configured diosgenin acetate, is described. Initially, solanidine was synthesized through a series of transformations including a cascade ring-switching process of furostan-26-acid, an epimerization of C25 controlled by the conformation of six-membered lactone ring, an intramolecular Schmidt reaction, and an imine reduction/intramolecular aminolysis process. To address the epimerization issue during Schmidt reaction, an improved synthesis was developed, which also led to a synthesis of 22-epi-solanidine. In this synthesis, selective transformation of azido lactone to azido diol and amino diol was realized through a reduction relay tactic. The azido diol was transformed to solanidine via an intramolecular Schmidt reaction/N-alkylation/reduction process and to 22-epi-solanidine via an intramolecular double N-alkylation process.

In Vitro Neuroprotective and Anti-Inflammatory Activities of Natural and Semi-Synthetic Spirosteroid Analogues

Two spirosteroid analogues were synthesized and evaluated for their in vitro neuroprotective activities in PC12 cells, against glutamate-induced excitotoxicity and mitochondrial damage in glucose deprivation conditions, as well as their anti-inflammatory potential in LPS/IFNγ-stimulated microglia primary cultures. We also evaluated the in vitro anti-excitotoxic and anti-inflammatory activities of natural and endogenous steroids. Our results show that the plant-derived steroid solasodine decreased PC12 glutamate-induced excitotoxicity, but not the cell death induced by mitochondrial damage and glucose deprivation. Among the two synthetic spirosteroid analogues, only the (25R)-5α-spirostan-3,6-one (S15) protected PC12 against ischemia-related in vitro models and inhibited NO production, as well as the release of IL-1β by stimulated primary microglia. These findings provide further insights into the role of specific modifications of the A and B rings of sapogenins for their neuroprotective potential.

Modulation of neurogenesis by targeting epigenetic enzymes using small molecules: an overview

Neurogenesis consists of a plethora of complex cellular processes including neural stem cell (NSC) proliferation, migration, maturation or differentiation to neurons, and finally integration into the pre-existing neural circuits in the brain, which are temporally regulated and coordinated sequentially. Mammalian neurogenesis begins during embryonic development and continues in postnatal brain (adult neurogenesis). It is now evident that adult neurogenesis is driven by extracellular and intracellular signaling pathways, where epigenetic modifications like reversible histone acetylation, methylation, as well as DNA methylation play a vital role. Epigenetic regulation of gene expression during neural development is governed mainly by histone acetyltransferases (HATs), histone methyltransferase (HMTs), DNA methyltransferases (DNMTs), and also the enzymes for reversal, like histone deacetylases (HDACs), and many of these have also been shown to be involved in the regulation of adult neurogenesis. The contribution of these epigenetic marks to neurogenesis is increasingly being recognized, through knockout studies and small molecule modulator based studies. These small molecules are directly involved in regeneration and repair of neurons, and not only have applications from a therapeutic point of view, but also provide a tool to study the process of neurogenesis itself. In the present Review, we will focus on small molecules that act predominantly on epigenetic enzymes to enhance neurogenesis and neuroprotection and discuss the mechanism and recent advancements in their synthesis, targeting, and biology.

Development and validation a liquid chromatography mass spectrometry for determination of solasodine in rat plasma and its application to a pharmacokinetic study

Solasodine is a poisonous alkaloid chemical compound that occurs in plants of the Solanaceae family. A simple and selective liquid chromatography mass spectrometry method for determination of solasodine in rat plasma was developed and validated over the range of 3-1,000 ng/mL. Chromatographic separation was achieved on a C18 (2.1 mm×50 mm, 3.5 μm) column with acetonitrile-0.1% formic acid in water as mobile phase with gradient elution. The flow rate was set at 0.4 mL/min. After addition of midazolam as internal standard (IS), liquid-liquid extraction by ethyl acetate was used as sample preparation. An electrospray ionization source was applied and operated in positive ion mode; selective ion monitoring mode was used for quantification with target ions m/z 414 for solasodine and m/z 326 for IS. Mean recoveries of solasodine in rat plasma were in the range of 87.6-94.1%. Matrix effects for solasodine were between 94.9% and 102.3%. Coefficient of variation of intra-day and inter-day precision were both <13%. The accuracy of the method ranged from 94.4% to 105.3%. The method was successfully applied to a pharmacokinetic study of solasodine after oral administration of 20mg/kg in rats.

The novel steroidal alkaloids dendrogenin A and B promote proliferation of adult neural stem cells

Dendrogenin A (DDA) and dendrogenin B (DDB) are new aminoalkyl oxysterols which display re-differentiation of tumor cells of neuronal origin at nanomolar concentrations. We analyzed the influence of dendrogenins on adult mice neural stem cell proliferation, sphere formation and differentiation. DDA and DDB were found to have potent proliferative effects in neural stem cells. Additionally, they induce neuronal outgrowth from neurospheres during in vitro cultivation. Taken together, our results demonstrate a novel role for dendrogenins A and B in neural stem cell proliferation and differentiation which further increases their likely importance to compensate for neuronal cell loss in the brain.

Application of hypoiodite-mediated aminyl radical cyclization to synthesis of solasodine acetate

Solasodine acetate, an anticancer steroidal alkaloid, was synthesized from diosgenin in 8 steps with an overall yield of 23%. A key synthetic step involves the formation of 5/6-oxazaspiroketal moiety via hypoiodite-mediated aminyl radical cyclization of a steroidal primary amine.

A steroid isolated from the water mold Achlya heterosexualis induces neurogenesis in vitro and in vivo

Using 22R-hydroxycholesterol as a sub-structure to screen natural compound databases, we identified a naturally occurring steroid (sc-7) with a 16-acetoxy-22R-hydroxycholesterol moiety, in which the hydroxyl groups in positions 3 and 22 are esterified by an acetoxy group and in which the carbon in position 26 carries a functional diacetylamino. sc-7 is an analog of the sex steroids dehydro-oogoniol and antheridiol, can be isolated from the water mold Achlya heterosexualis, and promoted neurogenesis in vitro and in vivo. Mouse embryonic teratocarcinoma P19 cells exposed to sc-7 for 2days followed by a 5-day wash-out differentiated into cholinergic neurons that expressed specific neuronal markers and displayed axonal formation. Axons continued growing up to 28days after treatment. In vivo, infusion of sc-7 for 2weeks into the left ventricle of the rat brain followed by a 3-week wash-out induced bromodeoxyuridine uptake by cells of the ependymal layer and subventricular zone that co-localized with doublecortin and glial fibrillary acidic protein immunostaining, demonstrating induction of proliferation and differentiation of neuronal progenitors. Migrating neuroblasts were also observed in the corpus callosum. Thus, under these experimental conditions, adult ependymal cells resumed proliferation and differentiation. Taken together, these results suggest that sc-7 is an interesting molecule for stimulating in situ neurogenesis from resident neuronal progenitors as part of neuron replacement therapy. sc-7 did not bind to nuclear steroid receptors and was not metabolized as a steroid, supporting our hypothesis that the neurogenic effect of sc-7 is not likely due to a steroid-like effect.

Caprospinol: discovery of a steroid drug candidate to treat Alzheimer's disease based on 22R-hydroxycholesterol structure and properties

The overall ability of the brain to synthesise neuroactive steroids led us to the identification of compounds that would reproduce aspects of neurosteroid pharmacology. The rate-determining step in neurosteroid biosynthesis is the import of the substrate cholesterol into the mitochondria, where it is metabolised into pregnenolone via the intermediate 22R-hydroxycholesterol. The levels of translocator protein 18-kDa, mediating the import of cholesterol into mitochondria, correlated with increased pregnenolone formation and reduced levels of 22R-hydroxycholesterol in biopsies from Alzheimer's disease (AD), but not age-matched control, brains. 22R-hydroxycholesterol was shown to protect against β-amyloid (Aβ(42) )-induced neurotoxicity. In search of 22R-hydroxycholesterol stable analogues, we identified the naturally occurring heterospirostenol, (22R,25R)-20α-spirost-5-en-3β-yl hexanoate (caprospinol) and derivatives that protect neuronal cells against Aβ(1-42) neurotoxicity. The neuroprotective effect of caprospinol is the result of a combination of overlapping properties, including: (i) the ability to bind to Aβ(42) and reduce plaque formation in the brain in vivo; (ii) interaction with components of the mitochondria respiratory chain resulting in an anti-uncoupling effect; (iii) the capacity to scavenge Aβ(42) monomers present in mitochondria; and (iv) the property of being a sigma-1 receptor ligand. In vivo, caprospinol crosses the blood-brain barrier, accumulates in the brain, and restores cognitive impairment in a pharmacological rat model of AD. Caprospinol is stable, does not bind to known steroid receptors, is devoid of mutagenic and genotoxic properties, and is devoid of acute toxicity in rodents. The pharmacokinetics and pharmacodynamics of caprospinol were studied, and long-term toxicity studies are under investigation, aiming to develop this compound as a disease-modifying drug for the treatment of AD.