Antidepressant-like Effect of the Eburnamine-Type Molecule Vindeburnol in Rat and Mouse Models of Ultrasound-Induced Depression.

Vindeburnol (VIND, RU24722, BC19), a synthetic molecule derived from the eburnamine-vincamine alkaloid group, has many neuropsychopharmacological effects, but its antidepressant-like effects are poorly understood and have only been described in a few patents. To reliably estimate this effect, vindeburnol was studied in a model of long-term variable-frequency ultrasound (US) exposure at 20-45 kHz in male Wistar rats and BALB/c mice. Vindeburnol was administered chronically for 21 days against a background of simultaneous ultrasound exposure at a dose of 20 mg/kg intraperitoneally (IP). Using four behavioral tests, the sucrose preference test (SPT), the social interaction test (SIT), the open field test (OFT), and the forced swimming test (FST), we found that the treatment with the compound diminished depression-like symptoms in mice and rats. The compound restored the ultrasound-related reduced sucrose consumption to control levels and increased social interaction time in mice and rats compared with those in ultrasound-exposed animals. Vindeburnol showed contraversive results of horizontal and vertical activity in both species and generally did not increase locomotor activity. At the same time, the compound showed a specific effect in the FST, significantly reducing the immobility time. Moreover, we found an increase in norepinephrine, dopamine, and its metabolite levels in the brainstem, as well as an increase in dopamine, 3-methoxytyramine, and 3,4-dihydroxyphenylacetic acid levels in the striatum. We also observed a statistically significant increase in tyrosine hydroxylase (TH) levels in the region containing the locus coeruleus (LC). We suggest that using its distinct chemical structure and pharmacological activity as a starting point could boost antidepressant drug discovery.

Vincamine as an agonist of G-protein-coupled receptor 40 effectively ameliorates diabetic peripheral neuropathy in mice.

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes, which has yet no curable medication. Neuroinflammation and mitochondrial dysfunction are tightly linked to DPN pathology. G-protein-coupled receptor 40 (GPR40) is predominantly expressed in pancreatic ß-cells, but also in spinal dorsal horn and dorsal root ganglion (DRG) neurons, regulating neuropathic pain. We previously have reported that vincamine (Vin), a monoterpenoid indole alkaloid extracted from Madagascar periwinkle, is a GPR40 agonist. In this study, we evaluated the therapeutic potential of Vin in ameliorating the DPN-like pathology in diabetic mice. Both STZ-induced type 1 (T1DM) and db/db type 2 diabetic (T2DM) mice were used to establish late-stage DPN model (DPN mice), which were administered Vin (30 mg·kg-1·d-1, i.p.) for 4 weeks. We showed that Vin administration did not lower blood glucose levels, but significantly ameliorated neurological dysfunctions in DPN mice. Vin administration improved the blood flow velocities and blood perfusion areas of foot pads and sciatic nerve tissues in DPN mice. We demonstrated that Vin administration protected against sciatic nerve myelin sheath injury and ameliorated foot skin intraepidermal nerve fiber (IENF) density impairment in DPN mice. Moreover, Vin suppressed NLRP3 inflammasome activation through either ß-Arrestin2 or ß-Arrestin2/IκBα/NF-κB signaling, improved mitochondrial dysfunction through CaMKKß/AMPK/SIRT1/PGC-1α signaling and alleviated oxidative stress through Nrf2 signaling in the sciatic nerve tissues of DPN mice and LPS/ATP-treated RSC96 cells. All the above-mentioned beneficial effects of Vin were abolished by GPR40-specific knockdown in dorsal root ganglia and sciatic nerve tissues. Together, these results support that pharmacological activation of GPR40 as a promising therapeutic strategy for DPN and highlight the potential of Vin in the treatment of this disease.

Disease-Modifying Effects of Vincamine Supplementation in Drosophila and Human Cell Models of Parkinson's Disease Based on DJ-1 Deficiency.

Parkinson's disease (PD) is an incurable neurodegenerative disorder caused by the selective loss of dopaminergic neurons in the substantia nigra pars compacta. Current therapies are only symptomatic and are not able to stop or delay its progression. In order to search for new and more effective therapies, our group carried out a high-throughput screening assay, identifying several candidate compounds that are able to improve locomotor ability in DJ-1ß mutant flies (a Drosophila model of familial PD) and reduce oxidative stress (OS)-induced lethality in DJ-1-deficient SH-SY5Y human cells. One of them was vincamine (VIN), a natural alkaloid obtained from the leaves of Vinca minor. Our results showed that VIN is able to suppress PD-related phenotypes in both Drosophila and human cell PD models. Specifically, VIN reduced OS levels in PD model flies. Besides, VIN diminished OS-induced lethality by decreasing apoptosis, increased mitochondrial viability, and reduced OS levels in DJ-1-deficient human cells. In addition, our results show that VIN might be exerting its beneficial role, at least partially, by the inhibition of voltage-gated sodium channels. Therefore, we propose that these channels might be a promising target in the search for new compounds to treat PD and that VIN represents a potential therapeutic treatment for the disease.

Potentiating Biosynthesis of Alkaloids and Polyphenolic Substances in Catharanthus roseus Plant Using ĸ-Carrageenan.

Catharanthus roseus is a medicinal plant that produces indole alkaloids, which are utilized in anticancer therapy. Vinblastine and vincristine, two commercially important antineoplastic alkaloids, are mostly found in the leaves of Catharanthus roseus. ĸ-carrageenan has been proven as plant growth promoting substance for a number of medicinal and agricultural plants. Considering the importance of ĸ-carrageenan as a promoter of plant growth and phytochemical constituents, especially alkaloids production in Catharanthus roseus, an experiment was carried out to explore the effect of ĸ-carrageenan on the plant growth, phytochemicals content, pigments content, and production of antitumor alkaloids in Catharanthus roseus after planting. Foliar application of ĸ-carrageenan (at 0, 400, 600 and 800 ppm) significantly improved the performance of Catharanthus roseus. Phytochemical analysis involved determining the amount of total phenolics (TP), flavonoids (F), free amino acids (FAA), alkaloids (TAC) and pigments contents by spectrophotometer, minerals by ICP, amino acids, phenolic compounds and alkaloids (Vincamine, Catharanthine, Vincracine (Vincristine), and vinblastine) analysis uses HPLC. The results indicated that all examined ĸ-carrageenan treatments led to a significant (p ≤ 0.05) increase in growth parameters compared to the untreated plants. Phytochemical examination indicates that the spray of ĸ-carrageenan at 800 mg L-1 increased the yield of alkaloids (Vincamine, Catharanthine and Vincracine (Vincristine)) by 41.85 µg/g DW, total phenolic compounds by 3948.6 µg gallic/g FW, the content of flavonoids 951.3 µg quercetin /g FW and carotenoids content 32.97 mg/g FW as compared to the control. An amount of 400 ppm ĸ-carrageenan treatment gave the best contents of FAA, Chl a, Chl b and anthocyanin. The element content of K, Ca, Cu, Zn and Se increased by treatments. Amino acids constituents and phenolics compounds contents were altered by ĸ-carrageenan.

ALK and ERBB2 Protein Inhibition is Involved in the Prevention of Lung Cancer Development by Vincamine.

BACKGROUND: According to the WHO report of 2022, 2.21 million new cases and 1.80 million deaths were reported for lung cancer in the year 2020. Therefore, there is an urgent need to explore novel, safe, and effective therapeutic interventions for lung cancer. OBJECTIVE: To find the potential targets of vincamine using a network pharmacology approach and docking studies and to evaluate the anti-cancer effect of vincamine on A549 cell line. METHODS: Hence, in the present study, we explored the anti-cancer potential of vincamine by using network pharmacology, molecular docking, and in vitro approaches. Network pharmacology demonstrated that the most common targets of vincamine are G-protein coupled receptors, cytosolic proteins, and enzymes. Among these targets, two targets, ALK and ERBB2 protein, were common between vincamine and non-small cell lung cancer. RESULTS: We discovered a link between these two targets and their companion proteins, as well as cancer-related pathways. In addition, a docking investigation between the ligand for vincamine and two targeted genes revealed a strong affinity toward these targeted proteins. Further, the in vitro study demonstrated that vincamine treatment for 72 h led to dosedependent (0-500 µM) cytotoxicity on the A549 lung cancer cell line with an IC50 value of 291.7 µΜ. The wound-healing assay showed that vincamine treatment (150 and 300 µM) significantly inhibited cell migration and invasion. Interestingly, acridine orange/ethidium bromide dual staining demonstrated that vincamine treatment induces apoptosis in A549 cells. Additionally, the dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay showed an increased level of reactive oxygen species (ROS) after the vincamine treatment, indicating ROS-mediated apoptosis in A549 cells. CONCLUSION: Altogether, based on our findings, we hypothesize that vincamine-induced apoptosis of lung cancer cells via ALK and ERBB2 protein modulation may be an attractive futuristic strategy for managing lung cancer in combination with chemotherapeutic agents to obtain synergistic effects with reduced side effects.

Vincamine, an active constituent of Vinca rosea ameliorates experimentally induced acute lung injury in Swiss albino mice through modulation of Nrf-2/NF-κB signaling cascade.

Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is one of the leading pulmonary inflammatory disorders causing significant morbidity and mortality. Vincamine is a novel phytochemical with promising anti-inflammatory properties. In the current work, the protective effect of vincamine was studied in vitro (Raw 264.7 macrophages) and in vivo against lipopolysaccharide (LPS) induced ALI in Swiss albino mice. Vincamine significantly reduced nitrite and TNF-α release from the LPS stimulated macrophages and increased the levels of IL-10, indicating potent anti-inflammatory effects. It was observed that vincamine at the dose of 40 mg/kg, significantly reduced LPS induced inflammatory cell count in blood and in bronchoalveolar lavage (BAL) fluid. Further, vincamine exerted potent suppression of inflammation by reducing the expression of proinflammatory cytokines, while significantly increased (p < 0.001) the expression of anti-inflammatory cytokine (IL-10 and IL-22). Interestingly, histological changes were reversed in vincamine treated groups in a dose-dependent manner. Immunohistochemical analysis revealed significantly enhanced expression of NF-κB, TNF-α and COX-2 while reduced expression of Nrf-2 in disease control group, which were significantly (p < 0.001) ameliorated by vincamine. We, to the best of our knowledge, report for the first time that vincamine possesses protective potential against LPS induced inflammation and oxidative stress, possibly by inhibiting the NF-κB cascade, while positively regulating the Nrf-2 pathway. These findings are of potential relevance for COVID-19 management concerning the fact that lung injury and ARDS are its critical features.

Vincamine Modulates the Effect of Pantoprazole in Renal Ischemia/Reperfusion Injury by Attenuating MAPK and Apoptosis Signaling Pathways.

Pantoprazole has an antioxidant function against reactive oxygen species (ROS). Vincamine, a herbal candidate, is an indole alkaloid of clinical use against brain sclerosis. The aim of the present experiment is to evaluate, on a molecular level for the first time, the value of vincamine in addition to pantoprazole in treating experimentally induced renal ischemia/reperfusion injury (IRI). One-hundred-and-twenty-eight healthy male Wistar albino rats were included. Serum creatinine, blood urea nitrogen, and malondialdehyde levels were assessed. ELISA was used to estimate the pro-inflammatory cytokines. The expression of Bcl-2 and Bax genes was assessed by quantitative real-time PCR. ERK1/2, JNK1/2, p38, cleaved caspase-3, and NF-κB proteins expressions were estimated using western blot assay. The kidneys were also histopathologically studied. The IRI resulted in impaired cellular functions with increased creatinine, urea nitrogen, malondialdehyde, TNF-α, IL-6, and IL-1ß serum levels, and up-regulated NF-ĸB, JNK1/2, ERK1/2, p38, and cleaved caspase-3 proteins. Furthermore, it down-regulated the expression of the Bcl-2 gene and upregulated the Bax gene. The treatment with vincamine, in addition to pantoprazole multiple doses, significantly alleviated the biochemical and histopathological changes more than pantoprazole or vincamine alone, whether the dose is single or multiple, declaring their synergistic effect. In conclusion, vincamine with pantoprazole multiple doses mitigated the renal IRI through the inhibition of apoptosis, attenuation of the extracellular signaling pathways through proinflammatory cytokines' levels, and suppression of the MAPK (ERK1/2, JNK, p38)-NF-κB intracellular signaling pathway.

Vincamine protects against cisplatin induced nephrotoxicity via activation of Nrf2/HO-1 and hindering TLR4/ IFN-γ/CD44 cells inflammatory cascade.

Cisplatin is a commonly prescribed chemotherapeutic agent for the treatment of different types of solid tumors. However, the high incidence of cisplatin-induced nephrotoxicity largely restricts its clinical efficacy in absence of both preventive and treatment options to combat its serious and life-threatening effects. Therefore, the current study investigated the reno-protective molecular mechanisms of vincamine against cisplatin nephrotoxicity. Vincamine (40 mg/kg P.O.) was given for 7 days, cisplatin was injected as single dose (10 mg/kg i.p.) at the seven day of the experiments. Animals were sacrificed after 72 h of cisplatin injection to allow nephrotoxicity. Vincamine pretreatment improved kidney functions and decreased kidney function tests as urea, creatinine and kidney injury molecule-1 (KIM-1), as well as it exhibited antioxidant properties by restoring balance between pro and anti-oxidants of malondialdehyde (MDA), myeloperoxidase (MPO), nuclear factor erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1). Moreover, vincamine hindered the inflammatory cascade via mediating Toll like receptor 4 (TLR4)- interferon gamma (IFNγ)-CD44 cells pathway and transforming growth factor beta (TGFß1). Additionally, vincamine retained DNA fragmentation. In conclusion, vincamine represents a promising intervention in limiting cisplatin nephrotoxicity by its anti-oxidant, anti-inflammatory, antiapoptotic mechanistic activities. Therefore, vincamine can be used as adjunct therapy with cisplatin to mitigate cisplatin-induced-AKI.

Vincamine, a safe natural alkaloid, represents a novel anticancer agent.

Vincamine, a well-known plant alkaloid, has been used as a dietary supplement and as a peripheral vasodilator to combat aging in humans. In this study, for the very first time, we demonstrated that vincamine can function as an anticancer agent in a human alveolar basal epithelial cell line A549 (IC50 = 309.7 µM). The anticancer potential of vincamine in A549 cells was assessed by molecular assays to determine cell viability, generation of intracellular ROS, nuclear condensation, caspase-3 activity and inhibition, and change in mitochondrial membrane potential (ΔΨm). In silico studies predicted that the anti-proliferative potential of vincamine is enhanced by its interaction with the apoptotic protein caspase-3, and that this interaction is driven by two hydrogen bonds and has a high free energy of binding (-5.64 kcal/mol) with an estimated association constant (Ka) of 73.67 µM. We found that vincamine stimulated caspase-3-dependent apoptosis and lowered mitochondrial membrane potential, which ultimately led to cytochrome C release. Vincamine was also found to quench hydroxyl free radicals and deplete iron ions in cancer cells. As a dietary supplement, vincamine is almost non-toxic in BEAS-2B and 3T3-L1 cells. Therefore, we propose that vincamine represents a safe anticancer agent in lung cancer cells. Its role in other cancers has yet to be explored.

Design, synthesis and biological evaluation of vincamine derivatives as potential pancreatic ß-cells protective agents for the treatment of type 2 diabetes mellitus.

A series of vincamine derivatives were designed, synthesized and evaluated as pancreatic ß-cells protective agents for type 2 diabetes mellitus. Most of the compounds displayed potent pancreatic ß-cells protective activities and five derivatives were found to exhibit 20-50-fold higher activities than vincamine. Especially for compounds Vin-C01 and Vin-F03, exhibited a remarkable EC50 value of 0.22 µM and 0.27 µM, respectively. Their pancreatic ß-cells protective activities increased approximately 2 times than vincamine. In cell viability assay, compounds Vin-C01 and Vin-F03 could effectively promote ß-cell survival and protect ß-cells from STZ-induced apoptosis. Further cellular mechanism of action studies demonstrated that their potent ß-cells protective activities were achieved by regulating IRS2/PI3K/Akt signaling pathway. The present study evidently showed that compounds Vin-C01 and Vin-F03 were two more potent pancreatic ß-cells protective agents compared to vincamine and might serve as promising lead candidates for the treatment of type 2 diabetes mellitus.

Involvement of Nrf2/HO-1 antioxidant signaling and NF-κB inflammatory response in the potential protective effects of vincamine against methotrexate-induced nephrotoxicity in rats: cross talk between nephrotoxicity and neurotoxicity.

Methotrexate (MTX) is a cytotoxic chemotherapeutic agent widely used in the treatment of cancer and autoimmune diseases like rheumatoid arthritis. However, its use has been limited by its nephrotoxicity. MTX-induced renal injury results in uremia which may influence both the peripheral and central nervous systems causing cognitive and memory problems. The nephroprotective and neuroprotective activities of vincamine (10, 20 and 40 mg/kg), a natural alkaloid with known anti-oxidant, anti-apoptotic and neuroprotective properties, were investigated against MTX-induced toxicity. MTX treatment increased the markers of kidney injury and relative kidney weight, lipid peroxidation, nuclear factor-κB (NF-κB), inflammatory markers, tumor necrosis factor-α, interleukin-1ß, myeloperoxidase and cyclooxygenase-2 and caspase-3 expressions, decreased catalase and superoxide dismutase activities, interleukin-10 and ATP levels and antioxidant proteins, nuclear factor erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1). Moreover, it disturbed rats' behavior in the locomotor activity test, Y-maze and passive avoidance task. Treatment with vincamine (40 mg/kg) effectively ameliorated MTX-induced renal injury via increasing the expression of Nrf2 and HO-1 suppressing oxidative stress, decreasing the expression of inflammatory markers, NF-κB and caspase-3 pathways and enhancing ATP levels. Additionally, it restored locomotor activity in the locomotor test and memory functions in passive avoidance and Y-maze tests.

The locus coeruleus neuroprotective drug vindeburnol normalizes behavior in the 5xFAD transgenic mouse model of Alzheimer's disease.

Damage to noradrenergic neurons in the Locus coeruleus (LC) occurs contributes to neuropathology and behavioral deficits in Alzheimer's disease (AD); methods to reduce LC damage may therefore be of benefit. We previously showed that vindeburnol, a derivative of the plant alkaloid vincamine, reduced neuroinflammation, amyloid burden, and LC damage in a mouse model of AD; however, effects on behavior were not tested. We now tested the effects of vindeburnol on anxiety-like behavior in 5xFAD mice which develop robust amyloid burden at early ages. During novel object recognition testing, we observed that 5xFAD mice spent more time exploring than wildtype littermates, and that time was reduced by vindeburnol. Vindeburnol also reduced hyperlocomotion in the 5xFAD mice which may have contributed to their increased exploration times. In an open field test, vindeburnol normalized the increase of time spent in the center, and the decrease of time spent near the walls in 5xFAD mice. Vindeburnol reduced amyloid burden in the hippocampus and cortex, areas that contribute to regulation of anxiety-like behavior. In vitro, vindeburnol increased neuronal BDNF expression in a cAMP-dependent manner; and inhibited phosphodiesterase activity with an EC50 near 50 µM. These findings suggest that cAMP-mediated increases in neurotrophic factors contribute to beneficial effects of vindeburnol within the context of LC damage, which may be of value for treatment of some neuropsychiatric symptoms of AD.

Antidiabetic, antihyperlipidemic and antioxidant effect of Vincamine, in streptozotocin-induced diabetic rats.

Diabetes mellitus is the most common endocrine disorder characterized by hyperglycemia resulting from defects in insulin secretion or insulin action. The present study was designed to investigate the antidiabetic effects of vincamine, one of the monoterpenoid indole alkaloid, in streptozotocin-induced diabetic rat model. Diabetes was induced in rats by an intraperitoneal injection of streptozotocin (40 mg/kg bw). Vincamine 20 and 30 mg/kg.bw were administrated orally as a single dose per day to the diabetic rats for 30 days. The vehicle control group received 0.5% dimethyl sulfoxide for the same duration. After 30 days of treatment, fasting blood glucose, glycosylated haemoglobin, total cholesterol, triglyceride, low-density lipoprotein cholesterol and very low-density lipoprotein cholesterol levels were significantly increased, whereas, body weight, plasma insulin, high-density lipoprotein cholesterol, antioxidant enzymes and reduced glutathione were markedly decreased in diabetic rats. Treatment with vincamine significantly restored these parameters to the normal level. The protective effect of vincamine was compared with glibenclamide, a well-known hypoglycemic drug. Our results clearly suggest that vincamine exhibit hypoglycemic, hypolipidemic and antioxidant activity. The anti-diabetic effect of vincamine was comparable to the protective effect of glibenclamide, suggesting its potential as a natural anti-diabetic compound with therapeutic benefits.

Vincamine as a GPR40 agonist improves glucose homeostasis in type 2 diabetic mice.

Vincamine, a monoterpenoid indole alkaloid extracted from the Madagascar periwinkle, is clinically used for the treatment of cardio-cerebrovascular diseases, while also treated as a dietary supplement with nootropic function. Given the neuronal protection of vincamine and the potency of ß-cell amelioration in treating type 2 diabetes mellitus (T2DM), we investigated the potential of vincamine in protecting ß-cells and ameliorating glucose homeostasis in vitro and in vivo. Interestingly, we found that vincamine could protect INS-832/13 cells function by regulating G-protein-coupled receptor 40 (GPR40)/cAMP/Ca2+/IRS2/PI3K/Akt signaling pathway, while increasing glucose-stimulated insulin secretion (GSIS) by modulating GPR40/cAMP/Ca2+/CaMKII pathway, which reveals a novel mechanism underlying GPR40-mediated cell protection and GSIS in INS-832/13 cells. Moreover, administration of vincamine effectively ameliorated glucose homeostasis in either HFD/STZ or db/db type 2 diabetic mice. To our knowledge, our current work might be the first report on vincamine targeting GPR40 and its potential in the treatment of T2DM.

Zafirlukast and vincamine ameliorate tamoxifen-induced oxidative stress and inflammation: Role of the JNK/ERK pathway.

AIMS: This study investigated the hepatoprotective effects of both zafirlukast and vincamine and their possible role in the treatment of tamoxifen-induced liver injury in rats. MATERIALS AND METHODS: Female Wistar rats were divided into five groups (10 rats each). Groups I and II received 1% Tween 80 and served as normal and tamoxifen controls, respectively. Groups III, IV and V were treated with zafirlukast (80 mg/kg), vincamine (10 mg/kg) and a combination of zafirlukast (80 mg/kg) and vincamine (10 mg/kg), respectively for 10 successive days. Tamoxifen was given orally to all groups, except for 1st group, in the dose of 45 mg/kg for 10 days to induce liver injury. Subsequently, rats were sacrificed for biochemical, histopathological, Immunohistochemistry, PCR and western blot assessment. KEY FINDINGS: Tamoxifen-induced liver injury was reflected by alterations in estimated biochemical parameters, activation of JNK/ERK pathway, increased expression of NF-κB, liver oxidative stress and inflammatory markers parallel to histopathological changes in liver tissue. Treatment of rats with zafirlukast and vincamine ameliorated tamoxifen induced hepatic cell injury via suppressing oxidative stress, inflammatory markers, caspases-3, p-JNK/p-ERK and NF-κB pathways. SIGNIFICANCE: Zafirlukast and vincamine may be regarded as potential therapeutic strategies with antioxidant and anti-inflammatory activities against tamoxifen-induced oxidative damage in rat liver.

Treatment of Vinca minor Leaves with Methyl Jasmonate Extensively Alters the Pattern and Composition of Indole Alkaloids.

Alkaloids extracted from mature Vinca minor leaves were fractionated by preparative HPLC. By means of HRMS and NMR data, the main alkaloids were identified as vincamine, strictamine, 10-hydroxycathofoline, and vincadifformine. Upon treatment with methyl jasmonate (MeJA), the pattern and composition of the indole alkaloids changed extensively. While 10-hydroxycathofoline and strictamine concentrations remained unaltered, vincamine and vincadifformine levels showed a dramatic reduction. Upon MeJA treatment, four other indole alkaloids were detected in high quantities. Three of these alkaloids have been identified as minovincinine, minovincine, and 9-methoxyvincamine. Whereas minovincinine and minovincine are known to occur in trace amounts in V. minor, 9-methoxyvincamine represents a novel natural product. Based on the high similarities of vincamine and 9-methoxyvincamine and their inverse changes in concentrations, it is postulated that vincamine is a precursor of 9-methoxyvincamine. Similarly, vincadifformine seems to be converted first to minovincinine and finally to minovincine. Because MeJA treatment greatly altered the alkaloidal composition of V. minor, it could be used as a potential elicitor of alkaloids that are not produced under normal conditions.

Ibogan, Aspidosperman, Vincamine, and Bisindole Alkaloids from a Malayan Tabernaemontana corymbosa: Iboga Alkaloids with C-20α Substitution.

Ten new indole alkaloids (1-10) comprising five ibogan, two aspidosperman, one vincamine, and two bisindole alkaloids, in addition to 32 known alkaloids, were isolated from the stem-bark extract of a Malayan Tabernaemontana corymbosa. The structures of these alkaloids were determined based on analysis of the NMR and MS data and, in five instances (1, 3, 5, 6, 8), confirmed by X-ray diffraction analysis. Two of the iboga alkaloids, conodusines B (2) and C (3), and the iboga-containing bisindole tabernamidine B (10) are notable for the presence of an α-substituted acetyl group at C-20 of the iboga carbon skeleton. The iboga alkaloid (+)-conodusine E (5) had MS and NMR data that were identical to those of (-)-ervatamine I, recently isolated from Ervatamia hainanensis. Establishment of the absolute configuration of (+)-conodusine E (5) was based on analysis of the ECD data, correlation with (-)-heyneanine, and X-ray analysis, which showed that (+)-5 belongs to the same enantiomeric series as exemplified by (-)-coronaridine. The configuration at C-20' of the previously reported Tabernaemontana bisindole alkaloid 19'-oxotabernamine (renamed tabernamidine B) required revision based on the present results. Several of the bisindoles showed pronounced in vitro growth inhibitory activity against drug-sensitive and vincristine-resistant KB cells.

In vitro characterization of transport and metabolism of the alkaloids: vincamine, vinpocetine and eburnamonine.

PURPOSE: Vincamine, vinpocetine and eburnamonine are alkaloids known for their neuroprotective attributes, enhancement of cerebrovascular blood flow and antitumor effect of their derivatives. However, the relative metabolic stability of these alkaloids and their extrusion by the drug efflux transporters expressed at the blood-brain barrier (BBB) are not clear. In this study, we developed rapid and sensitive methods for the detection of these alkaloids and investigated their relative metabolic stability and their interaction with drug efflux transporters. METHODS: UPLC methods were developed to analyze metabolic in vitro samples. Intrinsic clearance was determined using rat liver microsomal enzymes. Drug-stimulated transporter activity was estimated by measuring inorganic phosphate released from ATP spectrophotometrically. RESULTS: The UPLC methods quantification level ranged from 0.02 to 0.025 µg/mL, indicating high sensitivity. The intrinsic clearance of eburnamonine was significantly less than both vincamine and vinpocetine. Different concentrations of the three drugs (4, 20 and 100 µM) induced minimal stimulation of the ATPase activity of the Bcrp and Pgp membrane transporters. CONCLUSIONS: The developed simple, sensitive and reliable UPLC analysis methods can be utilized in future in vitro and in vivo studies. The three alkaloids demonstrated minimal interaction with the drug efflux transporters Pgp and Bcrp, concordant with the ability of these alkaloids to cross the BBB. The relative metabolic stability of eburnamonine compared to the other alkaloids suggests the use of eburnamonine or its derivatives as lead compounds for the development of antitumor and nootropic agents that need to cross the BBB and produce their pharmacological effects in the CNS.

The vincamine derivative vindeburnol provides benefit in a mouse model of multiple sclerosis: effects on the Locus coeruleus.

The endogenous neurotransmitter noradrenaline (NA) plays several roles in maintaining brain homeostasis, including exerting anti-inflammatory and neuroprotective effects. The primary source of NA in the CNS are tyrosine hydroxylase (TH)-positive neurons located in the Locus coeruleus (LC) which send projections throughout the brain and spinal cord. We recently demonstrated that dysregulation of the LC:Noradrenergic system occurs in experimental autoimmune encephalomyelitis as well as in MS patients, associated with damage occurring to LC neurons. Vindeburnol, a structural analog of the cerebral vasodilator vincamine, was previously reported to increase TH expression and activity in LC neurons. Female C57BL/6 mice were immunized with myelin oligodendrocyte glycoprotein (MOG)(35-55) peptide, and treated with vindeburnol at the first appearance of clinical signs. Clinical signs continued to increase for about 1 week, at which point mice in the vehicle group continued to worsen while vindeburnol-treated mice showed improvement. Pro-inflammatory cytokine production from splenic T cells was not reduced by vindeburnol suggesting primarily central actions of treatment. In the cerebellum, vindeburnol decreased astrocyte activation and reduced the number of demyelinated regions. Vindeburnol reduced astrocyte activation in the LC, reduced TH+ neuronal hypertrophy, increased expression of several genes involved in LC survival and maturation, and increased NA levels in the spinal cord. These results suggest that treatments with drugs such as vindeburnol which target LC survival or function could be of benefit in MS patients.

Aggressive behavior during social interaction in mice is controlled by the modulation of tyrosine hydroxylase expression in the prefrontal cortex.

The Balb/c strain and the C57BL/6 strain show constitutive differences for tyrosine hydroxylase expression, and noradrenaline (NA) prefrontal transmission. Male mice of these strains also show striking differences in social interaction behaviors, with an increased aggressiveness for the Balb/c strain. To test a potential link between these neurobiological and behavioral parameters, we evaluated the behavioral effects of chronic treatment of mice with BC19, a noreburnamine compound previously known as RU24722, found to modify cell organisation, tyrosine hydoxylase (TH) expression, and its activity into the locus coeruleus (LC). We compared the pharmacological effects between the two strains in social behaviors. Our results show that the emergence of additional TH-expressing (TH+) neurons in the rostral part of the LC of Balb/c mice was associated with an increase in the density of TH+ and noradrenergic (NA+) fibers in the molecular layer in the cingular (Cg1) and prelimbic (PrL) parts of the prefrontal cortex (PFC). BC19 treatment resulted in the near-equalization of the LC number of TH+ neurons and of the density of TH+ and NA+ fibers between both strains. The aggressiveness in Balb/c mice was considerably diminished by BC19 treatment, while the originally non aggressive behavior of C57Bl/6 mice was much less affected by BC19 treatment, despite a moderate increase in some offensive behaviors. In additional control experiments, we checked the effect of BC19 on a separate test for anxiety and assessed the effect of noradrenergic N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4) mediated lesions in C57BL/6 mice on social behaviors. In the present study we show that the BC19 effect in Balb/c mice was independent of anxiety as measured in the light/dark test and that DSP-4 lesions in C57BL/6 mice produced a robust increase in aggressive social interaction. Altogether, these results show that the noradrenergic system, and particularly its projections to the PFC, strongly modulates aggressive behaviors.