Search results for "ALKALOIDS"
showing 10 items of 182 documents
The problem of misidentification between edible and poisonous wild plants: Reports from the Mediterranean area
2018
Abstract Today, in many European countries, people are looking for wild edible plants to experience new tastes and flavors, by following the new trend of being green and environmentally friendly. Young borage and spinach leaves can be easily confused by inexpert pickers with those of other plants, including poisonous ones, such as Mandragora autumnalis Bertol. (mandrake) or Digitalis purpurea L. (foxglove), common in southern and northern Italy respectively. In the last twenty years, several cases of intoxication by accidental ingestion of mandrake and foxglove have been reported. The purpose of this work was to perform a pharmacognostic characterization of young leaves from borage, mandrak…
Biased predation could promote convergence yet maintain diversity within Müllerian mimicry rings of Oreina leaf beetles.
2019
Mullerian mimicry is a classic example of adaptation, yet Muller's original theory does not account for the diversity often observed in mimicry rings. Here, we aimed to assess how well classical Mullerian mimicry can account for the colour polymorphism found in chemically defended Oreina leaf beetles by using field data and laboratory assays of predator behaviour. We also evaluated the hypothesis that thermoregulation can explain diversity between Oreina mimicry rings. We found that frequencies of each colour morph were positively correlated among species, a critical prediction of Mullerian mimicry. Predators learned to associate colour with chemical defences. Learned avoidance of the green…
Effects of mowing on fungal endophytes and arbuscular mycorrhizal fungi in subalpine grasslands
2013
International audience; In French subalpine grasslands, cessation of mowing promotes dominance of Festuca paniculata, which alters plant diversity and ecosystem functioning. One of the mechanisms underpinning such effects may be linked to simultaneous changes in the abundance of fungal symbionts such as endophytes and arbuscular mycorrhizal fungi. In field conditions, mowing reduced the abundance of the endophyte Neotyphodium sp. in leaves of F. paniculata by a factor of 6, and increased mycorrhizal densities by a factor of 15 in the soil. In greenhouse experiments, the mycorrhizal colonization of Trifolium pratense and Allium porrum increased 3- fold and 3.8- fold respectively in mown vs u…
Cytotoxicity of sesquiterpene alkaloids from Nuphar plants toward sensitive and drug-resistant cell lines.
2018
Multi-drug resistance (MDR) is a critical problem in cancer chemotherapy. MDR causes the overexpression of ATP-binding cassette (ABC) transporters and mutations in tumor suppressor genes and oncogenes. To tackle this issue, in this study, we focused on Nuphar plants, which have been traditionally used as food. Sesquiterpene alkaloids (1–3) were isolated from N. japonicum and dimeric sesquiterpene thioalkaloids (4–10) were isolated from N. pumilum. P-glycoprotein-overexpressing CEM/ADR5000 cells were cross-resistant to 6,6′-dihydroxythiobinupharidine (10). Using in silico molecular docking, we calculated the binding energies and simulated the interactions of these compounds with the correspo…
Repurposing of Bromocriptine for Cancer Therapy
2018
Bromocriptine is an ergot alkaloid and dopamine D2 receptor agonist used to treat Parkinson’s disease, acromegaly, hyperprolactinemia, and galactorrhea, and more recently diabetes mellitus. The drug is also active against pituitary hormone-dependent tumors (prolactinomas and growth-hormone producing adenomas). We investigated, whether bromocriptine also inhibits hormone-independent and multidrug-resistant (MDR) tumors. We found that bromocriptine was cytotoxic towards drug-sensitive CCRF-CEM, multidrug-resistant CEM/ADR5000 leukemic cells as well as wild-type or multidrug-resistant ABCB5-transfected HEK293 cell lines, but not sensitive or BCRP-transfected multidrug-resistant MDA-MB-231 brea…
Effect of chronic exercise on myocardial electrophysiological heterogeneity and stability. Role of intrinsic cholinergic neurons: A study in the isol…
2018
[EN] A study has been made of the effect of chronic exercise on myocardial electrophysiological heterogeneity and stability, as well as of the role of cholinergic neurons in these changes. Determinations in hearts from untrained and trained rabbits on a treadmill were performed. The hearts were isolated and perfused. A pacing electrode and a recording multielectrode were located in the left ventricle. The parameters determined during induced VF, before and after atropine (1 mu M), were: fibrillatory cycle length (VV), ventricular functional refractory period (FRPVF), normalized energy (NE) of the fibrillatory signal and its coefficient of variation (CV), and electrical ventricular activatio…
Repurposing of plant alkaloids for cancer therapy: Pharmacology and toxicology.
2019
Drug repurposing (or repositioning) is an emerging concept to use old drugs for new treatment indications. Phytochemicals isolated from medicinal plants have been largely neglected in this context, although their pharmacological activities have been well investigated in the past, and they may have considerable potentials for repositioning. A grand number of plant alkaloids inhibit syngeneic or xenograft tumor growth in vivo. Molecular modes of action in cancer cells include induction of cell cycle arrest, intrinsic and extrinsic apoptosis, autophagy, inhibition of angiogenesis and glycolysis, stress and anti-inflammatory responses, regulation of immune functions, cellular differentiation, a…
CHK1 inhibitor sensitizes resistant colorectal cancer stem cells to nortopsentin
2021
Summary Limited therapeutic options are available for advanced colorectal cancer (CRC). Herein, we report that exposure to a neo-synthetic bis(indolyl)thiazole alkaloid analog, nortopsentin 234 (NORA234), leads to an initial reduction of proliferative and clonogenic potential of CRC sphere cells (CR-CSphCs), followed by an adaptive response selecting the CR-CSphC-resistant compartment. Cells spared by the treatment with NORA234 express high levels of CD44v6, associated with a constitutive activation of Wnt pathway. In CR-CSphC-based organoids, NORA234 causes a genotoxic stress paralleled by G2-M cell cycle arrest and activation of CHK1, driving the DNA damage repair of CR-CSphCs, regardless…
Synthesis, antitumor activity and CDK1 inhibiton of new thiazole nortopsentin analogues
2017
A new series of thiazole nortopsentin analogues was conveniently synthesized with fair overall yields. The antiproliferative activity of the new derivatives was tested against different human tumor cell lines of the NCI full panel. Four of them showed good antitumor activity with GI(50) values from micro to nanomolar level. The mechanism of the antiproliferative effect of these derivatives, was pro-apoptotic, being associated with externalization of plasma membrane phosphatidylserine and DNA fragmentation. The most active and selective of the new thiazoles confined viable cells in G2/M phase and markedly inhibited in vitro CDK1 activity. (C) 2017 Elsevier Masson SAS.
Social stress during adolescence activates long-term microglia inflammation insult in reward processing nuclei
2018
The experience of social stress during adolescence is associated with higher vulnerability to drug use. Increases in the acquisition of cocaine self-administration, in the escalation of cocaine-seeking behavior, and in the conditioned rewarding effects of cocaine have been observed in rodents exposed to repeated social defeat (RSD). In addition, prolonged or severe stress induces a proinflammatory state with microglial activation and increased cytokine production. The aim of the present work was to describe the long-term effects induced by RSD during adolescence on the neuroinflammatory response and synaptic structure by evaluating different glial and neuronal markers. In addition to an inc…