ABSTRACT
In this study, 2,3-dihydro-1H-indolizinium alkaloid-prosopilosidine (PPD), that was isolated from Prosopis glandulosa, was evaluated against C. neoformans in a murine model of cryptococcosis. In vitro and in vivo toxicity of indolizidines were also evaluated. Mice were infected via the tail vein with live C. neoformans. Twenty-four hours post-infection, the mice were treated with PPD once a day (i.p.) or twice a day (bid) orally, or with amphotericin B (Amp B) intraperitoneally (IP), or with fluconazole (Flu) orally for 5 days. The brains of all of the animals were aseptically removed and the numbers of live C. neoformans were recovered. In vitro toxicity of indolizidine alkaloids was determined in HepG2 cells. PPD showed to be potent in vivo activity against C. neoformans at a dose of 0.0625 mg/kg by eliminating ~76% of the organisms compared to ~83% with Amp B (1.5 mg/kg). In addition, PPD was found to be equally efficacious, but less toxic, at either 0.125 or 0.0625 mg/kg compared to Amp B (1.5 mg/kg) when it was administered bid (twice a day) by an i.p. route. When tested by an oral route, PPD (10 mg/kg) showed potent activity in this murine model of cryptococcosis with ~82% of organisms eliminated from the brain tissue, whereas Flu (15 mg/kg) reduced ~90% of the infection. In vitro results suggest that quaternary indolizidines were less toxic as compared to those of tertiary bases. PPD (20 mg/kg) did not cause any alteration in the plasma chemistry profiles. These results indicated that PPD was active in eliminating cryptococcal infection by oral and i.p. routes at lower doses compared to Amp B. or Flu.
Subject(s)
Cryptococcosis/drug therapy , Cryptococcosis/microbiology , Cryptococcus neoformans/physiology , Indolizidines/therapeutic use , Prosopis/chemistry , Administration, Oral , Alkaloids/administration & dosage , Alkaloids/chemistry , Alkaloids/pharmacology , Alkaloids/therapeutic use , Animals , BH3 Interacting Domain Death Agonist Protein/metabolism , Body Weight/drug effects , Cryptococcosis/blood , Cryptococcus neoformans/drug effects , Disease Models, Animal , Female , Hep G2 Cells , Humans , Indolizidines/administration & dosage , Indolizidines/blood , Indolizidines/chemistry , Mice , Treatment OutcomeABSTRACT
Microshoot cultures of the Chinese medicinal plant Securinega suffruticosa (Pall.) Rehd. were established and evaluated for the presence of therapeutically relevant indolizidine alkaloids securinine (S) and allosecurinine (AS). The cultures were maintained in shake flasks (SFs) and a bubble column bioreactor (BCB) using the modified Murashige's shoot multiplication medium supplemented with 1.0 mg l(-1) benzyladenine (BA), 3.0 mg l(-1) 2-isopentenyladenine (2iP), and 0.3 mg l(-1) 1-naphthaleneacetic acid (NAA). The influence of light and medium supplementation strategies with biosynthesis precursor (lysine (LY)) and nutrient formulations (casein hydrolysate (CH) and coconut water (CW)) on biomass growth and alkaloid production were investigated. SF cultures grown in the presence of light yielded up to 6.02 mg g(-1) dry weight (DW) S and 3.70 mg g(-1) DW AS, corresponding to the respective productivities of 98.39 and 60.21 mg l(-1). Among feeding experiments, CW supplementation proved most effective for SF-grown shoots, increasing biomass yield and AS productivity by 52 and 44 %, respectively. Maximum concentrations of securinine (3.25 mg g(-1) DW) and allosecurinine (3.41 mg g(-1) DW) in BCB cultures were achieved in the case of 1.0 g l(-1) LY supplementation. These values corresponded to the productivities of 42.64 and 44.47 mg per bioreactor, respectively.
Subject(s)
Alkaloids/biosynthesis , Alkaloids/therapeutic use , Biotechnology/methods , Euphorbiaceae/chemistry , Indolizidines/metabolism , Plant Shoots/growth & development , Tissue Culture Techniques , Azepines/metabolism , Biomass , Bioreactors , Culture Media/pharmacology , Euphorbiaceae/drug effects , Euphorbiaceae/radiation effects , Heterocyclic Compounds, Bridged-Ring/metabolism , Indolizidines/therapeutic use , Lactones/metabolism , Light , Piperidines/metabolism , Plant Shoots/drug effects , Plant Shoots/radiation effectsABSTRACT
The field of small-molecule inhibitors of protein-protein interactions is rapidly advancing and the specific area of inhibitors of the p53/MDM2 interaction is a prime example. Several groups have published on this topic and multiple compounds are in various stages of clinical development. Building on the strength of the discovery of RG7112, a Nutlin imidazoline-based compound, and RG7388, a pyrrolidine-based compound, we have developed additional scaffolds that provide opportunities for future development. Here, we report the discovery and optimization of a highly potent and selective series of spiroindolinone small-molecule MDM2 inhibitors, culminating in RO8994.
Subject(s)
Indoles/chemistry , Indolizidines/chemistry , Proto-Oncogene Proteins c-mdm2/antagonists & inhibitors , Spiro Compounds/chemistry , Apoptosis/drug effects , Binding Sites , Cell Line, Tumor , Cell Proliferation/drug effects , Drug Evaluation, Preclinical , Humans , Imidazolines/chemistry , Indoles/therapeutic use , Indoles/toxicity , Indolizidines/therapeutic use , Indolizidines/toxicity , Molecular Dynamics Simulation , Neoplasms/drug therapy , Protein Binding , Protein Structure, Tertiary , Proto-Oncogene Proteins c-mdm2/metabolism , Pyrrolidines/chemistry , Spiro Compounds/therapeutic use , Spiro Compounds/toxicity , Tumor Suppressor Protein p53/antagonists & inhibitors , Tumor Suppressor Protein p53/metabolism , para-Aminobenzoates/chemistryABSTRACT
The asymmetric total synthesis of the strongly cytotoxic phenanthroindolizidine alkaloid 3 was achieved. Using the same route, various derivatives were also synthesized. Cytotoxicity of those synthetic compounds was evaluated and compounds 19, 23, and 27 demonstrated potent cytotoxicities similar to that of 3. The in vivo antitumor efficacy of selected compounds was also evaluated and 23 demonstrated moderate antitumor efficacy.
