Effect of perezone on arrhythmias and markers of cell injury during reperfusion in the anesthetized rat

Perezone and its phenyl glycine derivative induce cytotoxicity via caspases on human glial cancer cells

The new phenyl glycine derivative of perezone was obtained in a single reaction step in ca. 80% yield which showed remarkable cytotoxic activity against the astrocytoma U-251 cell line. After 24 h of exposure, both perezone (IC50 = 6.83 ± 1.64 µM) and its phenyl glycine derivative (2.60 ± 1.69 µM) showed cytotoxic effect on U-251 cells but were five times less cytotoxic on the non-tumoral SVGp12 cell line (IC50 = 28.54 ± 1.59 and 31.87 ± 1.54 µM respectively). Both compounds induced cellular morphological changes (pyknosis or cytoplasmic vacuolization) and increased the expression of caspases 3, 8, and 9 genes related to apoptosis. In the acute toxicity study, phenyl glycine perezone (DL50 = 2000 mg/Kg) demonstrated to be less toxic than perezone (DL50 = 500 mg/Kg). Phenylglycine-perezone can envisage a beneficial therapeutic potential.

High variability of perezone content in rhizomes of Acourtia cordata wild plants, environmental factors related, and proteomic analysis

With the aim of exploring the source of the high variability observed in the production of perezone, in Acourtia cordata wild plants, we analyze the influence of soil parameters and phenotypic characteristics on its perezone content. Perezone is a sesquiterpene quinone responsible for several pharmacological effects and the A. cordata plants are the natural source of this metabolite. The chemistry of perezone has been widely studied, however, no studies exist related to its production under natural conditions, nor to its biosynthesis and the environmental factors that affect the yield of this compound in wild plants. We also used a proteomic approach to detect differentially expressed proteins in wild plant rhizomes and compare the profiles of high vs. low perezone-producing plants. Our results show that in perezone-producing rhizomes, the presence of high concentrations of this compound could result from a positive response to the effects of some edaphic factors, such as total phosphorus (Pt), total nitrogen (Nt), ammonium (NH4), and organic matter (O. M.), but could also be due to a negative response to the soil pH value. Additionally, we identified 616 differentially expressed proteins between high and low perezone producers. According to the functional annotation of this comparison, the upregulated proteins were grouped in valine biosynthesis, breakdown of leucine and isoleucine, and secondary metabolism such as terpenoid biosynthesis. Downregulated proteins were grouped in basal metabolism processes, such as pyruvate and purine metabolism and glycolysis/gluconeogenesis. Our results suggest that soil parameters can impact the content of perezone in wild plants. Furthermore, we used proteomic resources to obtain data on the pathways expressed when A. cordata plants produce high and low concentrations of perezone. These data may be useful to further explore the possible relationship between perezone production and abiotic or biotic factors and the molecular mechanisms related to high and low perezone production.

A Timeline of Perezone, the First Isolated Secondary Metabolite in the New World, Covering the Period from 1852 to 2020

This chapter covers a sesquiterpene quinone, commonly named perezone. This molecule is documented as the first secondary metabolite isolated in crystalline form in the New World in 1852. An introduction, with its structure, the IUPAC nomenclature, and the most recent physical and spectroscopic characterizations are firstly described initially. Alongside this, a timeline and scheme with summarized information of the history of this molecule is given including the "Códice Badiano de la Cruz, 1552, highlighting the year of its isolation culminating with information up to 2005. Subsequently, in a chronological order the most recent advances of the target molecule are included and organized in subsections covering the last 15-year period 2006-2020. Finally, recently submitted contributions from the laboratory of the authors are described. It is important to note that the details provided highlight the importance and relevance of perezone.

Green Approach Extraction of Perezone from the Roots of Acourtia platyphilla (A. Grey): A Comparison of Four Activating Modes and Supercritical Carbon Dioxide

Perezone, a sesquiterpene quinone, is a very important molecule due to its pharmacological activities in addition to the fact that it is considered to be the first secondary metabolite isolated in the new world (America–Mexico, 1852). This study aims to offer a green comparative study about the extraction of the target molecule from the roots of the vegetable specimen Acourtia platyphilla (A. Grey). The study was performed comparing five different modes of extraction: supercritical CO₂, electromagnetic infrared and microwave irradiations, mechanical-wave ultrasound versus typical mantle heating procedure. An exhaustive comparative-discussion of the obtained results is provided. It is worth noting that the corresponding quantifications were established using ¹H NMR, correlating appropriately the integrals of the vinylic proton H-6 of perezone with the aromatic singlet of p-dinitrobenzene employed as an internal reference. It is also important to highlight that the four presented procedures are novel modes to extract perezone. Finally, a complementary study about the solubility of the target sesquiterpene quinone related to the use of supercritical CO₂ is also reported.

Green Production of Indolylquinones, Derivatives of Perezone, and Related Molecules, Promising Antineoplastic Compounds

A green approach to produce the indolyl derivatives from four natural quinones (perezone, isoperezone, menadione, and plumbagin) was performed; in this regard, a comparative study was accomplished among the typical mantle heating and three nonconventional activating modes of reaction (microwave, near-infrared, and high speed ball milling or tribochemical), under solventless conditions and using bentonitic clay as a catalyst. In addition, the tribochemical production of isoperezone from perezone is also commented on. It is also worth noting that the cytotoxicity of the synthesized indolylquinones in human breast cancer cell was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, with the 3-indolylisoperezone being the most active. The structural attribution of the target molecules was performed by typical spectroscopic procedures; moreover, the experimental and computed1H and13C NMR chemical shifts data, with previous acquisition of the corresponding minimum energetic structures, were in good agreement.

Cardioprotective properties of citicoline against hyperthyroidism-induced reperfusion damage in rat hearts

Hyperthyroidism represents an increased risk factor for cardiovascular morbidity, especially when the heart is subjected to an ischemia/reperfusion process. The aim of this study was to explore the possible protective effect of the nucleotide citicoline on the susceptibility of hyperthyroid rat hearts to undergo reperfusion-induced damage, which is associated with mitochondrial dysfunction. Hence, we analyzed the protective effect of citicoline on the electrical behavior and on the mitochondrial function in rat hearts. Hyperthyroidism was established after a daily i.p. injection of triiodothyronine (at 2 mg/kg of body weight) during 5 days. Thereafter, citicoline was administered i.p. (at 125 mg/kg of body weight) for 5 days. In hyperthyroid rat hearts, citicoline protected against reperfusion-induced ventricular arrhythmias. Moreover, citicoline maintained the accumulation of mitochondrial Ca(2+), allowing mitochondria to reach a high transmembrane electric gradient that protected against the release of cytochrome c. It also preserved the activity of the enzyme aconitase that inhibited the release of cytokines. The protection also included the inhibition of oxidative stress-induced mDNA disruption. We conclude that citicoline protects against the reperfusion damage that is found in the hyperthyroid myocardium. This effect might be due to its inhibitory action on the permeability transition in mitochondria.

Citicoline (CDP-choline) protects myocardium from ischemia/reperfusion injury via inhibiting mitochondrial permeability transition

AIMS

Oxidative stress emerges after reperfusion of an organ following an ischemic period and results in tissue damage. In the heart, an amplified generation of reactive oxygen species and a significant Ca(2+) accumulation cause ventricular arrhythmias and mitochondrial dysfunction. This occurs in consequence of increased non-specific permeability. A number of works have shown that permeability transition is a common substrate that underlies the reperfusion-induced heart injury. The aim of this work was to explore the possibility that CDP-choline may circumvent heart damage and mitochondrial permeability transition.

MAIN METHODS

Rats were injected i.p. with CDP-choline at 20 mg/kg body weight. Heart electric behavior was followed during a closure/opening cycle of the left coronary descendent artery. Heart mitochondria were isolated from rats treated with CDP-choline, and their function was evaluated by analyzing Ca(2+) movements, achievement of a high level of the transmembrane potential, and respiratory control. Oxidative stress was estimated following the activity of the enzymes cis-aconitase and superoxide dismutase, as well as the disruption of mitochondrial DNA.

KEY FINDINGS

This study shows that CDP-choline avoided ventricular arrhythmias and drop of blood pressure. Results also show that mitochondria, isolated from CDP-choline-treated rats, maintained selective permeability, retained accumulated Ca(2+), an elevated value of transmembrane potential, and a high ratio of respiratory control. Furthermore, activity of cis-aconitase enzyme and mDNA structure were preserved.

SIGNIFICANCE

This work introduces CDP-choline as a useful tool to preserve heart function from reperfusion damage by inhibiting mitochondrial permeability transition.

A Novel Semisynthetic Anion Receptor: Synthesis and Ion Recognition of (1-H-pyrrol-2-yl)-4-oxo-perezone

We describe the synthesis of the novel 2-(1,5-dimethyl-4-oxo-hexyl)-3-hydroxy-5-methyl-6-pyrrolyl-1,4-benzoquinone 2 from the natural product perezone 1. The anion-guest properties of the new compound were evaluated in the presence of fluoride, chloride, bromide and iodide tetrabutylammonium salts using 1H NMR titration techniques in deuterated dichloromethane or dimethylformamide. The title compound showed interesting colorimetric behavior in the presence of inorganic salts.

Conformational analysis of perezone and dihydroperezone using vibrational circular dichroism

The vibrational circular dichroism (VCD) spectra of perezone and dihydroperezone measured from CDCl(3) solutions were quite similar, suggesting analogous conformations for both molecules. Their absolute configurations were confirmed by comparison of the experimental VCD spectrum of each compound with curves generated from theoretical calculations using density functional theory (DFT) at the B3LYP/DGDZVP level of theory taking into account their conformational mobility. Conformational analysis of the 8-(R) enantiomer showed 19 low energy conformers in a 2.4 kcal/mol energy range, while for 8-(R), with the saturated side alkyl chain, 34 conformers were considered in the first 2 kcal/mol. Initial analyses were carried out using a Monte Carlo searching with the MMFF94 molecular mechanics force field, all MMFF94 conformers were geometrically optimized using DFT at the B3LYP/6-31G(d) level of theory, followed by reoptimization and calculations of their vibrational frequencies at the B3LYP/DGDZVP level. Good agreement between the theoretical 8-(R) enantiomers and experimental VCD curves were observed for both.

Perezone and its isomer isoperezone induce caspase-dependent and caspase-independent cell death

In this study, we investigated the cytotoxic effect of perezone, a constituent isolated from the roots of Perezia spp. and of its synthetic isomer isoperezone on the K562 human leukemia cell line. Perezone showed greater cytotoxic effect than isoperezone but both compounds were found to induce cytotoxicity trough a caspase-dependent and a caspase-independent mechanisms; important changes in their light scattering properties, phosphatidylserine translocation and mitochondrial membrane potential disruption were detected by cytometry. The mechanism of death induction of each compound showed interesting concentration-dependent differences. Neither compound induced the apoptosis inducing factor.

Expression profiling identifies epoxy anthraquinone derivative as a DNA topoisomerase inhibitor

To discover novel drugs for neuroblastoma treatment, we have previously screened a panel of drugs and identified 30 active agents against neuroblastoma cells. Here we performed microarray gene expression analysis to monitor the impact of these agents on a neuroblastoma cell line and used the connectivity map (cMAP) to explore putative mechanism of action of unknown drugs. We first compared the expression profiles of 10 compounds shared in both our dataset and cMAP database and observed the high connectivity scores for 7 of 10 matched drugs regardless of the differences of cell lines utilized. The screen of cMAP for uncharacterized drugs indicated the signature of Epoxy anthraquinone derivative (EAD) matched the profiles of multiple known DNA targeted agents (topoisomerase I/II inhibitors, DNA intercalators, and DNA alkylation agents) as predicted by its structure. Similar result was obtained by querying against our internal NB-cMAP (http://pob.abcc.ncifcrf.gov/cgi-bin/cMAP), a database containing the profiles of 30 active drugs. These results suggest that Epoxy anthraquinone derivative may inhibit neuroblastoma cells by targeting DNA replication inhibition. Experimental data also demonstrate that Epoxy anthraquinone derivative indeed induces DNA double-strand breaks through DNA alkylation and inhibition of topoisomerase activity. Our study indicates that Epoxy anthraquinone derivative may be a novel DNA topoisomerase inhibitor that can be potentially used for treatment of neuroblastoma or other cancer patients.

Functional and metabolic implications of biotin deficiency for the rat heart

The tricarboxylic acid (TCA) cycle is the main ATP provider for the heart. TCA carbons must be replenished by anaplerosis for normal cardiac function. Biotin is cofactor of the anaplerotic enzymes pyruvate and propionyl-CoA carboxylases. Here, we found that in biotin deficient rats, both carboxylases decreased 90% in adipose tissue, jejunum and spleen, but in heart they conserved about 60% residual activity. We then investigated if under biotin deficiency (BtDEF), the heart is able to maintain its function in vivo and in isolated conditions, and during ischemia and reperfusion, where metabolism drastically shifts from oxidative to mainly glycolytic. Neither glucose nor octanoate oxidation were severely affected in BtDEF hearts, as assessed by mechanical performance, oxygen uptake or high-energy metabolite content; however, myocardial hexokinase activity and lactate concentration were reduced in deficient hearts. When challenged by ischemia and reperfusion injury, BtDEF hearts did not suffer more damage than the controls, although they lowered significantly their performance, when changed to ischemic conditions, which may have clinical implications. Post-ischemic increase in ADP/ATP ratio was similar in both groups, but during reperfusion there was higher rhythm perturbation in BtDEF hearts. By being relatively insensitive to biotin deficiency, cardiac tissue seems to be able to replenish TCA cycle intermediates and to maintain ATP synthesis.

Antifeedant and phytotoxic activity of the sesquiterpene p-benzoquinone perezone and some of its derivatives

The sesquiterpene p-benzoquinone perezone (1), isolated from Perezia adnata var. alamani (Asteraceae), and its non-natural derivatives isoperezone (2), dihydroperezone (3), dihydroisoperezone (4), and anilidoperezone (5) were tested as antifeedants against the herbivorous insects Spodoptera littoralis, Leptinotarsa decemlineata, and Myzus persicae. Compounds 1-5 exhibited strong antifeedant activity against L. decemlineata and M. persicae, and elicited a low response by S. littoralis. Antifeedant activity on L. decemlineata and M. persicae increased when the hydroxyl group at C-3 in perezone (1) was changed to C-6 to give isoperezone (2). The same effect was found with hydrogenation of the double bond of the alkyl chain of (1) to yield dihydroperezone (3). In contrast, hydrogenation of this double bond in isoperezone (2) to give dihydroisoperezone (4) led to a reduction in antifeedant activity. Determination of the phytotoxic activity of 1-5 revealed that 3 had a significant inhibition effect on Lactuca sativa radicle length growth.

Myocardial protective effect of octylguanidine against the damage induced by ischemia reperfusion in rat heart

This study shows that the hydrophobic cation octylguanidine protects against myocardial damage induced by ischemia-reperfusion. The protective effect of the amine was analyzed after 5 min of coronary occlusion followed by 5 min reperfusion in rat hearts. ECG tracings from rats treated with an i.v., injection of 5 mg/kg of octylguanidine showed a total absence of post-reperfusion arrhythmias, conversely to what was observed in untreated rats. The histological images showed that myocardium fibers from treated rats were in good shape and retained their striae, also there was absence of edema. Furthermore, the accumulation of 201Tl in hearts from these rats indicated that the tissue did not suffer disruption or impairment in membrane functions. The above correlated with the fact that mitochondria isolated from the ventricular free wall from treated rats preserved their ability to synthesize ATP. We propose that the protective effect of octylguanidine might be due to its documented inhibitory action on the opening of mitochondrial non-specific pores, a mechanism which is associated in heart injury as induced by reperfusion.

Hypothyroidism provides resistance to reperfusion injury following myocardium ischemia

A growing body of evidence has demonstrated that reperfusion injury may be mediated, in part, by mitochondrial Ca2+ overload that promotes non-selective permeability of the inner membrane. In this regard it is known that mitochondria from hypothyroid rats are resistant to membrane damage as induced by Ca2+. The purpose of this study was to evaluate the sensitivity of hearts from hypothyroid rats, to the damage by reperfusion, after an ischemic period of 5 min. The results were compared with those from control and hyperthyroid rats. Hypothyroidism was established by surgical removal of the thyroid gland; in turn hyperthyroidism was induced after a daily injection of 2 mg/kg of 3,5,3'-triiodothyronine for 4 days. ECG tracings from hypothyroid rats showed a total absence of post-reperfusion arrhythmias conversely to what was observed in control and hyperthyroid rats. The release of creatine kinase and aspartate amino transferase to the plasma in hypothyroid rats was found to be lower than that found in hyperthyroid and euthyroid rats. The histological studies showed that myocardial fibers from hypothyroid rats were in good condition and retained their striae and a remarkable near absence of edema was clearly observed.