Plasmodium falciparum metacaspase PfMCA-1 triggers a z-VAD-fmk inhibitable protease to promote cell death.

Activation of proteolytic cell death pathways may circumvent drug resistance in deadly protozoan parasites such as Plasmodium falciparum and Leishmania. To this end, it is important to define the cell death pathway(s) in parasites and thus characterize proteases such as metacaspases (MCA), which have been reported to induce cell death in plants and Leishmania parasites. We, therefore, investigated whether the cell death function of MCA is conserved in different protozoan parasite species such as Plasmodium falciparum and Leishmania major, focusing on the substrate specificity and functional role in cell survival as compared to Saccharomyces cerevisae. Our results show that, similarly to Leishmania, Plasmodium MCA exhibits a calcium-dependent, arginine-specific protease activity and its expression in yeast induced growth inhibition as well as an 82% increase in cell death under oxidative stress, a situation encountered by parasites during the host or when exposed to drugs such as artemisins. Furthermore, we show that MCA cell death pathways in both Plasmodium and Leishmania, involve a z-VAD-fmk inhibitable protease. Our data provide evidence that MCA from both Leishmania and Plasmodium falciparum is able to induce cell death in stress conditions, where it specifically activates a downstream enzyme as part of a cell death pathway. This enzymatic activity is also induced by the antimalarial drug chloroquine in erythrocytic stages of Plasmodium falciparum. Interestingly, we found that blocking parasite cell death influences their drug sensitivity, a result which could be used to create therapeutic strategies that by-pass drug resistance mechanisms by acting directly on the innate pathways of protozoan cell death

The plant-based immunomodulator curcumin as a potential candidate for the development of an adjunctive therapy for cerebral malaria

The clinical manifestations of cerebral malaria (CM) are well correlated with underlying major pathophysiological events occurring during an acute malaria infection, the most important of which, is the adherence of parasitized erythrocytes to endothelial cells ultimately leading to sequestration and obstruction of brain capillaries. The consequent reduction in blood flow, leads to cerebral hypoxia, localized inflammation and release of neurotoxic molecules and inflammatory cytokines by the endothelium. The pharmacological regulation of these immunopathological processes by immunomodulatory molecules may potentially benefit the management of this severe complication. Adjunctive therapy of CM patients with an appropriate immunomodulatory compound possessing even moderate anti-malarial activity with the capacity to down regulate excess production of proinflammatory cytokines and expression of adhesion molecules, could potentially reverse cytoadherence, improve survival and prevent neurological sequelae. Current major drug discovery programmes are mainly focused on novel parasite targets and mechanisms of action. However, the discovery of compounds targeting the host remains a largely unexplored but attractive area of drug discovery research for the treatment of CM. This review discusses the properties of the plant immune-modifier curcumin and its potential as an adjunctive therapy for the management of this complication

Cytochrome P450 1A2 (CYP1A2) activity, mammographic density, and oxidative stress: a cross-sectional study

INTRODUCTION: Mammographically dense breast tissue is a strong predictor of breast cancer risk, and is influenced by both mitogens and mutagens. One enzyme that is able to affect both the mitogenic and mutagenic characteristics of estrogens is cytochrome P450 1A2 (CYP1A2), which is principally responsible for the metabolism of 17β-estradiol. METHODS: In a cross-sectional study of 146 premenopausal and 149 postmenopausal women, we examined the relationships between CYP1A2 activity, malondialdehyde (MDA) levels, and mammographic density. In vivo CYP1A2 activity was assessed by measuring caffeine metabolites in urine. Levels of serum and urinary MDA, and MDA–deoxyguanosine adducts in DNA were measured. Mammograms were digitized and measured using a computer-assisted method. RESULTS: CYP1A2 activity in postmenopausal women, but not in premenopausal women, was positively associated with mammographic density, suggesting that increased CYP1A2 activity after the menopause is a risk factor for breast cancer. In premenopausal women, but not in postmenopausal women, CYP1A2 activity was positively associated with serum and urinary MDA levels; there was also some evidence that CYP1A2 activity was more positively associated with percentage breast density when MDA levels were high, and more negatively associated with percentage breast density when MDA levels were low. CONCLUSION: These findings provide further evidence that variation in the activity level of enzymes involved in estrogen metabolism is related to levels of mammographic density and potentially to breast cancer risk

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Profiling of polyphenols and sesquiterpenoids using different extraction methods in Muscari turcicum, an endemic plant from Turkey

Muscari turcicum, endemic to south Anatolia, Turkey, represents an unexplored crop plant, with potential therapeutic uses related to its phytochemical composition. In this work, the in vitro antioxidant and enzyme inhibitory activity of flower, leaf and bulb extracts, obtained using different extraction methods were evaluated. A comprehensive polyphenolic and sesquiterpene lactones profiling of the different extracts was also undertaken. For this purpose, UHPLC-QTOF mass spectrometry allowed us to putatively annotate 280 phytochemical compounds of which 162 were polyphenols and 118 were sesquiterpene lactones. The most abundant polyphenols were flavonoids (77 compounds), phenolic acids (34 compounds), and low molecular weight phenols (38 compounds). Muscari turcicum leaf methanol extract possessed the highest concentrations of low-molecular-weight phenolics, phenolic acids, and sesquiterpene lactones (20.61, 7.00, and 3.44 mg standard equivalent/g, respectively). The water extract of M. turcicum flower obtained by infusion showed prominent reducing (120.52 mg Trolox equivalent [TE]/g mg TE/g for both CUPRAC and FRAP) and radical scavenging potential (91.39 mg TE/g, for DPPH assay). Besides, M. turcicum flower methanol extract (13.44 mg EDTA equivalent/g) showed the highest metal chelating activity. Interestingly, methanol extracts obtained by Soxhlet extraction and maceration actively inhibited tyrosinase (129.36 mg kojic acid equivalent/g) and cholinesterases (5.15 mg galantamine equivalent [GALAE]/g and 6.16 mg GALAE/g, for acetyl and butyryl cholinesterase) respectively. Strong correlations (p < 0.01) were observed between polyphenols/sesquiterpenoids and observed biological activities. Scientific evidences presented in this study has provided baseline data for bioprospection of novel pharmaceutical/cosmetic candidates from Muscari turcicum, thus supporting its therapeutic exploitation

A comparative bio-evaluation and chemical profiles of Calendula officinalis L. extracts prepared via different extraction techniques

Calendula officinalis L., (marigold), well known for its medicinal properties, has been extensively studied for its therapeutic properties. Nonetheless, as far as the literature could establish, no study has attempted to comparatively assess the biological (antioxidant and enzyme inhibitory potential) of the flowers, leaves, and roots of C. officinalis extracted using conventional (maceration and Soxhlet extraction (SE)) and non-conventional extraction (homogenizer (HAE) and ultrasound (UAE) assisted extraction) techniques. The detailed phytochemical profile of each extract along with the concentration of specific bioactive compounds has also been established. Total phenolic content was highest for the flower extracts while flavonoid content was highest in the leaf extracts. Phytochemical profiling showed that the extraction method influenced the phytochemical composition of the extract. Nicotiflorin was identified in the flower extracts only while amentoflavone occurred only in the roots, inferring that the occurrence of bioactive compounds varies within a plant. The flower extracts showed highest antioxidant potential while the roots extracts were potent inhibitors of cholinesterase and tyrosinase. This study provides valuable data on the influence of extraction techniques on the recovery of bioactive compounds from plants. In an endeavor to scale-up extraction from plant considering the more efficient extraction method is of paramount importance. Moreover, the study highlighted the necessity to thoroughly examine the biological activities of various parts of a plant obtained via different extraction protocols

A Comparative Bio-Evaluation and Chemical Profiles of Calendula officinalis L. Extracts Prepared via Different Extraction Techniques

Calendula officinalis L., (marigold), well known for its medicinal properties, has been extensively studied for its therapeutic properties. Nonetheless, as far as the literature could establish, no study has attempted to comparatively assess the biological (antioxidant and enzyme inhibitory potential) of the flowers, leaves, and roots of C. officinalis extracted using conventional (maceration and Soxhlet extraction (SE)) and non-conventional extraction (homogenizer (HAE) and ultrasound (UAE) assisted extraction) techniques. The detailed phytochemical profile of each extract along with the concentration of specific bioactive compounds has also been established. Total phenolic content was highest for the flower extracts while flavonoid content was highest in the leaf extracts. Phytochemical profiling showed that the extraction method influenced the phytochemical composition of the extract. Nicotiflorin was identified in the flower extracts only while amentoflavone occurred only in the roots, inferring that the occurrence of bioactive compounds varies within a plant. The flower extracts showed highest antioxidant potential while the roots extracts were potent inhibitors of cholinesterase and tyrosinase. This study provides valuable data on the influence of extraction techniques on the recovery of bioactive compounds from plants. In an endeavor to scale-up extraction from plant considering the more efficient extraction method is of paramount importance. Moreover, the study highlighted the necessity to thoroughly examine the biological activities of various parts of a plant obtained via different extraction protocols

Hypericum triquetrifolium and H. neurocalycinum as Sources of Antioxidants and Multi-Target Bioactive Compounds: A Comprehensive Characterization Combining In Vitro Bioassays and Integrated NMR and LC-MS Characterization by Using a Multivariate Approach

Hypericum triquetrifolium and H. neurocalycinum were evaluated for their phytochemical content and in vitro bioactivity. NMR analyses were performed on the methanol extract of the aerial parts of H. triquetrifolium to establish the main classes of phytoconstituents. Then, LC-DAD-MSn analyses were performed in order to compare the composition of aerial parts and roots extracts of both Hypericum species, obtained using either methanol or water as solvents. Results, processed using multivariate data analysis, showed a significantly higher phenolic content of methanol extracts compared to water extracts, while minor qualitative differences were observed between the two. Distinctive flavonoid and PAC patterns were observed for H. triquetrifolium and H. neurocalycinum, and specific compounds were exclusively detected in one or the other species. Specifically, the phloroglucinols 7-epiclusianone, hyperfirin and hyperforin were present only in H. neurocalycinum, while hyperforin was detected only in H. triquetrifolium. Extracts were assayed using different in vitro tests to evaluate their antioxidant properties and their inhibitory activity against several enzymes, showing significant antioxidant and metal chelating activities. Furthermore, inhibitory properties against acetylcholinesterase, butyrylcholinesterase and tyrosinase were observed. Multivariate approaches were used to correlate biological data with the phytochemical composition of the different extracts. The results, showing positive correlations between specific chemical constituents and the measured bioactivities, represent preliminary data that could guide future studies aimed at isolating bioactive constituents from H. neurocalycinum and H. triquetrifolium for further pharmacological evaluations

Chemical profile, antioxidant, antimicrobial, enzyme inhibitory, and cytotoxicity of seven Apiaceae species from Turkey: a comparative study

Several Apiaceae species, used as both food and in complementary and alternative medicine, represents a rich source of potential valuable phytopharmaceuticals which necessitates scientific contemplation. In the present study, the antioxidant, enzyme inhibitory, antimicrobial, and cytotoxic properties of methanol extracts of seven Apiaceae species, (Chaerophyllum macrospermum (Willd. ex Spreng.) Fisch. & C.A.Mey. ex Hohen, Ferula rigidula Fisch. ex DC., Ferula orientalis L., Prangos ferulacea Lindl., Prangos peucedanifolia Fenzl., Ferulago setifolia K. Koch, and Pimpinella anthriscoides Boiss.) were evaluated. Species belonging to the Prangos genus exhibited the highest total phenolic content, namely P. peucedanifolia and P. ferulacea, with values of 47.90 and 44.44 mg gallic acid equivalent/g extract, respectively. P. peucedanifolia also displayed the highest radical scavenging capacity (81.53 and 102.70 mg Trolox equivalent [TE]/g extract for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS), respectively) and reducing power (165.87 and 100.09 mg TE/g extract for cupric reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP), respectively). C. macrospermum showed the most potent inhibition against Alzheimer's disease related enzymes, namely acetylcholinesterase (4.53 mg galantamine equivalent [GALAE]/g extract) and butyrylcholinesterase (3.22 mg GALAE/g extract). P. ferulacea (131.94 mg kojic acid (KAE) equivalent/g extract) and P. peucedanifolia (4.97 mmol acarbose equivalent (ACAE)/g extract) were potent inhibitors of tyrosinase and a-glucosidase, respectively. In general, studied species were able to reduce cellular viabilities. P. peucedanifolia possessed promising antibacterial potential against Bacillus cereus (Minimum inhibition concentration (MIC): 0.37 mg/mL), L. monocytogenes (MIC: 0.56 mg/mL), P. aeruginosa and Escherichia coli (MIC: 0.27 mg/mL), Salmonella typhimurium and Enterobacter cloacae (MIC: 0.75 mg/mL). F. rigidula showed the highest antifungal effect against Aspergillus ochraceus and Trichoderma viride (MIC: 0.10 mg/mL). The present findings could be the scientific starting point towards the pharmaceutical and/or commercial utilization of these Apiaceae species.Ministry of Education, Science and Technological Development, Republic of Serbia [451-03-68/2020-14/200007]info:eu-repo/semantics/publishedVersio