Centaurea behen leaf extract mediated green synthesized silver nanoparticles as antibacterial and removing agent of environmental pollutants with blood compatible and hemostatic effects.

The present study focused on evaluating the antibacterial properties, radical scavenging, and photocatalytic activities of Centaurea behen-mediated silver nanoparticles (Cb-AgNPs). The formation of Cb-AgNPs was approved by UV-Vis spectrometry, Fourier-transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy (SEM), energy dispersive X-ray and X-ray diffraction. The results showed that the obtained AgNPs have a maximum absorbance peak at 450 nm with spherical morphology and an average size of 13.03 ± 5.8 nm. The catalytic activity of the Cb-AgNPs was investigated using Safranin O (SO) solution as a cationic dye model. The Cb-AgNPs performed well in the removal of SO. The coupled physical adsorption/photocatalysis reaction calculated about 68% and 98% degradation of SO dye under solar irradiation. The Cb-AgNPs inhibited the growth of gram-negative or positive bacteria strains and had excellent DPPH radicals scavenging ability (100% in a concentration of 200 µg/ml) as well as a good effect on reducing coagulation time (at concentrations of 200 and 500 µg/mL reduced clotting time up to 3 min). Considering the fact that green synthesized Cb-AgNPs have antioxidant and antibacterial properties and have a good ability to reduce coagulation time, they can be used in wound dressings. As well as these NPs with good photocatalytic activity can be a suitable option for degrading organic pollutants.

Antimicrobial and antibiofilm activity of specialized metabolites isolated from Centaurea hyalolepis.

The discovery of plant-derived compounds that are able to combat antibiotic-resistant pathogens is an urgent demand. Over years, Centaurea hyalolepis attracted considerable attention because of its beneficial medical properties. Phytochemical analyses revealed that Centaurea plant species contain several metabolites, such as sesquiterpene lactones (STLs), essential oils, flavonoids, alkaloids, and lignans.The organic extract of C. hyalolepis plant, collected in Palestine, showed significant antimicrobial properties towards a panel of Gram-negative and Gram-positive bacterial strains when the Minimal Inhibitory Concentration (MIC) values were evaluated by broth microdilution assays. A bio-guided fractionation of the active extract via multiple steps of column and thin layer chromatography allowed us to obtain three main compounds. The isolated metabolites were identified as the STLs cnicin, 11ß,13-dihydrosalonitenolide and salonitenolide by spectroscopic and spectrometric analyses. Cnicin conferred the strongest antimicrobial activity among the identified compounds. Moreover, the evaluation of its antibiofilm activity by biomass assays through crystal violet staining revealed almost 30% inhibition of biofilm formation in the case of A. baumannii ATCC 17878 strain. Furthermore, the quantification of carbohydrates and proteins present in the extracellular polymeric substance (EPS) revealed the ability of cnicin to significantly perturb biofilm structure. Based on these promising results, further investigations might open interesting perspectives to its applicability in biomedical field to counteract multidrug resistant infections.

Glucose Uptake-Stimulating Metabolites from Aerial Parts of Centaurea sicula.

A comprehensive phytochemical investigation of aerial parts obtained from Centaurea sicula L. led to the isolation of 14 terpenoids (1-14) and nine polyphenols (15-23). The sesquiterpenoid group (1-11) included three structural families, namely, elemanolides (1-6), eudesmanolides (7 and 8), and germacranolides (9-11) with four unreported secondary metabolites (5-8), whose structure has been determined by extensive spectroscopic analysis, including 1D/2D NMR, HR-MS, and chemical conversion. Moreover, an unprecedented alkaloid, named siculamide (24), was structurally characterized, and a possible biogenetic origin was postulated. Inspired by the traditional use of the plant and in the frame of ongoing research on compounds with potential activity on metabolic syndrome, all the isolated compounds were evaluated for their stimulation of glucose uptake, disclosing remarkable activity for dihydrocnicin (10) and the lignan salicifoliol (15).

Centaurea mersinensis phytochemical composition and multi-dimensional bioactivity properties supported by molecular modeling.

Various studies conducted on Centaurea species indicate that the relevant plant is good source of bioactive phytochemicals. In this study, in vitro studies were used to determine bioactivity properties of methanol extract of Centaurea mersinensis - endemic species in Turkey - on extensive basis. Furthermore, the interaction of target molecules, identified for breast cancer and phytochemicals in the extract, was investigated via in silico analyses to support findings received in vitro. Scutellarin, quercimeritrin, chlorogenic acid and baicalin were primary phytochemicals in the extract. Methanol extract and scutellarin had higher cytotoxic effects against MCF-7 (IC50=22.17 µg/mL, and IC50=8.25 µM, respectively), compared to other breast cancer cell lines (MDA-MB-231, SKBR-3). The extract had strong antioxidant properties and inhibited target enzymes, especially α-amylase (371.69 mg AKE/g extract). The results of molecular docking indicate that main compounds of extract show high-strength bonding to the c-Kit tyrosine among target molecules identified in breast cancer, compared to other target molecules (MMP-2, MMP-9, VEGFR2 kinase, Aurora-A kinase, HER2). The tyrosinase kinase (1T46)-Scutellarin complex showed considerable stability in 150 ns simulation as per MD findings, and it was coherent with optimal docking findings. Docking findings and HOMO-LUMO analysis results corresponds with in vitro experiments. Medicinal properties of phytochemicals, which was determined to be suitable for oral use along with ADMET, were found to be within normal limits except for their polarity properties. In conclusion, in vitro and in silico studies indicated that the relevant plant yields promising results regarding its potential to develop novel and effective medicational products.Communicated by Ramaswamy H. Sarma.

Two new compounds from endemic Centaurea paphlagonica (Bornm.) Wagenitz and their cytotoxic activities.

Centaurea paphlagonica (Bornm.) Wagenitz is an endemic plant in Turkey. Pyrocatechol, vanillic acid, 3,4-dihydroxy benzoic acid, 5-O-caffeoylshikimic acid, tamarixetin, chlorogenic acid methyl ester, quercetin, 1,3-dicaffeoylquinic acid, tamarixetin-7-O-ß-D-glucopyranoside, quercimetrin, daucosterin, paphlagonicanin B, tamarixetin-7-O-ß-rutinoside, rutin, chlorogenic acid, isoorientin, orientin, 3-O-feruloylquinic acid, quercetagetin-3-methyl ether 6-O-ß-glucopyranoside, diosmetin 6-C-ß-glucopyranoside, quercetagetin 4'-methyl ether 7-O-ß-glucopyranoside, paphlagonicanin A, nepetin, cirsiliol, desacylcynaropicrin, and 8α-O-(2',3'-dihydroxyisobutyryl) desacylcynaropicrin were isolated from both flower and aerial parts of C. paphlagonica. These compounds were identified using 1D and 2D NMR methods and ESI-MS. The MTT assay assessed the antiproliferative activities of all isolated (known and new compounds) compounds on Caco-2, LNCaP, A549, HeLa, and HEK-293 cell lines. The 8α-O-(2',3'-dihydroxyisobutyryl) desacylcynaropicrin demonstrated the highest activity against CaCo-2 and HeLa cancer cell lines.

Centaurea triumfetii essential oil chemical composition, comparative analysis, and antimicrobial activity of selected compounds.

The essential oils from the Centaurea genus are well known for their pharmacological properties. The most abundant and dominant chemical components in Centaurea essential oils are ß-caryophyllene, hexadecanoic acid, spathulenol, pentacosane, caryophyllene oxide, and phytol. However, whether these dominant components are the key drivers for observed antimicrobial activity remains unclear. Thus, the aim of this study was dual. Here we provide comprehensive, literature-based data to correlate the chemical compounds in Centaurea essential oils with the tested antimicrobial activity. Secondly, we characterized the essential oil of Centaurea triumfettii All. squarrose knapweed using coupled system gas chromatography-mass spectrometry and tested its phytochemicals for antimicrobial activity against E. coli and S. epidermis using disc diffusion assay and monitoring their growth in Muller Hinton broth. The most abundant compounds in C. triumfettii essential oil were hexadecanoic acid (11.1%), spathulenol (10.8%), longifolene (8.8%), germacrene D (8.4%), aromadendrene oxide (6.0%) and linoleic acid (5.3%). Based on our analysis of literature data from other Centaurea essential oils, they were positively correlated with antimicrobial activity. Using an agar disk diffusion method, tested chemical constituents did not show experimental evidence to support this positive correlation to antimicrobial activity when we tested them as pure components. The antibacterial effect of essential oil constituents may be related to a complex synergistic, rather than a single component as suggested by performed network pharmacology analysis, underlying the theoretical interactions between the essential oil phytochemicals listed as potentially responsible for antimicrobial activity and should be confirmed in further in-depth studies. This is the first report on the comparative analysis of Centaurea essential oils with good antimicrobial activity, as well as the first analysis of chemical components of the essential oil from C. triumfettii and the first report of antimicrobial activity of the representative, pure components: aromadendrene, germacrene D, spathulenol, longifolene, and the mixture of selected chemical compounds. This work contributes to the body of knowledge on the genus Centaurea and C. triumfettii species.

Phytochemical and Cytogenetic Study of Two Centaurea Species from Croatia: the Particular Case of Diploid and Tetraploid C. salonitana.

Natural wild populations of C. rupestris and C. salonitana were studied to determine possible relationships between the volatile oil (VO) composition and ploidy level. The chemical composition of the volatile oil was investigated using the GC/MS technique. The predominant components of the VO of diploid and tetraploid C. salonitana were hexadecanoic acid and α-linoleic acids, while in C. rupestris they were germacrene D and ß-caryophyllene in one population and heptacosane and germacrene D, in another. The nuclear DNA amounts (2 C DNA), determined by flow cytometry, were 3.54 pg for C. rupestris, 3.39 pg for the diploid and 6.79 pg for the tetraploid population of C. salonitana. Evidence that the degree of ploidy solely influences the chemical composition of the essential oil of C. salonitana was not found. The results presented are the first data to be reported on the DNA content of the studied Centaurea populations from Croatia, as well as on the chemical composition of C. salonitana volatile oil.

Feature-Based Molecular Networking for the Exploration of the Metabolome Diversity of Common Egyptian Centaurea Species in Relation to Their Cytotoxic Activity.

Centaurea is a genus compromising over 250 herbaceous flowering species and is used traditionally to treat several ailments. Among the Egyptian Centaurea species, C. lipii was reported to be cytotoxic against multidrug-resistant cancer cells. In this context, we aimed to explore the metabolome of C. lipii and compare it to other members of the genus in pursuance of identifying its bioactive principles. An LC-MS/MS analysis approach synchronized with feature-based molecular networks was adopted to offer a holistic overview of the metabolome diversity of the Egyptian Centaurea species. The studied plants included C. alexandrina, C. calcitrapa, C. eryngioides, C. glomerata, C. lipii, C. pallescens, C. pumilio, and C. scoparia. Their constitutive metabolome showed diverse chemical classes such as cinnamic acids, sesquiterpene lactones, flavonoids, and lignans. Linking the recorded metabolome to the previously reported cytotoxicity identified sesquiterpene lactones as the major contributors to this activity. To confirm our findings, bioassay-guided fractionation of C. lipii was adopted and led to the isolation of the sesquiterpene lactone cynaropicrin with an IC50 of 1.817 µM against the CCRF-CEM leukemia cell line. The adopted methodology highlighted the uniqueness of the constitutive metabolome of C. lipii and determined the sesquiterpene lactones to be the responsible cytotoxic metabolites.

The essential oil composition of the endemic plant species Centaurea vandasii and chemotaxonomy of section Phalolepis (Asteraceae).

In the present study, the chemical composition of the essential oil from aerial parts of the endemic plant species, Centaurea vandasii Velen (sect. Phalolepis, Asteraceae), collected in its locus classicus in Rhodope Mts, Bulgaria, was evaluated by GC-MS. The main components of the oil were hexadecanoic acid (18.3%), tetradecanoic acid (13.8%), caryophyllene oxide (12.1%) and germacrene D (8.4%). Furthermore, a complete literature review on the composition of the essential oils of all the other taxa of Centaurea, belonging to section Phalolepis, studied so far, was performed. HCA (Hierarchical Cluster Analysis) and PCA (Principal Component Analyses) were used in order to demonstrate chemotaxonomical variations in the composition of the essential oils.

A threefold approach including quantum chemical, molecular docking and molecular dynamic studies to explore the natural compounds from Centaurea jacea as the potential inhibitors for COVID-19 / Uma abordagem tríplice incluindo química quântica, docking molecular e estudos dinâmicos moleculares para explorar os compostos naturais de Centaurea jacea como inibidores potenciais para Covid-19

In the current report, we studied the possible inhibitors of COVID-19 from bioactive constituents of Centaurea jacea using a threefold approach consisting of quantum chemical, molecular docking and molecular dynamic techniques. Centaurea jacea is a perennial herb often used in folk medicines of dermatological complaints and fever. Moreover, anticancer, antioxidant, antibacterial and antiviral properties of its bioactive compounds are also reported. The Mpro (Main proteases) was docked with different compounds of Centaurea jacea through molecular docking. All the studied compounds including apigenin, axillarin, Centaureidin, Cirsiliol, Eupatorin and Isokaempferide, show suitable binding affinities to the binding site of SARS-CoV-2 main protease with their binding energies -6.7 kcal/mol, -7.4 kcal/mol, -7.0 kcal/mol, -5.8 kcal/mol, -6.2 kcal/mol and -6.8 kcal/mol, respectively. Among all studied compounds, axillarin was found to have maximum inhibitor efficiency followed by Centaureidin, Isokaempferide, Apigenin, Eupatorin and Cirsiliol. Our results suggested that axillarin binds with the most crucial catalytic residues CYS145 and HIS41 of the Mpro, moreover axillarin shows 5 hydrogen bond interactions and 5 hydrophobic interactions with various residues of Mpro. Furthermore, the molecular dynamic calculations over 60 ns (6×106 femtosecond) time scale also shown significant insights into the binding effects of axillarin with Mpro of SARS-CoV-2 by imitating protein like aqueous environment. From molecular dynamic calculations, the RMSD and RMSF computations indicate the stability and dynamics of the best docked complex in aqueous environment. The ADME properties and toxicity prediction analysis of axillarin also recommended it as safe drug candidate. Further, in vivo and in [...].

No presente relatório, estudamos os possíveis inibidores de Covid-19 de constituintes bioativos de Centaurea jacea usando uma abordagem tripla que consiste em técnicas de química quântica, docking molecular e dinâmica molecular. Centaurea jacea é uma erva perene frequentemente usada em remédios populares de doenças dermatológicas e febre. Além disso, as propriedades anticâncer, antioxidante, antibacteriana e antiviral de seus compostos bioativos também são relatadas. A Mpro (proteases principais) foi acoplada a diferentes compostos de Centaurea jacea por meio de docking molecular. Todos os compostos estudados, incluindo apigenina, axilarina, Centaureidina, Cirsiliol, Eupatorina e Isokaempferide, mostram afinidades de ligação adequadas ao sítio de ligação da protease principal SARS-CoV-2 com suas energias de ligação -6,7 kcal / mol, -7,4 kcal / mol, - 7,0 kcal / mol, -5,8 kcal / mol, -6,2 kcal / mol e -6,8 kcal / mol, respectivamente. Dentre todos os compostos estudados, a axilarina apresentou eficiência máxima de inibidor, seguida pela Centaureidina, Isokaempferida, Apigenina, Eupatorina e Cirsiliol. Nossos resultados sugeriram que a axilarina se liga aos resíduos catalíticos mais cruciais CYS145 e HIS41 do Mpro, além disso a axilarina mostra 5 interações de ligações de hidrogênio e 5 interações hidrofóbicas com vários resíduos de Mpro. Além disso, os cálculos de dinâmica molecular em uma escala de tempo de 60 ns (6 × 106 femtossegundos) também mostraram percepções significativas sobre os efeitos de ligação da axilarina com Mpro de SARS-CoV-2 por imitação de proteínas como o ambiente aquoso. A partir de cálculos de dinâmica molecular, os cálculos RMSD e RMSF indicam a estabilidade e dinâmica do melhor complexo ancorado em ambiente [...].

Phytochemical Profiles, Antioxidant, Cytotoxic, and Anti-Inflammatory Activities of Traditional Medicinal Plants: Centaurea pichleri subsp. pichleri, Conyza canadensis, and Jasminum fruticans.

Centaurea pichleri subsp. pichleri, Conyza canadensis, and Jasminum fruticans are traditionally used plants grown in Turkey. Methanol extracts were obtained from these plants and pharmacological activity studies and phytochemical analyses were carried out. To evaluate the phytochemical composition, spectrophotometric and chromatographic techniques were used. The extracts were evaluated for antioxidant activity by DPPH●, ABTS●+ radical scavenging, and FRAP assays. The cytotoxic effects of the extracts were investigated on DU145 prostate cancer and A549 lung cancer cell lines. The anti-inflammatory effects of extracts were investigated on the NO amount, TNF-α, IFN-γ, and PGE 2 levels in lipopolysaccharide-stimulated Raw 264.7 cells. The richest extract in terms of phenolic compounds (98.19 ± 1.64 mgGAE/gextract) and total flavonoids (21.85 ± 0.64 mgCA/gextract) was identified as C. pichleri subsp. pichleri methanol extract. According to antioxidant activity determinations, the C. pichleri subsp. pichleri extract was found to be the most active extract. Finally, the C. pichleri subsp. pichleri methanol extract was revealed to be the most effective inhibitor of viability in the cytotoxic activity investigation, and the extract with the best anti-inflammatory action. The findings point to C. pichleri subsp. pichleri as a promising source of bioactive compounds in the transition from natural sources to industrial uses, such as new medications, cosmeceuticals, and nutraceuticals.

Phytochemical Analysis and Anti-Cancer Properties of Extracts of Centaurea castriferrei Borbás & Waisb Genus of Centaurea L.

The Centaurea L. (Asteraceae) genus includes many plant species with therapeutic properties. Centaurea castriferrei Borbás & Waisb is one of the least known and least described plants of this genus. The aim of the study was the phytochemical analysis of water and methanol-water extracts (7:3 v/v) obtained from the aerial parts of the plant as well as evaluation of their anticancer activity. Quantitative determinations of phenolic compounds and flavonoids were performed, and the antioxidant potential was measured using the CUPRAC method. The RP-HPLC/DAD analysis and HPLC-ESI-QTOF-MS mass spectroscopy were performed, to determine the extracts' composition. The antiproliferative activity of the obtained extracts was tested in thirteen cancer cell lines and normal skin fibroblasts using MTT test. Regardless of the extraction method and the extractant used, similar cytotoxicity of the extracts on most cancer cell lines was observed. However, the methanol-water extracts (7:3 v/v) contained significantly more phenolic compounds and flavonoids as well as showing stronger antioxidant properties in comparison to water extracts. Centaurea castriferrei Borbás & Waisb is a rich source of apigenin and its derivatives. In all tested extracts, chlorogenic acid and centaurein were also identified. In vitro research revealed that this plant may be a potential source of compounds with anticancer activity.

Guaiane-rich phytochemical profile of Centaurea kotschyi subsp. persica (Boiss.) Wagenitz and identification of hypoglycaemic metabolites.

Phytochemical investigation of the aerial parts obtained from the Turkish plant Centaurea kotschyi subsp. persica led to the isolation of nine sesquiterpene lactones belonging to the guaiane class, including the undescribed kotschyols A and B, a monoterpene lactone (daphnauranin E), four known lignans (matairesinol, matairesinoside, arctiin and arctigenin) and an undescribed dihydrobenzofuran neolignan (4-O-glucosylcrataegifin A). The structures of these compounds were defined by spectroscopic analysis, including ECD and 1D/2D NMR, and chemical conversion. Spurred from the traditional use of C. kotschyi subsp. persica and previous reports on the activity of its extracts, the isolated compounds were evaluated for their hypoglycaemic activity disclosing the bioactive components.

In vitro investigation of cytotoxic, antioxidant, apoptosis-inducing, and wound healing properties of endemic Centaurea fenzlii Reichardt extracts.

OBJECTIVE: Cancer is a formidable problem for global health, and the increasing burden necessitates the search for new and alternative treatments and/or approaches. For this reason, any approach to cancer treatment is extremely valuable. Recently, there has been increasing interest in the use of plant-derived compounds in the treatment of cancer. ​Many studies have shown that many of the best-selling anti-cancer drugs are of plant origin. Based on this, the cytotoxic potential of two extracts [C. fenzlii leaf extract (CFL) and C. fenzlii capitula extract (CFC)] from Centaurea fenzlii, a plant species endemic to Turkey, were tested in two different cancer cell lines (DLD1 and ARH77) and a healthy cell line (HUVEC). MATERIALS AND METHODS: Cytotoxic effects of the extracts were determined by MTT assay, changes in the mRNA expressions of the apoptotic genes (apaf, bax, bcl2, bcl2l11, casp3, gadd45a and hrk) were determined via the qRT-PCR technique, and the caspase3 enzyme activity was determined. In addition, the capacities of the extracts against invasion and migration were also evaluated. The chemical content and phenolic composition were evaluated via the gas chromatography-mass spectrometry (GC/MS) and high-performance liquid chromatography (HPLC) techniques. RESULTS: As a result, the extracts showed a selective cytotoxic effect in all the cancer cell lines examined, especially the DLD1 colorectal cell line. In addition, it has been determined that the extracts inhibit the invasion and migration of cells. CONCLUSIONS: The results of the study reveal that C. fenzlii, which has been found to have acceptable anti-cancer effects, should be investigated with more comprehensive studies.

Secretory Products in Petals of Centaurea cyanus L. Flowers: A Histochemistry, Ultrastructure, and Phytochemical Study of Volatile Compounds.

(1) Background: Centaurea cyanus L. is a medicinal plant whose flowers are widely used in herbal medicine. The aim of the study was to localise flower tissues that are responsible for the production of secretory products in petals and to analyse the volatile compounds. The volatile compounds of the flowers of this species have not been investigated to date. (2) Methods: Light, fluorescence, scanning and transmission electron microscopy techniques were used in the study. Lipophilic compounds were localised in the tissues using histochemical assays. Volatile compounds were determined with the use of solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). (3) Results: The study showed production of secretion in the petal parenchyma, whose ultrastructure has features of a secretory tissue. The lipophilic secretion was localised in the cells and intercellular spaces of the parenchyma and in the walls and surface of epidermal cells, where it accumulated after release through cuticle microchannels. Sesquiterpenes were found to constitute the main group of volatile compounds, with the highest content of ß-caryophyllene (26.17%) and α-humulene (9.77%). (4) Conclusions: Given the presence of some volatile components that are often found in resins (caryophyllene, delta-cadinene) and the abundant secretion residues on the epidermal surface, we suppose that the C. cyanus secretion released by the flowers is a resinaceous mixture (oleoresin), which is frequently found in plants, as shown by literature data. This secretion may play an important role in the therapeutic effects of C. cyanus flowers.

The essential oil composition of Centaurea immanuelis-loewii Degen growing wild in Bulgaria and chemotaxonomy of section Acrocentron.

In the present study, the chemical composition of the essential oil from aerial parts of the Balkan endemic, Centaurea immanuelis-loewii Degen (sect. Acrocentron, Asteraceae), collected in Bulgaria was evaluated by GC-MS. The main components of the oil were ß-caryophyllene (23.2%), germacrene D (13.7%) and caryophyllene oxide (12.4%). Furthermore, a complete literature review on the composition of the essential oils of all the other taxa of Centaurea, belonging to section Acrocentron, studied so far, was performed and the chemotaxonomical variations in the composition of the essential oils is discussed.[Formula: see text].

Antioxidant Potential of Flower Extracts from Centaurea spp. Depends on Their Content of Phenolics, Flavonoids and Free Amino Acids.

Scientists intensely search for new sources of antioxidants, perceived as important health-promoting agents. Some species of the large genus Centaurea provide raw materials for the pharmaceutical and cosmetic industries, as well as produce edible flowers. This is the first study that determines the content of total polyphenols, flavonoids, reducing sugars, free amino acids and the antioxidant potential in the flower extracts of C. nigra L., C. orientalis L. and C. phrygia L. The total polyphenol and flavonoid content is the highest in the extract of C. orientalis, and the lowest in that of C. phrygia. Similarly, C. orientalis shows the greatest scavenging activity on DPPH (1,1-diphenyl-2-picryl-hydrazyl), ABTS [2,2'-azobis(3-ethylbenzothiazoline-6-sulfonate)] and Fe3+ reducing power assays, whereas the lowest activity is found for C. phrygia. The highest content of reducing sugars is found in C. nigra, while C. orientalis has the highest levels of free amino acids. We find a strong positive correlation between total phenolics and flavonoids and the antioxidant capacity of all three Centaurea species. Moreover, the content of free amino acids strongly and positively correlates with the levels of total phenolics and flavonoids, antioxidant activity assessed by DPPH and ABTS assays and Fe3+ reducing power. Summing up, C. orientalis exhibits the strongest antioxidant potential of the investigated Centaurea species. This species could potentially be a natural source of antioxidant substances for the pharmacy, cosmetics and food industries. The content of free amino acids may be used as a marker of the antioxidant status of Centaurea species.

The Effect of Different Ester Chain Modifications of Two Guaianolides for Inhibition of Colorectal Cancer Cell Growth.

Several sesquiterpene lactones (STLs) have been tested as lead drugs in cancer clinical trials. Salograviolide-A (Sal-A) and salograviolide-B (Sal-B) are two STLs that have been isolated from Centaurea ainetensis, an indigenous medicinal plant of the Middle Eastern region. The parent compounds Sal-A and Sal-B were modified and successfully prepared into eight novel guaianolide-type STLs (compounds 1-8) bearing ester groups of different geometries. Sal-A, Sal-B, and compounds 1-8 were tested against a human colorectal cancer cell line model with differing p53 status; HCT116 with wild-type p53 and HCT116 p53-/- null for p53, and the normal-like human colon mucosa cells with wild-type p53, NCM460. IC50 values indicated that derivatization of Sal-A and Sal-B resulted in potentiation of HCT116 cell growth inhibition by 97% and 66%, respectively. The effects of the different molecules on cancer cell growth were independent of p53 status. Interestingly, the derivatization of Sal-A and Sal-B molecules enhanced their anti-growth properties versus 5-Fluorouracil (5-FU), which is the drug of choice in colorectal cancer. Structure-activity analysis revealed that the enhanced molecule potencies were mainly attributed to the position and number of the hydroxy groups, the lipophilicity, and the superiority of ester groups over hydroxy substituents in terms of their branching and chain lengths. The favorable cytotoxicity and selectivity of the potent molecules, to cancer cells versus their normal counterparts, pointed them out as promising leads for anti-cancer drug design.

Sesquiterpene Lactones with the 12,8-Guaianolide Skeleton from Algerian Centaurea omphalotricha.

In continuing our investigation on the chemical diversity of Algerian plants, we examined Centaurea omphalotricha, whose chemical composition has been poorly studied. The present work was aimed at characterizing the secondary metabolite pattern of the CHCl3 extract of the aerial parts of this plant that displayed antiproliferative properties in a preliminary screening on HeLa cell line. The chemical analysis led us to characterize the bioactive oxygenated terpenoid fraction which includes, within major known metabolites, two new minor sesquiterpene lactones, centaurolide-A (1) and centaurolide-B (2). The structures of two compounds exhibiting the 12,8-guaianolide skeleton were determined by spectroscopic methods as well as by chemical correlation with inuviscolide (3), a well-known bioactive guaianolide isolated from Dittrichia (=Inula) viscosa. Centaurolides A and B represent the first report of 8,12-guaianolide skeleton in Centaurea genus. The effect of new compounds 1 and 2 and inuviscolide (3) on HeLa cell has also been evaluated.

Spectroscopic, mineral, and antioxidant characteristics of blue colored powders prepared from cornflower aqueous extracts.

The present study aimed to prepare blue colored powders from an aqueous extract of cornflower petals. Low temperature (4 °C) aqueous extraction (1:20) and microencapsulation by freeze-drying were performed. A mixture of stabilizers (maltodextrin, guar gum, and lecithin) in a proportion of 10% to the amount of extract was used. The results indicated that the addition of 2% and 4% guar gum to maltodextrin (8-6%) significantly increased the efficiency of the process, but 4% guar gum caused the formation of amorphous particles; therefore, 2% guar gum addition was found to be the most optimal. The FT-IR and FT-Raman band characteristics for guar gum, lecithin, and maltodextrin dominated over those for anthocyanins contained in the powders made from cornflower petals. The blue powders had total phenolic content of 19.5-26.6 mg GAE/g DW. The antioxidant activity of the prepared powders measured by ABTS, CHEL, OH, and RED was high.