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In this study, genetic variability, antimicrobial activity and water-soluble vitamins content were investigated among Acacia ehrenbergiana, Acacia seyal, Acacia etbaica, Acacia tortilis and Acacia asak. Random Amplified Polymorphic DNA (RAPD), Inter Simple Sequence Repeats (ISSR) and mixed primers were used to evaluate the genetic variability among Acacia spp. 58 bands resulted from RAPD primers of which 51 unique bands, 7 polymorphic bands and no monomorphic bands with similarity values between 18.37% to 63.38%. ISSR primers showed 75 scorable bands of which 42 unique bands, 31 polymorphic bands and 2 monomorphic bands with similarity values ISSR (25% to 47.06%). Mixed primers showed 71 bands of which 41 unique bands, 29 polymorphic bands and one monomorphic band with similarity values ranged between 29.09% to 46.39%. RAPD and mixed primers separated Acacia ehrenbergiana from other investigated species while ISSR primers separated both Acacia etbaica and Acacia tortilis from other species. Antimicrobial activities were screened against six human pathogenic microorganisms (HPM) and four plant pathogenic fungi (PPF) by using agar well diffusion method. Except extract of dry bark of Acacia tortilis and fresh leaves of Acacia asak all others had significant antimicrobial activities against HPM and all extracts against PPF showed weak activities. High Performance Liquid Chromatography (HPLC) was used to estimate the vitamin B1, folic acid, B12 and B2 content among Acacia spp. The highest content of vitamin B1 and folic acid found in Acacia seyal fresh leaves, B12 in Acacia etbaica fresh leaves while B2 in Acacia asak dry bark. In conclusion, RAPD, ISSR and mixed primers showed ability to distinguish variability among Acacia spp., and those plants posses' natural antimicrobials agent and natural vitamins that could be used as an alternative to the synthetic drugs. [ABSTRACT FROM AUTHOR]

One of the important factors in molecular biology analysis is DNA extraction process to obtain high quality DNA. Previously, all attempts to extract DNA from date palm involved either the use of fresh leaves or germinated seeds. The aim of this study was to extract genomic DNA from various parts of three years old date palm fruit and to evaluate the genetic diversity among seven cultivars of date palm. The fruit of each cultivar was dissected into perianth, seed without embryo, zygotic embryo, and endocarp-mescocarp-epicarp to extract the DNA. The results showed that genomic DNA could be easily extracted in sufficient quantity from zygotic embryo. Both RAPD and ISSR markers could effectively determine the genetic relationship among date palm cultivars with polymorphism percentage ranging between 32.09% and 36.49% respectively. RAPD markers showed that cultivars with highest similarity value were Lbanah and Nabtat Ali (80.0%), followed by Khalas and Sukkary (73.81%), while the least were Ajwa and Safawi (59.56%). ISSR revealed that the highest similarity values were for Anbar and Khalas (88.0%), followed by Lbanah and Nabtat Ali (86.18%), while the least were Khalas and Safawi (73. 81%). [ABSTRACT FROM AUTHOR]

In the present study we used 2D-PAGE and Western blotting to investigate the expression of different isotypes of apyrase (EC 3.6.1.5) during imbibition, germination and initial growth of pea (Pisum sativum L. var. Alaska) seedlings in the dark. The 49 kDa apyrase was absent in the 10-h imbibed embryos, but began to appear after 16 h germination and increased with germination time. By 62 h, there were five isotypes present at pI 5.8, 6.0, 6.3, 6.6 and 6.8, with those at pI 6.0, 6.3, and 6.6 being most abundant and the one at pI 6.3 predominating, whereas the most acidic and basic isotypes were only present in significant amounts in seedlings after 62 h germination. Stems contained all five isotypes and had more pI 6.0, 6.3 and 6.6 isotype than the plumules, whereas in the roots there were very small amounts of all isotypes. Partial amino acid sequencing showed that all isotypes were identical with apy1, not the more recently described apy2. Apyrase activity was absent in imbibed embryos, but increased sharply during germination and reached a maximum after 62 h. Based upon the capability of the enzyme to hydrolyse ATP, CTP, GTP, TTP, UTP, and ADP (but not AMP), its susceptibility to various ATPase inhibitors, and coincidence of expression of the protein and enzyme activity, we estimate that 50–70% of the ATPase activity results from the 49 kDa apyrase. The present results suggest that isotypes of pI 6.0, 6.3, and 6.6 are physiologically important and strongly indicate a crucial role for apyrase in the differentiation and development of pea seedlings. [ABSTRACT FROM AUTHOR]

Rumex nervosus, common weed plant in Sarawat Mountains, Saudi Arabia, belongs to family Polygonaceae and usually used as traditional herbal medicines. In the current study, R. nervosus plants dissected into roots, stems, leaves, and flowers that collected from seven locations in Aseer region, Kingdom of Saudi Arabia. The antimicrobial activity of methanol and n-hexane extracts was investigated against three pathogenic bacterial strains and one pathogenic fungus by using agar well-diffusion method. The phytochemicals and vitamins content present in the methanol extracts was investigated by using gas chromatography-mass spectrometry (GC-MS) analysis and high-performance liquid chromatography (HPLC). The results revealed that all extracts showed significant activity against tested microbes. Methanol extracts demonstrated the highest degree of antimicrobial inhibition activity as compared with n-hexane extracts. The root extracts exhibited the highest inhibitory activity against the tested microbes. The GC-MS and HPLC indicated the presence of numerous phytochemicals in the different parts of R. nervosus as well as a set of vitamins including vitamins B1,B2,B12, and folic acid. In conclusion, the present study showed that methanol and n-hexane extracts of all parts of R. nervosus could be used as promising alternative drugs to treat bacterial and Candida spp. infections. [ABSTRACT FROM AUTHOR]

Background. Next-generation sequencing methods have been developed and proposed to investigate any query in genomics or clinical activity involving DNA. Technical advancement in these sequencing methods has enhanced sequencing volume to several billion nucleotides within a very short time and low cost. During the last few years, the usage of the latest DNA sequencing platforms in a large number of research projects helped to improve the sequencing methods and technologies, thus enabling a wide variety of research/review publications and applications of sequencing technologies. Objective. The proposed study is aimed at highlighting the most fast and accurate NGS instruments developed by various companies by comparing output per hour, quality of the reads, maximum read length, reads per run, and their applications in various domains. This will help research institutions and biological/clinical laboratories to choose the sequencing instrument best suited to their environment. The end users will have a general overview about the history of the sequencing technologies, latest developments, and improvements made in the sequencing technologies till now. Results. The proposed study, based on previous studies and manufacturers' descriptions, highlighted that in terms of output per hour, Nanopore PromethION outperformed all sequencers. BGI was on the second position, and Illumina was on the third position. Conclusion. The proposed study investigated various sequencing instruments and highlighted that, overall, Nanopore PromethION is the fastest sequencing approach. BGI and Nanopore can beat Illumina, which is currently the most popular sequencing company. With respect to quality, Ion Torrent NGS instruments are on the top of the list, Illumina is on the second position, and BGI DNB is on the third position. Secondly, memory- and time-saving algorithms and databases need to be developed to analyze data produced by the 3rd- and 4th-generation sequencing methods. This study will help people to adopt the best suited sequencing platform for their research work, clinical or diagnostic activities. [ABSTRACT FROM AUTHOR]

The P-glycoprotein (P-gp/ABCB1) is responsible for a xenobiotic efflux pump that shackles intracellular drug accumulation. Additionally, it is included in the dud of considerable antiviral and anticancer chemotherapies because of the multidrug resistance (MDR) phenomenon. In the search for prospective anticancer drugs that inhibit the ABCB1 transporter, the Natural Product Activity and Species Source (NPASS) database, containing >35,000 molecules, was explored for identifying ABCB1 inhibitors. The performance of AutoDock4.2.6 software to anticipate ABCB1 docking score and pose was first assessed according to available experimental data. The docking scores of the NPASS molecules were predicted against the ABCB1 transporter. Molecular dynamics (MD) simulations were conducted for molecules with docking scores lower than taxol, a reference inhibitor, pursued by molecular mechanics-generalized Born surface area (MM-GBSA) binding energy estimations. On the basis of MM-GBSA calculations, five compounds revealed promising binding affinities as ABCB1 inhibitors with ΔGbinding < −105.0 kcal/mol. The binding affinity and stability of the identified inhibitors were compared to the chemotherapeutic agent. Structural and energetical analyses unveiled great steadiness of the investigated inhibitors within the ABCB1 active site throughout 100 ns MD simulations. Conclusively, these findings point out that NPC104372, NPC475164, NPC2313, NPC197736, and NPC477344 hold guarantees as potential ABCB1 drug candidates and warrant further in vitro/in vivo tests. [ABSTRACT FROM AUTHOR]

Herein, a thorough comparative investigation for the potentiality of triel, tetrel, pnicogen, and chalcogen to engage in π-hole interactions with π-systems and Lewis bases was conducted. π-hole donors, namely, AlF3, SiF2O, PFO2, and SO3, were subjected to interact with benzene (BZN)/hexafluorobenzene (HFB) as electron-rich/electron-deficient π-systems and NH3, NCH, FH, and CO2 as Lewis bases. Using a wide range of quantum mechanical calculations, it was manifested that the investigated π-hole···π-system/Lewis base interactions exhibited preferential negative interaction energies with values up to −30.38 kcal/mol for AlF3···NH3 complex. π-hole···Lewis base complexes participated in a stronger π-hole bond than the π-hole···π-system analogs. In comparison, the reversed pattern was noticed for the π-hole···electron-deficient π-system. Quantum theory of atoms in molecules (QTAIM) analysis announced the closed-shell nature of all complexes under study except π-hole···NH3 interactions that recognized with a salient covalent nature. Symmetry-adapted perturbation theory-based energy decomposition analysis (SAPT-EDA) announced that the π-hole···π-system interactions were governed by the dispersion forces, whereas the π-hole···Lewis base interactions were dominated by the electrostatic terms. The emerging findings from the current work will establish a fruitful linchpin for the future progress of π-hole and π-system based interactions, which in turn lead to the amelioration of research in materials science, crystal engineering, and drug design. [ABSTRACT FROM AUTHOR]

Alternaria tenuissima was isolated from tomato showing symptoms of leaf spot disease cultivated under greenhouse conditions from Asir region, Saudi Arabia. The ability of salicylic acid (SA) and the newly prepared bioactive matter "Agrileen" (AG) to suppress the leaf spot disease of tomato was evaluated. Exogenous application of SA (0.5 and 1.0 mM) or AG (2.5 and 5%) enhanced the growth and plant yield of tomato in addition to the reduction of infection with A. tenuissima. Photosynthetic pigments, total proteins, free proline and the relative water content of leaves were also enhanced when either SA or AG was applied. The protein pattern showed an increase in band intensity in plants treated with SA that express the increase in gene expression involved in resistance against stress conditions. The results confirmed that the application of SA or AG could protect tomato plants against A. tenuissima infection either through the direct strength of the defense system and a reduction of the severity of the pathogen. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a recently emanating human infectious coronavirus that causes COVID-19 disease. On 11th March 2020, it has been announced as a pandemic by the World Health Organization (WHO). Recently, several repositioned drugs have been subjected to clinical investigations as anti-COVID-19 drugs. Here, in silico drug discovery tools were utilized to evaluate the binding affinities and features of eighteen anti-COVID-19 drug candidates against SARS-CoV-2 main protease (Mpro). Molecular docking calculations using Autodock Vina showed considerable binding affinities of the investigated drugs with docking scores ranging from − 5.3 to − 8.3 kcal/mol, with higher binding affinities for HIV drugs compared to the other antiviral drugs. Molecular dynamics (MD) simulations were performed for the predicted drug-Mpro complexes for 50 ns, followed by binding energy calculations utilizing molecular mechanics-generalized Born surface area (MM-GBSA) approach. MM-GBSA calculations demonstrated promising binding affinities of TMC-310911 and ritonavir towards SARS-CoV-2 Mpro, with binding energy values of − 52.8 and − 49.4 kcal/mol, respectively. Surpass potentialities of TMC-310911 and ritonavir are returned to their capabilities of forming multiple hydrogen bonds with the proximal amino acids inside Mpro's binding site. Structural and energetic analyses involving root-mean-square deviation, binding energy per-frame, center-of-mass distance, and hydrogen bond length demonstrated the stability of TMC-310911 and ritonavir inside the Mpro's active site over the 50 ns MD simulation. This study sheds light on HIV protease drugs as prospective SARS-CoV-2 Mpro inhibitors. [ABSTRACT FROM AUTHOR]

The Egyptian Sinai is a rich source of plant‐derived medicines from the highly represented Asteraceae family; however, the protocol for effective chemical extraction has not been standardized. To identify an effective extraction method for essential oils for highly represented species, Achillea fragrantissima, Artemisia judaica and Tanacetum sinaicum were analysed by hydro‐distillation (HD) vs microwave‐assisted (MA) extraction. A total of 82 metabolites were identified by gas chromatography‐mass spectrometry (GC‐MS). While oxygenated monoterpenes were the major class for both methods, MA extraction proved to be slightly more effective in extracting some ketones and alcohols such as piperitone and thymol, respectively. All the extracted EOs from the three plants exhibited significant antimicrobial potentialities in which T sinaicum ˃ A judaica > A fragrantissima. Interestingly, essential oils extracted by HD (vs MAE) exhibited greater lettuce phytotoxicity with respect to root and shoot growth as well as seed germination. Although the two extraction methods produce slightly different chemical profiles for the three analysed species, the plants aggregated similarly based on principal component analysis. [ABSTRACT FROM AUTHOR]

A new Tetrahydrofuran sesquiterpene 7,10‐Epoxy‐10‐methy‐dodeca‐1,6(14)‐diene‐3,4‐diol (1) along with three known Tetrahydrofuran sesquiterpene compounds 2,6,10‐trimethyl‐2,5:7,10‐dioxido‐dodeca‐3,11‐dien‐5‐ol (2), cis‐hydroxydavanone (3), and davana acid (4). All isolated metabolites were tested against MCF‐7, HCT‐116, and HepG‐2 cancer cell lines. Compound 2 showed potent activity against MCF‐7 (IC50 = 26 ± 0.4 μg/ml), HCT‐116 (IC50 = 30.4 ± 0.9 μg/ml), and HepG‐2 (IC50 = 20.5 ± 0.3 μg/ml) cancer cells. [ABSTRACT FROM AUTHOR]

Prosopis juliflora (P. juliflora) is a widespread phreatophytic tree, which belongs to the Fabaceae family. The goal of the present study is to investigate the potential anti-cancer effect of P. juliflora leave extracts and to identify its chemical composition. For this purpose, MCF-7 (breast), HepG2 (liver), and LS-174T (colorectal) cancer cell lines were cultivated and incubated with various concentrations of P. juliflora leave extracts, and its impact on cell viability, proliferation, and cell cycle stages was investigated. P. juliflora leave extracts induced concentration-dependent cytotoxicity against all tested cancer cell lines. The calculated IC50 was 18.17, 33.1 and 41.9 μg/ml for MCF-7, HePG2 and LS-174T, respectively. Detailed analysis revealed that the cytotoxic action of P. juliflora extracts was mainly via necrosis but not apoptosis. Moreover, DNA content flow cytometry analysis showed cell-specific anti-proliferative action and cell cycle stages arrest. In order to identify the anti-cancer constituents of P. juliflora, the ethyl extracts were analyzed by liquid chromatography-mass spectrometry. The major constituents identified in the ethyl extracts of P. juliflora leaves were hydroxymethyl-pyridine, nicotinamide, adenine, and poly-(methyl methacrylate) (PMMA). In conclusion, P. juliflora ethyl acetate extracts have a potential anti-cancer effect against breast adenocarcinoma, hepatocellular carcinoma, and colorectal adenocarcinoma, and is enriched with anti-cancer constituents. [ABSTRACT FROM AUTHOR]

We developed a green, inexpensive and simple method for the synthesis of silver nanoparticles from the Opuntia Ficus (OF) Indica fruit juice. The synthesized AgNPs were used as sensor for the detection of toxic metal (Hg2+) using colorimetric technique as well as to investigate the antimicrobial activities against number of clinical isolates of human microbes. The synthesized AgNPs nanoparticles were characterized using UV-Vis spectroscopy, FTIR spectroscopy, scanning electron microscopy and EDX methods. The green synthesized AgNPs showed surface plasmon resonance absorption band at 441 nm, which confirm the formation of AgNPs that were also established by FTIR and EDX analyses. The colour of AgNPs changes from blood red to white in the presence of Hg2+ only, which can be differentiated and detected by the naked eye within few seconds without the prerequisite of surface amendment from other metals (Co, Ni, Fe, Mn, Pb, Zn, Cr). A good linear response (R2=0.97) was obtained towards Hg2+ ions in the concentration range of 10-3 to 10-8M. In addition, all growth of the tested microbial stains ceased in varied range. OFAg-2 had the highest inhibition effect followed by OFAg-1, while OF did not show any antimicrobial activities. Candida albican and Klebsiella pneumonia are the most susceptible microbes by OFAg-2 and OFAg-1 respectfully. Klebsiella oxytocam, Proteus mirabilis and Klebsiella oxytoca had the moderate susceptibility from OFAg-2 and OF, while Staphylococcus aureus was found to be the lowest susceptible microbes. Therefore, OFAg-2 and OFAg-1 probably could be promising pharmaceutical agents against many microbial strains. [ABSTRACT FROM AUTHOR]

Isolation and identification of the indigenous yeasts of the rotten date fruits for possible production of bioethanol and single-cell protein was the aim of this study. Results showed that a considerable amount of date fruits is subjected to unfavorable conditions of storage that induce their rot and spoilage. From the rotten date fruits, ten yeast isolates were obtained and genetically identified by the sequence of D1/D2 domain of the 26S rRNA gene and phylogenetic analysis. The identity of these yeasts was: Hanseniaspora guilliermondii, H. uvarum (2 strains), H. opuntiae, Pichia kudriavzevii (2 strains), Issatchenkia orientalis, Wickerhamomyces anomalus, Yarrowia lipolytica and Zygosaccharomyces rouxii. The ability of these strains to ferment 20% of the spoilage date fruit juice evaluated on laboratory scale. Results proved that P. kudriavzevii KKUY-0151 and H. uvarum KKUY-0153 yielded 67.48 and 67.37 g/L respectively, of bioethanol as the highest producers. However, H. uvarum KKUY-0078, H. guilliermondii KKUY-0009 and Z. Rouxii KKUY-0157 produced the highest fresh biomass weight 31.76, 30.96 and 30.69 g/L, respectively as a single cell protein production. The study is a pioneer to investigate the endemic yeasts of the rotten date fruits. It concludes that some of the indigenous yeasts of the rotten date fruits are promising organisms in recycling the substrate into valuable products such as bioethanol and single-cell protein. © 2014 Friends Science Publishers [ABSTRACT FROM AUTHOR]

Phytochemical studies of the aerial parts of Euphorbia rigida afforded three triterpenes: betulin (1), cycloart-23Z-ene-3, 25-diol (2) and cycloartan-3, 24, 25-triol (3), firstly isolated from this plant. The structures and relative stereochemistry were determined on the basis of extensive spectroscopic analyses, including 1D and 2D NMR experiments (1H NMR, 13C NMR, COSY, NOESY, HMQC and HMBC). [ABSTRACT FROM AUTHOR]

Different species belonging to the genus Nephthea (Acyonaceae) are a rich resource for bioactive secondary metabolites. The literature reveals that the gastroprotective effects of marine secondary metabolites have not been comprehensively studied in vivo. Hence, the present investigation aimed to examine and determine the anti-ulcer activity of 4α,24-dimethyl-5α-cholest-8β,18-dihydroxy,22E-en-3β-ol (ST-1) isolated from samples of a Nephthea species. This in vivo study was supported by in silico molecular docking and protein–protein interaction techniques. Oral administration of ST-1 reduced rat stomach ulcers with a concurrent increase in gastric mucosa. Molecular docking calculations against the H+/K+-ATPase transporter showed a higher binding affinity of ST-1, with a docking score value of −9.9 kcal/mol and a pKi value of 59.7 nM, compared to ranitidine (a commercial proton pump inhibitor, which gave values of −6.2 kcal/mol and 27.9 µM, respectively). The combined PEA-reactome analysis results revealed promising evidence of ST-1 potency as an anti-ulcer compound through significant modulation of the gene set controlling the PI3K signaling pathway, which subsequently plays a crucial role in signaling regarding epithelialization and tissue regeneration, tissue repairing and tissue remodeling. These results indicate a probable protective role for ST-1 against ethanol-induced gastric ulcers. [ABSTRACT FROM AUTHOR]

Coronavirus disease 2019 (COVID-19) is a new pandemic characterized by quick spreading and illness of the respiratory system. To date, there is no specific therapy for Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2). Flavonoids, especially rutin, have attracted considerable interest as a prospective SARS-CoV-2 main protease (Mpro) inhibitor. In this study, a database containing 2017 flavone analogs was prepared and screened against SARS-CoV-2 Mpro using the molecular docking technique. According to the results, 371 flavone analogs exhibited good potency towards Mpro with docking scores less than −9.0 kcal/mol. Molecular dynamics (MD) simulations, followed by molecular mechanics-generalized Born surface area (MM/GBSA) binding energy calculations, were performed for the top potent analogs in complex with Mpro. Compared to rutin, PubChem-129-716-607 and PubChem-885-071-27 showed better binding affinities against SARS-CoV-2 Mpro over 150 ns MD course with Δ G binding values of −69.0 and −68.1 kcal/mol, respectively. Structural and energetic analyses demonstrated high stability of the identified analogs inside the SARS-CoV-2 Mpro active site over 150 ns MD simulations. The oral bioavailabilities of probable SARS-CoV-2 Mpro inhibitors were underpinned using drug-likeness parameters. A comparison of the binding affinities demonstrated that the MM/GBSA binding energies of the identified flavone analogs were approximately three and two times less than those of lopinavir and baicalein, respectively. In conclusion, PubChem-129-716-607 and PubChem-885-071-27 are promising anti-COVID-19 drug candidates that warrant further clinical investigations. [Display omitted] • A database containing 2017 flavone analogs was prepared and screened against SARS-CoV-2 Mpro using in silico techniques. • PubChem-129-716-607 and PubChem-885-071-27 demonstrated higher binding affinities against Mpro than rutin and baicalein. • PubChem-129-716-607 and PubChem-885-071-27 exhibited high stability inside the Mpro active site over 150 ns MD simulations. • PubChem-129-716-607 and PubChem-885-071-27 manifested promising drug-likeness properties. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent for the COVID-19 pandemic, which generated more than 1.82 million deaths in 2020 alone, in addition to 83.8 million infections. Currently, there is no antiviral medication to treat COVID-19. In the search for drug leads, marine-derived metabolites are reported here as prospective SARS-CoV-2 inhibitors. Two hundred and twenty-seven terpene natural products isolated from the biodiverse Red-Sea ecosystem were screened for inhibitor activity against the SARS-CoV-2 main protease (Mpro) using molecular docking and molecular dynamics (MD) simulations combined with molecular mechanics/generalized Born surface area binding energy calculations. On the basis of in silico analyses, six terpenes demonstrated high potency as Mpro inhibitors with ΔGbinding ≤ −40.0 kcal/mol. The stability and binding affinity of the most potent metabolite, erylosides B, were compared to the human immunodeficiency virus protease inhibitor, lopinavir. Erylosides B showed greater binding affinity towards SARS-CoV-2 Mpro than lopinavir over 100 ns with ΔGbinding values of −51.9 vs. −33.6 kcal/mol, respectively. Protein–protein interactions indicate that erylosides B biochemical signaling shares gene components that mediate severe acute respiratory syndrome diseases, including the cytokine- and immune-signaling components BCL2L1, IL2, and PRKC. Pathway enrichment analysis and Boolean network modeling were performed towards a deep dissection and mining of the erylosides B target–function interactions. The current study identifies erylosides B as a promising anti-COVID-19 drug lead that warrants further in vitro and in vivo testing. [ABSTRACT FROM AUTHOR]

Centaurothamnus maximus (family Asteraceae), is a leafy shrub indigenous to the southwestern Arabian Peninsula. With a paucity of phytochemical data on this species, we set out to chemically characterize the plant. From the aerial parts, two newly identified guaianolides were isolated: 3β-hydroxy-4α(acetoxy)-4β(hydroxymethyl)-8α-(4-hydroxy methacrylate)-1αH,5αH, 6αH-gual-10(14),11(13)-dien-6,12-olide (1) and 15-descarboxy picrolide A (2). Seven previously reported compounds were also isolated: 3β, 4α, 8α-trihydroxy-4-(hydroxymethyl)-lαH, 5αH, 6βH, 7αH-guai-10(14),11(13)-dien-6,12-olide (3), chlorohyssopifolin B (4), cynaropikrin (5), hydroxyjanerin (6), chlorojanerin (7), isorhamnetin (8), and quercetagetin-3,6-dimethyl ether-4'-O-β-d-pyranoglucoside (9). Chemical structures were elucidated using spectroscopic techniques, including High Resolution Fast Atom Bombardment Mass Spectrometry (HR-FAB-MS), 1D NMR; 1H, 13C NMR, Distortionless Enhancement by Polarization Transfer (DEPT), and 2D NMR (1H-1H COSY, HMQC, HMBC) analyses. In addition, a biosynthetic pathway for compounds 1–9 is proposed. The chemotaxonomic significance of the reported sesquiterpenoids and flavonoids considering reports from other Centaurea species is examined. [ABSTRACT FROM AUTHOR]