Chemical Composition and Biological Activity of Allium cepa L. and Allium × cornutum (Clementi ex Visiani 1842) Methanolic Extracts.
ABSTRACT: Here, we report a comparative study of the phytochemical profile and the biological activity of two onion extracts, namely Allium cepa L. and Allium × cornutum (Clementi ex Visiani 1842), members of the family Amaryllidaceae. The identification of flavonoids and anthocyanins, and their individual quantities, was determined by high-performance liquid chromatography (HPLC). The potency of both extracts to scavenge free radicals was determined by the DPPH (2,2'-diphenyl-1-picrylhydrazyl) radical-scavenging activity and oxygen radical absorbance capacity (ORAC) methods. The DNA protective role was further tested by the single-cell gel electrophoresis (COMET) assay and by Fenton's reagent causing double-strand breaks on the closed circular high copy pUC19 plasmid isolated from Escherichia coli. In the presence of both extracts, a significant decrease in DNA damage was observed, which indicates a protective role of Allium cepa and Allium × cornutum on DNA strand breaks. Additionally, cytotoxicity was tested on glioblastoma and breast cancer cell lines. The results showed that both extracts had antiproliferative effects, but the most prominent decrease in cellular growth was observed in glioblastoma cells.
Project description:BACKGROUND: Reconstruction of the parental origins of cultivated plants from wild relatives, especially after long periods of domestication, is not a trivial task. However, recent advances in molecular phylogenetics, among other approaches, have proved to be very informative in analyses of the origin and evolution of polyploid genomes. An established minor garden crop, triploid onion Allium × cornutum (Clementi ex Visiani, 1842) (2n = 3x = 24), is widespread in southeastern Asia and Europe. Our previous cytogenetic analyses confirmed its highly heterozygous karyotype and indicated its possible complex triparental genome origin. Allium cepa L. and Allium roylei Stearn were suggested as two putative parental species of A. × cornutum, whereas the third parental species remained hitherto unknown. RESULTS: Here we report the phylogenetic analyses of the internal transcribed spacers ITS1-5.8S-ITS2 of 35S rDNA and the non-transcribed spacer (NTS) region of 5S rDNA of A. × cornutum and its relatives of the section Cepa. Both ITS and NTS sequence data revealed intra-individual variation in triploid onion, and these data clustered into the three main clades, each with high sequence homology to one of three other species of section Cepa: A. cepa, A. roylei, and unexpectedly, the wild Asian species Allium pskemense B. Fedtsh. Allium pskemense is therefore inferred to be the third, so far unknown, putative parental species of triploid onion Allium × cornutum. The 35S and 5S rRNA genes were found to be localised on somatic chromosomes of A. × cornutum and its putative parental species by double fluorescent in situ hybridisation (FISH). The localisation of 35S and 5S rDNA in A. × cornutum chromosomes corresponded to their respective positions in the three putative parental species, A. cepa, A. pskemense, and A. roylei. GISH (genomic in situ hybridisation) using DNA of the three putative parental diploids corroborated the results of the phylogenetic study. CONCLUSIONS: The combined molecular, phylogenetic and cytogenetic data obtained in this study provided evidence for a unique triparental origin of triploid onion A. × cornutum with three putative parental species, A. cepa, A. pskemense, and A. roylei.
Project description:Species that belong to the genus Allium have been widely used for human food and traditional medicine. Their beneficial health effects, as well as the specific aroma, are associated with their bioactive chemical compounds, such as sulfur compounds and flavonoids. Gas chromatography and mass spectrometry (GC-MS) and reverse-phase high-performance liquid chromatography (reverse-phase HPLC) were used to identify organosulfur and amino acid content of triploid hybrid onion, Allium cornutum Clement ex Visiani, 1842, and common onion, Allium cepa L. Allium extracts were tested for their antiproliferative activity in three human cancer cell lines (HeLa, HCT116, and U2OS). DNA fragmentation and DAPI staining analysis were performed on HeLa cells to evaluate the effect of extracts on DNA damage and cell morphology. The mRNA expression of p53, Bax, and Caspase-3 genes involved in apoptosis were analyzed by real-time PCR. Using GC-MS, 27 compounds were found in two Allium species headspaces. Differences were noted among the main compound abundance in the headspace (although the major thiols and disulfides were qualitatively identic in both Allium species) and dipropyl disulfide, diisopropyl trisulfide, and (Z)-prop-1-enyl propyl trisulfide were predominant sulfides. Identification of amino acids and their quantities were determined by reverse-phase HPLC. Most abundant amino acids in both onions were arginine (Arg) and glutamic acid (Glu). The results of cytotoxicity testing confirmed antiproliferative effects of both species. The DNA fragmentation assay, DAPI staining and real time PCR analysis confirmed that A. cornutum and A. cepa extracts induced apoptosis in HeLa cells. This study presents the evidence for possible therapeutic use of A. cornutum and A. cepa extracts against human cervical carcinoma cell line.
Project description:Shallots are a valuable minor Allium crop, and are propagated vegetatively and maintained in home gardens across generations along the Croatian coast and island areas. Shallot landraces growing along the Croatian coast fall into three genotypes: Allium cepa Aggregatum group (2n = 2x = 16), A. × proliferum (Moench) Schard. (2n = 2x = 16), and A. × cornutum Clementi ex Vis. (2n = 3x = 24), among which A. × cornutum is the most widespread. The aim of this study was to differentiate shallot accessions collected from local farmers using morphological markers. Also, the chemical composition including phenolic content, phenolic profile, total antioxidant capacity, and mineral composition, of shallot accessions was compared with that of the local landraces of common onion, and with market available shallot and common onion cultivars. Based on morphological observations and using multivariate classification, shallot landraces were classified into three distinct groups. Properties, based on which A. × cornutum can be differentiated from A. cepa Aggregatum and A. × proliferum, are stamen morphology, stamen length, leaf and scape vegetative properties, number of bulbs in cluster, cluster mass, and bulb diameter. Flower diameter and flower pedicel length differentiate A. × cornutum and A. × proliferum from A. cepa Aggregatum. Significant variability was observed in the biochemical profiles across tested accessions. Compared with the commercial common onion cultivars, local shallot accessions have higher bulb N, P, and K content. The major phenolic compounds identified in shallots were quercetin-4′-glucoside and quercetin-3,4′-diglucoside. Additionally, several other minor phenolic compounds were also identified. Morphological and biochemical profiles were evaluated using Partial Least Square (PLS) analysis. Specific morphological traits and biochemical markers for possible species identification are proposed.
Project description:Appropriate effluent treatment processes are expected to significantly reduce the toxicity of effluents before they are released to the natural environment. The present study was aimed to assess the spatial and temporal variations of the physical and chemical water quality parameters of a natural water body receiving treated textile effluents and to assess the chromosomal abnormalities induced by the treated textile effluents. Four sampling sites (A: effluent discharge point; B: 100?m downstream from site A along the tributary; C: 200?m downstream from site A along the tributary; D: 100?m upstream from site A along the tributary) were selected associated to a tributary that received treated textile effluent. The physical and chemical water quality parameters were measured in the composite water samples collected from the study sites, and Allium cepa bioassay was conducted using aged tap water as the control. Sampling was conducted in both rainy and dry seasons. The conductivity, TDS, COD, and colour intensity of the water samples collected from the study sites were significantly higher during the dry season compared to those in the rainy season. Allium cepa root meristematic cells exposed to water samples from sites A, B, and C showed a significantly high interphase and prophase indices compared to those exposed to aged tap water and upstream site during both rainy and dry seasons. The mitotic index of the root tip cells of Allium cepa bulbs exposed to the water samples collected from the effluent discharge point (site A) and from the 100?m downstream site from site A (site B) was significantly lower than that of the other sites in both rainy and dry seasons. However, the mitotic index of the root tip cells of Allium cepa bulbs exposed to the water samples from the upstream site was not significantly different from that of the control treatment during both sampling seasons. The bioassay indicated that the mitotic index and phase index of the root meristematic cells of Allium cepa can be affected by the treated textile effluents released to the water body and the occurrence of C metaphase, chromosomal adherence, bridges, disturbed anaphase, vagrant chromosomes, and chromosomal breaks indicated that the treated textile effluent receiving tributary can possibly contain genotoxic and mutagenic compounds which can induce chromosomal abnormalities.
Project description:Species of the genus Allium are well known for their large genomes. Allium cepa is of great economic significance. Among vegetables, it ranks second after tomato in terms of the global production value. However, there is limited genomics information available on A. cepa. In this study, we sequenced the A. cepa genome at low-coverage and annotated repetitive sequences by using a combination of next-generation sequencing (NGS) and bioinformatics tools. Nearly 92% of 16?Gb haploid onion genome were defined as repetitive sequences, organized in 162 clusters of at least 0.01 percent of the genome. Of these, a proportion representing 40.5% of the genome were further analyzed in detail to obtain an overview of representative repetitive elements present in the A. cepa genome. Few representative satellite repeats were studied by fluorescence in situ hybridization (FISH) and southern blotting. These results provided a basis for evolutionary cytogenomics within the Allium genus.
Project description:Food dyes are important component of food in this fast life. Metanil yellow and carmoisine are two azo dyes which are being used at an alarming rate for increasing visual appearance and consumer validity of food. There is a lot of controversy regarding the genotoxicity of these two dyes. In the present study genotoxicity of two food dyes metanil yellow and carmoisine was evaluated using Allium cepa as indicator. The effect of these two azo dyes was determined at concentration of 0.25 %, 0.50 %, 0.75 % and 1.0 % for 24 h and 48 h of exposure period using root meristematic cells of Allium cepa. Some genotoxicity parameters like mitotic indices and chromosomal aberrations were studied. It was found that both metanil yellow and carmoisine caused a significant reduction in mitotic index and also produce different kinds of chromosomal aberrations mostly at higher concentration and longer exposure period. The different kinds of aberrations that were observed in meristematic cells after treatment with both metanil yellow and carmoisine are disorientation at metaphase, metaphase stickiness, anaphase stickiness, anaphase bridge, c-mitosis and chromosome breaks. The genotoxicity of carmoisine was found very high as compared to metanil yellow at all concentrations and exposure periods. Thus it was concluded from the present study that carmoisine and metanil yellow have genotoxic activities and should be taken in very control and limited doses.
Project description:Knowledge of the fascinating world of DNA repeats is continuously being enriched by newly identified elements and their hypothetical or well-established biological relevance. Genomic approaches can be used for comparative studies of major repeats in any group of genomes, regardless of their size and complexity. Such studies are particularly fruitful in large genomes, and useful mainly in crop plants where they provide a rich source of molecular markers or information on indispensable genomic components (e.g., telomeres, centromeres, or ribosomal RNA genes). Surprisingly, in Allium species, a comprehensive comparative study of repeats is lacking. Here we provide such a study of two economically important species, Allium cepa (onion), and A. sativum (garlic), and their distantly related A. ursinum (wild garlic). We present an overview and classification of major repeats in these species and have paid specific attention to sequence conservation and copy numbers of major representatives in each type of repeat, including retrotransposons, rDNA, or newly identified satellite sequences. Prevailing repeats in all three studied species belonged to Ty3/gypsy elements, however they significantly diverged and we did not detect them in common clusters in comparative analysis. Actually, only a low number of clusters was shared by all three species. Such conserved repeats were for example 5S and 45S rDNA genes and surprisingly a specific and quite rare Ty1/copia lineage. Species-specific long satellites were found mainly in A. cepa and A. sativum. We also show in situ localization of selected repeats that could potentially be applicable as chromosomal markers, e.g., in interspecific breeding.
Project description:MicroRNAs are small non-coding RNAs of 21-24 nucleotides in length that acts as important modulators of gene expression related to numerous biological processes including development and defense response in eukaryotes. However, only a limited report on onion (Allium cepa) miRNAs is available and their associated role in growth and development of onion is not yet clear. Therefore, it is of interest to identify miRNAs and their targets in Allium cepa using the genome survey sequences (GSSs) and expressed sequence tags (ESTs) and deduce the functions of the target genes using gene ontology (GO) terms. We report 14 potential miRNAs belonging to 13 different families (miR162, miR168, miR172c, miR172e, miR398, miR400, miR414, miR1134, miR1223, miR6219, miR7725, miR8570, miR8703 and miR8752). BLAST analysis using psRNATarget server predicted 39 potential targets for the identified miRNAs majority of which were transcription factors implicated in plant growth, development, hormone signaling and stress responses. These data forms the basis for further analysis and verification towards understanding the miRNA mediated regulatory mechanism in Allium cepa.
Project description:The centromere is a unique part of the chromosome combining a conserved function with an extreme variability in its DNA sequence. Most of our knowledge about the functional centromere organization is obtained from species with small and medium genome/chromosome sizes while the progress in plants with big genomes and large chromosomes is lagging behind. Here, we studied the genomic organization of the functional centromere in Allium fistulosum and A. cepa, both species with a large genome (13 Gb and 16 Gb/1C, 2n = 2x = 16) and large-sized chromosomes. Using low-depth DNA sequencing for these two species and previously obtained CENH3 immunoprecipitation data we identified two long (1.2 Kb) and high-copy repeats, AfCen1K and AcCen1K. FISH experiments showed that AfCen1K is located in all centromeres of A. fistulosum chromosomes while no AcCen1K FISH signals were identified on A. cepa chromosomes. Our molecular cytogenetic and bioinformatics survey demonstrated that these repeats are partially similar but differ in chromosomal location, sequence structure and genomic organization. In addition, we could conclude that the repeats are transcribed and their RNAs are not polyadenylated. We also observed that these repeats are associated with insertions of retrotransposons and plastidic DNA and the landscape of A. cepa and A. fistulosum centromeric regions possess insertions of plastidic DNA. Finally, we carried out detailed comparative satellitome analysis of A. cepa and A. fistulosum genomes and identified a new chromosome- and A. cepa-specific tandem repeat, TR2CL137, located in the centromeric region. Our results shed light on the Allium centromere organization and provide unique data for future application in Allium genome annotation.
Project description:Plants of the Allium genus produce sulphur compounds that give them a characteristic (alliaceous) flavour and mediate for their medicinal use. In this study, the chemical composition and antimicrobial properties of Allium cepa red cv. and A. sativum in the context of three different drying processes were assessed using metabolomics. Bulbs were dried using either microwave, air drying, or freeze drying and further subjected to chemical analysis of their composition of volatile and non-volatile metabolites. Volatiles were collected using solid phase micro-extraction (SPME) coupled to gas chromatography-mass spectrometry (GC/MS) with 42 identified volatiles including 30 sulphur compounds, four nitriles, three aromatics, and three esters. Profiling of the polar non-volatile metabolites via ultra-performance liquid chromatography coupled to high resolution MS (UPLC/MS) annotated 51 metabolites including dipeptides, flavonoids, phenolic acids, and fatty acids. Major peaks in GC/MS or UPLC/MS contributing to the discrimination between A. sativum and A. cepa red cv. were assigned to sulphur compounds and flavonoids. Whereas sulphur conjugates amounted to the major forms in A. sativum, flavonoids predominated in the chemical composition of A. cepa red cv. With regard to drying impact on Allium metabolites, notable and clear separations among specimens were revealed using principal component analysis (PCA). The PCA scores plot of the UPLC/MS dataset showed closer metabolite composition of microwave dried specimens to freeze dried ones, and distant from air dried bulbs, observed in both A. cepa and A. sativum. Compared to GC/MS, the UPLC/MS derived PCA model was more consistent and better in assessing the impact of drying on Allium metabolism. A phthalate derivative was found exclusively in a commercial garlic preparation via GC/MS, of yet unknown origin. The freeze dried samples of both Allium species exhibited stronger antimicrobial activities compared to dried specimens with A. sativum being in general more active than A. cepa red cv.