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:Onions are one of the most widely grown vegetable crops. As production increases, so does the generation of waste from various parts of the onion, raising the need for efficient ecological disposal and use of such waste products. However, onion waste products are a rich source of antioxidants with a range of biological properties, therefore, they could potentially be used in food and pharmaceutical industries. In the present study, we identified the main flavonols and anthocyanins in peel extracts of <i>Allium × cornutum</i> Clement ex Visiani, 1842, and two varieties of <i>Allium cepa</i> L. and tested their antioxidant, antimicrobial and antiproliferative properties. Quercetin 3,4'-diglucolside, quercetin 4'-monoglucoside and quercetin are the most abundant flavonols in all onion extracts detected by high-performance liquid chromatography (HPLC) method. The composition of anthocyanins varied in all extracts. 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays showed that the triploid onion <i>A. × cornutum</i> had the highest antioxidant power. Evaluation of antimicrobial activity by broth microdilution assay also showed that <i>A. × cornutum</i> had higher antimicrobial activity compared to the red and yellow onion varieties. Comparable antiproliferative activity was confirmed for all onion extracts tested on three cancer cell lines: Hela (cervical cancer cell line), HCT116 (human colon cancer cell line) and U2OS (human osteosarcoma cell line). The most abundant onion flavonols (quercetin 3,4'-diglucoside and quercetin 4'-monoglucoside) showed weaker antimicrobial as well as antiproliferative properties compared to the extracts, leading to the conclusion that other phytochemicals besides flavonols contribute to the biological activity of onion peel extracts. The results demonstrate the antioxidant and antimicrobial properties of onion peels, which have promising potential as cancer cell proliferation inhibitors.
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:<h4>Introduction</h4>Staining is an important histological process; however, the use of non-toxic and environmentally friendly products is generally required. We explored the staining quality of two natural plants, <i>Allium cepa</i> skin and <i>Sorghum bicolor</i> seed extract on the cytoplasm.<h4>Materials and methods</h4>Distilled water at 37 °C and 1% acid-ethanol were respectively used to extract the dyes from <i>Allium cepa</i> skin and <i>Sorghum bicolor seed</i>.<h4>Result</h4>The application of these two dyes on rodent tissue showed an excellent cytoplasmic histomorphology.<h4>Conclusion</h4><i>Allium cepa</i> skin and <i>Sorghum bicolor</i> seed extracts are good cytoplasmic dyes when used as counterstain for haematoxylin.
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:BACKGROUND: Vegetables of the genus Allium are widely consumed but remain poorly understood genetically. Genetic mapping has been conducted in intraspecific crosses of onion (Allium cepa L.), A. fistulosum and interspecific crosses between A. roylei and these two species, but it has not been possible to access genetic maps and underlying data from these studies easily. DESCRIPTION: An online comparative genomics database, AlliumMap, has been developed based on the GMOD CMap tool at http://alliumgenetics.org. It has been populated with curated data linking genetic maps with underlying markers and sequence data from multiple studies. It includes data from multiple onion mapping populations as well as the most closely related species A. roylei and A. fistulosum. Further onion EST-derived markers were evaluated in the A. cepa x A. roylei interspecific population, enabling merging of the AFLP-based maps. In addition, data concerning markers assigned in multiple studies to the Allium physical map using A. cepa-A. fistulosum alien monosomic addition lines have been compiled. The compiled data reveal extensive synteny between onion and A. fistulosum. CONCLUSIONS: The database provides the first online resource providing genetic map and marker data from multiple Allium species and populations. The additional markers placed on the interspecific Allium map confirm the value of A. roylei as a valuable bridge between the genetics of onion and A. fistulosum and as a means to conduct efficient mapping of expressed sequence markers in Allium. The data presented suggest that comparative approaches will be valuable for genetic and genomic studies of onion and A. fistulosum. This online resource will provide a valuable means to integrate genetic and sequence-based explorations of Allium genomes.
Project description:<i>Allium</i> sect. <i>Cepa</i> (Amaryllidaceae) comprises economically important plants, yet resolving the phylogenetic relationships within the section has been difficult as nuclear and chloroplast-based phylogenetic trees have been incongruent. Until now, phylogenetic studies of the section have been based on a few genes. In this study, we sequenced the complete chloroplast genome (plastomes) of four central Asian species of sect. <i>Cepa</i>: <i>Allium oschaninii</i>, <i>A. praemixtum</i>, <i>A. pskemense</i> and <i>A. galanthum</i>. Their chloroplast (cp) genomes included 114 unique genes of which 80 coded proteins. Seven protein-coding genes were highly variable and therefore promising for future phylogenetic and phylogeographic studies. Our plastome-based phylogenetic tree of <i>Allium</i> sect. <i>Cepa</i> revealed two separate clades: one comprising the central Asian species <i>A. oschaninii</i>, <i>A. praemixtum</i>, and <i>A. pskemense</i>, and another comprising <i>A. galanthum</i>, <i>A. altaicum</i>, and two cultivated species, <i>A. cepa</i> and <i>A. fistulosum</i>. These findings contradict previously reported phylogenies that relied on ITS and morphology. Possible explanations for this discrepancy are related to interspecific hybridization of species ancestral to <i>A. galanthum</i> and <i>A. cepa</i> followed by chloroplast capture; however, this is impossible to prove without additional data. Our results suggest that the central Asian <i>Allium</i> species did not play a role in the domestication of the common onion. Among the chloroplast genes, <i>rpoC2</i> was identified as a gene of choice in further phylogeographical studies of the genus <i>Allium.</i>
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.