Variability in blood platelet inhibitory activity of Allium (Alliaceae) species accessions

In the past 20 yr, the presence of blood platelet inhibitory activity in plant species from the genus Allium has been confirmed by a range of clinical and in vitro investigations. Although a number of Allium species have been identified as possessing antiplatelet properties, little is known of the variability for this trait among accessions in these species. Experiments were conducted to assess variability in antiplatelet activity of 58 Allium (Alliaceae) accessions. Extracts were prepared from a diverse collection of 16 Allium species accessions, 33 cultivated accessions of Allium cepa including standard cultivars, inbred lines, and open-pollinated populations, and nine Allium cepa plant introductions of diverse origin. Platelet inhibitory activity was determined via a platelet aggregation assay with human platelet-rich plasma. Relative in vitro inhibition of platelet aggregation was measured for each accession and control samples, and inhibition constants (IC₅₀) were calculated. Dose-dependent inhibition was observed and measured for each Allium accession. Significant (P < 0.01) IC₅₀ variability was detected among accessions, with the lowest accession IC₅₀ values exhibiting nearly 50-fold greater inhibition of aggregation than the highest accession IC₅₀ values. IC₅₍₎ variability among Allium cepa accessions was ≈ 12 times less than among Allium species accessions. Results from this investigation demonstrate substantial variability for efficacy of the antiplatelet factor among Allium accessions.     

Allium brussalisii (Alliaceae), a new species from Greece

Allium brussalisii , from Mount Parnitha near Athens (Sterea Hellas, Greece), is described as a species new to science and compared with related species of Allium section Codonoprasum and Allium section Brevispatha. It is a diploid species (2n = 2x = 16) that flowers in early autumn. On the basis of its unilateral and more or less entire spathe and the simple filaments, it resembles species of Allium section Brevispatha; however, its sectional taxonomy remains unclear as, on the basis of several other morphological, cytological, and ecological characteristics, it also resembles species of Allium section Codonoprasum. The new species is presently known only from the type locality and is of particular interest for the phylogeny of the genus. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 140–146.     

The effect of species of Allium on soil bacteria in relation to germination of sclerotia of Sclerotium cepivorum Berk

Extracts made from Allium species were shown to exhibit marked antibiotic properties in a variety of tests. However, no evidence was obtained to suggest that intact Allium seedlings exude antibiotic compounds in sufficient quantity to cause inhibition of bacteria in the soil or in assay tests in the laboratory. Germination of sclerotia of Sclerotium cepivorum was induced by Allium extracts which were too dilute to cause antibiotic responses in laboratory tests using a number of bacteria. Synthetic methyl-methanethiolsulphinate had little effect on germination of sclerotia. The specific reversal, by Allium species and their extracts, of the mycostatic effect of unsterile soil on sclerotia of S. cepivorum does not appear to be due to antibiotic effects.     

Comparative study of antioxidant capacity in organs of different Allium species

Cultivated and wild Allium species were investigated in order to compare the antioxidant capacity of their leaves and bulbs. Leaf and bulb anti-oxidative enzymes and scavenger activities, along with quantities of non-enzymic antioxidants, malonyl-dialdehyde and OH radicals were determined. Results obtained suggest that leaves possess higher anti-oxidant and scavenging activities than bulbs in the majority of cultivated and wild Allium species examined. Cultivation of some wild species such as A. flavum L., A. schoenoprasum L. and A. ursinum L. could be conducted in the future in order to produce Allium species with high antioxidant capacity in leaves and bulbs.     

Germination of sclerotia of Sclerotium cepivorum Berk. under aseptic conditions

The response of sclerotia of Sclerotium cepivorum to a number of plant extracts and nutrient solutions was tested, aseptically, on agars, silica gels, filter paper discs, and on columns of soil. There was no specific response of sclerotia to extracts of Allium species in any of these experiments, whereas in unsterile soil consistently high levels of germination were obtained only with Allium extracts. It was shown that sclerotia are subject to the mycostatic influence of unsterile soil. With S. cepivorum soil mycostasis appears to be specifically reversed by Allium species or by water extracts made from them.     

Phylogenetic relationships among cultivated Allium species from restriction enzyme analysis of the chloroplast genome

Summary The genus Allium contains many economically important species, including the bulb onion, chive, garlic, Japanese bunching onion, and leek. Phylogenetic relationships among the cultivated alliums are not well understood, and taxonomic classifications are based on relatively few morphological characters. Chloroplast DNA is highly conserved and useful in determining phylogenetic relationships. The size of the chloroplast genome of Allium cepa was estimated at 140 kb and restriction enzyme sites were mapped for KpnI, PstI, PvuII, SalI, XbaI, and XhoI. Variability at restriction enzyme sites in the chloroplast DNA was studied for at least three accessions of each of six cultivated, old-world Allium species. Of 189 restriction enzyme sites detected with 12 enzymes, 15 mutations were identified and used to estimate phylogenetic relationships. Cladistic analysis based on Wagner and Dollo parsimony resulted in a single, most-parsimonious tree of 16 steps and supported division of the species into sections. Allium species in section Porrum were distinguished from species in sections Cepa and Phyllodolon. Two species in section Rhiziridium, A. schoenoprasum and A. tuberosum, differed by five mutations and were placed in separate lineages. Allium cepa and A. fistulosum shared the loss of a restriction enzyme site and were phylogenetically closer to each other than to A. schoenoprasum. This study demonstrates the usefulness of restriction enzyme site analysis of the chloroplast genome in the elucidation of phylogenetic relationships in Allium.     

Pollen morphology of some species belonging to Codonoprasum and Allium sections of Allium (Liliaceae-Alliaceae) genus

Pollen morphology of 14 Allium L. species grown in Turkey, that belong to the sections Codonoprasum and Allium, were investigated under LM (light microscopy) and by SEM (scanning electron microscopy). However, the pollens of 5 species were investigated under TEM (transmission electron microscopy). Detailed pollen morphological characteristics are given for Allium in the family on the basis of the results presented here together with data from the literature. The genera Allium homogeneous in both aperture type and exine ornamentation. It is suggested that some palynological characters, such as aperture type and the presence of an operculum, could be of taxonomic value at the section level.     

Seed testa micromorphology of thirty‐eight species of Allium (Amaryllidaceae) from central Asia,and its taxonomic implications

Micromorphological characteristics of the seed testa of 38 species belonging to 19 sections and seven subgenera of Allium from central Asia have been evaluated with a scanning electron microscope (SEM). Several taxonomically significant characters were found. The results showed that the epidermis consists of polygonal cells with different dimensions, that the cellular arrangement is tight or loose with or without reticulate tissue, and that the arrangement of cells is regular or irregular. The main variation was found in the anticlinal walls, of which the outline could be straight, straight to arched, arched or undulating like an S or U. Convex and (or) concave verrucate periclinal walls occurred in all species investigated. Based on the characteristics of the anticlinal and periclinal walls of the 38 species, six groups of Allium were distinguished, and a dichotomous key for them is presented. The cellular arrangement and periclinal and anticlinal wall traits of the 38 species of Allium were found stable and distinct within a species, but showed great differences among species. We conclude that seed epidermal characteristics provide useful and important information for distinguishing species of Allium, and thus they have taxonomic significance.     

Amounts of ribosomal DNA inAllium (Liliaceae)

Eight species ofAllium subgen.Allium sect.Allium have been studied at the cytological level by means of karyological analyses and at the biochemical level with regard to the proportions of ribosomal DNA. All the species have a basic genome of x = 8.A. sativum, A. commutatum, A. ampeloprasum, andA. vineale possess approximately 0.050% rDNA and two nucleolus organizer regions per basic chromosome set.A. sphaerocephalon andA. arvense have two nucleolus organizers, andA. amethystinum three nucleolus organizers per haploid (n = x) genome: the three species possess approximately 0.075% rDNA.A. acutiflorum has five nucleolus organizer regions per haploid genome and 0.121% rDNA. An attempt to relate these differences with functional and ecological characteristics indicates that evolutionary variation of rDNA proportions is not casual. Such data also can help to define systematic affinities and circumscribe infrageneric taxa.     

Chromosome diversity and evolution in Allium (Allioideae,Amaryllidaceae)

Despite extensive literature on the diversity of karyotypes in Allium is available, no attempt to analyse these data together, within a robust phylogenetic framework, has been carried out so far. Thus, we examined patterns and trends in chromosome evolution across the genus. Based on literature survey, karyo-morphometric features for 207 species belonging to 12 subgenera of Allium were obtained. Included in the data-set were basic chromosome number (x), somatic chromosome number (2n), total haploid (monoploid) chromosome length (THL) and three different measures defining karyotype structure: CV_CI, measuring how heterogeneous are centromeres positions in a karyotype, CV_CL and M_CA, quantifying interchromosomal and intrachromosomal karyotype asymmetry, respectively. Trends in karyotype evolution were analysed by phylogenetic regressions and independent contrasts. Mean karyotypes highlighted differences and similarities in karyotype structure between the 12 subgenera. Further differences were noted when the two parameters for analysing karyotype asymmetry were assessed. In addition, by examining the effects of increasing karyotype dimensions (a proxy for genome size) on karyotype structure and asymmetry, it was shown that in Allium species, the DNA was added proportionally to their arm lengths. Overall, p = 8 and somehow intermediate karyotype asymmetry levels seem to represent plesiomorphic character-states in Allium.     

Chemical constituents and medicinal properties of Allium species

Allium species, belonging to Alliaceae family, are among the oldest cultivated vegetables used as food. Garlic, onions, leeks and chives, which belong to this family, have been reported to have medicinal properties. The Allium species constituents have been shown to have antibacterial and antioxidant activities, and, in addition, other biological properties. These activities are related to their rich organosulfur compounds. These organosulfur compounds are believed to prevent the development of cancer, cardiovascular, neurological, diabetes, liver diseases as well as allergy and arthritis. There have also been reports on toxicities of these compounds. The major active compounds of Allium species includes, diallyl disulfide, diallyl trisulfide, diallyl sulfide, dipropyl disulfide, dipropyl trisulfide, 1-propenylpropyl disulfide, allyl methyl disulfide and dimethyl disulfide. The aim of this review is to focus on a variety of experimental and clinical reports on the effectiveness, toxicities and possible mechanisms of actions of the active compounds of garlic, onions, leek and chives.

     

Relationships among Old and New World Alliums according to ITS DNA sequence analysis

 Phylogenetic analysis of ITS DNA sequences of various Old and New World Alliums suggests the reinclusion of Nectaroscordum and affirms the reestablishment of Caloscordum as subgenera of genus Allium. The results sanction the elimination of the Old World Allium species from subg. Amerallium Traub and endorse Wendelbo’s definition of subg. Molium (excluding sect. Porphyrason). Received: 29 July 1998 / Accepted: 13 August 1998     

A Detailed Chemical and Biological Investigation of Twelve Allium Species from Eastern Anatolia with Chemometric Studies

Allium species are widely consumed as food all over the world. The phenolic profile of ethanol extracts of aerial parts and roots of 12 Allium species, collected from five different Eastern Anatolia regions, were studied using LC-MS/MS. In vitro antioxidant, anticholinesterase, cytotoxic and antimicrobial activities were also tested. The multivariate analyses were performed using principal component and hierarchical cluster analyses. Seventeen of 27 standard compounds were detected in all Allium species. The major components were mainly identified as quinic acid, malic acid, vanillin, and p-coumaric acid. The aerial parts possessed better antioxidant activity than roots. Aerial parts of A. atroviolaceum, A. chrysantherum, A. kharputense, and A. shirnakiense exhibited high cytotoxic activity against DLD-1 colon cancer cell lines (IC₅₀ 12.5 μg/mL). A. shatakiense and A. vineale demonstrated good antimicrobial activity against S. aureus and E. coli (MIC 75 μg/mL). According to chemometric analysis, differences were detected between aerial parts and the roots. The aerial parts of A. atroviolaceum, A. chrysantherum, A. kharputense, and A. shirnakiense could be potent in the pharmaceutical industry while A. shatakiense and A. vineale in the food industry after further investigations.     

Phylogenetic relationships of Iranian Allium sect. Allium (Amaryllidaceae,Allioideae) as inferred from nrDNA ITS,cpDNA rps16 and trnL–F sequences

Allium is a particularly species rich (more than 800 species) and economically important genus, with numerous taxonomic problems at all levels of classification. In this study, we try to uncover the phylogenetic relationships of the common leek Allium ampeloprasum based on selected samples of this species and its putative relatives in A. sect. Allium from Iran. The silica‐dried leaf samples of 56 accessions representing 23 species of Allium were sequenced; 53 sequences of nrDNA ITS, 35 sequences of plastid rps16 and 52 sequences of trnL–F were generated and additional accessions were extracted from GenBank in order to cover all recognized main lineages in the genus. Maximum Parsimony and Bayesian Inference generated similar trees, but the placement of A. ampeloprasum and its relatives differed slightly between the nuclear and the plastid phylogenies. In the nrITS tree, A. ampeloprasum is retrieved as a highly supported clade with A. iranicum, while in the combined plastid tree A. ampeloprasum formed a highly supported clade with A. vineale. This supports the hypothesis of a possible hybrid origin of A. ampeloprasum. Allium iranicum formed a clade in the plastid tree, but was resolved as paraphyletic in the nrITS tree, probably due to presence of multiple non‐concerted copies of nrITS. Close relationships are suggested between the following species: A. aznavense and A. wendelboi with A. talyschense, A. erubescens and A. rotundum with A. scorodoprasum and A. abbasii with A. phanerantherum.     

Molecular and morphological characterization of Leveillula (Ascomycota: Erysiphales) on monocotyledonous plants

Leveillula on monocotyledonous plants have been recorded as L. taurica by several authors, whereas the fungus on Allium has been described as an independent species, namely L. allii, by some authors. We sequenced ca 600 bp of the rDNA ITS region for two Leveillula specimens from Allium and Polianthes (both from monocotyledons) and compared them with several already published sequences from Leveillula isolates from dicotyledons. Pair-wise percentages of sequence divergences were calculated for all Leveillula isolates. The ITS sequence of the Polianthes isolate was identical to L. taurica on Helianthus and Vicia. The sequence of the Allium isolate was 99.5 % identical to L. taurica on Euphorbia, Haplophylum, Peganum, etc. These results suggest close relationships between monocot and dicot pathogenic Leveillula species. The identity between two monocot isolates was 98.4 %. Phylogenetic analysis revealed that the two monocot isolates do not group into a clade together. This result suggests that Leveillula acquired parasitism to monocots at least twice independently.     

Bioactive Saponins from Allium and Aster Plants

Plants belonging to the genera Allium and Aster are widely distributed in nature and have been used as food and/or medicine. Their wide use was mainly due to the medicinal properties attributed to these plants since ancient times, recently supported by epidemiological and laboratory studies. Saponin compounds, responsible for many pharmacological activities, are quite abundant in these plants. Thus, a deep knowledge about the saponin composition of these vegetables appears to be essential and could promote the discovery of new potential leads. As part of our continuing research aimed at the identification of bioactive metabolites, we have addressed our attention to several Allium and Aster species. The study resulted in the isolation of over fifty saponins of furostane, spirostane, cholestane, and oleane-type structures. Some of the isolated compounds exhibited promising antiproliferative, antifungal, and antispasmodic activities. Their structure, distribution and bioactivity will be reported here together with a brief overview of the literature on Allium and Aster saponins.     

The cytogeographical distribution pattern ofAllium (Alliaceae) in the Greek Peninsula and Islands

Greece is considered as a secondary centre of evolution for the genusAllium since it possesses about 50% of the species known from the whole Flora Europaea area. In the present investigation 44 GreekAllium spp. have been studied and new chromosome counts are reported from 40 populations and 17 species. The distribution of the different cytotypes (x = 7, x = 8, x = 11 and 2n = 2x, 3x, 4x, 5x, 6x, 7x) in Greece is discussed. From the four phytogeographical subdivisions recognized, South continental Greece shows the greatest species and karyotype diversity. This phenomenon is probably due to the geographical position and to the geological history of this area which has received species and populations from different directions. Subsequently, hybridization apparently has been of evolutionary importance.The genusAllium in Greece I.     

Botrytis sinoallii: a new species of the grey mould pathogen on Allium crops in China

A study was conducted to identify Botrytis spp. isolated from bulb onion, green onions, garlic, and garlic chives grown in Hubei Province of China. Based on colony morphology and conidial characteristics, 367 strains of Botrytis spp. were identified as five distinct species, namely, B. cinerea, B. squamosa, B. porri, B. byssoidea, and an undescribed Botrytis species (Botrytis sp.), which accounted for 64.3, 29.9, 3.3, 0.3, and 2.2%, respectively. The previously undescribed species is herein described as a new species, B. sinoallii sp. nov., which is characterized by production of numerous small sclerotia on potato dextrose agar. Phylogenetic analysis using partial sequences of three nuclear genes (G3PDH, HSP60, and RPB2) showed that B. sinoallii forms a unique lineage, which is closely related to B. squamosa, a well-known species on Allium crops, but distantly related to the other species of Botrytis on Allium crops, including B. cinerea, B. porri, B. aclada, B. allii, B. byssoidea, B. globosa, and B. sphaerosperma. Results of inoculation tests showed that B. sinoallii is a newly identified agent that can cause leaf blight of green onion, garlic, and garlic chives. Potential impact of B. sinoallii on production of Allium crops in China is discussed.