Genus Onosma Research Articles

Systematics and evolutionary history of the Asterotricha group of the genus Onosma (Boraginaceae) in central and southern Europe inferred from AFLP and nrDNA ITS data

Onosma is a species-rich genus with complicated patterns of morphological and karyological variation, and controversial taxonomic treatments. In the present study we focused on the Asterotricha group, one of three major infrageneric groups, in the area of central and southern Europe. Ribosomal internal transcribed spacer (ITS) sequences and amplified fragment length polymorphism (AFLP) markers were used to assess species differentiation and relationships, and to gain insight into the evolutionary history of the group. ITS data supported the monophyly of the asterotrichous taxa. Six genetically differentiated entities were resolved by AFLP markers, corresponding to O. echioides, O. heterophylla s.l., O. thracica including O. rigida, O. malkarmayorum, O. taurica, and O. stellulata. Onosma stellulata is identified as the most differentiated lineage within the Asterotricha group, which is consistent with its unique chromosome number. Within O. heterophylla s.l., recognition of O. viridis as a species distinct from O. heterophylla s.str. is supported. On the other hand, O. tornensis appears to be conspecific with O. viridis. Inferring from the patterns of genetic diversity and divergence, the evolutionary history of O. heterophylla s.l. is discussed. Genetic variation within the polymorphic Apennine–Dalmatian O. echioides is almost continuous and shaped by isolation by distance, thus none of the previous intraspecific taxonomic concepts are valid. The assumed hybrid origin of O. malkarmayorum is supported, and its affinity to potential ancestors, O. heterophylla s.l. and O. thracica incl. O. rigida, is indicated. Future studies of asterotrichous Onosma species should focus on diversity centers in the eastern Mediterranean and Asia Minor, to build up a comprehensive taxonomic concept of the group and to clarify its evolution.

Shikonin derivatives from the roots of Onosma nigricaule (Boraginaceae)

The genus Onosma (Boraginaceae) is represented by 87 species in Turkey [1]. The roots of some Onosma species are used for wound healing and burns [2,3] in Turkey. Onosma nigricaule is an endemic species for Turkey [1] and its roots are used for wound healing and burns in Erzurum Province. In this sudy, the roots of O. nigricaule (500g) were extracted with n-hexane:dichloromethane (1:1) (2L x 3) and then filtered. The filtrate was evaporated at 40°C. Three shikonin derivatives (deoxyshikonin (1), β,β-dimethylacryl shikonin (2), and acetyl shikonin (3)) were isolated from this extract by using several chromatographic methods. The structures of the pure compounds were elucidated by using 1H-NMR and 13C-NMR Spectroscopy, and ESI-MS.

Hypoglycemic activity of Onosma hispidum (Ratanjot)

Background: Onosma hispidum (Ratanjot) belongs to the family Boraginaceae. The genus Onosma has about 150 known species in Asia. It has been found to be effective as an antioxidant, anti-inflammatory, and antimicrobial agent and promotes healing in burns, foot ulcers, and wounds. Aim: To study the effect of O. hispidum on blood glucose level in glucoseloaded, normal, and hyperglycemic rats. Settings: Department of Pharmacy, Bundelkhand University, Jhansi, Uttar Pradesh, India. Design: An experimental study was designed. Materials and Methods: The methanolic root extracts of O. hispidum are compared with glibenclamide for their influence on fasting blood glucose in glucose-loaded, normoglycemic, and alloxan-induced (120 mg/kg i.p) hyperglycemic rats. Statistical Analysis: The data were analysed by one way analysis of variance followed by Dunnett’s test (P < 0.01). Results: In glucose-loaded, normal and hyperglycemic rats, the methanolic root extract of O. hispidum at the dose of 100 mg/kg p.o. reduced blood glucose significantly as compared to control, and it was almost as effective as glibenclamide. Conclusion: The methanolic root extract of O. hispidum has hypoglycemic action. As diabetes is associated with hyperglycemia and several other pathological changes such as infections, inflammation, foot ulcers and impairment of wound healing, these additional effects besides hypoglycemic effect of O. hispidum may be proved as a breakthrough in the treatment of diabetes. Biochemical and receptor oriented molecular studies are required to find out the exact mechanism of hypoglycemic action of O. hispidum.

Characterization of Onosma bracteosum Hausskn. & Bornm. and Onosma thracicum Velen. Based on Fatty Acid Compositions and α-Tocopherol Contents of the Seed Oils

Turkey is one of the important centres of origin for genus Onosma ( Boraginaceae ) with about 95 species including 48 endemics (ca.50%). A very limited number of investigations for fatty acid patterns and α-­tocopherol contents of the seed oils were reported in this genus. Some differences were observed in total oil (18.8-24.0%) and α-tocopherol contents (1.66-46.03%) between species. Major unsaturated fatty acids were α-linolenic (38.70-41.05%), linoleic (16.13-18.38%) and oleic acids (11.86-12.96%) respectively. Palmitic (6.32­7.71%), E¤-linolenic (6.36-6.92%) and stearic (2.15-2.32%) acids showed considerable levels. Other fatty acid concentrations were at minor concentrations below 1 % of the seed oils. Total oil content in addition to oleic and α-linolenic acids quantified at higher levels in endemic O. bracteosum . The other fatty acids and α-tocopherol were observed at higher concentrations in O. thracicum . Some variations were examined in quantities, total percentages and the ratios of saturated and unsaturated fatty acids as additional chemotaxonomic markers. Differences for whole series of fatty acids were not significant between species but, significantly difference was found based on six calculated ratios of the fatty acids (p<0.05). Investigated Onosma species could be evaluated as the alternative wild sources for the production of essential fatty acids (EFA) including α-linolenic (ω-3), linoleic and unusual E¤-linolenic (ω-6) acids.

Palynological analysis of five selected Onosma taxa

Pollen size and exine structure of the following five Onosma L. species from Slovakia and Italy were studied by light and scanning electron microscopy: Onosma echioides, O. tornensis, O. visianii, O. arenaria, and O. pseudoarenaria. Among the taxa studied, O. echioides has the smallest pollen grains in average (10.5–17.5 × 8.0–14.5 µm), and O. pseudoarenaria the largest grains in average (15.3–20.5 × 12.3–16.3 µm). Pollen grains of all 5 species are small sized, 3-syncolporate, subprolate, heteropolar, with ovate equatorial outlines and circular to rounded triangular polar outlines; the tectum is microechinate. A positive correlation is found between pollen size and chromosome number. The value of pollen characters for taxonomic purposes and the position of the taxa studied within the genus Onosma are discussed.

Karyotypes and genome size ofOnosmaspecies from northern limits of the genus in Carpathians

Karyology and genome size of four species of the genus Onosma from northern border of the area of the genus in Slovakia were studied. Different chromosome number is characteristic for each of the studied repre- sentatives. O. tornensis (2n=14) has 7 pairs of homologous S (short) chromosomes 1.62 - 2.94 µm long, 5 pairs are metacentric and 2 pairs are submetacentric; nuclear DNA content: 1.56 pg/2C. O. visianii (2n=18) has 9 pairs of homologous chromosomes 1.91 - 3.18 µm long, 3 pairs are metacentric, 4 pairs submetacentric and 2 pairs are sub- acrocentric (one pair bears satellites); nuclear DNA content 4.12 pg/2C. O. arenaria (2n=20) has 6 pairs of homolo- gous metacentric L (long) chromosomes 3.22 - 4.33 µm long and 8 unpaired S chromosomes 1.07 - 2.36 µm long, 7 of these chromosomes are metacentric and 1 submetacentric; nuclear DNA content 5.15 pg/2C. O. pseudoarenaria (2n=26) has 6 pairs of homologous metacentric L chromosomes 3.36 - 5.03 µm long and 7 pairs of homologous metacentric S chromosomes 1.07 - 2.36 µm long and nuclear DNA content 5.74 pg/2C. Conspicuous difference in chromosome structure of particular species and in their DNA content is further discussed in the paper.