ABSTRACT
Phytochemical analysis of aerial flowering parts of Euphorbia spinidens Bornm. ex Prokh. from Euphorbiaceae family (local name: Farfion-e-dandaneh-khari) led to the isolation of five diterpenes based on myrsinane backbone. Using HRESI-MS, 1D, and 2D NMR, they were identified as two previously unreported: 33,7,14,15(ß)-tetraacetyl-5(α)-butanoyl-13α(17)epoxy-8,10(18)-myrsinadiene (1), 7,14,15(ß)-triacetyl-3(ß),5(α)-dibutanoyl-13α(17)epoxy-8,10(18)-myrsinadiene (2), and three known diterpenes: 3,7,14,15(ß)-tetraacetyl-5(α)-propanoyl-13(17)-epoxy-8,10(18)-myrsinadiene (3), and 3,7,10,14,15(ß)-Pentaacetyl-5(α)-butanoyl-13,17-epoxy-8-myrsinene (4), 3,7,10,14,15(ß)-pentaacetyl-5(α)-propanoyl-13,17-epoxy-8-myrsinene (5). Compound 5 was previously reported in the roots of the same plant but without NMR data. Therefore, its mass pattern,1H-, and 13C-NMR data are reported. The cytotoxicity and proapoptotic properties of 1-3 were evaluated against EJ-138 bladder carcinoma cells through standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay for cytotoxicity screening and annexin V-FITC/PI apoptosis detection kit. In the cytotoxicity assay, the IC50 values found against EJ-138 were: (1) 41.6 ± 3.54 µM; (2) 38.4 ± 2.54 µM; (3) 57.3 ± 5.4 µM, whilst the IC50 value of doxorubicin was 1.7 ± 0.3 µM, respectively. In apoptosis assay, total apoptosis of compounds 1-3 at higher concentrations (100 µM) were 57.6 ± 3.54, 46.3 ± 2.82, and 57.2 ± 4.35%, respectively.
ABSTRACT
Astragalus section Hymenostegis is one of the important characteristic elements of thorn-cushion formations in the Irano-Turanian floristic region. In this paper, we examined the chromosome number of 17 species (15 new reports) and provide estimates of genome size for 62 individuals belonging to 38 taxa of A. sect. Hymenostegis, some species outside this section, plus two Oxytropis species. Based on chromosome counts 11 species were found to be diploid (2n = 16), four species tetraploid (2n = 32) and two taxa hexaploid (2n = 48). From genome size measurements on silica-gel dried material, three ploidy levels (2x, 4x and 6x) were inferred, with a majority of species being diploid. The 2C values reach from 2.07 pg in diploid Astragalus zohrabi to 7.16 pg in hexaploid A. rubrostriatus. We found indications that species might occur with different cytotypes. A phylogenetic framework using nrDNA ITS sequences was constructed to understand the evolution of ploidy changes and genome sizes. It showed that genome size values among the studied taxa differ only slightly within ploidy levels and are nearly constant within most species and groups of closely related taxa within the genus Astragalus. The results of this study show that there is a rather strong correlation between genome sizes and chromosome numbers in sect. Hymenostegis. The resolution of the ITS-based phylogenetic tree is too low to infer evolutionary or environmental correlations of genome size differences. Polyploidization seems to contribute to the high species number in Astragalus, however, in sect. Hymenostegis it is not the main driver of speciation.
