The genus Centaurea L. is one of the largest genera in the family Asteraceae. The number of taxa included in this genus ranges from 500 to 600 worldwide. Iran is one of the major centers of diversity for this genus. Pollen morphology has proved useful in the systematics of Asteraceae, as well as in that of some of its genera and species. The pollen morphology of 19 taxa of the genus Centaurea was investigated in detail by light and scanning electron microscopy. Examination under light microscopy showed pollen grains to be tricolporate, isopolar, radially symmetrical, oblate spheroidal, prolate spheroidal, subprolate, tectum perforate and scabrate. Based on the exine ornamentation observed under scanning electron microscopy, we identified two types of pollen grains, designated type I (dense acute spinules) and type II (sparse spinules). All of the taxa evaluated resemble Wagenitz's Jacea type. We present micrographs of pollen grains, together with descriptions of the characteristics of their structure. We found that the pollen characters (shape, exine structure, sculpturing) were useful for classification.

Durante os últimos anos, várias espécies de Cousinia (Asteraceae) têm sido identificadas no Irã. No entanto, dados acerca de suas atividades biológicas permanecem limitados. O principal propósito desta pesquisa foi avaliar a potencial citotoxidade e os efeitos inibitórios de metaloproteinases da matriz (MMP) de sete extratos etanólicos de Cousinia utilizando um modelo de linhagem celular (Fibrosarcoma-WEHI 164). Além disso, investigamos a atividade antibacteriana destes extratos etanólicos de Cousinia, utilizando o método de difusão em disco. Dentre os extratos etanólicos, o extrato total de C. sulabadensis promoveu inibição significativa da atividade de MMP de maneira dose-resposta (49,2 ± 0,51, p < 0,05). Todavia, este extrato exibiu o menor efeito de citotoxicidade em todas as concentrações testadas. A concentração necessária para produzir uma taxa de 50% de morte celular (IC50) com C. shulabadensis foi 304,5 ± 0,61 µg/mL. A IC50 calculada para a citotoxicidade dos outros extratos de espécies de Cousinia situou-se entre 18,4 ± 0,59 e 87,9 ± 0,58 µg/mL. A maior atividade antibacteriana foi observada para o extrato total de Cousinia phyllocephala. Em conclusão, este estudo corrobora que espécies de Cousinia mostram uma notável inibição da atividade de metaloproteinases da matriz. Os concomitantes efeitos inibitórios de MMP e baixa citotoxicidade observados em C. sulabadensis devem direcionar este extrato para futuros estudos de potenciais fitoterápicos anti-invasivos.

During the past several years, various species of Cousinia (Asteraceae) have been authenticated in Iran. However, data concerning their biological activities remain limited. The main purpose of this research was to assess potential cytotoxicity and matrix metalloproteinases (MMP) inhibitory effects of seven ethanol extracts of Cousinia using a cell line model (Fibrosarcoma-WEHI 164). We further investigated the antibacterial activity of these Cousinia ethanol extracts, using disk diffusion method. Among the ethanol extracts, the total extract of C. sulabadensis elicited significant inhibition of MMP activity in a dose-response fashion (49.2 ± 0.51, p < 0.05). However, this extract exhibited the lowest cytotoxicity effect at all tested concentrations. The concentration necessary to produce a 50% cell death rate (IC50) with C. shulabadensis was 304.5 ± 0.61 µg/mL. The calculated IC50 for cytotoxicity of the other Cousinia species extracts ranged between 18.4 ± 0.59 to 87.9 ± 0.58 µg/mL. The highest antibacterial activity was observed for the total extract of Cousinia phyllocephala. In conclusion, this study supports that Cousinia species display a remarkable inhibition of matrix metalloproteinases activity. The concomitant MMP-inhibitory and low cytotoxicity effects observed in C. sulabadensis might coin this extract for future potential anti-invasive herbal medicine studies.

Meiotic studies of ploidy level, chromosome paring and chiasma frequency were performed on 11 Cousinia (Asteraceae) species of the section Serratuloideae. The diploid number of the species studied was 2n = 2x = 24 and 26 so these species possess two different basic numbers (x = 12 or 13), a phenomenon common to other sections of the genus. The chromosome numbers of 9 species are reported here for the first time. When the 2n = 24 and 2n = 26 species were subjected to cluster analysis based on relative meiotic characters two different clusters were formed indicating their distinctness. Our data support the results obtained from morphometry, anatomy, pollen morphology and molecular studies of the genus Cousinia.