Organogenesis and embryogenesis in several hypericum perforatum genotypes

St John’s wort (Hypericum perforatum) is a valuable plant used as a herbal remedy or in phytopharmaceutical drugs to treat a variety of physical ailments. Much research has been performed to study the biochemical production of secondary metabolites of in vitro cultured plants or organs. However, all of these studies have looked at the regeneration of plants from explants in only one genotype. In addition, no study has revealed the mechanism of plant regeneration in H. perforatum, i.e. organogenesis or somatic embryogenesis. We found that different genotypes Helos, Topas, Elixir, and Numi responded similarly to regeneration medium. The regeneration responses (i.e. callus, root, or shoot production) of identical explants from different genotypes were similar. However, the source of explant material (leaves, hypocotyls, and roots) from the same genotype had significant effects on the response to media and plant regeneration frequency. Using scanning electron microscopy and light microscopy, the progress of organogenesis and embryogenesis under similar culture conditions was recorded. Root segments were the most responsive explants, producing the maximum number of shoots per explant of all the genotypes.Fundação para a Ciência e a Tecnologia (FCT) - POCTI/AGR/40 283/2001, SFRH/BPD/17102/2004

Hypericum perforatum Ocimum basilicum Laurus nobilis Antioxidant activity Flavonoid Antibacterial activity ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF SELECTED ARMENIAN MEDICINAL PLANTS

ABSTRACT The antioxidant potentials of ethanolic and aqueous extracts of Hypericum perforatum, Ocimum basilicum, Laurus nobilis leaves were evaluated by 2, 2-diphenyl-l-picrylhydrazyl radical (DPPH) assay. Simultaneously total flavonoids content and antibacterial potential of all the tested extract was also monitored. The highest radical scavenging capacity (RSC) was reported in ethanolic extract of H. perforatum leaves while the lowest RSC was reported in the aqueous extract of L. nobilis. The ethanolic extracts of L. nobilis posses more DPPH radical scavenging action, than their aqueous extracts. Ethanolic and aqueous extracts of H. perforatum shows significant antioxidant activity, it is near to inhibition capacities while ethanolic extract of O. basilicum leaf has exhibited small activity as compared with its aqueous extract. RSC of ethanolic extracts can correlates with flavonoids content. The antiradical activity of ethanolic and aqueous extracts of L.nobilis leaf can also correlate with total flavonoids content, while such type of correlation was not reported in the case of H. perforatum and O. basilicum leaves extracts. RSC of tested extracts can be ranged in the following way: quercetin > rutin > eth. H. perforatum > aq. H. perforatum > aq. O. basilicum > eth L.nobilis > eth. O. basilicum > aq. L.nobilis. All the ethanolic extracts express more antibacterial activity than aqueous extracts

Effect of various elicitors on lignan biosynthesis in callus cultures of Linum austriacum

Effects of elicitors (mannan, β-1,3-glucan, and ancymidol) on the activity of several key enzymes participating in lignan biosynthesis were studied in Linum austriacum L. cell cultures. The activities of L-phenylalanine ammonia-lyase, polyphenoloxydase, tyrosine ammonia-lyase, soluble phenoloxidase, and membrane-bound and soluble oxidases were assayed. The elicitors under study affected various steps in the metabolic pathway of lignan biosynthesis. Elevated enzyme activity accompanied an elicitor-enhanced synthesis of podophyllotoxins and peltatins.4 page(s