Toxic Potential and Metabolic Profiling of Two Australian Biotypes of the Invasive Plant Parthenium Weed (Parthenium hysterophorus L.).

Parthenium weed (Parthenium hysterophorus L.) is an invasive plant species in around 50 countries and a 'Weed of National Significance' in Australia. This study investigated the relative toxicity of the leaf, shoot and root extracts of two geographically separate and morphologically distinct biotypes of parthenium weed in Queensland, Australia. Parthenium weed exhibited higher phytotoxic, cytotoxic and photocytotoxic activity in leaf tissue extracts in contrast to shoot and root. The germination and seedling growth of a dicot species (garden cress) were inhibited more than those of a monocot species (annual ryegrass) using a phytotoxicity bioassay. The cytotoxicity of leaf extracts was assessed in a mouse fibroblast cell suspension assay and increased under high ultraviolet A(UV-A) radiation. A major secondary metabolite, parthenin, was found in abundance in leaf extracts and was positively correlated with cytotoxicity but not with photocytotoxicity or phytotoxicity. Ambrosin and chlorogenic acid were also detected and were positively correlated with germination inhibition and the inhibition of radicle elongation, respectively. In addition, other currently unidentified compounds in the leaf extracts were positively correlated with phytotoxicity, cytotoxicity and photocytotoxicity with two to three molecules strongly correlated in each case. Both parthenium weed biotypes investigated did not differ with respect to their relative toxicity, despite their reported differences in invasive potential in the field. This suggests that secondary chemistry plays a limited role in their invasion success.

Examination of common ragweed's (Ambrosia artemisiifolia L.) allelopathic effect on some weed species.

In the last decades the importance of some weed species increased in Hungary. The common ragweed (Ambrosia artemisiifolia L.) also belongs to this group. The allelopathic effect of watery extract made from different plant parts of common ragweed (air dried leafy shoots, seeds) were studied on the germination and growth of some weed species. The extracts were prepared with tap water, chopped dry plant materials were added to water and 24 hours later the material was filtered. The germination took place in a Binder KBW type thermostat in dark. 25 seeds were put into one Petri-dish, adding 15 ml plant extract to each in four repeats. The timing of germination was checked in every two days and the rate of growth was estimated after a week, by counting the numbers of germinated seeds and measuring the length of the radicle and plumula. The measured data were statistically analysed and the effect of extracts on germinating ratio and seedling length were evaluated.

Alterações anátomo-histopatológicas em ratos submetidos à dieta com extrato de broto de samambaia (Pteridium aquilinum var. arachnoideum) de dois municípios do estado do Paraná / Macroscopic and microscopic changes in rats fed on a bracken fern diet (Pteridium aquilinum var. arachnoideum) from different regions of Parana State, Brazil

The carcinogenicity of bracken fern harvest from two regions of Paraná State to induce hematury in rats was studied. In order to do that, 33 Wistar rats were divided in three groups. Groups I and II received an aqueous extract of bracken fern from Londrina-PR or Ibaiti-PR, respectively, in drinking water for 60 days. Group III, control group, received regular plain water with no bracken fern. After 15 months, euthanasia was performed in all animals and samples were collected for histology examination. Histologic analysis revealed that two animals of Group II had ileal adenocarcinoma and soft tissue fibroma of leg.