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

Abstract

<jats:p>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.</jats:p>

Parthenin—A Sesquiterpene Lactone with Multifaceted Biological Activities: Insights and Prospects

“…A mixture of parthenin with another STL, coronopilin, modulated the afferent neurons and murine tracheal rings [ 89 ]. A strong correlation was observed between parthenin, and cytotoxicity induced by P. hysterophorus extracts in mouse fibroblast cell suspension [ 90 ]. The level of cytotoxicity was enhanced when the cells were exposed to UV-A radiation, which suggests that the compound may cause photosensitisation in animals and humans [ 90 ].…”

The Impact of Parthenium Weed-Amended Substrates on the Germination and Early Growth of a Range of Pasture and Crop Species

“…This suggests that the leaf litter produced by one to two parthenium weed plants can reduce seedling emergence from other plant species that may be present in the seed bank. A major source of these chemicals is undoubtedly the aerial parts where certain allelochemicals are contained within the multitude of trichrome hairs that cover the surface of the leaves and stems that can be released directly to the soil during rainfall [29][30][31]. Additionally, continuing inputs of compounds may also play an important role in the growth inhibition under the field conditions where parthenium weed is growing with either crops or pasture species.…”

Allelopathic Effect of Serphidium kaschgaricum (Krasch.) Poljak. Volatiles on Selected Species

“…Compositae plants can negatively affect other plants, especially some invasive plants such as Ambrosia artemisiifolia L. [ 14 ], Eupatorium adenophorum (Spr.) [ 15 ], Ageratum conyzoides (L.) L. [ 16 ], Parthenium hysterophorus L. [ 17 ], Xanthium italicum Morretti, and so on [ 13 ]. For instance, leaf extracts of P. hysterophorus exhibited high phytotoxic, cytotoxic and photocytotoxic activity on seed germination and seedling growth of garden cress and annual ryegrass [ 17 ].…”

“…[ 15 ], Ageratum conyzoides (L.) L. [ 16 ], Parthenium hysterophorus L. [ 17 ], Xanthium italicum Morretti, and so on [ 13 ]. For instance, leaf extracts of P. hysterophorus exhibited high phytotoxic, cytotoxic and photocytotoxic activity on seed germination and seedling growth of garden cress and annual ryegrass [ 17 ]. Sesquiterpenoids such as xanthatin, 1α, 5α-epoxyxanthatin, 4-epiisxanthanol and 4-epixanthanol were isolated from X. spinosum that were phytotoxic against the tested plants Amaranthus retroflexus L. and Poa annua L. [ 11 ].…”