An Overview: The Toxicity of Ageratina adenophora on Animals and Its Possible Interventions

Ageratina adenophora is one of the major invasive weeds that causes instability of the ecosystem. Research has reported that A. adenophora produces allelochemicals that inhibit the growth and development of food crops, and also contain some toxic compounds that cause toxicity to animals that consume it. Over the past decades, studies on the identification of major toxic compounds of A. adenophora and their toxic molecular mechanisms have been reported. In addition, weed control interventions, such as herbicides application, was employed to reduce the spread of A. adenophora. However, the development of therapeutic and prophylactic measures to treat the various A. adenophora—induced toxicities, such as hepatotoxicity, splenotoxicity and other related disorders, have not been established to date. The main toxic pathogenesis of A. adenophora is oxidative stress and inflammation. However, numerous studies have verified that some extracts and secondary metabolites isolated from A. adenophora possess anti-oxidation and anti-inflammation activities, which implies that these extracts can relieve toxicity and aid in the development of drug or feed supplements to treat poisoning-related disorders caused by A. adenophora. Furthermore, beneficial bacteria isolated from rumen microbes and A. adenophora can degrade major toxic compounds in A. adenophora so as to be developed into microbial feed additives to help ameliorate toxicity mediated by A. adenophora. This review presents an overview of the toxic mechanisms of A. adenophora, provides possible therapeutic strategies that are available to mitigate the toxicity of A. adenophora and introduces relevant information on identifying novel prophylactic and therapeutic measures against A. adenophora—induced toxicity.

Ageratina adenophora Disrupts the Intestinal Structure and Immune Barrier Integrity in Rats

The aim of this study was to investigate the effects of Ageratina adenophora on the intestines morphology and integrity in rat. Rats were randomly divided into two groups and were fed with 10 g/100 g body weight (BW) basal diet and 10 g/100 g BW experimental diet, which was a mixture of A. adenophora powder and basal diet in a 3:7 ratio. The feeding experiment lasted for 60 days. At days 28 and 60 of the experiment, eight rats/group/timepoint were randomly selected, weighed, and sacrificed, then blood and intestinal tissues were collected and stored for further analysis. The results showed that Ageratina adenophora caused pathological changes and injury in the intestine, elevated serum diamine oxidase (DAO), D-lactate (D-LA), and secretory immunoglobulin A (sIgA) levels, reduced occludin levels in intestinal tissues, as well as increased the count of intraepithelial leukocytes (IELs) and lamina propria leukocytes (LPLs) in the intestine (p < 0.05 or p < 0.01). In addition, the mRNA and protein (ELISA) expressions of pro-inflammation cytokines (IL-1β, IL-2, TNF-α, and IFN-ϒ) were elevated in the Ageratina adenophora treatment groups, whereas anti-inflammatory cytokines such as IL-4 and IL-10 were reduced (p < 0.01 or p < 0.05). Therefore, the results obtained in this study indicated that Ageratina adenophora impaired intestinal function in rats by damaging the intestine structure and integrity, and also triggered an inflammation immune response that led to intestinal immune barrier dysfunction.

Evaluation of Botanicals of Invasive Plant Species and Fungicides against Fungal Pathogens of Forest Nursery

Investigation of plants that possess natural antimicrobial substances for plant protection has been recognized as a promising disease management strategy. Alternaria alternata, Fusarium solani, Macrophomina spp., and Pestalotiopsis spp. isolated from diverse hosts such as Azadirachta indica, Melia dubia, Saraca indica and Quercus leucotrichophora produce important diseases in forest nurseries such as leaf blight, leaf spot, and wilt. In this study, botanicals from two invasive plant species, Ageratina adenophora and Ageratum conyzoides, were prepared and tested against plant diseases. Two botanicals (Methanolic extract obtained from the leaves of these two invasive species) and two fungicides were evaluated for their fungal growth inhibitory effects. At 1.5 percent concentration, the methanolic extract of Ageratina adenophora was found highly effective, inhibiting the growth of Macrophomina spp., (71.94%) followed by Pestalotiopsis spp. (70.20%), Alternaria alternate (51.92%) and Fusarium solani (47.03%). Whereas, Systemic chemical fungicide Thiophanate methylat 1.5% concentration showed maximum mycelial growth inhibition of Alternaria alternata (77.20%) and Macrophomina spp. (82.43%) and being deadlier to Pestalotiopsis spp. (100%) and Fusarium solani (100%). Their comparative analysis showed that higher doses of Ageratina adenophora caused either more or almost equal pathogen growth inhibition than lower doses of Chlorothalonil for certain fungi. Thus, promoting eco-friendly disease management strategies such as botanical control would be beneficial in reducing the need for pesticides.

Phytotoxic effects of invasive Ageratina adenophora on two native subtropical shrubs in Nepal

The response of native plants to allelopathic interference of invasive species may differ from species to species. In this study, the phytotoxic effects of Ageratina adenophora were tested on two native shrubs (Osbeckia stellata and Elsholtzia blanda) of Nepal. Both the shrubs were grown in pots under treatments of A. adenophora fresh leaves and root leachates, and litter. Then, the seedling length and biomass were compared among the treatments. The results show that A. adenophora litter has stimulatory effects but the leachates from fresh leaves and root are phytotoxic to the growth and development of native shrubs. Infrared Spectroscopy (IR) analysis confirmed the presence of O–H (Hydroxyl), N–H (Amines), C≡C (Alkynes), and C–H stretching (Aromatic) or C–O–C stretching (Ethers) in the leachates representing harmful allelochemicals. The invaded soil by A. adenophora had low pH and a high amount of organic matter, total nitrogen, phosphorus, and potassium than the uninvaded soil. The results indicate that the native O. stellata and E. blanda are harmed by A. adenophora in nature by leaching of allelochemicals and probably by reducing the soil pH. Overall, this study has provided valuable insights regarding the effects of A. adenophora invasion on native shrubs and revealing the potential mechanism of its invasiveness.

Antimicrobial Study of Green Synthesized Silver Nanoparticles (AgNPs) by Using Ageratina adenophora and its Characterization

Green chemistry refers to the design of chemical product and processes that reduce or eliminate the generation of hazardous substances. Silver nanoparticles (AgNPs) were synthesized successfully from AgNO3 through a simple green synthetic route using Ageratina adenophora leaf extract which acts as both reducing and capping agents. As synthesized AgNPs were characterized with the help of X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. XRD study shows crystalline nature of silver nanoparticles and average particle size was calculated as 24 nm using Debye Scherrer equation. Functional group responsible for the reduction of silver ion was investigated using FTIR spectroscopy. Hydroxyl group, amine group, aliphatic amine group were detected from FTIR analysis. Further, the green synthesized nanoparticles were found to be highly toxic against bacteria: Bacillus subtilis and Escherichia coli showing zone of inhibition of 11 mm and 9 mm, respectively. Int. J. Appl. Sci. Biotechnol. Vol 9(2): 128-132.

Assessment of invasion of Ageratina adenophora in the plantation forest of Nepal

Large-scale plantations of pine species were done in the bare hills of the Middle Mountain region of Nepal during the early 1980s. There is a growing concern on the sustainability of the planted pine forests in the country due to the presence of invasive alien plant species (IAPS). Invasive alien plant species are considered as one of the drivers of forest degradation and deforestation. Ageratina adenophora is one of the problematic IAPS found in the planted pine forests throughout the country. In this study, we employed different treatments to control the invasion of A. adenophora in the planted pine (Pinus patula) forest. The research design included four different treatments, viz., (i) control, (ii) stem felling, (iii) floor clearance, and (iv) stem felling cum floor clearance in one block (Block I), which was replicated in another block (Block II). The data were collected using circular sample plots with 2m radius. The ANOVA and TukeyHSD Tests were applied during the analysis process so as to determine the effects of treatments on invasion of A. adenophora. The "floor clearance treatment" was found to be significantly effective to reduce the presence of A. adenophora in the planted pine forest. On the contrary, the "opening of forest cover treatment" was found to be conducive to this invasive species to invade the area. The "stem felling cum floor clearance treatment" could be an effective strategy to control invasion of A. adenophora in planted forest, but as it demands a high cost, it is likely to be appropriate for small forest areas where promotion of regeneration is of high priority.

Potential use of Helianthus tuberosus to suppress the invasive alien plant Ageratina adenophora under different shade levels

Background An ecological approach for managing biological invasions in agroecosystems is the selection of alternative crop species to manage the infestation of invasive alien plants through competition. In the current study, plant growth, photosynthesis, and competitive ability of the crop Helianthus tuberosus L. (Jerusalem artichoke) and the invasive alien plant Ageratina adenophora (Spreng.) R. M. King and H. Rob were compared under varying shade levels by utilizing a de Wit replacement series method. We hypothesized that H. tuberosus had higher competitive ability than A. adenophora even under shaded conditions. Results The results showed the main stem, leafstalk length, leaf area, underground biomass, and aboveground biomass of A. adenophora were significantly lower compared to H. tuberosus in monoculture although A. adenophora had a greater number of branches that were longer on average. Under full sunlight, the total shoot length (stem + branch length), main stem length and branch length of A. adenophora were significantly suppressed (P < 0.05) by increasing proportions of H. tuberosus, and the same morphological variables of H. tuberosus were significantly higher with decreasing proportions of H. tuberosus. With increasing shade rates and plant ratios, the plant height, branch, leaf, and biomass of both plants were significantly suppressed, but to a greater degree in the case of A. adenophora. The net photosynthetic rate (Pn) of H. tuberosus and A. adenophora increased gradually from July to September, then decreased in October. The Pn of H. tuberosus was consistently higher than that of A. adenophora. Although the Pn for both species was significantly reduced with increasing shade rates and plant ratios, A. adenophora experienced greater inhibition than H. tuberosus. The relative yield (RY) of A. adenophora was significantly less than 1.0 (P < 0.05) in mixed culture under all shade levels, indicating that the intraspecific competition was less than interspecific competition. The RY of H. tuberosus was significantly less than 1.0 under 40–60% shade and greater than 1.0 (P < 0.05) under 0–20% shade in mixed culture, respectively, showing that intraspecific competition was higher than interspecific competition under low shade, but the converse was true under high shade. The relative yield total (RYT) of A. adenophora and H. tuberosus was less than 1.0 in mixed culture, indicating that there was competition between the two plants. The fact that the competitive balance (CB) index of H. tuberosus was greater than zero demonstrated a higher competitive ability than A. adenophora even at the highest shade level (60%). Conclusions Our results suggest that H. tuberosus is a promising replacement control candidate for managing infestations of A. adenophora, and could be widely used in various habitats where A. adenophora invades.