Background. Parthenium hysterophorus pollen induces chronic clinical conditions such as allergic rhinitis and bronchial asthma. Among the plethora of proteins in the pollens, only few were reported to induce allergy. Currently sensitization to P. hysterophorus pollen allergen is diagnosed by skin prick test (SPT) using the entire pollen extract instead of using the specific allergen. Methods. In P. hysterophorus sensitized patients, SPT was done using the crude pollen extract, 40 kDa allergenic pollen protein and two commercially synthesized allergen epitopes (17 and 24) of P. hysterophorus. Dot-blot of allergen epitopes was done using P. hysterophorus sensitized sera. Crude pollen extract (1, 1.25, 2.5, 5 and 10 µg/mL), 40 kDa allergenic protein (3 µg/mL), and allergen epitopes (3µg/mL) were used to perform Basophil Activation Test (BAT). Results. Crude pollen extract at 2.5, 5, 10 μg/mL and 40 kDa allergenic protein at 3μg/mL concentrations induced wheal and flare reaction by around 15 minutes, whereas commercially synthesized allergen epitopes at 3μg/mL induced wheal and flare reactions in less than 10 minutes. Allergen epitopes (3 µg/mL) revealed strong reactivity with sensitized patient\'s IgE in dot-blot analysis. Basophil activation Test using crude pollen extract (2.5, 5, 10 µg/mL), 40 kDa allergenic protein (3 µg/mL), and allergenic epitopes (3µg/mL) indicated significant basophil activation (as measured by CD63 expression) in sensitized patients. Conclusions. The 40 kDa allergenic protein and its allergenic epitopes (17 and 24) induced phenotypic and cellular immune responses in P. hysterophorus sensitized individuals. The tested allergenic epitopes (17 and 24) induced faster wheal and flare reactions in comparison with the crude extract and the 40 kDa allergenic protein. The novel 40kDa allergenic protein and its allergen epitopes identified here may be useful for the development of component-resolved diagnosis (CRD) while also serving as a potential therapeutic lead for desensitization treatment for P. hysterophorus pollen induced allergy.

Parthenium hysterophorus L., an invasive alien species and notorious weed, offers various benefits to the medical and agrochemical industries. This study aimed to evaluate the antioxidant and insecticidal activities of P. hysterophorus flower extract and conduct chemical profiling to identify the phytoconstituents responsible for these biological effects. The antioxidant activity was assessed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, while gas chromatography mass spectrometry (GCMS) analysis was employed for chemical configuration evaluation. Our findings demonstrate that the dichloromethane (DCM) extract of P. hysterophorus exhibits potent radical scavenging activity (95.03%). Additionally, phytochemical analysis revealed significant amounts of phenols and flavonoids in the distilled water and ethyl acetate extracts (103.30 GAEg-1 and 138.67 QEg-1, respectively). In terms of insecticidal activity, the flower extract displayed maximum mortality rates of 63.33% and 46.67% after 96 hours of exposure at concentrations of 1000 μgmL-1 and 800 μgmL-1, respectively, with similar trends observed at 72 hours. Furthermore, the P. hysterophorus extracts exhibited LC50 values of 1446 μgmL-1 at 72 hours and 750 μgmL-1 at 96 hours. Imidacloprid, the positive control, demonstrated higher mortality rates at 96 hours (97.67%) and 72 hours (91.82%). Moreover, the antioxidant activity of P. hysterophorus extracts exhibited a strong correlation with phenols, flavonoids, and extract yield. GCMS analysis identified 13 chemical compounds, accounting for 99.99% of the whole extract. Ethanol extraction yielded the highest percentage of extract (4.34%), followed by distilled water (3.22%), ethyl acetate (3.17%), and dichloromethane (2.39%). The flower extract of P. hysterophorus demonstrated significant antioxidant and insecticidal activities, accompanied by the presence of valuable chemical compounds responsible for these biological effects, making it a promising alternative to synthetic agents. These findings provide a novel and fundamental basis for further exploration in purifying the chemical compounds for their biological activities.

Parthenium hysterophorus L. has become a weed of global concern owing to its fast expansion and invasive character. In order to study the status of this noxious weed and its impact on floristic diversity in Dhauladhar foothills, the study was conducted during the year 2021-2022 in culturable wastelands of Dhauladhar ranges in Kangra district of Himachal Pradesh, India. The impact of Parthenium hysterophorus L. on associated species at different altitudes and aspects was observed. Our observations depicted that Parthenium hysterophorus L. has been growing more vigorously in the northern aspect than the southern aspect with the density of 37.78 m-2 and 21.62 m-2, respectively. The highest density of this noxious weed was recorded in the altitudinal range of 600-1200 m (34.32 m-2) while it was not observed beyond 1805 m above sea level. The invasion of Parthenium hysterophorus L. significantly affected the plant density of other species. The descending order of the species as per dominance was observed as Cynodon dactylon, Trifolium repens, Oxalis latifolia, Parthenium hysterophorus L., and Ageratum houstonianum. The average number of species and species density were observed more in non-invaded sites (9.35 and 27.67 m-2) than in invaded sites (7.10 and 20.60 m-2). Species abundance and plant cover were observed more in non-invaded sites (28.73 and 657.90 m2 ha-1) than in invaded sites (22.70 and 322.30 m2 ha-1). Species diversity, richness, and evenness were reported to decline in invaded sites (1.56, 0.95, and 0.81, respectively) with respect to the non-invaded sites (1.94, 1.16, and 0.88, respectively). The study highlights the significant concerns associated with the invasive weed within the plant communities. Understanding its invasive status holds considerable implications for local afforestation initiatives, forest management strategies, and conservation policies. Furthermore, this investigation lays a foundational groundwork for implementing effective measures to get rid of this alien weed.

Parthenium hysterophorus is the commonest cause of plant dermatitis in India. It classically causes airborne contact dermatitis (ABCD), characterized by pruritic, eczematous, and lichenified lesions involving predominantly the face and flexural areas. Over time, however, a transition to chronic actinic dermatitis (CAD) pattern, with prominent involvement of sun-exposed sites, may occur. Management involves strict protective measures and topical and oral corticosteroids or immunomodulatory agents but often leads to only limited success. We report a patient with a chronic and extensive mixed ABCD-CAD pattern of parthenium dermatitis recalcitrant to conventional treatment, with rapid resolution after initiation of treatment with tofacitinib.

Parthenium hysterophorus L. (Asteraceae) is a highly prevalent invasive species in subtropical regions across the world. It has recently been seen to shift from low (subtropical) to high (sub-temperate) elevations. Nevertheless, there is a dearth of research investigating the adaptive responses and the significance of leaf functional traits in promoting the expansion to high elevations. The current study investigated the variations and trade-offs among 14 leaf traits (structural, photosynthetic, and nutrient content) of P. hysterophorus across different elevations in the western Himalayas, India. Plots measuring 20 × 40 m were established at different elevations (700 m, 1100 m, 1400 m, and 1800 m) to collect leaf trait data for P. hysterophorus. Along the elevational gradient, significant variations were noticed in leaf morphological parameters, leaf nutrient content, and leaf photosynthetic parameters. Significant increases were observed in the specific leaf area, leaf thickness, and chlorophyll a, total chlorophyll and carotenoid content, as well as leaf nitrogen and phosphorus content with elevation. On the other hand, there were reductions in the amount of chlorophyll b, photosynthetic efficiency, leaf dry matter content, leaf mass per area, and leaf water content. The trait-trait relationships between leaf water content and dry weight and between leaf area and dry weight were stronger at higher elevations. The results show that leaf trait variability and trait-trait correlations are very important for sustaining plant fitness and growth rates in low-temperature, high-irradiance, resource-limited environments at relatively high elevations. To summarise, the findings suggest that P. hysterophorus can expand its range to higher elevations by broadening its functional niche through changes in leaf traits and resource utilisation strategies.

The sustainable utilization of resources motivate us to create eco-friendly processes for synthesizing novel carbon nanomaterials from waste biomass by minimizing chemical usage and reducing energy demands. By keeping sustainability as a prime focus in the present work, we have made the effective management of Parthenium weeds by converting them into carbon-based nanomaterial through hydrothermal treatment followed by heating in a tube furnace under the nitrogen atmosphere. The XPS studies confirm the natural presence of nitrogen and oxygen-containing functional groups in the biomass-derived carbon. The nanostructure has adopted a layered two-dimensional structure, clearly indicated through HRTEM images. Further, the nanomaterials are analyzed for their ability towards the electrochemical detection of mercury, with a detection limit of 6.17 μM, while the limit of quantification and sensitivity was found to be 18.7 μM and 0.4723 μM μA-1 cm-2, respectively. The obtained two-dimensional architecture has increased the surface area, while the nitrogen and oxygen functional groups act as an active site for sensing the mercury ions. This study will open a new door for developing metal-free catalysts through a green and sustainable approach by recycling and utilization of waste biomass.

Parthenium hysterophorus, a globally widespread weed, poses a significant threat to agricultural ecosystems due to its invasive nature. We investigated the chloroplast genome of P. hysterophorus in this study. Our analysis revealed that the chloroplast genome of P. hysterophorus spans a length of 151,881 base pairs (bp). It exhibits typical quadripartite structure commonly found in chloroplast genomes, including inverted repeat regions (IR) of 25,085 bp, a small single copy (SSC) region of 18,052 bp, and a large single copy (LSC) region of 83,588 bp. A total of 129 unique genes were identified in P. hysterophorus chloroplast genomes, including 85 protein-coding genes, 36 tRNAs, and eight rRNAs genes. Comparative analysis of the P. hysterophorus plastome with those of related species from the tribe Heliantheae revealed both conserved structures and intriguing variations. While many structural elements were shared among the species, we identified a rearrangement in the large single-copy region of P. hysterophorus. Moreover, our study highlighted notable gene divergence in several specific genes, namely matK, ndhF, clpP, rps16, ndhA, rps3, and ndhD. Phylogenetic analysis based on the 72 shared genes placed P. hysterophorus in a distinct clade alongside another species, P. argentatum. Additionally, the estimated divergence time between the Parthenium genus and Helianthus (sunflowers) was approximately 15.1 million years ago (Mya). These findings provide valuable insights into the evolutionary history and genetic relationships of P. hysterophorus, shedding light on its divergence and adaptation over time.

Nine undescribed sesquiterpene lactones, including two pseudoguaianolide dimers (1 and 2), a pseudoguaiac dilactone (3), and six pseudoguaianolides (4-9), along with 13 known analogues (10-22) were isolated from Parthenium hysterophorus. Among them, hysterolide A (1) possesses an unusual carbon skeleton with a unique cyclobutane ring connecting two pseudoguaianolides. Hysterolide C (3) is a sesquiterpene dilactone incorporating a bicyclo[5.1.0]octane core. Spectroscopic analyses, 13C NMR and ECD calculations, and X-ray diffraction elucidated their structures and absolute configurations. Moreover, all the isolates were assayed for their anti-inflammatory activities by inhibiting LPS-induced nitric oxide production in BV-2 microglia cells, wherein, nine compounds displayed significant inhibitory activities with IC50 of 0.52-6.32 μM. Furthermore, the preliminary structure-activity relationship was also established.

Parthenium weed poses significant threats to cropping systems, socioeconomic structures, and native ecosystems. The pronounced impact is primarily attributed to its rapid and efficient invasion mechanism. Despite that the detrimental effects of Parthenium weed are widely acknowledged, an in-depth scientific comprehension of its invasion mechanism, particularly regarding modifications in structural and functional attributes under natural conditions, is still lacking. To bridge this knowledge gap and formulate effective strategies for alleviating the adverse consequences of Parthenium weed, a study was conducted in the more cultivated and densely populated areas of Punjab, Pakistan. This study was focused on fifteen distinct populations of the star weed (Parthenium hysterophorus L.) to investigate the factors contributing to its widespread distribution in diverse environmental conditions. The results revealed significant variations in growth performance, physiological traits, and internal structures among populations from different habitats. The populations from wastelands exhibited superior growth, with higher accumulation of soluble proteins (TSP) and chlorophyll content (Chl a&b, TChl, Car, and Chl a/b). These populations displayed increased root and stem area, storage parenchyma, vascular bundle area, metaxylem area, and phloem area. Significant leaf modifications included thicker leaves, sclarification around vascular bundles, and widened metaxylem vessels. Roadside populations possessed larger leaf area, enhanced antioxidant activity, increased thickness of leaves in terms of midrib and lamina, and a higher cortical proportion. Populations found in agricultural fields depicted enhanced shoot biomass production, higher levels of chlorophyll b, and an increased total chlorophyll/carotenoid ratio. Additionally, they exhibited increased phloem area in their roots, stems, and leaves, with a thick epidermis only in the stem. All these outcomes of the study revealed explicit structural and functional modifications among P. hysterophorus populations collected from different habitats. These variations were attributed to the environmental variability and could contribute to the widespread distribution of this species. Notably, these findings hold practical significance for agronomists and ecologists, offering valuable insights for the future management of Parthenium weed in novel environments and contributing to the stability of ecosystems.

Parthenium hysterophorous, a widespread weed in India, contributes a substantial amount of lignocellulosic biomass. The key objective of this study is to evaluate the feasibility of producing xylanase enzyme from P. hysterophorus weed biomass using the fungus Aspergillus niger. The impact of various physiological factors was confirmed through a two-step approach: first, a one-factor-at-a-time (OFAT) investigation, and subsequently, employing the RSM-based CCD method in statistical design. This research revealed that the RSM-based model led to the optimization of enzyme activity, resulting in a value of 2098.08 IU/gds for xylanase. This was achieved with an incubation time of 4.5 days, a medium pH of 6, and a cultivation temperature of 32.5 °C. Additionally, a pretreatment involving 1% NaOH and a 30-min autoclave treatment was found to alter the chemical composition of lignocellulose substrates (cellulose 43.87% and xylan 28.7%), thereby enhancing the efficiency of enzymatic hydrolysis. Moreover, fermentable sugars were produced by autoclave-assisted alkali pretreatment (NaOH-1.0% w/v) at rates of 219.6 ± 2.05 mg/gds-1 by utilizing the crude xylanase from A. niger and 291.3 ± 1.2 mg/gds-1 from commercial xylanase enzyme. Our study revealed that P. hysterophorus served as a viable and affordable substrate for fermentable sugar liberation, and xylanase is a rate-limiting enzyme in enzymatic saccharification.