Evaluation of the phytotoxic effect of the essential oil from Artemisia absinthium

Potential of utilizing pathogen-derived mycotoxins as alternatives to synthetic herbicides in controlling the noxious invasive plant Xanthium italicum

Discovery of environmentally friendly agents for controlling alien invasive species (AIS) is challenging and in urgent need as their expansion continues to increase. Xanthium italicum is a notorious invasive weed that has caused serious ecological and economic impacts worldwide. For the purpose of exploring the possibility of utilizing herbicidal mycotoxins to control this species, three compounds, a new compound, curvularioxide (1), a new naturally occurring compound, dehydroradicinin (2), and a known compound, radicinin (3), were isolated via activity-guided fractionation from the secondary metabolites of the pathogenic Curvularia inaequalis, which was found to infect X. italicum in natural habitats. All isolated compounds exhibited potent herbicidal activity on receiver species. It is noteworthy to mention that their effects on X. italicum in our bioassays were equivalent to the commercial herbicide glyphosate. Subsequent morphological analysis revealed that application of radicinin (3) severely hindered X. italicum seedlings' hypocotyl and root development. Malondialdehyde content and the activity of catalase and peroxidase of the seedlings were also significantly different from the control, implying the occurrence of induced oxidative stress. Our results suggest that pathogens infecting invasive plants might be valuable resources for developing safer herbicides for controlling weeds. © 2023 Society of Chemical Industry.

Chemical composition and allelopathic potential of Schinus molle L. (Anacardiaceae) essential oils against common weeds of wheat crop

This study aims to determine the chemical composition of essential oil (EO) extracted from the aerial parts of Schinus molle L., as well as its phytotoxicity on germination and seedling growth against some invasive weed species of cereal crops and wheat (Triticum durum, cultivar Chen'S). Gas chromatography/mass spectrometry (GC-MS) identified 51 components (representing 95.26% of the total EO composition). Shyobunone (10.14%), 1-phellandrene (9.63%), α-cadinol (7.46%), δ-cadinene (7.45%), and germacrene D (7.09%) were the most abundant compounds. The effect of EO on weed species germination, root and shoot growth was moderate to strong. When 0.02% and 0.03% of the oil were applied, EO had a strong phytotoxic effect, resulting in 100% failure of Bromus rigidus germination. In addition to determining the responsible compound, the observed phytotoxicity suggestedthat S. molle essential oil could be used as an environmentally friendly biopesticide.

The Essential Oil of Petroselinum crispum (Mill) Fuss Seeds from Peru: Phytotoxic Activity and In Silico Evaluation on the Target Enzyme of the Glyphosate Herbicide

Petroselinum crispum (Mill) Fuss is an aromatic plant belonging to the Apiaceae family and used in gastronomy as a spice. Several studies have been developed in leaves but studies are limited in seeds, especially the essential oils obtained from seeds. The aim of this study was to determine the phytochemical profile of the volatile compounds of this essential oil by gas-chromatography-mass spectrometry (GC-MS) in order to evaluate its phytotoxic activity on Lactuca sativa seeds and to carry out an in silico analysis on the target enzyme of the herbicide glyphosate 5-enolpyruvylshikimate 3-phosphate synthase (EPSP). The essential oil was obtained by steam distillation for two hours and then was injected into a GC-MS, the phytotoxic assay was carried out on Lactuca seeds and the in silico evaluation on the EPSP synthase focused on the volatile compounds similar to glyphosate, docking analysis, and molecular dynamics to establish the protein-ligand stability of the most active molecule. The chromatographic analysis revealed 47 compounds, predominated by three compounds with the most abundant percentage in the total content (1,3,8-ρ-menthatriene (22.59%); apiole (22.41%); and β-phellandrene (15.02%)). The phytotoxic activity demonstrated that the essential oil had a high activity at 5% against L. sativa seed germination, inhibition of root length, and hypocotyl length, which is comparable to 2% glyphosate. The molecular docking on EPSP synthase revealed that trans-p-menth-6-en-2,8-diol had a high affinity with the enzyme EPSP synthase and a better stability during the molecular dynamic. According to the results, the essential oil of P. crispum seeds presented a phytotoxic activity and might be useful as a bioherbicide agent against weeds.

Phytochemistry, Pharmacology and Mode of Action of the Anti-Bacterial Artemisia Plants

Over 70,000 people die of bacterial infections worldwide annually. Antibiotics have been liberally used to treat these diseases and, consequently, antibiotic resistance and drug ineffectiveness has been generated. In this environment, new anti-bacterial compounds are being urgently sought. Around 500 Artemisia species have been identified worldwide. Most species of this genus are aromatic and have multiple functions. Research into the Artemisia plants has expanded rapidly in recent years. Herein, we aim to update and summarize recent information about the phytochemistry, pharmacology and toxicology of the Artemisia plants. A literature search of articles published between 2003 to 2022 in PubMed, Google Scholar, Web of Science databases, and KNApSAcK metabolomics databases revealed that 20 Artemisia species and 75 compounds have been documented to possess anti-bacterial functions and multiple modes of action. We focus and discuss the progress in understanding the chemistry (structure and plant species source), anti-bacterial activities, and possible mechanisms of these phytochemicals. Mechanistic studies show that terpenoids, flavonoids, coumarins and others (miscellaneous group) were able to destroy cell walls and membranes in bacteria and interfere with DNA, proteins, enzymes and so on in bacteria. An overview of new anti-bacterial strategies using plant compounds and extracts is also provided.

Phytotoxic, insecticidal, and antimicrobial activities of Ajania tibetica essential oil

The chemical profile of Ajania tibetica essential oil (EO) and its phytotoxic, insecticidal, and antimicrobial activities were assessed. Monoterpenes (79.05%) and sesquiterpenes (10.33%) were dominant in the EO, with camphor, (+/-)-lavandulol and eucalyptol being the major constituents, representing 55.06% of the total EO. The EO possessed potent phytotoxicity against Poa annua and Medicago sativa starting from 0.5 mg/mL, and when the concentration rose to 5 mg/mL, seed germination of both tested species was 100% suppressed. Ajania tibetica EO displayed significant pesticidal activity against Aphis gossypii with an LC50 value of 17.41 μg/mL; meanwhile, the EO also showed antimicrobial activity against Escherichia coli, Bacillus subtilis, Verticillium dahlia and Aspergillus niger using broth microdilution and disc diffusion methods. For the tested bacterial and fungal strains, the EO exhibited a repressing effect, with minimum inhibitory concentrations (MICs) ranging from 0.3125 to 1.25 mg/mL for bacteria and from 1.25 to 2.5 mg/mL for fungi, whereas the minimum microbicidal concentrations (MMCs) were 5 mg/mL for bacteria and 2.5 mg/mL for fungi. Our study is the first report on the chemical profile as well as the phytotoxicity, insecticidal and antimicrobic activity of A. tibetica EO, indicating its potential value as an alternative synthetic pesticide.

Phytochemical Profiling, Antioxidant, Antimicrobial and Cholinesterase Inhibitory Effects of Essential Oils Isolated from the Leaves of Artemisia scoparia and Artemisia absinthium

The current studies were focused on the phytochemical profiling of two local wild Artemisia species, Artemisia scoparia and Artemisia absinthium leaves’ essential oils, extracted via the hydro distillation method along with evaluation of their antioxidant as well as antimicrobial effects. The constituents of EOs were identified using a combined gas chromatography-mass spectrometric (GC-MS) technique. A total of 25 compounds in A. scoparia essential oil (EOAS) were identified, and 14 compounds with percentage abundance of >1% were tabulated, the major being tocopherol derivatives (47.55%). A total of nine compounds in Artemisia absinthium essential oil (EOAA) were enlisted (% age > 1%), the majority being oleic acid derivatives (41.45%). Strong antioxidant effects were pronounced by the EOAS in DPPH (IC50 = 285 ± 0.82 µg/mL) and in ABTS (IC50 = 295 ± 0.32 µg/mL) free radical scavenging assays. Both the EOs remained potent in inhibiting the growth of bacterial species; Escherichia coli (55−70%) and Shigella flexneri (60−75%) however remained moderately effective against Bacillus subtilis as well as Staphylococcus aureus. Both EOAS and EOAA strongly inhibited the growth of the tested fungal species, especially Aspergillus species (up to 70%). The oils showed anti-cholinesterase potential by inhibiting both Acetylcholinesterase (AChE; IC50 = 30 ± 0.04 µg/mL (EOAS), 32 ± 0.05 µg/mL (EOAA) and Butyrylcholinesterase (BChE; IC50 = 34 ± 0.07 µg/mL (EOAS), 36 ± 0.03 µg/mL (EOAA). In conclusion, the essential oils of A. scoparia and A. absinthium are promising antioxidant, antimicrobial and anticholinergic agents with a different phytochemical composition herein reported for the first time.

Phytochemical Analysis, Antioxidant Potential, and Cytotoxicity Evaluation of Traditionally Used Artemisia absinthium L. (Wormwood) Growing in the Central Region of Saudi Arabia

Artemisia absinthium, a plant distributed worldwide, has been reported for its numerous traditional uses, and its phytoconstituents have been investigated in several previous publications. The current study was designed to investigate the chemistry and quality; i.e., the antioxidant and cytotoxic activities, of A. absinthium volatile oil from plant species growing in the central area of Saudi Arabia compared to reported data for the plant growing in other parts of the world. Gas chromatography-mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GC-FID) spectroscopic analyses, in addition to in vitro antioxidant and cytotoxic assays, were conducted to fulfill the aims, and integrated the study's conclusion. A total of 34 compounds representing 99.98% of the essential oil of the plant were identified; among them, cis-davanone was found at the highest concentration (52.51%) compared to the other constituents. In addition, α-gurjunene (7.15%), chamazulene (3.38%), camphene (3.27), γ-eudesmol (2.49%), pinocarvone (2.18%), and ocimenone (2.03%) were also identified as major constituents of the plant's essential oil. The total percentage of davanones (53%) was the highest percentage found in the plant species growing elsewhere in the world. The antioxidant assays; i.e., the total antioxidant capacity (TAC), ferric-reducing antioxidant power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl-scavenging activity (DPPH-SA), evidenced the potential in vitro antioxidant activity of the A. absinthium essential oil, with 35.59, 10.54, and 24.00 mg Trolox equivalent per gram of the essential oil. In addition, the metal-cheating activity (MCA) of the essential oil was measured at 29.87 mg ethylenediaminetetraacetic acid (EDTA) equivalent per gram of the essential oil. Moreover, a limited cytotoxic effect of the essential oil against all tested cell lines was observed, which might be considered as an indicator of the safety of A. absinthium as a worldwide edible plant. In conclusion, the study confirmed the variations in the A. absinthium essential oil constituents in response to the environmental conditions. The study also highlighted the potential health benefits of the plant's essential oil as an antioxidant agent.