Chemical Diversity and Anti-Insect Activity Evaluation of Essential Oils Extracted from Five Artemisia Species

Artemisia fragrans Willd. Essential Oil: Chemical Profile and Insecticidal Potential against the Confused Flour Beetle, Tribolium confusum du Val

The confused flour beetle, Tribolium confusum du Val, is one of the cosmopolitan and polyphagous storage insect pests. The frequent application of chemical insecticides has resulted in several side effects, including threats to human health and non-target organisms and the resistance of insect pests. In the current study, the fumigant toxicity and feeding deterrence potential of Artemisia fragrans Willd. essential oil on T. confusum adults were investigated. The essential oil was rich in terpenic compounds, in which α-thujone (27.8%) and 1,8-cineole (22.8%) were dominant. The essential oil displayed significant fumigant toxicity on T. confusum, where a concentration of 35.3 μL/L caused 100% mortality of the treated adults after 48 h. The LC30 and LC40 values (lethal concentrations to kill 30% and 40% of tested insects: 15.1 and 18.4 μL/L, respectively) significantly decreased the nutritional indices of the pest, including the consumption index, relative consumption rate, and relative growth rate. The feeding deterrence index of the essential oil were calculated as being 62.29 and 48.66% for the concentrations of 15.1 and 18.4 μL/L after 5 days, respectively. Accordingly, A. fragrans essential oil can be considered an efficient, available, and natural alternative to detrimental chemical pesticides in the management of T. confusum.

Preparation and Application of Volatilized Wormwood Essence Derived Naturally into Green Insecticide

Naturally occurring substances and their derivatives function as vital resources for pesticides that can be used in fields, such as insecticide production and fungicide development. As a botanical entity displaying multifaceted biological functions, wormwood has received thorough scrutiny across multiple sectors. The insect repellency potency combined with antibacterial and antifungal activities of wormwood position it as a potential candidate for prospective development into eco-friendly chemical pesticides. In this research, Wormwood essential oil was procured via ethanol water under ultrasonic scenarios and subsequently diluted with PEG 400 to formulate green chemical pesticides. The defensive efficacy of this green pesticide on plants was validated through 2 weeks of clustered plant growth experiments. Active constituents that exerted their effects were scrutinized by GC-MS. Furthermore, this green pesticide also displays efficacious effects on the prevention and management of aphids, exhibiting a dose-dependent relationship. 4-terpenol, eucalyptol, carvacrol, and L-borneol were identified by GC-MS as the predominant active constituents in this green chemical pesticide. Wormwood can be leveraged to develop green chemical pesticides, which can protect plants without contaminating the environment.

Artemisia santonicum L. and Artemisia lerchiana Web. Essential Oils and Exudates as Sources of Compounds with Pesticidal Action

The application of natural products for pest control is important in modern farming. In the present study, Artemisia santonicum L. and Artemisia lerchiana Weber essential oil and exudate profiles were determined, and their potential as inhibitors of seed germination, acetylcholinesterase, and phytopathogenic mycelium growth were evaluated. Essential oils (EO) were obtained via hydrodistillation and exudates (AE) by washing aerial parts of the species with acetone. EO and AE's composition was identified using GC/MS. Eucalyptol (1,8-cineole) and camphor were found to be the main components of A. lerchiana EO, while β-pinene, trans-pinocarveol, α-pinene, α-terpineol, and spathulenol were established as major compounds of A. santonicum EO. Strong inhibition on Lolium perenne seed germination was found at 2 µL/mL and 5 mg/mL using aqueous solutions of EO and AE, respectively. An inhibitory effect on acetylcholinesterase was established, with an IC50 value of 64.42 and 14.60 μg/mL for EO and 0.961, >1 mg/mL for the AE of A. lerchiana and A. santonicum, respectively. The low inhibition on the mycelium growth of studied phytopathogenic fungi was established by applying 2 µL of EO and 15 µL of 100 mg/mL of AE, with the exception of A. lerchiana AE against Botrytis cinerea. These results show that the studied EO and AE exhibited strong phytotoxic and AChE inhibitory activities, providing new data for these species.

Rapid Detection of Potential Natural Food Preservatives and Identification of Artemisia Species via High-Sensitivity Photoionization Mass Spectrometry

Natural food preservatives are being sought extensively as a safe alternative to chemical food preservatives. This study aimed to identify potential natural preservatives from herbs using single-photon ionization time-of-flight mass spectrometry (SPI-TOF-MS). Five Artemisia species and four other herbs were analyzed, and the random forest (RF) algorithm was used to simulate olfaction and distinguish the Artemisia species by identifying the characteristic peaks of volatile terpenoids (VTPs). Results showed that the terpenoid synthase (TPS) gene family was expanded in Artemisia species, potentially contributing to the increased production of VTPs, which have potential as natural preservatives and specifically identify these species. The limits of detections (LODs) for principle VTPs in Artemisia species were as low as 22-39 parts-per-trillion-by-volume (pptv) using SPI-TOF-MS. This study highlights the potential for headspace mass spectrometry to be used in the development of natural preservatives and the identification of plant species.

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.