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This study aimed to assess the chemical composition and pesticidal activities of essential oils (EOs) from Cautleya spicata rhizomes and aerial parts. The EOs were assessed against root-knot nematodes (Meloidogyne incognita) by mortality and hatchability bioassays and the phytotoxicity of the EOs was determined against Raphanus raphanistrum subspp. Sativus (radish) and Cichorium intybus (chicory) seeds. In-silico screening of the primary constituents of EOs and five chosen target proteins of the nematode was conducted to predict the expected mechanism of action of these oils. p-Cymene and β-pinene were the key compounds in the EOs from the rhizomes and aerial parts. The EO from the aerial parts (LC50 value = 0.555 µL/mL for nematode mortality assay and IC50 value = 0.016 µL/mL for nematode egg hatchability after 96 h) exhibited significantly higher nematicidal activity than the rhizome EO. However, rhizome EO showed higher phytotoxic activity against radish (R. raphanistrum) with lower IC50 values (0.157 and 0.123 µL/mL for RLI and SLI, respectively) and chicory (C. intybus) seeds (100% inhibition at 1.0 µL/mL concentration). Docking studies revealed the strongest inhibitory actions of β-selinene against acetylcholinesterase (AChE) and cytochrome c oxidase (CytC), spathulenol against glutathione S-transferase (GST-1), and β-eudesmol against heat shock protein 90 (HSP90) and odorant response gene-3 (ODR3) proteins. The study unveiled the chemical diversity present in both the EOs and rhizomes of C. spicata along with their considerable potential as plant-based pesticidal agents effective against nematodes and weed species.

The essential oils and aroma derived from the leaves (L), stems (St), and spikes (s) of Piper nigrum L. cv. Guajarina were extracted; the essential oils were extracted using hydrodistillation (HD), and steam distillation (SD), and the aroma was obtained by simultaneous distillation and extraction (SDE). Chemical constituents were identified and quantified using GC/MS and GC-FID. Preliminary biological activity was assessed by determining the toxicity against Artemia salina Leach larvae, calculating mortality rates, and determining lethal concentration values (LC50). The predominant compounds in essential oil samples included α-pinene (0–5.6%), β-pinene (0–22.7%), limonene (0–19.3%), 35 linalool (0–5.3%), δ-elemene (0–10.1%), β-caryophyllene (0.5–21.9%), γ-elemene (7.5–33.9%), and curzerene (6.9–31.7%). Multivariate analysis, employing principal component analysis (PCA) and hierarchical cluster analysis (HCA), revealed three groups among the identified classes and two groups among individual compounds. The highest antioxidant activity was found for essential oils derived from the leaves (167.9 41 mg TE mL−1). Larvicidal potential against A. salina was observed in essential oils obtained from the leaves (LC50 6.40 μg mL−1) and spikes (LC50 6.44 μg mL−1). The in silico studies demonstrated that the main compounds can interact with acetylcholinesterase, thus showing the potential molecular interaction responsible for the toxicity of the essential oil in A. salina.

The objective of the current study was to evaluate the altitudinal variability in chemical compounds, nematicidal, insecticidal, herbicidal, and antifungal activity of the essential oils of H. coronarium collected from four different habitats of Tarai and Kumaun region of Uttarakhand. Essential oils were hydro-distilled from rhizomes of H. coronarium, and their yield varied from 0.05 to 0.25% (v/w). Based on GC-MS analysis, the major compounds observed were 1, 8-cineole (12.21–18.27%), coronarin E (10.20–14%), α-terpineol (5.32–10.13%), terpinen-4-ol (2.20–4.67%), α-pinene (4.90–8.77%), Z-caryophyllene (4.67–12.29%), and linalool (1.96–4.62%). To visually observe the variation in the oil composition profile of essential oils, heat map clustering, Venn diagram, and principal component analysis (PCA) were performed. To evaluate the pesticidal properties, the essential oils were tested under laboratory conditions. Additionally, significant nematicidal activity was demonstrated by essential oils against Meloidogyne incognita, good insecticidal activity against Spodoptera litura, and moderate herbicidal activity on Raphanus raphanistrum subsp. sativus, and effective antifungal activity against Fusarium oxysporum and Curvularia lunata was observed in the current investigation.

The essential oils (EOs) of Guatteria schomburgkiana (Gsch) and Xylopia frutescens (Xfru) (Annonaceae) were obtained by hydrodistillation, and their chemical composition was evaluated by gas chromatography-mass spectrometry (GC/MS). Herbicide activity was measured by analyzing the seed germination percentage and root and hypocotyl elongation of two invasive species: Mimosa pudica and Senna obtusifolia. The highest yield was obtained for the EO of Xfru (1.06%). The chemical composition of Gsch was characterized by the presence of the oxygenated sesquiterpenes spathulenol (22.40%) and caryophyllene oxide (14.70%). Regarding the EO of Xfru, the hydrocarbon monoterpenes α-pinene (35.73%) and β-pinene (18.90%) were the components identified with the highest concentrations. The germination of seeds of S. obtusifolia (13.33 ± 5.77%) showed higher resistance than that of seeds of M. pudica (86.67 ± 5.77%). S. obtusifolia was also more sensitive to the EO of Xfru in terms of radicle (55.22 ± 2.72%) and hypocotyl (71.12 ± 3.80%) elongation, while M. pudica showed greater sensitivity to the EO of Gsch. To screen the herbicidal activity, the molecular docking study of the major and potent compounds was performed against 4-hydroxyphenylpyruvate dioxygenase (HPPD) protein. Results showed good binding affinities and attributed the strongest inhibitory activity to δ-cadinene for the target protein. This work contributes to the study of the herbicidal properties of the EOs of species of Annonaceae from the Amazon region.

A comparative study of volatiles, antioxidant activity, phytotoxic activity, as well as in silico molecular docking and ADMET study, was conducted for essential oils from three Vitex species, viz., V. agnus-castus, V. negundo, and V. trifolia. Essential oils (OEs) extracted by hydrodistillation were subjected to compositional analysis using GC-MS. A total number of 37, 45, and 43 components were identified in V. agnus-castus, V. negundo, and V. trifolia, respectively. The antioxidant activity of EOs, assessed using different radical-scavenging (DPPH, H2O2 and NO), reducing power, and metal chelating assays, were found to be significant as compared with those of the standards. The phytotoxic potential of the EOs was performed in the receptor species Raphanusraphanistrum (wild radish) and the EOs showed different levels of intensity of seed germination inhibition and root and shoot length inhibition. The molecular docking study was conducted to screen the antioxidant and phytotoxic activity of the major and potent compounds against human protein target, peroxiredoxin 5, and 4-hydroxyphenylpyruvate dioxygenase protein (HPPD). Results showed good binding affinities and attributed the strongest inhibitory activity to 13-epi-manoyl oxide for both the target proteins.