Insecticidal activities of the essential oil of Rhynchanthus beesianus rhizomes and its constituents against two species of grain storage insects

Preparation and characterization of a modified Canna starch as a wall material for the encapsulation of methyleugenol improves its antifungal activity against Fusarium trichothecioides

In this study, α-amylase (α-A) and 2-octenylsuccinic anhydride (OSA)-modified Canna starch (Cs) were prepared and characterized as wall materials and encapsulated with methyleugenol (α-A-OSA-Cs-methyleugenol); their in vitro antifungal activity against Fusarium trichothecioides (F. trichothecioides) was also investigated. The encapsulation efficiency under optimal encapsulation conditions was 83.98%. The results of particle size, polydispersity index (PDI), zeta potential, electron scanning microscopy and Fourier transform infrared spectroscopy showed that the modified Cs had superior physicochemical properties; it was also demonstrated that methyleugenol successfully entered the pores of Cs. The in vitro release study showed that α-A-OSA-Cs could effectively reduce their volatility under different temperature environments. α-A-OSA-Cs have excellent performance as slow-release wall materials, and after encapsulation with methyleugenol, the inhibition ability of F. trichothecioides mycelium growth was dose-dependent and improved, extending the shelf life of potatoes, which has good commercial value in the field of slow-release preservatives.

First investigation of the chemical composition, antioxidant, antimicrobial and larvicidal activities of the essential oil of the subspecies Ononis angustissima Lam. subsp. filifolia Murb

This study is the first to explore the essential oil of Ononis angustissima Lam. subsp. filifolia Murb., a subspecies growing in the Algerian northeastern Sahara. The chemical composition was evaluated by GC/GC-EIMS. Antioxidant activity was evaluated using two methods. Thirty-four (91.6%) individual components were identified. The main constituents were linalool (12.6%), hexahydrofarnesylacetone (8.4%), β-eudesmol (6.6%), α-cadinol (6.4%) and T-cadinol (6.1%). The findings provide a chemical basis for understanding relationships between North African subspecies, supporting botanical and genetic classification. The oil exhibited moderate scavenging activity against DPPH radicals (IC50 = 102.30 µg/ml) and high activity in the β-carotene bleaching assay (91.346%). Antimicrobial tests revealed effectiveness against Gram-positive bacteria (Staphylococcus aureus ATCC 25923 and ATCC 43300), limited impact on Gram-negative bacteria (Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922), and good inhibition against Aspergillus niger and Scedosporium apiospermum. A notable larvicidal activity was observed against Date Moth, particularly on L2 larvae.

Identification of Terpenoid Compounds and Toxicity Assays of Essential Oil Microcapsules from Artemisia stechmanniana

Plant essential oils, as biological pesticides, have been reviewed from several perspectives and play a key role in chemical ecology. However, plant essential oils show rapid degradation and vulnerability during actual usage. In this study, we conducted a detailed analysis of the compounds present in the essential oils of A. stechmanniana using gas chromatography-mass spectrometry (GC-MS). The results showed seventeen terpenoid compounds in the A. stechmanniana oil, with four major terpenoid compounds, i.e., eucalyptol (15.84%), (+)-2-Bornanone (16.92%), 1-(1,2,3-Trimethyl-cyclopent-2-enyl)-ethanone (25.63%), and (-)-Spathulenol (16.38%), in addition to an amount of the other terpenoid compounds (25.26%). Indoor toxicity assays were used to evaluate the insecticidal activity of Artemisia stechmanniana essential oil against Aphis gossypii, Frankliniella occidentalis, and Bactericera gobica in Lycium barbarum. The LC₅₀/LD₅₀ values of A. stechmanniana essential oils against A. gossypii, F. occidentalis, and B. gobica were 5.39 mg/mL, 0.34 mg/L, and 1.40 μg/insect, respectively, all of which were highly efficient compared with azadirachtin essential oil. Interestingly, A. stechmanniana essential oil embedded in β-cyclodextrin (microencapsule) remained for only 21 days, whereas pure essential oils remained for only 5 days. A field efficacy assay with the A. stechmanniana microencapsule (AM) and doses at three concentrations was conducted in Lycium barbarum, revealing that the insecticidal activities of AM showed high efficiency, maintained a significant control efficacy at all concentrations tested, and remained for 21 days. Our study identified terpenoid compounds from untapped Artemisia plants and designed a novel method against pests using a new biopesticide on L. barbarum.

Insight into the phytochemical profile and antimicrobial activities of Amomum subulatum and Amomum xanthioides: an in vitro and in silico study

Introduction

Medicinal plants have been considered as potential source of therapeutics or as starting materials in drugs formulation.

Methods

The current study aims to shed light on the therapeutic potential of the Amomum subulatom and Amomum xanthioides Fruits by analyzing the phytochemical composition of their seeds and fruits using gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) techniques to determine the presence of bioactive components such as flavonoids, phenols, vitamins, steroids, and essential oils.

Results and Discussion

The protein content is usually higher than the total lipids in both species except the fruit of A. subulatum which contain more lipids than proteins. The total protein contents for A. subulatum were 235.03 ± 21.49 and 227.49 ± 25.82 mg/g dry weight while for A. xanthioides were 201.9 ± 37.79 and 294.99 ± 37.93 mg/g dry weight for seeds and fruit, respectively. The Carvacrol levels in A. subulatum is 20 times higher than that in A. xanthioides. Lower levels of α-Thujene, Phyllanderenes, Ascaridole, and Pinocarvone were also observed in both species. According to DPPH (2,2-diphenylpicrylhydrazyl) assay, seed the extract of A. subulatum exhibited the highest antioxidant activity (78.26±9.27 %) followed by the seed extract of A. xanthioides (68.21±2.56 %). Similarly, FRAP (Ferric Reducing Antioxidant Power) assay showed that the highest antioxidant activity was exhibited by the seed extract of the two species; 20.14±1.11 and 21.18±1.04 µmol trolox g-1 DW for A. subulatum and A. xanthioides, respectively. In terms of anti-lipid peroxidation, relatively higher values were obtained for the fruit extract of A. subulatum (6.08±0.35) and the seed extract of A. xanthioides (6.11±0.55). Ethanolic seed extracts of A. subulatum had the highest efficiency against four Gram-negative bacterial species which causes serious human diseases, namely Pseudomonas aeruginosa, Proteus vulgaris, Enterobacter aerogenes, and Salmonella typhimurium. In addition, P. aeruginosa was also inhibited by the fruit extract of both A. subulatum and A. xanthioides. For the seed extract of A. xanthioides, large inhibition zones were formed against P. vulgaris and the fungus Candida albicans. Finally, we have in silico explored the mode of action of these plants by performing detailed molecular modeling studies and showed that the antimicrobial activities of these plants could be attributed to the high binding affinity of their bioactive compounds to bind to the active sites of the sterol 14-alpha demethylase and the transcriptional regulator MvfR.

Conclusion

These findings demonstrate the two species extracts possess high biological activities and therapeutical values, which increases their potential value in a number of therapeutic applications.