Essential oil from Duguetia lanceolata St.-Hil. (Annonaceae): Suppression of spoilers of stored-grain

Recent advancements on use of essential oils as preservatives against fungi and mycotoxins spoiling food grains

Spoilage of grains by mycotoxigenic fungi poses a great threat to food security and human health. Conventionally used chemical agents to prevent grain fungi contamination cause increasingly significant problems such as microbial resistance, residual toxicity and environmental unfriendliness. In recent years, plant essential oils (EOs) have become a hot spot in the research of control of grain fungi and mycotoxins, due to their extensive sources, non-toxicity, environmental friendliness and good antifungal efficiency. The current review aims to provide an overview of the prevention of fungi and mycotoxins in grain through EOs. The antifungal and toxin inhibition efficiency of different EOs and their effective components are investigated. The inhibition mechanism of EOs on fungi and mycotoxins in grains is introduced. The influence of EOs treatment on the change of grain quality is also discussed. In addition, the formulations and techniques used to overcome the disadvantages of EOs application are introduced. The results of recent studies have confirmed that EOs provide great potential for controlling common fungi and mycotoxins in grains, and enhancing quantity and quality safety of grains.

Role of Polyphenols from the Aqueous Extract of Aloysia citrodora in the Inhibition of Aflatoxin B1 Synthesis in Aspergillus flavus

Aflatoxin B1 (AFB1) is a mycotoxin considered a potent carcinogen for humans that contaminates a wide range of crops. Various strategies have been established to reduce or block the synthesis of AFB1 in food and feed. The use of aqueous extracts derived from plants with high antioxidant activity has been a subject of study in recent years due to their efficacy in inhibiting AFB1. In this study, we assessed the effect of Aloysia citrodora aqueous extract on Aspergillus flavus growth and on AFB1 production. A bio-guided fractionation followed by High Performance Liquid Chromatography (HPLC) and Mass spectrometry analysis of the active fraction were applied to identify the candidate molecules responsible for the dose-effect inhibition of AFB1 synthesis. Our results revealed that polyphenols are the molecules implicated in AFB1 inhibition, achieving almost a total inhibition of the toxin production (99%). We identified luteolin-7-diglucuronide as one of the main constituents in A. citrodora extract, and demonstrated that it is able to inhibit, by itself, AFB1 production by 57%. This is the first study demonstrating the anti-Aflatoxin B1 effect of this molecule, while other polyphenols surely intervene in A. citrodora anti-AFB1 activity.

First Report on the Chemical Composition, Antioxidant Capacity, and Preliminary Toxicity to Artemia salina L. of Croton campinarensis Secco, A. Rosário & PE Berry (Euphorbiaceae) Essential Oil, and In Silico Study

Croton campinarensis Secco, A. Rosário & PE Berry is an aromatic species recently discovered in the Amazon region. This study first reports the chemical profile, antioxidant capacity, and preliminary toxicity to A. salina Leach of the essential oil (EO) of this species. The phytochemical profile of the essential oil was analyzed by gas chromatography (GC/MS) and (GC-FID). The antioxidant capacity of the EO was measured by its inhibition of ABTS^•+ and DPPH^• radicals. Molecular modeling was used to evaluate the mode of interaction of the major compounds with acetylcholinesterase (AChE). The results indicate that the EO yield was 0.24%, and germacrene D (26.95%), bicyclogermacrene (17.08%), (E)-caryophyllene (17.06%), and δ-elemene (7.59%) were the major compounds of the EO sample. The EO showed a TEAC of 0.55 ± 0.04 mM·L^-1 for the reduction of the ABTS^•+ radical and 1.88 ± 0.08 mM·L^-1 for the reduction of the DPPH^• radical. Regarding preliminary toxicity, the EO was classified as toxic in the bioassay with A. salina (LC₅₀ = 20.84 ± 4.84 µg·mL^-1). Through molecular docking, it was found that the majority of the EO components were able to interact with the binding pocket of AChE, a molecular target related to toxicity evaluated in A. salina models; the main interactions were van der Waals and π-alkyl interactions.

Phytochemical Profile, Antioxidant Potential and Toxicity Evaluation of the Essential Oils from Duguetia and Xylopia Species (Annonaceae) from the Brazilian Amazon

The essential oils (EOs) of Duguetia echinophora, D. riparia, Xylopia emarginata and X. frutescens (Annonaceae) were obtained by hydrodistillation and the chemical composition was analyzed by GC-MS. An antioxidant assay using the ABTS and DPPH radicals scavenging method and cytotoxic assays against Artemia salina were also performed. We evaluated the interaction of the major compounds of the most toxic EO (X. emarginata) with the binding pocket of the enzyme Acetylcholinesterase, a molecular target related to toxicity in models of Artemia salina. The chemical composition of the EO of D. echinophora was characterized by β-phellandrene (39.12%), sabinene (17.08%) and terpinolene (11.17%). Spathulenol (22.22%), caryophyllene oxide (12.21%), humulene epoxide II (11.86%) and allo-aromadendrene epoxide (10.20%) were the major constituents of the EO from D. riparia. Spathulenol (5.65%) and caryophyllene oxide (5.63%) were the major compounds of the EO from X. emarginata. The EO of X. frutescens was characterized by α-pinene (20.84%) and byciclogermacrene (7.85%). The results of the radical scavenger DPPH assays ranged from 15.87 to 69.38% and the highest percentage of inhibition was observed for the EO of X. emarginata, while for ABTS radical scavenging, the antioxidant capacity of EOs varied from 14.61 to 63.67%, and the highest percentage of inhibition was observed for the EO of X. frutescens. The EOs obtained from D. echinophora, X. emarginata and X. frutescens showed high toxicity, while the EO of D. riparia was non-toxic. Because the EO of X. emarginata is the most toxic, we evaluated how its major constituents were able to interact with the Acetylcholinesterase enzyme. The docking results show that the compounds are able to bind to the binding pocket through non-covalent interactions with the residues of the binding pocket. The species X. emarginata and X. frutescens are the most promising sources of antioxidant compounds; in addition, the results obtained for preliminary cytotoxicity of the EOs of these species may also indicate a potential biological activity.

Essential Oils of Duguetia Species A. St. Hill (Annonaceae): Chemical Diversity and Pharmacological Potential

Duguetia A. St. Hill (Annonaceae) is recognized as one of the major genera with approximately 100 species, 67 of which are found in Brazil (29 of those are endemic). They are arboreal species with edible fruits known as “pindaíba”, “pindaíva” “pinha”, and “envira” in Brazil. Many Duguetia species, in particular, have been used in traditional medicine to treat renal colic, stomachache, rheumatism, cough, toothache, muscle pain, fever, gastrointestinal pain, and breathing difficulties. In this study, we reviewed the chemical constituents and pharmacological properties of essential oils (EOs) from Duguetia species. A total of 12 species were found, along with their EO chemical constituents and bioactivities. Bicyclogermacrene, humulene epoxide II, spathulenol, germacrene D, caryophyllene oxide, viridiflorene, α-pinene, β-caryophyllene, and β-pinene were the main chemical constituents reported. The pharmacological effects of Duguetia species EOs included anti-inflammatory, antinociceptive, antibacterial, antifungal, antioxidant, anti-trypanosoma, cytotoxic and antitumor properties. This information adds to our understanding of the potential of the EOs of Duguetia species.

Variation in Peperomia pellucida growth and secondary metabolism after rhizobacteria inoculation

Peperomia pellucida L. Kunth is a herb well-known for its secondary metabolites (SM) with biological potential. In this study, the variations in the SM of P. pellucida during association with rhizobacteria were evaluated. Plants were inoculated with Enterobacter asburiae and Klebsiella variicola, which were identified by sequencing of the 16S rRNA gene. The data were evaluated at 7, 21, and 30-day post inoculation (dpi). Plant-bacteria symbiosis improved plant growth and weight. Total phenolic content and phenylalanine ammonia lyase enzyme activity had a significant increase mainly at 30 dpi. P. pellucida was mainly composed of phenylpropanoids (37.30-52.28%) and sesquiterpene hydrocarbons (39.28-49.42%). The phenylpropanoid derivative 2,4,5-trimethoxy-styrene (ArC2), the sesquiterpene hydrocarbon ishwarane, and the phenylpropanoid dillapiole were the major compounds. Principal component analysis (PCA) of the classes and compounds ≥ 2.0% indicated that plants colonized by E. asburiae had a reduction in the content of sesquiterpene hydrocarbons and an increase in phenylpropanoids and derivatives. Plants treated with this bacterium also had an increase in the content of 2,4,5-trimethoxystyrene at 30 dpi. Plants inoculated with K. variicola had significant increases only in the content of the classes monoterpene hydrocarbons and 'other compounds' (hydrocarbons, esters, ketones, etc.). These data suggest that the production of plant secondary metabolites can be modified depending on the type of rhizobacteria inoculated.

Essential Oils from Annonaceae Species from Brazil: A Systematic Review of Their Phytochemistry, and Biological Activities

The present work involves a systematic review of the chemical composition and biological effects of essential oils from the Annonaceae species collected in Brazil from 2011 to 2021. Annonaceae is one of the most important botanical families in Brazil, as some species have economic value in the market as local and international fruit. In addition, the species have useful applications in several areas-for instance, as raw materials for use in cosmetics and perfumery and as medicinal plants. In folk medicine, species such as Annona glabra L. and Xylopia sericea A. St.-Hil. are used to treat diseases such as rheumatism and malaria. The species of Annonaceae are an important source of essential oils and are rich in compounds belonging to the classes of mono and sesquiterpenes; of these compounds, α-pinene, β-pinene, limonene, (E)-caryophyllene, bicyclogermacrene, caryophyllene oxide, germacrene D, spathulenol, and β-elemene are the most abundant. The antimicrobial, anti-inflammatory, antileishmania, antioxidant, antiproliferative, cytotoxic, larvicidal, trypanocidal, and antimalarial activities of essential oils from the Annonaceae species in Brazil have been described in previous research, with the most studies on this topic being related to their antiproliferative or cytotoxic activities. In some studies, it was observed that the biological activity reported for these essential oils was superior to that of drugs available on the market, as is the case of the essential oil of the species Guatteria punctata (Aubl.) R. A. Howard., which showed a trypanocidal effect that was 34 times stronger than that of the reference drug benznidazol.

Acaricidal Activity of Annonaceae Plants for Dermanyssus gallinae (Acari: Dermanyssidae) and Metabolomic Profile by HPLC-MS/MS

The poultry red mite Dermanyssus gallinae (De Geer) is the most important haematophagous ectoparasite in the poultry industry. The use of synthetic acaricides for this control is presenting risks related to human food. In this sense, plant secondary metabolites are promising for controlling this pest. Thus, this study aimed to evaluate the acaricidal activity of Duguetia lanceolata A.St.-Hil. (stem bark), Xylopia emarginata Mart. (stem bark), and Xylopia sericea A.St.-Hil. (stem bark and fruits) against D. gallinae. Additionally, the secondary metabolite profile of the X. emarginata was analysed by UFLC-DAD-ESI(+)-MS/MS (micrOTOF-QII) and data analysis was performed using the Molecular Networking. In a topical application test, all plant species tested showed bioactivity, in that order of toxicity with the respective probability survival: X. emarginata (stem bark) (0.28) > X. sericea (stem barks) (0.35) > X. sericea (fruits) and D. lanceolata (stem bark) (0.47). The most promising results were found for X. emarginata (LC₅₀ = 331.769 μg/cm²). It is noteworthy that the LC₅₀ of the insecticide cypermethrin was 1234.4 μg/cm², which was 73% higher than that of X. emarginata. The metabolomic profile of X. emarginata revealed the presence of alkaloids, amides, terpenoids, and phenolic compounds. This is the first report of X. emarginata acaricidal activity against D. gallinae and exploratory chemical analysis by untargeted metabolomics and the molecular network of this plant.