Optimization, validation and application of headspace solid-phase microextraction gas chromatography for the determination of 1-nitro-2-phenylethane and methyleugenol from Aniba canelilla (H.B.K.) Mez essential oil in skin permeation samples

Antifungal Activity of Aniba canelilla (Kunth) Mez Essential Oil and Its Main Compound 1-Nitro-2-Phenylethane against Dermatophytes

The essential oil of Aniba canelilla (Kunth) Mez (EOAC), an Amazon plant composed of a rare nitro compound, has shown scientific evidence of antifungal activity but is still unexplored against dermatophytes. The antifungal susceptibility of EOAC and its main compound, 1-nitro-2-phenylethane (NP), was evaluated against dermatophytes (Trichophyton rubrum, T. mentagrophytes and Microsporum canis), evidencing antifungal activity with an inhibitory concentration lower than 256 μg/mL. The mechanism of action was also evaluated, and it is suggested that EOAC and NP have fungicidal action in the fungal membrane, since the antifungal activity occurs through a modification of the shape of the conidial structures of the fungus, showing the permeability of the intracellular content due to the visually observed plasmolysis and cytosolic extravasation through an osmotic process. These results suggest the essential oil and its main compound are promising plant-derived alternatives for treating ungual dermatophytosis.

Development by design of experiment and validation of a HPLC-UV method for simultaneous quantification of 1-nitro-2-phenylethane and methyleugenol: Application to nail permeation/retention studies

Aniba canelilla (Kunth) Mez is an aromatic tree from Amazon region whose essential oil presents 1-nitro-2-phenylethane (NP) and methyleugenol (ME) as major compounds. Several properties are attributed to Aniba canelilla essential oil (ACEO), such as antifungal. Onychomycoses are fungal nail infections that require novel therapeutic alternatives, especially topical ones. However, to ensure the success of topical therapy, the active compound should be able to penetrate/permeate the nail plate, which is challenging due to the highly keratinized composition of this structure. Thus, the aims of this article were to develop, validate and apply a high-performance liquid chromatography method (HPLC-UV) to quantify NP and ME in porcine hoof extract (PHE) and receptor fluid (RF) during in vitro permeation/retention studies in nail model, for which porcine hoof membranes were used. For method development, two Designs of Experiment (DoE) were adopted: 23 Full Factorial and Box-Behnken. Retention times of 5.65 and 7.49 min were achieved for NP and ME, respectively. The method was full validated for NP and ME quantification in receptor fluid, in accordance with the recommended parameters by ICH Q2(R1) Guideline. In addition, the method was full validated for NP and ME quantification in porcine hoof extract, considering the parameters and criteria of ICH M10 Guideline. In vitro permeation/retention studies were carried out in nail model, and promising results were obtained. NP reached the receptor fluid in the order of 441.1 ± 92.1 µg/cm2 at 72 h. The amount of NP and ME retained into porcine hoof membrane was 1272.6 ± 225.7 µg/cm2 and 84.7 ± 20.4 µg/cm2, respectively, at 72 h. Our findings open perspective to develop topical formulations containing ACEO as active compound aiming the management of onychomycosis.

Determination of Eugenol Residues in Fish Tissue, Transport, and Temporary Water of Aquatic Product by Gas Chromatography-Tandem Mass Spectrometry with Application of the Electrospun Nanofibrous Membrane

Using gas chromatography-tandem mass spectrometry and electrospun nanofibrous membrane, we developed and validated a simple, rapid, and sensitive methodology for quantifying eugenol residues in fish tissue and water samples. Fish tissue extract and water samples (315 samples) collected from three southeastern China provinces (Shanghai, Zhejiang, and Fujian), originating from eight provinces of Zhejiang, Jiangsu, Shandong, Guangdong, Fujian, Anhui, Shanghai, and Jiangxi, from April 2021 to April 2023 were filtered with an electrospun nanofiber membrane, extracted with trichloromethane/n-hexane, and directly concentrated to dry after simple purification. An internal standard of p-terphenyl in n-hexane and 5-µL injection volumes of the solutions was used to analyze eugenol via internal calibration with a minimum concentration of 0.5 µg/L in water samples and 0.1 µg/kg in aquatic product samples. The highest amount of eugenol was detected in Fujian province, possibly due to the higher temperature during transportation, while the lowest amount was found in Shanghai, which mainly uses temporary fish-culture devices. This is a fast, inexpensive, and effective method for testing large quantities of fish water and meat samples.

Development, validation and application of a gas chromatography method for the determination of dillapiole from Piper aduncum essential oil in skin permeation samples

The essential oil extracted from the leaves of Piper aduncum has antifungal, insecticidal and antibacterial activity. Studies with its main compound, dillapiole (DIL) revealed antibacterial and anti-inflammatory potential. Despite all this bioactivity, there is no updated report on the development and validation of analytical and bioanalytical methodology to quantify DIL in skin samples. A selective, precise, accurate and adequate method for the determination of DIL in solutions, porcine ear skin samples and receptor fluid was developed and validated by headspace extraction-gas chromatography with flame ionization detection (HS-GC-FID). HS-GC-FID was applied to determine DIL in Franz cell permeation and retention studies using porcine ear skin samples. In the HS-GC-FID method, matrix-related interferences were not observed at the peak of the DIL retention time. The results showed a high recovery (>97%) after the extraction procedure, allowing the quantification of DIL in complex matrices. In vitro permeation/retention for DIL showed cumulative amounts permeated in the order: receptor fluid (21.98 ± 1.19 μg/cm² ) > epidermis (15.40 ± 1.20 μg/cm² ) > dermis (9.52 ± 1.13 μg/cm² ). HS-GC-FID was successfully validated and the results point to DIL transdermal permeation and to the potential to develop pharmaceutical formulations for skin delivery to treat inflammation or infections.

Method Validation and Evaluation of Safrole Persistence in Cowpea Beans Using Headspace Solid-Phase Microextraction and Gas Chromatography

Bioinsecticides are regarded as important alternatives for controlling agricultural pests. However, few studies have determined the persistence of these compounds in stored grains. This study aimed at optimizing and validating a fast and effective method for extraction and quantification of residues of safrole (the main component of Piper hispidinervum essential oil) in cowpea beans. It also sought to assess the persistence of this substance in the grains treated by contact and fumigation. The proposed method used headspace solid-phase microextraction (HS-SPME) and gas chromatography with a flame ionization detector (GC/FID). Factors such as temperature, extraction time and type of fiber were assessed to maximize the performance of the extraction technique. The performance of the method was appraised via the parameters selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy. The LOD and LOQ of safrole were 0.0057 and 0.019 μg kg⁻¹, respectively and the determination coefficient (R²) was >0.99. The relative recovery ranged from 99.26 to 104.85, with a coefficient of variation <15%. The validated method was applied to assess the persistence of safrole residue in grains, where concentrations ranged from 1.095 to 0.052 µg kg⁻¹ (contact) and from 2.16 to 0.12 µg kg ⁻¹ (fumigation). The levels measured up from the fifth day represented less than 1% of the initial concentration, proving that safrole have low persistence in cowpea beans, thus being safe for bioinsecticide use. Thus, this work is relevant not only for the extraction method developed, but also for the possible use of a natural insecticide in pest management in stored grains.

Chemical Diversity and Therapeutic Effects of Essential Oils of Aniba Species from the Amazon: A Review

Lauraceae families have great diversity in the world's tropical regions and are represented mainly by aromatic shrubs and trees with significant production of essential oils (EOs). This work presents a review of the EO chemical profiles from specimens of Aniba, including their seasonal variations, geographical distributions, and biological activities in the Amazon biome. Based on the survey, 15 species were reviewed, representing 167 oil samples extracted from leaves, twig barks, and woods. Brazilian Amazon was the most representative geographic area in the number of specimens, highlighting the locations Belém, (Pará state, PA) (3 spp., 37 samples), Santarém (PA) (3 spp., 10 samples), Carajás (PA) (3 spp., 7 samples), and Manaus (Amazonas state, AM) (3 spp., 16 samples). The main compound classes identified in oils were benzenoids and phenylpropanoids, represented by 1-nitro-2-phenylethane, benzyl salicylate, benzyl benzoate and methyleugenol, along with terpenoids, especially monoterpenes and sesquiterpenes, such as linalool, α-phellandrene, β-phellandrene, β-selinene, and spathulenol. The EOs from Aniba showed considerable variation in the chemical profiles according to season and collection site. The hierarchical cluster analysis classified the samples into two main groups according to chemical composition. This review highlights its comprehensive and up-to-date information on history, conservation, traditional uses, chemosystematics, pharmacological potential of Aniba species.

Headspace Solid-Phase Microextraction: Validation of the Method and Determination of Allyl Isothiocyanate Persistence in Cowpea Beans

Essential oils are widely recognized as an efficient and safe alternative for controlling pests in foods. However, a few studies have determined the persistence of these compounds in stored grains. The present study optimized and validated a fast and effective method for extraction and quantification of allyl isothiocyanate (AITC-the main component of mustard essential oil) residue in cowpea beans. It also investigated the persistence of this substance in the grains. The proposed method employs headspace solid-phase microextraction (HS-SPME) and gas chromatography with a flame ionization detector (GC/FID). For optimizing it, a central composite design (CCD) was used, where the best conditions for the extraction of the AITC were achieved using 15 min fiber exposure at 30 °C. The performance of the method was assessed by studying selectivity, linearity, limits of detection (LOD) and quantification (LOQ), precision, and accuracy. The LOD and LOQ for AITC were 0.11 and 0.33 μg kg^-1, respectively. The determination coefficient (R ²) was above 0.99. The relative recovery rate ranged from 108.2 to 114.8%, with an interday coefficient of variation below 9%. After 36 h, no residue was detected in the samples, demonstrating that the AITC has low persistence and can be safely used as a bioinsecticide for grains.

Antimicrobial substances from Amazonian Aniba (Lauraceae) species

Extracts and six isolated substances from Aniba (Lauraceae) Amazonian species A. parviflora, A. panurensis and A. rosaeodora were analysed in vitro to their antibacterial, antiparasitic and antiplasmodial activities. NMR and MS experiments led to the identification of three styrylpyrones (5,6-dihydrokawain [I], 4-methoxy-11,12-methylenedioxy-6-trans-styryl-pyran-2-one [II] and rel-(6R,7S,8S,5'S)-4'-methoxy-8-(11,12-dimethoxyphenyl-7-[6-(4-methoxy-2-pyranyl)]-6-(E)-styryl-1'-oxabicyclo[4,2,0]oct-4'-en-2'-one [III]), a pyridine alkaloid (anibine [IV]) and two kavalactones (tetrahydroyangonin [V] and dihydromethysticin [VI]). The best antibacterial result was observed at the hexane fraction of A. panurensis (MIC 7.8 μg/mL against the three bacteria). Equal MIC were observed by the extract and dichloromethane fraction of A. panurensis against S. simulans and S. aureus; and 15.62 μg/mL against MRSA. Similarly, only A. panurensis extracts showed in vitro activities against Tripanossoma cruzi and Leishmania amazonensis parasites. In Plasmodium falciparum assay, 5,6-dihydrokawain was considered an active antimalarial (14.03 μM), and substances II (132.94 μM) and III (41.84 μM) presented moderate activities.