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The present study was carried out to investigate the proximate composition, fatty acid (FA) profile and volatile compounds (VC) of cooked green licuri (Syagrus coronata) - an unripe stage that is then cooked - and naturally ripe licuri almonds. The FA profiles were determined by gas chromatography (GC) and the VC composition was evaluated using headspace-solid-phase microextraction coupled with GC-MS. The cooked green licuri presented higher moisture, and lower contents of ashes, proteins and lipids than naturally ripe licuri almonds. The FA profiles of cooked green licuri and naturally ripe licuri almonds showed that saturated FAs were predominant (80%) in both samples, and the concentrations of lauric, palmitic, and oleic acids in naturally ripe licuri almonds were higher than those in cooked green licuri. Limonene was the predominant compound in naturally ripe licuri almonds. The main class of VC in the cooked green licuri were aldehydes, with 3-methyl-butanal and furfural being the main species. Alcohols, such as 3-methyl-butanol and 2-heptanol, were the main class of VC in naturally ripe licuri almonds. Among the volatile compounds, 1-hexanol and 2-nonanone contributed to the aroma of cooked green licuri almonds, whereas 2-heptanone, ethanol, and limonene contributed to the aroma of naturally ripe licuri almonds (almonds not subjected to any cooking process). In a word, cooked green licuri and naturally riped licuri almonds, despite having different proximate compositions, present similar fatty acid profile and distinct aromatic characteristics. Therefore, cooked green licuri and naturally riped licuri almonds are an alternative source of nutrient and could be investigated for the use in the food industry to enhance flavor and aroma to new products.

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Different bioproducts can be obtained by changing operative condition of biotechnological process, and this bioprocess aspect is a significant approach to be adopted on industrial scale leading to the creation of new natural aroma. Thus, this study aimed to investigate the culture conditions and optimization of the biotransformation of limonene into limonene-1,2-diol using Pestalotiopsis mangiferae LaBMicrA-505 obtained from the Brazilian Amazon. The study started with the investigation of the establishment of culture, followed by optimization of the conditions for biotransformation of R-(+)-limonene to limonene-1,2-diol, using shake flasks. The fresh biomass of P. mangiferae LaBMicrA-505 obtained in liquid media supplemented with yeast-malt extract under with 72 h (stationary phase) performed better diol productivity when compared to other biomasses. Finally, in the modeling of contour plots and surface responses of a central composite design, the use of 4 g l- 1 biomass, 2% of the substrate at 24 °C, 120 rpm, and pH of 6.0 could maximize the production of limonene-1,2-diol, accumulated up to 98.34 ± 1.53% after 96 h of reaction. This study contributed to identified operational condition for the R-(+)-limonene bioconversion scale-up. The endophytic fungus P. mangiferae LaBMicrA-505 proved to be a potent biocatalyst to biotechnologically produce limonene-1,2-diol, an aroma compounds with interesting bioactive features that up to now has been manufactured by extraction from plants with long and not environmentally friendly procedures.

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The present article aims to evaluate the antifungal and antivirulence effect of the phytoconstituent Limonene against Candida spp. Antifungal assays were performed, where the concentration capable of inhibiting 50 % of fungal growth, the growth inhibition curve, the minimum fungicidal concentration, the evaluation of the modifying effect with fluconazole, the inhibitory effect of the substances on the morphological transition of Candida spp. and the statistical analysis of the results were determined. With this study, it was seen that limonene demonstrated growth inhibition for the strains tested and when associated the natural compound with Fluconazole, there was potentiation of the effect of the drug, since the inhibition of growth by the combination occurred at lower concentrations against all strains tested, when compared to the drug alone, which inhibited growth at the highest concentration. In the test to determine the Minimum Fungicidal Concentration of the products tested alone and in combination, it was found that in the case of Candida strains, growth inhibition by limonene occurred at a concentration of 1024 µg/mL. For Fluconazole, growth impairment ranged from > 1024 µg/mL to 256 µg/mL for the strains. And when combined, limonene potentiated the action of FCZ, making fungal colonization unfeasible at concentrations below 1024 µg/mL. Regarding the morphological transition from yeast to hyphae, limonene was used at concentrations of 1024 µg/mL and 512 µg/mL, and it was found that, for CA and CK, the filaments were reduced in number and size at the highest concentration and against CT, the morphological transition from yeast to hyphae/pseudohyphae was totally inhibited, and if compared to the growth control, limonene was able to reduce fungal growth at concentrations greater than 512 µg/mL. This compound has antimicrobial activity described, due to its ability to interfere in the gene expression of the fungus, the limited therapeutic options and the recent emergence of multidrug-resistant Candida species represent a significant challenge for human medicine and highlight the need for new therapeutic approaches, and in this study a great potential of limonene was revealed in relation to the perspective of increasing the efficiency of commercial drug. This work can bring an important contribution to the scientific database, while emphasizing that in-depth studies and tests on the subject, in order to better investigate its effectiveness and mechanisms by which they exert their effects, are still necessary.

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Developing new pesticides poses a significant challenge in designing next-generation natural insecticides that selectively target specific pharmacological sites while ensuring environmental friendliness. In this study, we aimed to address this challenge by formulating novel natural pesticides derived from secondary plant metabolites, which exhibited potent insecticide activity. Additionally, we tested their effect on mitochondrial enzyme activity and the proteomic profile of Ae. aegypti, a mosquito species responsible for transmitting diseases. Initially, 110 key compounds from essential oils were selected that have been reported with insecticidal properties; then, to ensure safety for mammals were performed in silico analyses for toxicity properties, identifying non-toxic candidates for further investigation. Subsequently, in vivo tests were conducted using these non-toxic compounds, focusing on the mosquito's larval stage. Based on the lethal concentration (LC), the most promising compounds as insecticidal were identified as S-limonene (LC50 = 6.4 ppm, LC95 = 17.2 ppm), R-limonene (LC50 = 9.86 ppm, LC95 = 27.7 ppm), citronellal (LC50 = 40.5 ppm, LC95 = 68.6 ppm), R-carvone (LC50 = 61.4 ppm, LC95 = 121 ppm), and S-carvone (LC50 = 62.5 ppm, LC95 = 114 ppm). Furthermore, we formulated a mixture of R-limonene, S-carvone, and citronellal with equal proportions of each compound based on their LC50. This mixture specifically targeted mitochondrial proteins and demonstrated a higher effect that showed by each compound separately, enhancing the insecticidal activity of each compound. Besides, the proteomic profile revealed the alteration in proteins involved in proliferation processes and detoxification mechanisms in Ae. aegypti. In summary, our study presents a formulation strategy for developing next-generation natural insecticides using secondary plant metabolites with the potential for reducing the adverse effects on humans and the development of chemical resistance in insects. Our findings also highlight the proteomic alteration induced by the formulated insecticide, showing insight into the mechanisms of action and potential targets for further exploration in vector control strategies.

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A series of 38 thiosemicarbazone derivatives based on camphene and limonene were evaluated for their antiproliferative activity. Among them, 19 were synthesized and characterized using proton and carbon-13 nuclear magnetic resonance (1H and 13C NMR). For initial compound selection, human melanoma cells (SK-MEL-37) were exposed to a single concentration of a compound (100 µM) for 24, 48, and 72 hours, and cell detachment was visually observed. Cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Nineteen compounds (4, 6, 8, 11, 13, 14, 15, 16, 17, 18, 20, 22, 25, 26, 31, 3', 4', 6', and 9') yielded cell viability below 20%. Subsequently, IC50 values for these compounds were determined, ranging from 11.56 to 55.38 µM, after 72 hours of treatment. Compound 17 (o-hydroxybenzaldehyde (-)-camphene-based thiosemicarbazone) demonstrated the lowest IC50 value, followed by compound 4 (benzaldehyde (-) camphene-based thiosemicarbazone) at 12.84 µM. Regarding compound 4, we observed the induction of a characteristic ladder pattern of DNA fragmentation through gel electrophoresis. Furthermore, fluorescence, flow cytometry and scanning microscopy assays revealed morphological changes consistent with apoptosis induction. Additionally, the measurement of caspase 6 and 8 activity in cellular extracts after treatment for 2, 4, 6, and 24 hours suggested the potential involvement of the extrinsic apoptosis pathway in the mechanism of action of compound 4. Further investigations, including molecular docking studies, are required to fully explore the potential of compound 4 and the other selected compounds, highlighting their promising role in future melanoma therapy research.

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Invasomes have been widely exploited to enhance the percutaneous permeation of drugs. On the other hand, few studies have been dedicated to evaluating how their composition impacts the interaction with the skin, vesicle rigidity and stability, which was the focus of this investigation. Light scattering and spectroscopic techniques were considered for vesicle characterization. The addition of cholesterol (CHOL) into the phosphatidylcholine (PC) vesicles led to increased membrane rigidity (from PC:CHOL 5:0.5) and a concentration-dependent disorder effect on skin domains. Nevertheless, these vesicles were showed to be less stable. Ethanol, in turn, resulted in larger and more flexible vesicles, which can be attributed to its preferential distribution in headgroups of PC. The effect of limonene on membrane rigidity was dependent on the vesicle composition. It reduced the rigidity when few constituents were considered, but an opposite effect was observed for vesicles containing PC, CHOL, ethanol and limonene. Competitive effects of limonene and CHOL by the same domains in PC could explain these findings. Limonene was crucial to obtaining more monodisperse vesicles and it showed a synergistic action with CHOL in the disruption of lipid domains in the skin. Invasomes were more stable than liposomes. CHOL-free invasomes showed to be stable for up to 40 days at room temperature.

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Tetranychus urticae Koch (Acari: Tetranychidae), the two-spotted spider mite, is a pest that limits strawberry production in Mexico. Little is known about the interactions that occur between T. urticae and healthy strawberry plants or strawberry plants infested by conspecific spider mites. Therefore, in this study we evaluated the attraction of T. urticae to healthy strawberry plants mediated by volatile organic compounds (VOCs), and to plants damaged by conspecifics mediated by herbivore-induce plant volatiles (HIPVs). First, we conducted dual-choice tests using a Y-tube olfactometer with plants and extracts obtained through dynamic aeration. The volatile composition of the extracts was identified using gas chromatography-mass spectrometry (GC-MS). Once the compounds were identified, we also conducted dual-choice tests with selected synthetic compounds. Tetranychus urticae exhibited greater attraction to both healthy and damaged plants compared to the control (clean air). However, when healthy and damaged plants were offered simultaneously, there was no significant preference observed. Bioassays with extracts obtained by dynamic aeration yielded similar results. The identified compounds were terpenes and aromatic hydrocarbons. We found qualitative and quantitative changes between the VOCs emitted by the healthy plant and the HIPVs from mite-damaged plants. The individual compounds α-pinene (10 ng), pseudocumene (10 ng), and limonene (1 ng) and 10 ng of the blend made of α-pinene + pseudocumene + mesitylene + limonene (5:34:57:4) attracted more T. urticae than the control. However, the binary blend of pseudocumene + limonene (91:9) was more attractive than the other binary or three-compound blends evaluated. These results may contribute to developing strategies for the management of this pest.

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In the present study, the essential oil from dry leaves of Steiractinia sodiroi (Hieron.) S.F. Blake is described for the first time. The plant material, collected in the Province of Loja (Ecuador), was analytically steam-distilled in a Marcusson-type apparatus, affording an essential oil with a 0.2 ± 0.12% yield. The volatile fraction was submitted to GC-MS and GC-FID analyses, on two stationary phases of different polarity. A total of sixty-seven compounds, corresponding to 95.6-91.2% by weight of the whole oil mass, on the two columns respectively, were detected and quantified with at least one column. The quantification was carried out calculating the relative response factors of each constituent according to their combustion enthalpy. The major components were limonene (25.6-24.9%), sabinene (11.7-12.4%), germacrene D (7.7-7.0%), α-pinene (7.8-6.9%), δ-cadinene (7.3-7.0%), (E)-ß-caryophyllene (4.8-4.5%), and bicyclogermacrene (3.6-3.0%). The chemical composition was complemented with the enantioselective analysis of some major chiral compounds, conducted by means of two ß-cyclodextrin-based capillary columns. Three constituents, (S)-(+)-α-phellandrene, (R)-(-)-1-octen-3-ol, and (S)-(-)-limonene were enantiomerically pure, whereas (1R,5R)-(+)-ß-pinene, (1S,5S)-(-)-sabinene, (R)-(-)-terpinen-4-ol, (R)-(+)-α-terpineol, and (R)-(+)-germacrene D presented an enantiomeric excess. Finally, α-pinene was present as a racemic mixture.

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R-(+)-Perillic acid, a promising anticancer and immunomodulatory agent, is the major product from the biotransformation of R-(+)-limonene-rich orange essential oil by the yeast Yarrowia lipolytica. Due to the abundance and low cost of orange essential oil, which is a byproduct of the citrus industry, we attempted to improve the biotransformation process by optimizing yeast cell mass production. Then, the whole process was transposed and adapted to a 2-L instrumented bioreactor. Cell mass production was optimized in shaker flasks using a statistical experimental design. The optimized medium (g·L-1: 22.9 glucose, 7.7 peptone, 4.1 yeast extract and 1.0 malt extract) resulted in a 13.0 g·L-1 final cell concentration and 0.18 g cell·L-1·h-1 productivity. A further increase to 18.0 g·L-1 was achieved in a 2-L bioreactor upon fed-batch culture. High-purity limonene bioconversion was performed in the same bioreactor utilizing top aeration to diminish terpene volatilization; as a result, 839.6 mg·L-1 perillic acid accumulated after 48 h. Under the same conditions, industrial orange essential oil afforded 806.4 mg·L-1 perillic acid. The yeast growth medium optimization resulted in a twofold increase in biomass accumulation and a reduction in growth medium nitrogen sources, which lowered the catalytic biomass production cost. Compared with conventional bottom aeration, the bioreactor top aeration strategy resulted in higher bioconversion rates. The conditions developed for high-purity limonene bioconversion were successfully applied to low-cost orange essential oil, showing the robustness of Y. lipolytica yeast.

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Limonene is the main component of citrus essential oils, and can reach a concentration of up to 96%. Popularly known for its potential therapeutic effects on the body, among these we point out its broad antimicrobial activity against various types of pathogens. Therefore, the purpose of this study was to address the antimicrobial and antifungal properties of limonene compared to microorganisms of interest in dentistry, based on a bibliometric study and literature review. The following databases were analyzed: PubMed, Google Scholar, SciELO and Science Direct, from which ten articles published between 2011-2021 were selected. Most of results indicate a satisfactory antimicrobial potential, besides providing important data and perspectives regarding the indication and clinical use, in addition to innovative therapeutic modalities for diseases that affect the oral cavity, such as tooth decay, periodontal disease and candidosis.

El limoneno es el componente principal de los aceites esenciales cítricos, y puede alcanzar una concentración de hasta el 96%. Popularmente conocido por sus potenciales efectos terapéuticos en el organismo, entre ellos se destacan su amplia actividad antimicrobiana frente a diversos tipos de patógenos. Por lo tanto, el objetivo de este estudio fue abordar las propiedades antimicrobianas y antifúngicas del limoneno en comparación con microorganismos de interés en la odontología, a partir de un estudio bibliométrico y una revisión bibliográfica. Se analizaron las siguientes bases de datos: PubMed, Google Scholar, SciELO y Science Direct, de las cuales se seleccionaron diez artículos publicados entre 2011-2021. La mayoría de los resultados indican un potencial antimicrobiano satisfactorio, además de proporcionar datos y perspectivas importantes con respecto a la indicación y el uso clínico, así como modalidades terapéuticas innovadoras para enfermedades que afectan la cavidad oral, como caries, enfermedad periodontal y candidosis.

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