Explore the vast range of titles available.

Citral is an oxygenated–monoterpenoid found as a major component in lemongrass essential oil (> 68%) in its isomeric forms of geranial (E−) and neral (Z−). For the value addition of this low-value essential oil, a novel catalytic process has been developed for transformation of citral to enantiospecific (+)-citronellal using 12% Ni–HT-530. The different amounts of Ni were doped through hydrothermal process and calcined at varying temperatures (490, 530, and 570 °C). The performance of composite prepared through hydrothermal process was compared with the wet impregnation method. The composite of hydrothermal process followed by calcination at 530 °C was highly potential for selective conversion of citral to (+)-citronellal. The effects of variables such as reaction time, temperature, hydrogen-pressure, and catalyst-dosage on citral conversion to (+)-citronellal were examined. The citral conversion (99%) was attained with 95% selectivity to citronellal in a ratio of catalyst to citral (1:6) under 110 psi H2 pressure at 90 °C for 90 min using 12% Ni–HT-530. Furthermore, the direct conversion of citral in lemongrass oil was studied at above optimized condition. The result indicated that the synthesized catalyst is equally effective in transforming citral in lemongrass oil to organoleptically superior (+)-citronellal with 93% selectivity. The selective conversion of citral to (+)-citronellal not only increases the fragrance value of the essential oil, but also increases the scope for various industrial applications like fine chemical synthesis and pharmaceutical applications.

In this work, vanadium replaced molybdenum atoms generating catalysts with general formulae H3+nPMo12-nVnO40 (n = 0,1, 2 and 3), which were used in the acetalization of alkyl alcohols with terpene aldehyde (β-citronellal and methyl alcohol were model substrates). The initial focus was evaluating how the vanadium load impact the catalytic activity of phosphomolybdic acids and trying to link this effect with their structural properties. A comparison of performance achieved by the catalysts revealed that among phosphomolybdic acids (i.e., with V1, V2, and V3 atoms/per anion), the vanadium monosubstituted phosphomolybdic acid was the most active and selective toward the formation of β-citronellyl acetal. The effects of main reaction variables such as time, temperature, catalyst load, type of alcohol, and vanadium load on conversion and selectivity of the reactions were investigated. Remarkably, while in methyl alcohol, only acetal was formed, in the presence of other alkyl alcohols terpene ethers (geranyl and β-citronellyl) were also obtained. Their highest activity of H4PMo11VO40 was attributed to the greatest Brønsted acidity strength, as demonstrated by the acidity measurements and infrared spectroscopy analysis. This catalyst has advantages over traditional liquid mineral acid catalysts and provides an alternative route to synthesize acetal and terpene ethers.

Prins intramolecular cyclization of citronellal giving desired product isopulegol was performed using different modified zeolites BETA (Si/Al ratio 25, 38 and 75 modified with iron or zinc of 1, 5 or 10 wt.% by wet impregnation method). In case of materials BETA Si/Al 38 and 75 led material impregnation with metal to increase of material catalytic activity (accompanied with increase of amount of weak acid sites detected using temperature programmed desorption). Material BETA 38 with loading 1 wt.% of Fe provided 97% citronellal conversion and 94% selectivity of isopulegol formation (90 °C, toluene, 24 h). Graphic Abstract

Essential oil-based bioherbicides are a promising avenue for the development of eco-friendly pesticides. This study formulated nanoemulsions containing citronella ( Cymbopogon nardus ) essential oil (CEO) as an herbicidal product using a high-pressure homogenization method with hydrophilic-lipophilic balance (HLB) values ranging 9–14.9 for the surfactant mixture (Tween 60 and Span 60). The CEO was high in monoterpene compounds (36.333% geraniol, 17.881% trans -citral, 15.276% cis -citral, 8.991% citronellal, and 4.991% β -citronellol). The nanoemulsion at HLB 14 was selected as optimal due to having the smallest particle size (79 nm, PI 0.286), confirmed by transmission electron microscopy. After 28 days of storage, particle size in the selected formulation changed to 58 and 140 nm under 4 °C and 25 °C, respectively. Germination and seedling growth assays with Echinochloa crus-galli showed that the nanoemulsion exerted a significant dose-dependent inhibitory effect at all tested HLBs (9–14.9) and concentrations (100–800 µL/L). The inhibitory effect was greatest at HLB 14. Treatment of E. cruss-galli seed with the HLB 14 nanoemulsion significantly reduced seed imbibition and α -amylase activity. Our findings support that CEO nanoemulsions have a phytotoxic effect and hence herbicidal properties for controlling E. cruss-galli . Accordingly, this nanoemulsion may have potential as a bioherbicide resource.

Abstract Onychomycosis is the most common disease affecting the nail unit and accounts for at least 50% of all nail diseases. In addition, Candida albicans is responsible for approximately 70% of onychomycoses caused by yeasts. This study investigated the antifungal effect of (R) and (S)-citronellal enantiomers, as well as its predictive mechanism of action on C. albicans from voriconazole-resistant onychomycoses. For this purpose, in vitro broth microdilution and molecular docking techniques were applied in a predictive and complementary manner to the mechanisms of action. The main results of this study indicate that C. albicans was resistant to voriconazole and sensitive to the enantiomers (R) and (S)-citronellal at a dose of 256 and 32 µg/mL respectively. In addition, there was an increase in the minimum inhibitory concentration (MIC) of the enantiomers in the presence of sorbitol and ergosterol, indicating that these molecules possibly affect the integrity of the cell wall and cell membrane of C. albicans. Molecular docking with key biosynthesis proteins and maintenance of the fungal cell wall and plasma membrane demonstrated the possibility of (R) and (S)-citronellal interacting with two important enzymes: 1,3-β-glucan synthase and lanosterol 14α-demethylase. Therefore, the findings of this study indicate that the (R) and (S)-citronellal enantiomers are fungicidal on C. albicans from onychomycoses and probably these substances cause damage to the cell wall and cell membrane of these micro-organisms possibly by interacting with enzymes in the biosynthesis of these fungal structures. Resumo A onicomicose é a doença mais comum que afeta a unidade ungueal e representa pelo menos 50% de todas as doenças ungueais. Além disso, a Candida albicans é responsável por aproximadamente 70% das onicomicoses causadas por leveduras. Nesse estudo, foi investigado o efeito antifúngico dos enantiômeros (R) e (S)-citronelal, bem como seu mecanismo de ação preditivo sobre C. albicans de onicomicoses resistentes ao voriconazol. Para este propósito, foram aplicadas técnicas in vitro de microdiluição em caldo e docking molecular de forma preditiva e complementar para os mecanismos de ação. Os principais resultados deste estudo indicam que C. albicans foi resistente ao voriconazol e sensível aos enantiômeros (R) e (S)-citronelal na dose de 256 e 32 µg/mL respectivamente. Além disso, houve aumento da concentração inibitória mínima (CIM) dos enantiômeros na presença do sorbitol e do ergosterol, indicando que estas moléculas possivelmente afetem a integridade da parede e da membrana celular de C. albicans. O docking molecular com proteínas chave da biossíntese e manutenção da parede celular e da membrana plasmática fúngica, demonstraram a possibilidade do (R) e (S)-citronelal interagir com duas importantes enzimas: 1,3-β-glucan sintase e lanosterol 14α-demetilase. Portanto, os achados desse estudo indicam que os enantiômeros (R) e (S)-citronelal são fungicidas sobre C. albicans de onicomicoses e provavelmente essas substâncias causem danos a parede e a membrana celular desses microrganismos possivelmente por interagir com as enzimas da biossíntese destas estruturas fúngicas.

The prominent cultivation of lemongrass (Cymbopogon spp.) relies on the pharmacological incentives of its essential oil. Lemongrass essential oil (LEO) carries a significant amount of numerous bioactive compounds, such as citral (mixture of geranial and neral), isoneral, isogeranial, geraniol, geranyl acetate, citronellal, citronellol, germacrene-D, and elemol, in addition to other bioactive compounds. These components confer various pharmacological actions to LEO, including antifungal, antibacterial, antiviral, anticancer, and antioxidant properties. These LEO attributes are commercially exploited in the pharmaceutical, cosmetics, and food preservations industries. Furthermore, the application of LEO in the treatment of cancer opens a new vista in the field of therapeutics. Although different LEO components have shown promising anticancer activities in vitro, their effects have not yet been assessed in the human system. Hence, further studies on the anticancer mechanisms conferred by LEO components are required. The present review intends to provide a timely discussion on the relevance of LEO in combating cancer and sustaining human healthcare, as well as in food industry applications.

Recurrent catheter‐associated urinary tract infections (CAUTIs) in catheterized patients, increase their morbidity and hospital stay at substantial costs for healthcare systems. Hence, novel and efficient strategies for mitigating CAUTIs are needed. In this work, a bio‐based nanocomposite coating is engineered with bactericidal, antibiofilm, and antioxidant properties on commercial silicone catheters using a combined ultrasound/nanoparticles (NPs) driven coating approach. This approach integrates citronellal‐loaded lauryl gallate NPs (CLG_NPs), as both antimicrobial and structural elements, with chitosan (CS), in a substrate‐independent sonochemical coating process. The hybrid CS/CLG_NPs coating shows pH‐dependent citronellal release, strong antibacterial activity toward the common CAUTI pathogens Escherichia coli and Staphylococcus aureus, alongside strong antioxidant activity, and biocompatibility to fibroblast and keratinocytes. Moreover, the nano‐enabled coating significantly mitigated bacterial biofilm formation after a week in a simulated human bladder environment, outperforming the commercially‐available silicone catheters. These results underscore the potential of the novel biopolymer nanocomposites obtained by ultrasound coating technology, offering a straightforward antimicrobial/antibiofilm solution for indwelling medical devices. A stable bio‐based nanocomposite coating for urinary catheters is developed using a simple, environmentally‐friendly sonochemical process. The coating, integrating antimicrobial, antibiofilm, and antioxidant properties, effectively tackled multiple early‐stage pathogenic factors associated with catheter‐associated urinary tract infections. In a simulated bladder, it outperformed commercial silicone catheters, maintaining efficacy for one week and offering a straightforward solution to combat medical device infections.

The southern house mosquito, Culex quinquefasciatus, has one of the most acute and eclectic olfactory systems of all mosquito species hitherto studied. Here, we used Illumina sequencing to identify olfactory genes expressed predominantly in antenna, mosquito’s main olfactory organ. Less than 50% of the trimmed reads generated by high-quality libraries aligned to a transcript, but approximately 70% of them aligned to the genome. Differential expression analysis, which was validated by quantitative real-time PCR on a subset of genes, showed that approximately half of the 48 odorant-binding protein genes were enriched in antennae, with the other half being predominantly expressed in legs. Similar patterns were observed with chemosensory proteins, “plus-C” odorant-binding proteins, and sensory neuron membrane proteins. Transcripts for as many as 43 ionotropic receptors were enriched in female antennae, thus making the ionotropic receptor family the largest of antennae-rich olfactory genes, second only to odorant receptor (OR) genes. As many as 177 OR genes have been identified, including 36 unique transcripts. The unique OR genes differed from previously annotated ORs in internal sequences, splice variants, and extended N or C terminus. One of the previously unknown transcripts was validated by cloning and functional expression. When challenged with a large panel of physiologically relevant compounds, CquiOR95b responded in a dose-dependent manner to ethyl 2-phenylacteate, which was demonstrated to repel Culex mosquitoes, and secondarily to citronellal, a known insect repellent. This transcriptome study led to identification of key molecular components and a repellent for the southern house mosquito.

One of the primary therapeutic approaches for managing Alzheimer’s disease (AD) involves the modulation of Acetylcholine esterase (AChE) activity to elevate acetylcholine (ACh) levels inside the brain. The current study employed computational chemistry approaches to evaluate the inhibitory effects of CTN on AChE. The docking results showed that Citronellal (CTN) and standard Donepezil (DON) have a binding affinity of −6.5 and −9.2 Kcal/mol, respectively, towards AChE. Further studies using molecular dynamics (MD) simulations were carried out on these two compounds. Binding free energy calculations and ligand-protein binding patterns suggested that CTN has a binding affinity of −12.2078. In contrast, DON has a much stronger binding relationship of −47.9969, indicating that the standard DON has a much higher binding affinity than CTN for AChE. In an in vivo study, Alzheimer-type dementia was induced in mice by scopolamine (1.5 mg/kg/day i.p) for 14 days. CTN was administered (25 and 50 mg/kg. i.p) along with scopolamine (SCO) administration. DON (0.5 mg/kg orally) was used as a reference drug. CTN administration significantly improved the mice’s behavior as evaluated by the Morris water maze test, evident from decreased escape latency to 65.4%, and in the CPS test, apparent from reduced escape latency to 69.8% compared to the positive control mice. Moreover, CTN significantly increased the activities of antioxidant enzymes such as catalase and superoxide dismutase (SOD) compared to SCO. Furthermore, CTN administration significantly decreased SCO-induced elevated AChE levels in mice. These results were supported by histopathological and in silico molecular docking studies. CTN may be a potential antioxidant and neuroprotective supplement.

Nematicidal potential of essential oils (EOs) has been widely reported. Terpenoids present in most of the essential oils have been reported responsible for their bioactivity though very less is known about their modes of action. In the present study, an in vitro screening of nine Eos, namely, Citrus sinensis (OEO), Myrtus communis (MTEO), Eucalyptus citriodora (CEO), Melaleuca alternifolia (TEO), Acorus calamus (AEO), Commiphora myrrha (MREO), Cymbopogon nardus (CNEO), Artemisia absinthium (WEO), and Pogostemon cablin (PEO) against Meloidogyne incognita revealed OEO, CNEO, and TEO as most effective with LC 50 39.37, 43.22, and 76.28 μg ml –1 respectively. EOs had varying compositions of mono- and sesquiterpenes determined by gas chromatography-mass spectrometry (GC-MS) analysis. The in silico molecular interactions screening of major EO constituents and the seven selected target proteins of the nematode indicated highest binding affinity of geraniol-ODR1 (odorant response gene 1) complex (ΔG = -36.9 kcal mol –1 ), due to extensive H-bonding, hydrophobic and π-alkyl interactions. The relative binding affinity followed the order: geraniol-ODR1 > β-terpineol-ODR1 > citronellal-ODR1 > l -limonene-ODR1 > γ-terpinene-ODR1. Taken together, the cumulative in vitro and computational bioefficacy analysis related to the chemoprofiles of EOs provides useful leads on harnessing the potential of EOs as bionematicides. The insight on biochemical ligand–target protein interactions described in the present work will be helpful in logical selection of biomolecules and essential oils for development of practically viable bionematicidal products.