Oil Terpenes Research Articles

Correction: Translational perspectives on the therapeutic potential of Hyptis crenata essential oil terpenes in smooth muscle function.

Correction: Translational perspectives on the therapeutic potential of Hyptis crenata essential oil terpenes in smooth muscle function.

Translational Perspectives on the Therapeutic Potential of Hyptis Crenata Essential Oil Terpenes in Smooth Muscle Function.

Monoterpenes and sesquiterpenes are classes of organic compounds found in various natural products, such as the essential oil of Hyptis crenata (EOHc). The therapeutic potential of these terpenes present in EOHc is evidenced by their effect on smooth muscle and potential clinical applications. Among the highlighted monoterpenes, such as sabinene, α-pinene, and β-pinene, a relaxing effect on rat intestinal smooth muscles is observed, attributed to interaction with calcium channels. Furthermore, monoterpenoids like borneol, cineole, and linalool also demonstrate vasorelaxant properties, suggesting potential in the treatment of cardiovascular conditions. Sesquiterpenes, such as caryophyllene and aromadendrenes, exhibit relaxing effects in various smooth muscle tissues, such as rat uterus and guinea pig ileum, indicating pharmacological potential in these areas. The translational exploration of targets, such as calcium channels and G protein-coupled receptors, highlights the importance of these compounds in discovering new therapies based on natural products for treating various medical conditions.

Human Metabolism and Urinary Elimination Kinetics of the Fragrance Geraniol after Oral Dosage.

Geraniol is a fragrance with a characteristic rose-like smell, naturally occurring in terpene oil and also chemically synthesized on a large scale. Geraniol is widely used in consumer products such as cosmetics, personal care products, and household cleaners and as an additive in foods. An experimental study in human volunteers was carried out to investigate the metabolism and elimination kinetics of geraniol. Three subjects were orally exposed to geraniol in two different dosages (25 or 250 mg). In each case, one pre-exposure urine sample and all urine voids for 72 h after exposure were collected separately. The geraniol metabolites Hildebrandt acid, geranic acid, 3-hydroxycitronellic acid, and 8-carboxygeraniol were analyzed in every sample after enzymatic hydrolysis and liquid-liquid extraction using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Maximum urinary concentrations of the metabolites were measured between 1 and 5 h after oral dosing, and elimination half-lives were determined to be about 2-4 h. The predominant metabolite found in urine was Hildebrandt acid with 34.4 ± 5.6% of the ingested dose, followed by geranic acid (12.7 ± 5.6%), 3-hydroxycitronellic acid (2.2 ± 0.4%), and 8-carboxygeraniol (0.19 ± 0.09%). In total, the four metabolites determined represent 41.7-55.5% of the ingested dose. Only 8-carboxygeraniol is, however, a specific metabolite, while the other three target analytes are also formed from other terpenes like citral. Within this study, conversion factors were calculated, which allow for a rough estimate of the total geraniol uptake by back-calculation from metabolite concentrations of spot urine samples. Taking the conversion factor for all four metabolites into account, a mean daily uptake of geraniol of 1.43 mg was estimated from 41 urine samples of occupationally nonexposed adults. The metabolites Hildebrandt acid, geranic acid, 3-hydroxycitronellic acid, and 8-carboxygeraniol in urine are suitable biomarkers of exposure for geraniol and can be used for human biomonitoring studies.

A terpene synthase supergene locus determines chemotype in Melaleuca alternifolia (tea tree).

Leaf oil terpenes vary categorically in many plant populations, leading to discrete phenotypes of adaptive and economic significance, but for most species, a genetic explanation for the concerted fluctuation in terpene chemistry remains unresolved. To uncover the genetic architecture underlying multi-component terpene chemotypes in Melaleuca alternifolia (tea tree), a genome-wide association study was undertaken for 148 individuals representing all six recognised chemotypes. A number of single nucleotide polymorphisms in a genomic region of c. 400 kb explained large proportions of the variation in key monoterpenes of tea tree oil. The region contained a cluster of 10 monoterpene synthase genes, including four genes predicted to encode synthases for 1,8-cineole, terpinolene, and the terpinen-4-ol precursor, sabinene hydrate. Chemotype-dependent null alleles at some sites suggested structural variants within this gene cluster, providing a possible basis for linkage disequilibrium in this region. Genotyping in a separate domesticated population revealed that all alleles surrounding this gene cluster were fixed after artificial selection for a single chemotype. These observations indicate that a supergene accounts for chemotypes in M. alternifolia. A genetic model with three haplotypes, encompassing the four characterised monoterpene synthase genes, explained the six terpene chemotypes, and was consistent with available biparental cross-segregation data.

Functionality of hydrophobic groups of surfactants in the flotation of anode active materials

In the present paper, the effect of surface activity and the role of hydrophobic groups of four different frothers (2-octanol, terpenic oil, methyl isobutyl carbinol (MIBC), and sodium dodecyl benzene sulfonate (SDBS)) on the collector-less floatability of anode-active materials were studied. Fourier-transform infrared spectroscopy (FTIR) and zeta potential analyses were applied to detect functional groups and particle surface charge, respectively. The floatability of the material was examined using an XFG flotation cell in the absence and presence of these frothers. The experimental results showed that the functional groups on the surface of anode active materials (AAM) including CH3, C-O-O, and aromatic rings reacted with a frother and increased the recovery of the particles by 15%. Also, the presence of phenolic resin on the particle surface caused the functional groups on the surface of the particles to interact with frother molecules and improved the recovery of the particles by acting as a collector. Furthermore, the zeta potential of the particles after the addition of surfactant (at pH 7) showed a negative shift because of the particle hydrophobicity and agglomeration of particles. In addition, the results of contact angle and FTIR analyses showed that materials had a greater contact angle after using various surfactants and successful interaction occurred between the AAM surface and the hydrocarbon tail of the surfactants. The flotation results demonstrated that the recovery of AAM without any surfactants was zero but it was increased as the following order of 2-octanol ≫ terpenic oil > SDBS > MIBC.

Bioinsecticidal activity of cajeput oil to pyrethroid-susceptible and -resistant mosquitoes

Mosquito-borne diseases are a significant threat to human health. The frequent and repetitive application of insecticides can result in the selection of resistant mosquito populations leading to product failures for reducing community disease transmission. It is important that new interventions are discovered and developed for reducing mosquito populations and, in turn, protecting human health. Plant essential oils are promising chemical interventions for reducing mosquito populations. The myrtle family, Myrtaceae, has numerous species to be studied as potential bioinsecticides. Here, we combined toxicological, biochemical, and neurophysiological approaches to provide evidence for cajeput oil and terpene constituents to elicit bioinsecticidal activity to pyrethroid-susceptible and -resistant Aedes aegypti. We show cajeput oil terpenes to enhance cAMP production, increase ACh levels, inhibit in vivo and in vitro AChE activity, and disrupt spike discharge frequencies of the mosquito CNS. This study presents the first report on the bioinsecticidal activity of cajeput oil terpenes to pyrethroid-susceptible and -resistant mosquitoes and provides comparative data for the octopaminergic system as a putative molecular target for the bioinsecticides with implications for resistance management.

Preliminary Assessment of Repellency and Toxicity of Essential Oils against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) on Stored Organic Corn Grains

Insect infestation of cereal grains during post-harvest storage not only causes significant grain loss, but also reduces grain quality and makes grains more susceptible to mold infection. Synthetic pesticides are banned from being used in organic grain storage setting due to their high toxicity. The main insect damaging stored corn grains is maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). The purpose of this study was to evaluate insect repellency and insecticidal potentials of some generally recognized as safe (GRAS) essential oils (EOs) (including cinnamon, clove, thyme, oregano, and orange terpene oils) at concentrations of 1–20% against the maize weevil using an olfactometer and a simulated fumigation method, respectively. The olfactory tests show that cinnamon oil had the highest repellency (90%) to the weevils among the EOs tested. The insecticidal activity study indicates that maize weevil mortality increased with EO concentration and storage time with cinnamon, clove, and thyme oils being more effective. No weevil death was observed at 1% EOs; weevil mortality was 3.3–36% at 5%, which varied with the type of EO and storage time. At 10% or higher concentrations, all tested EO showed comparable or higher insecticidal activity than pirimiphos methyl-positive control at its recommended concentration (5 mg/kg corn). No significant increase in weevil mortality was observed with further increase in EO concentration, with exceptions of oregano oil and thyme oil. The highest weevil mortality levels were observed at week 7 for 15% cinnamon oil (100%) and eugenol (100%), followed by 20% thyme oil (93%). The study indicates that some EOs have great potential to serve as synthetic insecticide alternatives to protect organic corn grains from maize weevil damage during storage. This is important to food security, safety and environmental health.

Influence of operating parameters on nanobubble-assisted flotation of graphite

Although many studies have focused on processing of lithium-ion batteries (LiBs), there is a considerable lack of information concerning the application of nanobubbles (NBs) in their floatabilities. To cover this knowledge gap, the current study aims at exploring the effect of key operating parameters on flotation of two types of graphite i.e., lithium-ion batteries’ graphite (LIBG) and natural ore graphite (NOG) in the presence of NBs. For this purpose, the effects of NB solution ratio, impeller speed, air flow rate, as well as dosage and type of collector and frother on recovery of graphite were investigated in the presence and absence of NBs. Three frothers (i.e., methyl isobutyl carbinol (MIBC), terpenic oil, and 2-octanol), and three collectors (i.e., n-dodecane, kerosene and diesel oil) were employed for comparison purposes using an XFG micro-flotation unit. The hydrodynamic cavitation and dynamic light scattering (DLS) methods were utilized to produce and characterize ultrafine bubbles, respectively. The DLS results confirmed the bubble size distribution ranged between 180 and 400 nm. The maximum recovery of graphite particles (ca. 98%) was obtained for the LIBG particles, at an impeller speed of 1000 rpm, air flow rate of 0.4 L/min, using 2-octanol as a frother, and n-dodecane as a collector. Further, the influential order of the frothers was found as 2-octanol > terpenic oil > MIBC. According to the flotation results, the presence of NBs increased the LIBG flotation recovery and its kinetic rate by 15% and 33%, respectively.

Distribution Patterns of Essential Oil Terpenes in Native and Invasive Solidago Species and Their Comparative Assessment.

The importance of invasive Solidago L. species to the environment creates a new approach to controlling their spread through the use of potentially high value raw materials. The aim of this study was to assess the distribution patterns of volatile compounds in the four Solidago spp., by identifying common and species-specific compounds with their potentials, and to confirm the origin of the spontaneous hybrid Solidago × niederederi on the basis of comparative assessment of essential oil (EO) profiles. Plant material in the flowering phase was collected in mixed populations from six different sites. The EOs were isolated separately from the leaf and the inflorescence samples by hydrodistillation for 3 h. The chemical analysis was performed by gas chromatography—mass spectrometry. Multivariate data analysis was employed to explain the interspecies relationships among Solidago spp. The results revealed the similarity among Solidago spp. EO profiles, which were dominated by monoterpenes and oxygenated compound fractions. Solidago spp. differed in species distinctive terpenes and their distribution between accessions and plant parts. Volatile compound patterns confirmed the origin of Solidago × niederederi between Solidago canadensis and Solidago virgaurea, with the higher contribution of alien species than native ones. Correct taxonomic identification of species is highly essential for the targeted collection of raw material from the wild for different applications. Solidago spp. can be considered to be underutilized sources of bioactive secondary metabolites.

Silicon recovery from metallurgical-grade silicon refined slag by flotation using terpenic oil as surfactant

MG-Si (Metallurgical grade silicon) refined slag is mainly composed of silicate and MG-Si. With the increased generation of MG-Si refined slag, the loss of silicon resources has become increasingly severe. Therefore, there is an urgent need to develop methods for silicon recovery from MG-Si refined slag. In this work, silicon recovery was realized by flotation using terpenic oil as the surfactant. Flotation results revealed that with the increasing concentration of terpenic oil, the recovery rate of Si increased from 20.97 ± 0.75% to 77.42 ± 4.40%. The water contact angle of the recovered silicon surface changed from 46.74° to 60.15°. This indicated that the hydrophobicity of the silicon surface increased due to the adsorption of terpenic oil. Meanwhile, the results of adsorption capacity measurements showed that terpenic oil has strong selectivity for adsorption on silicon. The thickness of the layer of terpenic oil on the silicon surface increased with the increasing concentration of the added terpenic oil. These results demonstrated that the addition of terpenic oil was strongly beneficial for the silicon recovery by flotation. This study seeks to provide a more feasible and effective technical route for the large-scale recovery of silicon from MG-Si refined slag. The development of such a route is highly significant for reducing the loss of silicon resources and the clean and sustainable development of silicon industry.

Influence of Terpenic Oil on Flotation Behavior of Sphalerite and Implication for the Selective Separation

Terpenic oil (TO) is commonly used as a flotation frother for the selective separation of sulfide minerals. As a frother, most reports have mainly focused on its effect on froth stability and froth entrainment, whereas its influence on the floatability of sulfide minerals has received little attention. In this work, the influence of TO on the flotation behavior of sphalerite was investigated by using microflotation tests, contact angle and zeta potential measurements, and FT-IR and SEM-EDS analyses. Microflotation tests conducted in a modified Hallimond tube indicated that compared with the collector potassium butyl xanthate (KBX), the flotation recovery of sphalerite was significantly increased when TO was added to the pulp, but the recovery of Cu-activated sphalerite with the addition of TO was lower than that with the addition of KBX. Contact angle measurements demonstrated that the contact angle of sphalerite was distinctly increased by the addition of TO, but the contact angle of sphalerite treated with TO was lower than that treated with KBX after Cu activation. Zeta potential measurements demonstrated that the zeta potential of sphalerite particles was slightly decreased when treated with TO, and the isoelectric point (IEP) was decreased from 3.3 to 3.1 due to the interaction of TO with sphalerite particles. FT-IR and SEM-EDS confirmed that TO could be adsorbed on the sphalerite surface on the formation of the oil film due to its low solubility, thereby increasing the surface hydrophobicity of the sphalerite. In addition, the TO absorbed on the surface acts as a bridging role and promotes the hydrophobic agglomeration of sphalerite particles. These results suggest that except for froth entrainment, the influence of TO on the flotation behavior of sphalerite may be another reason for the misreporting of sphalerite in concentrates.

Froth flotation separation of carbon from barium slag: Recycling of carbon and minimize the slag

Barium slag is a kind of solid waste derived from the carbon reduction process of producing barium salt. Carbon is one of the main components in barium slag with a content of more than 10%. In this study, a barium slag was characterized using XRF, XRD and SEM-EDS, and froth flotation test was introduced to recover the carbon in the barium slag. In the process of froth flotation test, diesel was selected as a collector and terpenic oil was selected as a frother for carbon separation. The flotation influences of pulp pH, collector dosage, frother dosage and flotation time were investigated. The results showed that the obtained carbon concentrate had a carbon grade of 63.25% and its recovery was 82.70% under the conditions of pH 8.50, diesel 600 g/t, terpenic oil 500 g/t, and flotation time 5 min. SEM-EDS analysis results revealed that the flotation concentrate was coarse and its particle sizes had a homogeneous distribution. The findings of this research provide a new pathway for barium slag utilization. The carbon obtained from the flotation test in this study can be recycled as raw materials, while the reduction of the remaining tailings can be utilized as building material additives.

Inhibitory Effect of Some Selected Essential Oil Terpenes on Fungi Causing Superficial Infection in Human Beings

Dermatophytosis is a serious fungal infection of superficial keratinized tissue in man and animal. At least one million people in India were suffering from this infection. Present investigation deals with the screening and study of 6 major compounds of essential oils like myrcene, linalool, citral, geraniol, limonene and citronellol against Candida albicans, Microsporum gypseum, M. canis and Trichophyton rubrum. The minimum inhibitory concentration was determined through semi-solid agar antifungal testing methods. Among all these compounds geraniol and citronellol exhibited excellent antidermatophytic activities. MIC of geraniol was ranged from 0.025 μL/mL to 0.1 μL/mL. MIC of citronellol was obtained > 0.012 μL/mL to 0.1 μL/mL concentrations. MIC of citral was ranged from 0.05 μL/mL to 0.2 μL/mL. Linalool also showed strong antifungal behavior against all tested microorganisms. Myrcene and limonene were found to be very less effective compounds as compared to others. M. canis was found to be resistant from both myrcene and limonene.

The treatment of childhood progressive bilateral multiple renal stone disease: A role of essential oil terpenes

Background: The association of childhood urolithiasis with idiopathic hypercalciuria plus idiopathic hyperuricosuria has been infrequently reported in children. Treatments of childhood urolithiasis include treatment of the underlying metabolic, and the use of essential oil preparations of terpenic which contains pinene (31%), camphene (15%), borneol (10%), anethol (4%), fenchone (4%) and cineol (3%), which have been used with important benefits. Urinex (Pharco Co.) is the essential oil preparations mostly available in the Middle East. The aim of this paper is to emphasize the possible adjunctive role of essential oil preparations of terpenic in the management of serious childhood urolithiasis.

Quantitative determination of urinary metabolites of geraniol by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Geraniol is a fragrance which occurs in natural terpene oil or is chemically synthesized on a large scale. It is used in a wide variety of consumer products such as perfumes, deodorants, household products and cosmetics. Hence, not only industry workers in the production of geraniol, but also consumers can come into contact with the substance. Human biomonitoring (HBM), i.e. the analytical determination of substances and their metabolites in human biological material, is a key element in the analysis and assessment of the distribution and intensity of occupational and environmental exposure of humans. Therefore, a procedure for the quantitative determination of the urinary metabolites Hildebrandt acid, geranic acid, 3-hydroxycitronellic acid and 8-carboxygeraniol as potential biomarkers of geraniol exposure was developed and validated. The method is based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) after enzymatic hydrolysis and liquid-liquid extraction (LLE) of the target analytes. The limit of quantification (LOQ) is 1.5 μg L-1 for 8-carboxygeraniol, 2.7 μg L-1 each for Hildebrandt acid and geranic acid, and 1.8 μg L-1 for 3-hydroxycitronellic acid. The method was applied to urine samples of 41 persons without occupational exposure to geraniol. Hildebrandt acid and geranic acid were detected in all samples, 8-carboxygeraniol in 83% and 3-hydroxycitronellic acid in 81% of the samples. Hildebrandt acid (median: 313 μg L-1, range: 37-1966 μg L-1) was the most abundant metabolite, followed by geranic acid (93 μg L-1; 9-477 μg L-1), 3-hydroxycitronellic acid (18 μg L-1; <LOQ to 70 μg L-1) and 8-carboxygeraniol (9 μg L-1; <LOQ to 46 μg L-1). Hildebrandt acid, geranic acid and 3-hydroxycitronellic acid apparently represent larger relative fractions of the eliminated metabolites, but they are not strictly specific for geraniol since they are metabolites of other terpenes as well, such as citral. In contrast, geraniol seems to be the only parent compound for 8-carboxygeraniol, which makes this metabolite a promising candidate for specific human biomonitoring and risk assessment.

High marker density GWAS provides novel insights into the genomic architecture of terpene oil yield in Eucalyptus.

Terpenoid-based essential oils are economically important commodities, yet beyond their biosynthetic pathways, little is known about the genetic architecture of terpene oil yield from plants. Transport, storage, evaporative loss, transcriptional regulation and precursor competition may be important contributors to this complex trait. Here, we associate 2.39million single nucleotide polymorphisms derived from shallow whole-genome sequencing of 468 Eucalyptus polybractea individuals with 12 traits related to the overall terpene yield, eight direct measures of terpene concentration and four biomass-related traits. Our results show that in addition to terpene biosynthesis, development of secretory cavities, where terpenes are both synthesized and stored, and transport of terpenes were important components of terpene yield. For sesquiterpene concentrations, the availability of precursors in the cytosol was important. Candidate terpene synthase genes for the production of 1,8-cineole and α-pinene, and β-pinene (which comprised >80% of the total terpenes) were functionally characterized as a 1,8-cineole synthase and a β/α-pinene synthase. Our results provide novel insights into the genomic architecture of terpene yield and we provide candidate genes for breeding or engineering of crops for biofuels or the production of industrially valuable terpenes.

A novel method for desulfurization and purification of fluorite concentrate using acid leaching and reverse flotation of sulfide

Fluorite, one of the major raw materials for fluoride in China, is mainly associated with sulfide and calcite minerals. The presence of these sulfide and calcite minerals cause the pipe blockage and efficiency loss during the production of anhydrous hydrofluoric acid (AHF). Worldwide, direct flotation techniques are utilized to beneficiate the fluorite into the chemical grades, but their separation efficiency remained limited due to similar flotability behaviors of fluorite, sulfide and calcite in fatty acid. In the present study, a novel method based on the acid leaching and reverse flotation has been envisaged for the purification and desulfurization of fluorite concentrates containing higher concentrations of sulfur and calcium. Leaching tests were performed by using hydrochloric acid, whereas the reverse flotation experiments were performed by using butyl xanthate as the collector and terpenic oil as the foaming agent. Leaching results showed that, calcite mineral dissolved and the fatty acid lost its collecting and foaming activities under the action of hydrochloric acid. The reverse flotation tests demonstrated that weight percent of sulfides, which are the main causes of blockage in AHF production, was substantially reduced from the fluorite concentrate. Interestingly, this method has been successfully implemented in Shizhuyuan fluorite dressing plant in China for the upgradation of fluorite concentrate. Calcite and sulfur contents of the concentrate were reduced from 4% to 0.01% and 0.5%–0.01%, respectively, and the grade of fluorite concentrate improved from 93.2% to more than 97% with a slight loss of fluorite. Furthermore, the safety in production of AHF was ensured with increased profit from the concentrator.

A fundamental study of monovalent and divalent ions on froth properties in the presence of terpenic oil

A fundamental study of monovalent and divalent ions on froth properties in the presence of terpenic oil

Efficiently removing Pb(II) from wastewater by graphene oxide using foam flotation

The removal of Pb(II) from wastewater by graphene oxide (GO) using foam flotation was first investigated. Effects of initial solution pH, and the dosage of GO, emulsified kerosene and terpenic oil on the Pb(II) removal and turbidity of the residual solution were systematically examined. The experimental results showed that the initial solution pH and dosage of GO significantly affected the removal of Pb(II), and more than 99% of Pb(II) could be removed under the optimum conditions. The turbidity of the residual solution could decrease to 1.4 NTU at the optimal dosage of emulsified kerosene and terpenic oil. Moreover, the flotation-desorption cycles were carried out to evaluate the practical reusability of GO, and the Pb(II) removal maintained as high as 84.9% in the sixth regeneration. It indicated that GO could be efficiently reused in the process of foam flotation. This study provides an effective strategy for the selection of an optimized method to remove the spent GO from solution compared with the conventional methods including sedimentation, centrifugation and filtration, etc.

Bubble size distribution in cyclonic zone of a novel flotation column

ABSTRACTIn order to investigate bubble size distribution (BSD) in the cyclonic flotation column, a series of tests were conducted to study flow velocity distribution (FVD) and BSD by using the method of particle image velocimetry (PIV). Foaming performance of the n-octyl alcohol is more applicable than both of n-butyl alcohol and terpenic oil. At different circulation volume conditions, BSD range lies in 0–800 μm, and a large number of tiny bubbles (<90 μm) are generated. Besides, the curve presents a normal distribution in 90–180 μm. With the increase in circulation volume, bubble size decreases. BSD determined by cyclonic flow effect plays a crucial role on bubble mineralization with fine particle in cyclonic zone of the flotation column.