Functional Characterization of PmDXR, a Critical Rate-Limiting Enzyme, for Turpentine Biosynthesis in Masson Pine (Pinus massoniana Lamb.)

As one of the largest and most diverse classes of specialized metabolites in plants, terpenoids (oprenoid compounds, a type of bio-based material) are widely used in the fields of medicine and light chemical products. They are the most important secondary metabolites in coniferous species and play an important role in the defense system of conifers. Terpene synthesis can be promoted by regulating the expressions of terpene synthase genes, and the terpene biosynthesis pathway has basically been clarified in Pinus massoniana, in which there are multiple rate-limiting enzymes and the rate-limiting steps are difficult to determine, so the terpene synthase gene regulation mechanism has become a hot spot in research. Herein, we amplified a PmDXR gene (GenBank accession no. MK969119.1) of the MEP pathway (methyl-erythritol 4-phosphate) from Pinus massoniana. The DXR enzyme activity and chlorophyll a, chlorophyll b and carotenoid contents of overexpressed Arabidopsis showed positive regulation. The PmDXR gene promoter was a tissue-specific promoter and can respond to ABA, MeJA and GA stresses to drive the expression of the GUS reporter gene in N. benthamiana. The DXR enzyme was identified as a key rate-limiting enzyme in the MEP pathway and an effective target for terpene synthesis regulation in coniferous species, which can further lay the theoretical foundation for the molecularly assisted selection of high-yielding lipid germplasm of P. massoniana, as well as provide help in the pathogenesis of pine wood nematode disease.

Turpentine Derived Secondary Amines for Sustainable Crop Protection: Synthesis, Activity Evaluation and QSAR Study

In this study, we will report on the synthesis and application of efficient botanical agrochemicals from turpentine for sustainable crop protection. Two series of turpentine derived secondary amines were synthesized and identified by FT-IR, 1H NMR, 13C NMR, and HRMS. The herbicidal activities against Echinochloa crus-galli were evaluated. The potential toxicity of the synthesized compounds was tested by MTT cytotoxicity analysis. The effect of structure of the synthesized secondary amines and corresponding Schiff base compounds on their activities was investigated by quantitative structure-activity relationship (QSAR) study. All target products were found to be low toxicity, with similar or higher herbicidal activities than commercial herbicides diuron and Glyphosate. Results of QSAR study showed that a best four-descriptor QSAR model with R2 of 0.880 and Rloo2 of 0.818 was obtained. The four descriptors most relevant to the herbicidal activities are the min valency of a N atom, the max total interaction for a C-H bond, the relative number of aromatic bonds, and the min partial charge (Qmin).

High Add Valued Application of Turpentine in Crop Production through Structural Modification and QSAR Analysis

Turpentine is a volatile component of resin, which is an abundant forest resource in Southern China. As one of the most important components, the integrated application of β-pinene has been studied. The broad-spectrum evaluation of β-pinene and its analogues has, therefore, been necessary. In an attempt to expand the scope of agro-activity trials, the preparation and the evaluation of the herbicidal activity of a series of β-pinene analogues against three agricultural herbs were carried out. In accordance with the overall herbicidal activity, it is noteworthy that compounds 6k, 6l, and 6m demonstrated extreme activity with IC₅₀ values of 0.065, 0.065, and 0.052 mol active ingredients/hectare against E. crus-galli. The preliminary structure-activity relationship (SAR) was analyzed and the compounds with the appropriate volatility and substituent type that had beneficial herbicidal activity were analyzed. Simultaneously, the quantitative structure-activity relationship (QSAR) model was built and the most important structural features were indicated, which was, to a certain extent, in line with the SAR study. The study aimed to study the application of the forest resource turpentine in agriculture as a potential and alternative approach for comprehensive utilization.

Sulfate turpentine: a resource of tick repellent compounds

Compounds with tick (Ixodes ricinus) repellent properties were isolated from sulfate turpentine consisting of Norway spruce (80%) and Scots pine (20%) from southern Sweden. The turpentine was divided into two fractions by distillation under reduced pressure resulting in one monoterpene hydrocarbon fraction and a residual containing higher boiling terpenoids. The monoterpene fraction was further oxidized with SeO2 to obtain oxygenated monoterpenes with potential tick repellent properties. The oxidized fraction and the high boiling distillation residual were each separated by medium pressure liquid chromatography. The fractions were tested for tick repellency and the compounds in those with highest tick repellency were identified by GC-MS. The fractions with highest repellency contained, mainly (-)-borneol, and mixtures of (+)- and (-)-1-terpineol and terpinen-4-ol. The enantiomers of borneol showed similar tick repellent properties.

Formulation, and physical, in vitro and ex vivo evaluation of transdermal ibuprofen hydrogels containing turpentine oil as penetration enhancer

The aim of the present study was to investigate the transdermal permeation enhancing capability of turpentine oil for ibuprofen from hydrogels. Ibuprofen 1% w/v hydrogels were developed with carboxypolymethylene with and without turpentine oil. Turpentine oil was incorporated in increasing concentrations, i.e. 0.5, 1, 1.5, 2, 2.5 and 3% of the total gel formulation, and its permeation enhancing effect was examined. Gels were examined physically for pH, viscosity, spreadability, extrudability, smoothness and appearance. To study the in vitro and ex vivo permeation potential of formulated gels, permeation studies were performed with a Franz diffusion cell using cellulose membrane and excised rabbit abdominal skin. Ibuprofen hydrogel with 3% turpentine oil showed a maximum flux of 10.87 mg/cm2/h across artificial skin and 17.26 mg/cm2/h across rabbit abdominal skin.

Larvicidal effect of Eucalyptus grandis essential oil and turpentine and their major components on Aedes aegypti larvae

In the search for new alternatives for the control of Aedes aegypti the larvicidal activity of Eucalyptus grandis essential oil and pine resin essential oil (turpentine) and their major components (alpha- and beta-pinene and 1,8-cineole) was determined. Gas chromatography-mass spectroscopy analysis of E. grandis essential oil revealed that its major components are alpha-pinene and 1,8-cineole. Similar analysis of turpentine obtained by distillation of the resin pitch of conifers showed that alpha- and beta-pinene are the only major components. Third and early 4th instars of the CIPEIN-susceptible strain of Ae. aegypti were exposed to acetonic solutions of E. grandis essential oil, turpentine, and their major components for 24 h. Turpentine, with an LC50 of 14.7 ppm, was more active than the essential oil of E. grandis (LC50: 32.4 ppm). Larvicidal activity of the essential oil components showed that alpha- and beta-pinene present low LC50 values (15.4 and 12.1 ppm, respectively), whereas pure 1,8-cineole showed an LC50 of 57.2 ppm. These results suggest that alpha-pinene in E. grandis and alpha- and beta-pinene in turpentine serve as the principal larvicidal components of both oils. Results obtained on larvicidal effects of essential oil of Eucalyptus grandis and turpentine could be considered a contribution to the search for new biodegradable larvicides of natural origin.

New woody and ambery notes from cedarwood and turpentine oil

The development of a new product in the chemical industry is still driven by needs like technical properties, price/performance ratio, biodegradability, or product safety. However, in terms of improving more and more on ecological criteria, summarized under such catchphrases as sustainable development or green chemistry, another important aspect is to use renewable resources as starting materials. This is not significantly new in fragrance chemistry, and there are a lot of raw materials in the perfume oils that are derived from molecules of renewable resources. Two commonly used materials are: longifolene (from turpentine oil) and cedrene (from cedarwood oil). These compounds are very suitable for the synthesis of woody and ambery notes, and even though it seemed that all possibilities were exhausted, it is actually still feasible to discover new molecules with excellent olfactory properties such as Ambrocenide (50a), which is available in three steps from alpha-cedrene. Some of these molecules will be treated in this review, both with respect to synthesis as well as structural and sensory aspects.

[Analysis of terpineol and improvement of technology process in terpineol production]

A method for the separation and determination of terpineol oil by temperature programming capillary gas chromatography has been established. An OV-1 fused silica capillary column (30 m x 0.32 mm i.d. x 0.25 microns) was used with a temperature increase rates of 1.5 degrees C/min from 70 degrees C to 100 degrees C, 5 degrees C/min from 100 degrees C to 160 degrees C, 10 degrees C/min from 160 degrees C to 220 degrees C and then hold for 2 min. The main chemical components and their relative contents of the terpineol oil, terpinene oil, red and yellow oils of middle oils in the terpineol production and natural terpineol were analyzed by capillary gas chromatography-Fourier transform infrared spectrometry (GC-FTIR) and gas chromatography-mass spectrometry (GC-MS). The typical chromatograms of these oils are given. It has offered the information of the boiling points of the chemical compounds, and it is helpful to reutilize them after their separation by rectification. The results showed that the main compounds of the heavy cut of terpineol were longifolene and beta-caryophyllene. They are from the raw material, terpinene oil. The main compounds in the natural terpineol oil were eucalyptol, trans-4-thujanol, p-isopropenyl toluene, cis-4-thujanol, linalool, camphor, borneol, 4-terpineol, alpha-terpineol and safrole. The contents of beta-terpineol and gamma-terpineol were not so high as in synthetic terpineol.

Exposure to dust, resin acids, and monoterpenes in softwood lumber mills

A study to assess exposure to potential respiratory hazards in a large lumber mill processing spruce (Picea engelmannii and glauca), pine (Pinus contorta), and fir (Abies lasiocarpa) used a random sampling strategy to assess exposures for all jobs in the sawmill, planer mills, and yard. Personal samples for inhalable particulate were collected to measure exposure to dust and resin acids (abietic acid and pimaric acid). To estimate wood dust exposure, rather than overall dust, the resin acid content within dust was used in combination with observations of job tasks and proximity to dust sources. Passive dosimeters were used to measure exposure to alpha-pinene, beta-pinene, delta3-carene, and other unidentified wood volatiles suspected to be monoterpenes. The GM of the 220 inhalable particulate samples was 1.0 mg/m3 whereas the mean abietic acid, pimaric acid, and estimated wood dust levels were 7.2 microg/m3, 0.6 microg/m3, and 0.5 mg/m3, respectively. The GMs of the 222 monoterpene samples were 0.1 mg/m3 for alpha-pinene, 0.3 mg/m3 for beta-pinene, 0.1 mg/m3 for delta3-carene, and 0.5 mg/m3 for the unidentified wood volatiles. Monoterpene exposures were much lower than those observed in other studies conducted in Sweden and Finland. The results of this exposure assessment highlight the importance of considering the content of airborne particulates in lumber mills as well as potential exposure to wood chemicals.

[Analysis of terpene/maleic anhydride adduct and its derivatives by GC]

The retention behaviors of terpene/maleic anhydride adduct(TMA, 1) and its esterification derivatres(2) on OV-17 and SE-30 columns has been studied. The relationships between adjusted retention time and column temperature for the two compounds were linear. The shape of both peaks was more symmetrical on OV-17 column than on SE-30 column. It was found that the peak area was unaffected when the temperature of injector was higher than 260 degrees C.

Solubilizing efficiency of different gutta-percha solvents: a comparative study

A study was conducted to comparatively evaluate the efficiency of different solvents for dissolving gutta-percha. Halothane, chloroform, xylene, acetone, isopropyl alcohol, turpentine, oil of mela-leuca and eucalyptol were used as solvents for dissolving standardized gutta-percha discs. Halothane, chloroform and xylene were markedly superior solvents of gutta-percha in comparison with the others. There was no significant difference among the three (p > 0.05). Eucalyptol, turpentine and oil of melaleuca were relatively less efficient. Acetone and isopropyl alcohol did not dissolve gutta-percha, being similar in this respect to distilled water.

Using rectified turpentine oil in endodontic retreatment

A clinical technique for using rectified turpentine oil to soften and dissolve gutta-percha to facilitate retreatment is described. Turpentine oil should be heated to 160 degrees F (71 degrees C) to increase its reactivity before delivery to the canal space.

Effect of temperature on rectified turpentine oil as a gutta-percha solvent

The purpose of this study was to determine the effect of increasing the temperature on the ability of rectified turpentine oil to dissolve gutta-percha. Rectified turpentine oil was warmed to 158 degrees F and then exposed to gutta-percha. This resulted in a significant increase (p < 0.01) in the ability of rectified turpentine oil to dissolve gutta-percha.

Effect of essential oils on the setting time of Kerr pulp canal sealer

Setting times were determined for Kerr pulp canal sealer and the powder component of Kerr pulp canal sealer mixed with different liquid essential oils. The mean setting time of Kerr pulp canal sealer was 16.5 min. The mean setting times for the powder component of Kerr pulp canal sealer mixed with pure eugenol or for the standard liquid component of Kerr pulp canal sealer with rectified turpentine oil were 16.5 and 18.0 min, respectively. There was no significant difference in setting times among the three groups. The addition of rectified turpentine oil to the liquid component of Kerr pulp canal sealer did not have a significant effect on setting time.