China
Africa
Explore chapters and articles related to this topic
Monographs of essential oils that have caused contact allergy / allergic contact dermatitis
Published in Anton C. de Groot, Monographs in Contact Allergy, 2021
Neem oil is a light brownish to brownish clear mobile liquid which has an oily, woody and dusty, slightly animalistic odor. In two neem oils obtained by hydrodistillation, over 65 chemicals have been identified. The 10 major compounds found in neem essential oil (one quantitative publication only [3]) are shown in table 6.47.1. Over 80% of the oil is composed of fatty acids (>60%) and alkanes (3).
Use of Linear Retention Indices in GC-MS Libraries for Essential Oil Analysis
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Emanuela Trovato, Giuseppe Micalizzi, Paola Dugo, Margita Utczás, Luigi Mondello
Evans and Smith (Evans and Smith, 1961b, 1962) suggested a molecular retention index, derived from the equation proposed by Kováts, which was defined as the molecular weight of a hypothetical n-alkane presenting the identical retention of the compound being investigated. The formula of that hypothetical n-alkane equivalent to the target compound is CIH2I′+2 and will possess an effective molecular weight according to the following relation: where I = 100I′, whereas I′ is the number of carbon atoms and Me is the molecular weight of the hypothetical n-alkane. The difference between that hypothetical and the real molecular weight may be a useful parameter to correlate retention and chemical structure. In the same year, Evans (Evans and Smith, 1961a,b) proposed a further system, defined as the theoretical nonane value, determining first the retention value as proposed by Kováts and then transferring to a system in which n-nonane is the standard.
Aliphatic and Aromatic Hydrocarbons
Published in Frank A. Barile, Barile’s Clinical Toxicology, 2019
Hydrocarbons (HCs) are composed of carbon and hydrogen molecules whose carbon–carbon (C–C) bonds are composed of either all single (saturated) bonds or combinations of single and multiple (unsaturated) bonds. Aliphatic HCs, the term usually pertaining to fats or oils, applies to straight, open chains of carbon atoms, rather than ring structures, the simplest of which are the saturated HCs (alkanes). In addition, alkanes exist as unbranched straight chains or branched (for butane or longer chains), depending on the structural isomerism. Multiple C–C bonds result when hydrogens are removed from the alkanes, yielding unsaturated HCs such as alkenes (double C–C bonds) and alkynes (triple C–C bonds). Alicyclic HCs are saturated ring structures consisting of three or more carbon atoms. Unlike the aromatic chemicals (see next subsection), cyclopropane, cyclobutane, cyclopentane, and cyclohexane, for example, have three-, four-, five-, and six-membered rings, respectively, but do not exhibit double bonds within the rings.
Research progress of ophthalmic preparations of immunosuppressants
Published in Drug Delivery, 2023
Ye Liu, Haonan Xu, Na Yan, Zhan Tang, Qiao Wang
In addition to the aforementioned formulations, Novaliq, Heidelberg, Germany has developed CsA (Wirta et al., 2019) and tacrolimus (De Majumdar et al., 2017) eye drops based on EyeSolTM®, the first anhydrous drug delivery technology platform for the treatment of the dry eye. This technology mainly uses semi-fluorinated alkanes as solvents, adding insoluble drugs directly to semi-fluorinated alkanes, and adding ethanol or oily medium as a solution. Figure 6 shows that semifluorinated alkanes (Agarwal et al., 2018) consist of at least one non-fluorinated alkane segment and one perfluorinated alkane segment in which some hydrogen atoms are replaced by fluorine. Semifluorinated alkanes are straight or branched chain alkanes. It is the company’s patented product, for which dozens of related patents have been applied for. CyclASolTM—a dissolvable cyclosporine eye drop made from semifluorinated alkane 1-perfluorobutyl-pentane—is being developed by the Chinese company Hengrui.
The combined effect of essential oils on wood physico-chemical properties and their antiadhesive activity against mold fungi: application of mixture design methodology
Published in Biofouling, 2023
Moulay Sadiki, Mounyr Balouiri, Soumya Elabed, Fadoua Bennouna, Mohammed Lachkar, Saad Ibnsouda koraichi
The essential oils’ composition was determined by Gas chromatography coupled with mass spectrometry (GC/MS). The analysis was performed on GC Hewlett-Packard type (HP/Agilent 6890) with flame ionization detector (FID). It is coupled with a mass spectrometer (HP 5973 series) equipped with an HP-5MS capillary column (30 m x 0.25 mm, film thickness is 0.25 µm). The chromatography carrier gas was helium (1.2 mL min−1). The column temperature was programmed from 45 to 240 °C at 2 °C min−1. The fragmentation was done by impact electronics in a field of 70 eV. Essential oils were diluted in methanol (1/20 v/v). A sample volume of 2 µL was injected in a split mode (leakage ratio: 1/20) at a temperature of 250 °C. Identification of the components was made by the comparison of their mass spectra with those of the NIST MS search database (NIST 98), and by comparison of their retention indices (IR) with those of the Adams terpene library (Adams 2007). The retention indices were determined in relation to the homologous series of n-alkanes (C9-C23) under the same operating conditions.
Design, synthesis and biological evaluation of 4-bromo-N-(3,5-dimethoxyphenyl)benzamide derivatives as novel FGFR1 inhibitors for treatment of non-small cell lung cancer
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2018
Zixin Xie, Donghua Cheng, Lu Luo, Guoliang Shen, Suwei Pan, Yaqian Pan, Bo Chen, Xuebao Wang, Zhiguo Liu, Yuan Zhang, Faqing Ye
As outlined in Scheme 1, we designed and synthesised three series of compounds (Table 1). In the A series, we primarily aimed to increase the hydrophobic effects by introducing chain alkanes. In the B series, our goal is to increase the binding to protein-binding sites and increase the space utilisation of compounds in hydrophobic pocket 2 and near solvent domains, so we substituted them with benzene rings to create π–π interactions. Finally, in the C series, we added a sulphur oxygen double bond to increase the formation of hydrogen bonds with other amino acid residues of FGFR1, thereby increasing the adhesion strength of the compounds with FGFR1 protein.