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Graphene from Essential Oils
Published in Amir Al-Ahmed, Inamuddin, Graphene from Natural Sources, 2023
Terpenes are widely distributed in nature constituting the largest class of secondary metabolites with more than 50,000 molecules isolated and identified until today. Plants, animals, microorganisms, algae, endophytes and marine life produce them. They are part of the nonsaponifiable isoprenic lipids. This class of lipids is characterized like the other lipids by its insolubility in water and its solubility in organic solvents. These molecules have a common metabolic origin that is isoprene (2-methyl-1,3-butadiene). This precursor is synthesized via the mevalonate route from acetyl-CoA. Another pathway has been demonstrated in several bacteria and a green alga (Scenedesmus obliquus) leading to the production of isoprene from 2-methyl-d-erythritol-4-phosphate. This class contains EOs, resins, steroids, vitamins and polymers (latex and rubber). This class is also characterized by structural diversity, which gives these molecules different biological activities. These molecules can be simple hydrocarbons, oxygenated, sulfurized or aromatic hydrocarbons. Depending on the number of associated isoprenic units, there are monoterpenes (C10), sesquiterpenes (C15), diterpenes (C20), sesterterpenes (C25), triterpenes (C30), tetraterpenes (C40) and polyterpenes (Cn) (Paduch et al., 2007; Marouf and Tremblin, 2009; Martins et al., 2017; Parveen et al., 2018).
Terpenoids in Cancer Treatment
Published in Dijendra Nath Roy, Terpenoids Against Human Diseases, 2019
Arghya Adhikary, Shaswati Das, Mousumi Bhattacharjee
Monoterpenoids: Monoterpenoids are formed from geranyl diphosphate. Many monoterpenes are non-nutritive dietary components found in the essential oils of citrus fruits, cherry, mint and herbs. Geraniol, an acyclic dietary monoterpene, represents the only monoterpene that has been studied in vitro against liver cancer cells such as HepG2 (Thoppil and Bishayee 2011). Geraniol has been shown to inhibit the growth of HepG2 human hepatic carcinoma cells by decreasing 3-hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase, the major rate-limiting enzyme in cholesterol biosynthesis in mammals. Another monoterpenoid, d-Limonene is a major component of citrus peel oil and has been well investigated in regards to both breast and prostate cancer. It is well established as a chemopreventive and therapeutic agent against many tumour cells and has chemopreventive activity against rodent mammary cancer during the initiation phase as well as the progression phase. Cinnamomum monoterpenoid subamone has been found to be cytotoxic against the hormonal prostate cancer cell lines DU-145 and LNCaP. The monoterpenes stylosin and tschimgine, extracted from Ferula ovina, have potent cytotoxic activity against melanoma (Chinembiri et al., 2014).
Terpenes and Terpenoids
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
The essential oils of plants contain an abundance of monoterpenes, sesquiterpenes, and diterpenes. The most common structural monoterpenes are derivatives of geraniol, the main constituent of geranium oil. Menthol is the chief component of peppermint oil. d-Limonene composes over 90% of lemon oil. α-Pinene is found in the oil of rosemary. Camphor is the main component of sage oil. Iridoids are interesting monoterpenes, which have been isolated from ants. Monoterpenes are used in flavor and perfume industries because of their attractive odors, high volatilities, and low molecular weights.78 Most of these are synthesized and usually trigger symptoms in individuals with chemical sensitivity. Several monoterpenes are found in turpentine. The rosin acids are diterpenes. Vitamin A is the best-known open-chain diterpene. The triterpenes that are obtainable from shark liver oil may be converted to cholesterol and many other steroids. The carotenoid pigments are the best-known tetraterpenes. The function of terpenes in plants, which has been previously described as being a protectant for heat and other organisms, is not always so clear. Terpenes sometimes possess toxic properties that link to the protection of the species. Animals do not eat some types of terpenes. The same protective properties appear to trigger and exacerbate symptoms in individuals with chemical sensitivity.
Elevated O3 threatens biological communications mediated by plant volatiles: A review focusing on the urban environment
Published in Critical Reviews in Environmental Science and Technology, 2023
Noboru Masui, Kaori Shiojiri, Evgenios Agathokleous, Akira Tani, Takayoshi Koike
The effect of BVOCs on O3 formation depends on the characteristics of the emitted compounds, and plant phenological patterns (Panopoulou et al., 2020). There are many types of BVOC emitters, such as high/low/non-emitters, isoprene, and monoterpene (MT) emitters. The composition of each group varies widely (Tani & Mochizuki, 2021) as shown in Table S1 (Supporting Information). For example, in the same genus, Quercus serrata (isoprene emitter), Q. ilex (MT emitter), and Q. acutissima (non-emitter) can be categorized into different groups based on their ability to emit BVOCs. Similarly, different BVOCs emission abilities were also found in Fagus trees, specifically between European beech (Fagus sylvatica), an MT emitter, and Japanese beech (F. crenata), a non-emitter (van Meeningen et al., 2016; Tani & Mochizuki, 2021).
Waste tire pyrolysis and desulfurization of tire pyrolytic oil (TPO) – A review
Published in Journal of the Air & Waste Management Association, 2023
Moshe Mello, Hilary Rutto, Tumisang Seodigeng
GC-MS analysis is usually performed to quantify the concentration of aliphatic and aromatic hydrocarbons found in TPO. The TPO naphtha-like fraction contains high percentages of benzene, toluene, and xylene fractions (Campuzano et al. 2020, Campuzano et al. 2021a). The GC-MS analysis reported the most dominant chemical species is Limonene, with 70–85% purity (Cunliffe and Williams 1998; Laresgoiti et al. 2004). Limonene is a monoterpene formed in plants by condensing two isoprene molecules. Since all tires contain some natural rubber (an isoprene polymer), the abundant limonene could result from the depolymerization and molecular rearrangement of the isoprene units in natural rubber during the pyrolysis (Januszewicz et al. 2020 a,b). Depending on the rubber composition within the tire and the pyrolysis process conditions, the composition of TPO can either be dominated by aromatic or aliphatic compounds. This is mainly because tire rubbers are composed of SBR made of aromatic and aliphatic compounds (Laresgoiti et al. 2004). Banar et al. and Islam et al. reported that aliphatic compounds are the most dominant chemical species from their TPO. On the contrary, other researchers have found aromatic compounds in abundance compared to aliphatic compound species (Cunliffe and Williams 1998; de Marco Rodriguez et al. 2001). An endless and complex number of alkanes, alkenes, and polycyclic aromatic hydrocarbons (PAH) are present in TPO. This fact makes it difficult to tabulate the GC-MS analysis results obtained by various researchers around the globe.
A monoterpene antioxidant, linalool, mitigates benzene-induced oxidative toxicities on hematology and liver of male rats
Published in Egyptian Journal of Basic and Applied Sciences, 2021
Olaniyi Solomon Ola, Temitope Ayooluwa Sofolahan
Hepatic necrosis resulted from increased lipid peroxidation and serum activities of liver-specific biomarker enzymes like AST and ALT has been reported in animals intoxicated with benzene [42]. Plasma ALT and AST are used as markers of liver injury as their significant elevation in the plasma is linked to their leakage from damaged hepatocytes [43–45]. ALP is associated with cell membrane and its relative increase in plasma is associated with impairment of intrahepatic and extrahepatic bile flow and hepatobiliary injury [46,47]. The result of this research work shows that these marker enzymes were significantly increased in leukocytosis rats due to benzene exposure. However, administration of linalool buffered cellular integrity of liver cell as observed in significant reduction in the activities of these liver function enzymes in animals treated with monoterpene linalool when compared with untreated group. Therefore, linalool functions in alleviating the toxicity of benzene on liver damage.