Metabolism of Terpenoids in Animal Models and Humans
K. Hüsnü Can Başer, Gerhard Buchbauer in Handbook of Essential Oils, 2020
Limonene is one of the most common terpenes found in aromatic plants. The (+)-isomeric form is more abundantly present in plants than the racemic mixture and the (–)-isomeric form. (+)-Limonene has an orange odor and is a major constituent of citrus peel oils such as Citrus aurantium sp. aurantium and Citrus limon, whereas (+)-limonene is found in the essential oil of Abies procera and dipentene in turpentine oil. (+)-Limonene is extensively used as fragrance in perfumery and household products (O'Neil, 2006; Bornscheuer et al., 2014). Several research groups have successfully described the biotransformation of (+)-limonene in vitro (rat and human liver microsomes) and in vivo (rat, mice, guinea pigs, dogs, rabbits, and human volunteers and patients). As shown in Figure 10.15, (+)-limonene is extensively biotransformed to several metabolites, whereat in humans, the main biotransformation products are perillyl alcohol; perillic acid and its isomer; cis- and trans-dihydroperillic acid; cis- and trans-carveol; limonene-1,2-diol; limonene-10-ol; uroterpenol; several glucuronides of perillic acid; and limonene-10-ol (Crowell et al., 1992; Miyazawa et al., 2002; Shimada et al., 2002; Schmidt and Göen, 2017b).
Monoterpenes-Based Pharmaceuticals: A Review of Applications In Human Health and Drug Delivery Systems
Megh R. Goyal, Durgesh Nandini Chauhan in Plant- and Marine-Based Phytochemicals for Human Health, 2018
Limonene (C10H16), also known as 3,1-methyl-4-(1-methylethenyl)-cyclohexene or 4-isopropenyl-1-methylcyclohexene, is a chiral molecule as well as colorless liquid hydrocarbon classified as a cyclic terpene.60 Limonene is the main component of the essential oils of Citrus (30–70 wt.% in different species). Apart from it, other significant components are: αand β-pinene, γ-terpinene, terpinolene, or sabinene.4, 132 Racemic limonene is called dipentene. This compound has two isomers (Fig. 4.5):41R-(+)-limonene or L-limonene: Occurring mainly in mint oil and having turpentine-like aroma;S-(−)-limonene or D-limonene: More widespread than L-isomer and characterized by a strong orange aroma.52 It can be used in chemical synthesis as a precursor to carvone and as a renewablesbased solvent in cleaning products.
Chemopreventive Agents
David E. Thurston, Ilona Pysz in Chemistry and Pharmacology of Anticancer Drugs, 2021
Limonene (Figure 12.28) is a colorless aliphatic hydrocarbon liquid, classified as a cyclic monoterpene. Used as a flavoring in the food industry, it is a major component of the oil from the peel of citrus fruits, and accounts in part for the fragrance and taste of oranges and lemons. Limonene has been reported to have similar chemopreventive properties to those for thymoquinone but has been less widely researched so the precise mechanisms involved remain unclear.
Flavonoid constituents and protective efficacy of Citrus reticulate (Blanco) leaves ethanolic extract on thioacetamide-induced liver injury rats
Published in Biomarkers, 2023
Usama W. Hawas, Mohamed A. El-Ansari, Abeer F. Osman, Asmaa F. Galal, Lamia T. Abou El-Kassem
Furthermore, the leaves have been traditionally used in the treatment of rheumatic pain, high fever, inflammation, ulcer, and tumour and have been reported to effectively inhibit 1 L-1α-inflammatory cytokine (Yesilada et al.1995, Yesilada et al.1997). In particular, Citrus species contain many important phytochemical compounds such as ascorbic and hydroxycinnamic acids (Manthey and Grohmann 2001, Rapisarda et al. 1999), acridone alkaloids (Samuel et al. 2019, Ye et al. 2022), flavonoids; flavones, flavanones, chalcones, and dihydrochalcones (Wu 1987, Han et al. 2010, Montero-Calderon et al. 2019), provitamin A carotenoids (β-cryptoxanthin) as violaxanthin esters (Giuffrida et al. 2010), and apocarotenoids (β-citraurin) (Luan et al. 2020, Rodrigo et al. 2013). These bioactive metabolites reduce the reactive oxygen species (ROS) and inflammatory mediators in the body, thereby decreasing the risk of metabolic syndrome including diabetes, cardiovascular disease, neurodegenerative diseases, and cancer (Saini et al. 2022). In addition, Citrus essential oil is rich in limonin and terpenes (D-limonene and γ-terpinene) (Raspo et al. 2020, Rossi et al. 2020). This oil is considered an economical product due to its flavouring, antioxidant, and antimicrobial properties (Ambrosio et al.2019).
Analyses on the influence of normal nasal morphological variations on odorant transport to the olfactory cleft
Published in Inhalation Toxicology, 2022
Ryan M. Sicard, Reanna Shah, Dennis O. Frank-Ito
In addition, our simulations results suggest that the diffusion of limonene and acetaldehyde in the olfactory cleft behaved similarly, and are both different in comparison to dinitrotoluene. The relative variability of odorant flux for limonene and acetaldehyde in the olfactory cleft was much smaller than dinitrotoluene. One plausible explanation for the similar behavior noticed in limonene and acetaldehyde may be due to each odorant’s chemical composition. Limonene is a completely nonpolar, insoluble compound, solely containing hydrogens and carbons (Weinhold and Mlynski 2004). Acetaldehyde, although slightly polar and miscible in all proportions of water, is generally composed of hydrogens and carbons with the exception of one oxygen (National Center for Biotechnology Information 2004a). Nonetheless, it is important to note that the amount of odorant flux in the olfactory cleft was much greater for acetaldehyde than limonene. On the other hand, dinitrotoluene is a large, highly polar and soluble compound, containing two nitrogen and four oxygens (National Center for Biotechnology Information 2004b). Another possible explanation relates to the simulated exposure concentrations levels, dinitrotoluene was simulated at much smaller concentrations than limonene and acetaldehyde, and given its high density (Lawson et al. 2012), it could have influenced its diffusive flux in the olfactory cleft quite differently than the other two odorants (limonene and acetaldehyde).
Breathing new life into clinical testing and diagnostics: perspectives on volatile biomarkers from breath
Published in Critical Reviews in Clinical Laboratory Sciences, 2022
Jordan J. Haworth, Charlotte K. Pitcher, Giuseppe Ferrandino, Anthony R. Hobson, Kirk L. Pappan, Jonathan L. D. Lawson
Perhaps due to the historical significance of liver diseases in breath research, a number of studies have been performed exploring VOCs on breath in association with CLDs, particularly cirrhosis (Table 3). The most consistent output of these studies, despite their variation in methodologies, has been the identification of elevated limonene on breath as a prospective biomarker associated with the development of cirrhosis [92–96]. Unlike the classical approach of using endogenous biomarkers produced within the body, limonene on breath is thought to originate solely from exogenous dietary sources. Limonene is a terpene abundant in citrus fruit and is widely used in the food industry as flavoring agent. Dietary limonene is processed by CYP liver enzymes and, as such, it is plausible to expect that reduced liver function would slow or arrest the metabolic conversion of limonene [97].
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