Received: 19 September 2018 Revised: 11 January 2019 Accepted: 9 February 2019 DOI: 10.1002/ptr.6327 RESEARCH ARTICLE Plant polyprenols reduce demyelination and recover impaired oligodendrogenesis and neurogenesis in the cuprizone murine model of multiple sclerosis Marina Y. Khodanovich1 | Anna O. Pishchelko1 | Valentina Y. Glazacheva1 | Edgar S. Pan1 | Elena P. Krutenkova1 | Vladimir B. Trusov2 | Vasily L. Yarnykh1,3 1 Laboratory of Neurobiology, Tomsk State University, Tomsk, Russian Federation Recent studies showed hepatoprotective, neuroprotective, and immunomodulatory 2 Prenolica Limited (formerly Solagran Limited), properties of polyprenols isolated from the green verdure of Picea abies (L.) Karst. This Biotechnology Company, Melbourne, Victoria, Australia study aimed to investigate effects of polyprenols on oligodendrogenesis, neurogenesis, 3 Department of Radiology, University of and myelin content in the cuprizone demyelination model. Demyelination was induced Washington, Seattle, WA, USA by 0.5% cuprizone in CD‐1 mice during 10 weeks. Nine cuprizone‐treated animals Correspondence received daily injections of polyprenols intraperitoneally at a dose of 12‐mg/kg body Marina Y. Khodanovich, Laboratory of weight during Weeks 6–10. Nine control animals and other nine cuprizone‐treated Neurobiology, Tomsk State University, 36 Lenina Ave., Tomsk 634050, Russian received sham oil injections. At Week 10, brain sections were stained for myelin basic Federation. protein, neuro‐glial antigen‐2, and doublecortin to evaluate demyelination, Email: [email protected] oligodendrogenesis, and neurogenesis. Cuprizone administration caused a decrease Funding information in myelin basic protein in the corpus callosum, cortex, hippocampus, and the caudate Ministry of Education and Science of the Russian Federation, Grant/Award Number: putamen compared with the controls. Oligodendrogenesis was increased, and 18.2583.2017/4.6; Russian Science Founda- neurogenesis in the subventricular zone and the dentate gyrus of the hippocampus tion, Grant/Award Number: 18‐15‐229 was decreased in the cuprizone‐treated group compared with the controls. Mice treated with cuprizone and polyprenols did not show significant demyelination and dif- ferences in oligodendrogenesis and neurogenesis as compared with the controls. Our results suggest that polyprenols can halt demyelination, restore impaired neurogenesis, and mitigate reactive overproduction of oligodendrocytes caused by cuprizone neurotoxicity. KEYWORDS cuprizone model, demyelination, long‐chain isoprenoid alcohols, neurogenesis, oligodendrogenesis, plant polyprenols 1 | INTRODUCTION polyphenols, which contain multiple phenolic structural units, polyprenols consist of hydrophilic and hydrophobic parts: a hydroxyl Polyprenols are bioactive long‐chain isoprenoid alcohols that occur group and a long unsaturated, mainly of poly‐cis configuration, in various plants. Unlike more popular in the area of nutrition isoprenyl chain. Depending on the source, chain length of natural -------------------------------------------------------------------------------------------------------------------------------- This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2019 The Authors Phytotherapy Research Published by John Wiley & Sons Ltd Phytotherapy Research. 2019;33:1363–1373. wileyonlinelibrary.com/journal/ptr 1363 1364 KHODANOVICH ET AL. polyprenols varies from 6 to 40 isoprene units (Roslinska, Walinska, testosterone and polyprenols on β‐amyloid‐induced impairment in Swiezewska, & Chojnacki, 2002; Zhang et al., 2015). gonadectomized rats. A similar effect of polyprenol treatment was A small amount of polyprenols in the form of free alcohols, carbox- described by Wang, He, Yan, Zheng, and Liu (2014) on the D‐galactose ylic esters, and phosphate esters is present in cell membranes (Zhang mouse model of Alzheimer's disease. In this study, polyprenols et al., 2015). Bacterial and some plant membranes contain unsaturated improved the D‐galactose‐induced cognitive impairment in Morris polyisoprenols (polyprenols), whereas unicellular eukaryotes, fungi, water maze, passive and active avoidance tests, and an open‐field test animal, and some plant tissues contain saturated polyisoprenols via enhancing oxidative defense and affecting generation and dissimi- (dolichols; Roslinska et al., 2002). After administration in small ani- lation of Aβ‐related enzymes. In a clinical electroencephalography mals, polyprenols were found in high concentrations in the liver, kid- study (Soultanov et al., 2010), polyprenol treatment of patients with neys, and lungs and in lesser concentration in the brain, spleen, and chronic alcoholism enhanced the alpha‐rhythm power and decreased other organs (Chojnacki & Dallner, 1988). Upon subfractionation of pathological excitation in the frontal brain areas. the liver, most of the polyisoprenoids were recovered in the Mild immunomodulating and antiviral properties of polyprenyl mitochondrial‐lysosomal fraction (Jakobsson, Swiezewska, Chojnacki, phosphates were shown by Pronin et al. (2002). The authors reported & Dallner, 1989). In the liver, polyprenols are mostly modified to inhibition of an early phase of interleukin 1 and Con A interaction in metabolically more active forms via α‐saturation and phosphoryla- spleen cells, lypoxigenase activity, and expression of interleukin 2 tion by a specific kinase (Chojnacki & Dallner, 1988). The dolichol receptors by polyprenyl phosphates. At the same time, phosprenyl phosphate cycle plays an important role in biosynthesis of mem- stimulated natural killer cell activity and early TNF‐α production brane and intracellular glycoproteins. Phosphates of polyisoprenoids, (Pronin et al., 2002). due to their hydrophobic properties, act as carriers of glycosyl resi- Due to participation in glycan biosynthesis and N‐linked protein dues across membranes during glycosylation reactions (Walinska, glycosylation, polyprenyl phosphates and dolichyl phosphate are 2004), C‐ and O‐protein mannosylation, and cell wall biosynthesis important regulators of cell proliferation. It was shown that the rate (Hartley & Imperiali, 2012). Due to a large number of unsaturated of dolichyl phosphate and glycoprotein synthesis is linked to the carbon bonds, polyprenols are prone to oxidation, being precursors growth rate of Chinese hamster ovary cells and cell division (Hartley of a variety of compounds, including terpenes and steroids & Imperiali, 2012; Swiezewska & Danikiewicz, 2005). Moreover, the (Walinska, 2004). studies have confirmed that dolichyl phosphate is a rate‐limiting sub- Polyprenols and their metabolites have attracted considerable strate in N‐linked glycosylation and is thereby a key factor in cellular attention due to their proven hepatoprotective, antioxidant, neuro- development (Hartley & Imperiali, 2012; Swiezewska & Danikiewicz, protective, immunomodulating, and proliferative activity. Yang, 2005). Inhibition of polyisoprenol biosynthesis resulted in abnormal Wang, Ye, and Li (2011) and J. Yu et al. (2012) demonstrated hepa- gastrulation, which correlated with the inability of the cell to produce toprotective effect of polyprenols in the model of tetrachloride‐ glycoproteins. Addition of exogenous dolichol allowed for normal gas- induced hepatic damage using liver function tests and histology. trulation, suggesting that dolichyl phosphate is a limiting reagent for The authors associated the effect with a reduction of oxidative dam- N‐linked glycosylation of proteins and subsequent cellular transforma- age, downregulation of pro‐fibrogenic stimuli, inhibition of activation tions (Hartley & Imperiali, 2012). of hepatic stellate cells, and protection of hepatocytes. In a pilot We hypothesize that the spectrum of biological activity of clinical study, 30‐day polyprenol treatment of patients with chronic polyprenols may be of significant interest in treatment of multiple alcoholism (Soultanov et al., 2010) resulted in significant improve- sclerosis (MS), a chronic inflammatory demyelinating and neurodegen- ment of blood biochemistry according to the clinical liver, pancreas, erative disorder. In addition to traditional anti‐inflammatory MS thera- and kidney tests. pies, the use of complementary and alternative herbal medicine gained The effect of polyprenols of natural origin was investigated in ani- substantial attention over the past years as a way to alleviate neuro- mal models of Alzheimer's disease. In particular, Fedotova et al. (2016) logical deficit and augment neuroprotection (Mojaverrostami, and Fedotova, Soultanov, Nikitina, Roschin, and Ordayn (2012) Bojnordi, Ghasemi‐Kasman, Ebrahimzadeh, & Hamidabadi, 2018; showed that 4‐week administration of polyprenols ameliorates cogni- Zarshenas, Ansari, Dadbakhsh, & Mohammadi, 2018). The search for tive impairment caused by intracerebroventricular injection of β‐ new agents that could enable the restoration of damaged myelin and amyloid (Acs et al., 2009; Bakker & Ludwin, 1987; Barnett & Prineas, prevent neurodegeneration is of crucial importance for further prog- 2004; Deshmukh et al., 2013; Festing, 2014; Iwasa et al., 2014; ress in the treatment of this condition. Given the effect of polyprenols Khodanovich et al., 2016; Lucchinetti et al., 2000; Vega‐Riquer, in various neurological and cognitive conditions demonstrated in ani- Mendez‐Victoriano, Morales‐Luckie,