Abstract
Roots of kava (Piper methysticum) plant are used in almost all Pacific Ocean cultures to prepare a drink with sedative, anesthetic and euphoric properties. One of the main active ingredients of the extract are kava lactones. Here, kava root CO2 extract and three kavalactones, DL-kavain, dihydrokavain and yangonin (isolated from whole extract by column chromatography) were tested for their inhibitory action on recombinant homomeric human α1 glycine receptors expressed in HEK293 cells. Kava CO2 root extract, as well as the individual components DL-kavain, dihydrokavain and yangonin inhibited glycine receptor activity in a dose-dependent manner. DL-kavain was the most potent inhibitor (IC50 = 0.077 ± 0.002 mm), followed by yangonin (IC50 = 0.31 ± 0.04 mm) and dihydrokavain (IC50 = 3.23 ± 0.10 mm) which were 4- and 40-fold less active than DL-kavain, respectively. Application of kava root extract did not reduce maximum currents, but increased EC50 of glycine. Simultaneous application of kava extract and strychnine showed additive inhibition, suggesting that binding of kavalactones and strychnine on the receptor is mutually exclusive. Overall, kavalactones exert a moderate inhibitory effect on the human α1 glycine receptor with DL-kavain being the most potent constituent.
Acknowledgments
We thank Flavex Naturextrakte (Rehlingen-Siersburg, Germany) for a gift of Kava kava extract, and Mohamed Abdelhalim (Department of Pharmaceutical Chemistry, German University in Cairo) for gas chromatography-mass spectrometry (GC-MS) analysis. The excellent technical support by Mousa Abdalla is gratefully acknowledged.
Conflict of interest statement: The authors report no conflict of interest.
References
Assessment Report. (2017). Assessment report on Piper methysticum G. Forst rhizoma. European Medicinal Agency, Committee on Herbal Medicinal Products.Search in Google Scholar
Backhauss, C. and Krieglstein, J. (1992). Extract of kava (Piper methysticum) and its methysticin constituents protect brain tissue against ischemic damage in rodents. Eur. J. Pharmacol. 215, 265–269.10.1016/0014-2999(92)90037-5Search in Google Scholar
Baum, S.S., Hill, R., and Rommelspacher, H. (1998). Effect of kava extract and individual kavapyrones on neurotransmitter levels in the nucleus accumbens of rats. Prog. Neuropsychopharmacol. Biol. Psychiatry 22, 1105–1120.10.1016/S0278-5846(98)00062-1Search in Google Scholar
Breitinger, H.G. (2012). Drug synergy – mechanisms and methods of analysis. In: Toxicity and Drug Testing, W. Acree, ed. (IntechOpen), pp. 143–166. DOI: 10.5772/30922.10.5772/30922Search in Google Scholar
Breitinger, H.G. (2014). Glycine Receptors (Chichester: eLS. John Wiley & Sons Ltd).10.1002/9780470015902.a0000236.pub2Search in Google Scholar
Breitinger, H.G. and Becker, C.M. (2002). The inhibitory glycine receptor – simple views of a complicated channel. ChemBioChem 3, 1042–1052.10.1002/1439-7633(20021104)3:11<1042::AID-CBIC1042>3.0.CO;2-7Search in Google Scholar
Breitinger, U. and Breitinger, H.G. (2016). Augmentation of glycine receptor alpha3 currents suggests a mechanism for glucose-mediated analgesia. Neurosci. Lett. 612, 110–115.10.1016/j.neulet.2015.11.051Search in Google Scholar
Breitinger, H.G., Geetha, N., and Hess, G.P. (2001). Inhibition of the serotonin 5-HT3 receptor by nicotine, cocaine, and fluoxetine investigated by rapid chemical kinetic techniques. Biochemistry 40, 8419–8429.10.1021/bi0106890Search in Google Scholar
Breitinger, H.G., Lanig, H., Vohwinkel, C., Grewer, C., Breitinger, U., Clark, T., and Becker, C.-M. (2004). Molecular dynamics simulation links conformation of a pore-flanking region to hyperekplexia-related dysfunction of the inhibitory glycine receptor. Chem. Biol. 11, 1339–1350.10.1016/j.chembiol.2004.07.008Search in Google Scholar
Breitinger, U., Raafat, K.M., and Breitinger, H.G. (2015). Glucose is a positive modulator for the activation of human recombinant glycine receptors. J. Neurochem. 134, 1055–1066.10.1111/jnc.13215Search in Google Scholar
Breitinger, U., Sticht, H., and Breitinger, H.G. (2016). Modulation of recombinant human a1 glycine receptors by mono- and disaccharides: a kinetic study. ACS Chem. Neurosci. 7, 1077–1087.10.1021/acschemneuro.6b00044Search in Google Scholar
Breitinger, U., Bahnassawy, L.M., Janzen, D., Roemer, V., Becker, C.-M., Villmann, C., and Breitinger, H.G. (2018). PKA and PKC modulators affect ion channel function and internalization of recombinant alpha1 and alpha1-beta glycine receptors. Front. Mol. Neurosci. 11, 154.10.3389/fnmol.2018.00154Search in Google Scholar
Cass, H. (2004). Herbs for the nervous system: ginkgo, kava, valerian, passionflower. Semin. Integr. Med. 2, 82–88.10.1016/j.sigm.2004.07.001Search in Google Scholar
Chua, H.C., Christensen, E.T., Hoestgaard-Jensen, K., Hartiadi, L.Y., Ramzan, I., Jensen, A.A., Absalom, N.L., and Chebib, M. (2016). Kavain, the major constituent of the anxiolytic kava extract, potentiates GABAA receptors: functional characteristics and molecular mechanism. PLoS One 11, e0157700.10.1371/journal.pone.0157700Search in Google Scholar
Compendium. (2015). Piper Methysticum Root and Rhizome – Identification. Herbal Medicines Compendium. https://hmc.usp.org/monographs/piper-methysticum-root-and-rhizome-0-2.Search in Google Scholar
Dinh, L.D., Simmen, U., Bueter, K.B., Bueter, B., Lundstrom, K., and Schaffner, W. (2001). Interaction of various Piper methysticum cultivars with CNS receptors in vitro. Planta Med. 67, 306–311.10.1055/s-2001-14334Search in Google Scholar
Enna, S.J. and Norton, S. (2012). Herbal Supplements and the Brain: Understanding their Health Benefits and Hazards, 1st edition. (Upper Saddle River, NJ, USA: FT Press Science Series, Pearson Education Inc.). ISBN 978-0132824972.Search in Google Scholar
Friese, J. and Gleitz, J. (1998). Kavain, dihydrokavain, and dihydromethysticin non-competitively inhibit the specific binding of [3H]-batrachotoxinin-A 20-alpha-benzoate to receptor site 2 of voltage-gated Na+ channels. Planta Med. 64, 458–459.10.1055/s-2006-957482Search in Google Scholar
Garrett, K.M., Basmadjian, G., Khan, I.A., Schaneberg, B.T., and Seale, T.W. (2003). Extracts of kava (Piper methysticum) induce acute anxiolytic-like behavioral changes in mice. Psychopharmacology (Berl). 170, 33–41.10.1007/s00213-003-1520-0Search in Google Scholar
Gleitz, J., Friese, J., Beile, A., Ameri, A., and Peters, T. (1996a). Anticonvulsive action of (+/−)-kavain estimated from its properties on stimulated synaptosomes and Na+ channel receptor sites. Eur. J. Pharmacol. 315, 89–97.10.1016/S0014-2999(96)00550-XSearch in Google Scholar
Gleitz, J., Gottner, N., Ameri, A., and Peters, T. (1996b). Kavain inhibits non-stereospecifically veratridine-activated Na+ channels. Planta Med. 62, 580–581.10.1055/s-2006-957981Search in Google Scholar
Gounder, R. (2006). Kava consumption and its health effects. Pac. Health Dialog 13, 131–135.Search in Google Scholar
Grunze, H., Langosch, J., Schirrmacher, K., Bingmann, D., Von Wegerer, J., and Walden, J. (2001). Kava pyrones exert effects on neuronal transmission and transmembraneous cation currents similar to established mood stabilizers – a review. Prog. Neuropsychopharmacol. Biol. Psychiatry 25, 1555–1570.10.1016/S0278-5846(01)00208-1Search in Google Scholar
Gunthorpe, M.J. and Lummis, S.C.R. (1999). Diltiazem causes open channel block of recombinant 5-HT3 receptors. J. Physiol. 519(Pt. 3), 713–722.10.1111/j.1469-7793.1999.0713n.xSearch in Google Scholar PubMed PubMed Central
Heftmann, E. (2004). Chromatography: fundamentals and applications of chromatography and related differential migration methods, Vol. 69B (Amsterdam: Elsevier).Search in Google Scholar
Hoover, J.M., Kaye, A.D., Ibrahim, I.N., Fields, A.M., and Richards, T.A. (2006). Analysis of responses to kava kava in the feline pulmonary vascular bed. J. Med. Food 9, 62–71.10.1089/jmf.2006.9.62Search in Google Scholar
Ivic, L., Sands, T.T., Fishkin, N., Nakanishi, K., Kriegstein, A.R., and Stromgaard, K. (2003). Terpene trilactones from Ginkgo biloba are antagonists of cortical glycine and GABA(A) receptors. J. Biol. Chem. 278, 49279–49285.10.1074/jbc.M304034200Search in Google Scholar
Jaracz, S., Nakanishi, K., Jensen, A.A., and Stromgaard, K. (2004). Ginkgolides and glycine receptors: a structure-activity relationship study. Chemistry 10, 1507–1518.10.1002/chem.200305473Search in Google Scholar
Jussofie, A., Schmiz, A., and Hiemke, C. (1994). Kavapyrone enriched extract from Piper methysticum as modulator of the GABA binding site in different regions of rat brain. Psychopharmacology 116, 469–474.10.1007/BF02247480Search in Google Scholar
Kretzschmar, R., Meyer, H.J., and Teschendorf, H.J. (1970). Strychnine antagonistic potency of pyrone compounds of the kavaroot (Piper methysticum Forst.). Experientia 26, 283–284.10.1007/BF01900097Search in Google Scholar
Kubatova, A., Miller, D.J., and Hawthorne, S.B. (2001). Comparison of subcritical water and organic solvents for extracting kava lactones from kava root. J. Chromatogr. A 923, 187–194.10.1016/S0021-9673(01)00979-7Search in Google Scholar
Kumar, V. (2006). Potential medicinal plants for CNS disorders: an overview. Phytother. Res. 20, 1023–1035.10.1002/ptr.1970Search in Google Scholar
Lebot, V. and Levesque, J.Ó. (1996). Genetic control of kavalactone chemotypes in Piper methysticum cultivars. Phytochemistry 43, 397–403.10.1016/0031-9422(96)00209-9Search in Google Scholar
Lebot, V., Merlin, M., and Lindstrom, L. (1997). Kava: The Pacific Elixir: The Definite Guide to its Ethnobotany, History and Chemistry, Vol ISBN 0-89281-726-7 (Rochester: Healing Arts Press).Search in Google Scholar
Ligresti, A., Villano, R., Allara, M., Ujvary, I., and Di Marzo, V. (2012). Kavalactones and the endocannabinoid system: the plant-derived yangonin is a novel CB(1) receptor ligand. Pharmacol. Res. 66, 163–169.10.1016/j.phrs.2012.04.003Search in Google Scholar PubMed
Maleeva, G., Buldakova, S., and Bregestovski, P. (2015). Selective potentiation of alpha 1 glycine receptors by ginkgolic acid. Front. Mol. Neurosci. 8, 64.10.3389/fnmol.2015.00064Search in Google Scholar PubMed PubMed Central
Martin, H.B., McCallum, M., Stofer, W.D., and Eichinger, M.R. (2002). Kavain attenuates vascular contractility through inhibition of calcium channels. Planta Med. 68, 784–789.10.1055/s-2002-34443Search in Google Scholar
Mulholland, P.J. and Prendergast, M.A. (2002). Post-insult exposure to (+/−) kavain potentiates N-methyl-D-aspartate toxicity in the developing hippocampus. Brain Res. 945, 106–113.10.1016/S0006-8993(02)02745-2Search in Google Scholar
Munte, T.F., Heinze, H.J., Matzke, M., and Steitz, J. (1993). Effects of oxazepam and an extract of kava roots (Piper methysticum) on event-related potentials in a word recognition task. Neuropsychobiology 27, 46–53.10.1159/000118952Search in Google Scholar PubMed
Pittler, M.H. and Ernst, E. (2003). Kava extract for treating anxiety. Cochrane Database Syst. Rev., CD003383.10.1002/14651858.CD003383Search in Google Scholar PubMed
Raafat, K., Breitinger, U., Mahran, L., Ayoub, N., and Breitinger, H.G. (2010). Synergistic inhibition of glycinergic transmission in vitro and in vivo by flavonoids and strychnine. Toxicol. Sci. 118, 171–182.10.1093/toxsci/kfq245Search in Google Scholar PubMed
Raduege, K.M., Kleshinski, J.F., Ryckman, J.V., and Tetzlaff, J.E. (2004). Anesthetic considerations of the herbal, kava. J. Clin. Anesth. 16, 305–311.10.1016/j.jclinane.2003.08.009Search in Google Scholar PubMed
Sarris, J., LaPorte, E., and Schweitzer, I. (2011). Kava: a comprehensive review of efficacy, safety, and psychopharmacology. Aust. N. Z. J. Psychiatry 45, 27–35.10.3109/00048674.2010.522554Search in Google Scholar PubMed
Sarris, J., Stough, C., Bousman, C.A., Wahid, Z.T., Murray, G., Teschke, R., Savage, K.M., Dowell, A., Ng, C., and Schweitzer, I. (2013). Kava in the treatment of generalized anxiety disorder: a double-blind, randomized, placebo-controlled study. J. Clin. Psychopharmacol. 33, 643–648.10.1097/JCP.0b013e318291be67Search in Google Scholar PubMed
Savage, K., Firth, J., Stough, C., and Sarris, J. (2018). GABA-modulating phytomedicines for anxiety: a systematic review of preclinical and clinical evidence. Phytother. Res. 32, 3–18.10.1002/ptr.5940Search in Google Scholar PubMed
Shan, Q., Haddrill, J.L., and Lynch, J.W. (2001). Ivermectin, an unconventional agonist of the glycine receptor chloride channel. J. Biol. Chem. 276, 12556–12564.10.1074/jbc.M011264200Search in Google Scholar PubMed
Shimoda, L.M., Showman, A., Baker, J.D., Lange, I., Koomoa, D.L., Stokes, A.J., Borris, R.P., and Turner, H. (2015). Differential regulation of calcium signalling pathways by components of Piper methysticum (‘Awa). Phytother. Res. 29, 582–590.10.1002/ptr.5291Search in Google Scholar
Singh, Y.N. (1983). Effects of kava on neuromuscular transmission and muscle contractility. J. Ethnopharmacol. 7, 267–276.10.1016/0378-8741(83)90002-8Search in Google Scholar
Singh, Y.N. (2005). Potential for interaction of kava and St. John’s wort with drugs. J. Ethnopharmacol. 100, 108–113.10.1016/j.jep.2005.05.014Search in Google Scholar
Steiner, G.G. (2000). The correlation between cancer incidence and kava consumption. Hawaii Med. J. 59, 420–422.Search in Google Scholar
Tawfiq, R.A., Nassar, N.N., El-Eraky, W.I., and El-Denshary, E.S. (2014). Enhanced efficacy and reduced side effects of diazepam by kava combination. J. Adv. Res. 5, 587–594.10.1016/j.jare.2013.08.002Search in Google Scholar
Teschke, R., Sarris, J., and Lebot, V. (2011). Kava hepatotoxicity solution: a six-point plan for new kava standardization. Phytomedicine 18, 96–103.10.1016/j.phymed.2010.10.002Search in Google Scholar
Teschke, R., Sarris, J., and Lebot, V. (2013). Contaminant hepatotoxins as culprits for kava hepatotoxicity – fact or fiction? Phytother. Res. 27, 472–474.10.1002/ptr.4729Search in Google Scholar
Thompson, A.J., Lester, H.A., and Lummis, S.C. (2010). The structural basis of function in Cys-loop receptors. Q. Rev. Biophys. 43, 449–499.10.1017/S0033583510000168Search in Google Scholar
Tzeng, Y.M. and Lee, M.J. (2015). Neuroprotective properties of kavalactones. Neural Regen. Res. 10, 875–877.10.4103/1673-5374.158335Search in Google Scholar
Walden, J., von Wegerer, J., Winter, U., Berger, M., and Grunze, H. (1997). Effects of kawain and dihydromethysticin on field potential changes in the hippocampus. Prog. Neuropsychopharmacol. Biol. Psychiatry 21, 697–706.10.1016/S0278-5846(97)00042-0Search in Google Scholar
Whitton, P.A., Lau, A., Salisbury, A., Whitehouse, J., and Evans, C.S. (2003). Kava lactones and the kava-kava controversy. Phytochemistry 64, 673–679.10.1016/S0031-9422(03)00381-9Search in Google Scholar
Woelk, H. (1995). Kava-Spezialextrakt – Wirksame Phytotherapie bei Angststörungen [Kava special extract – effective phytotherapy of anxiety disorders]. In: Phytopharmaka in Forschung und klinischer Anwendung [Phytopharmaceuticals in Research and Clinical Application], D. Loew and N. Rietbrock, eds. (Darmstadt: Steinkopff/Springer), pp. 151–158.10.1007/978-3-642-85434-7_13Search in Google Scholar
Yévenes, G.E. and Zeilhofer, H.U. (2011). Molecular sites for the positive allosteric modulation of glycine receptors by endocannabinoids. PLoS One 6, e23886.10.1371/journal.pone.0023886Search in Google Scholar
Yuan, C.S., Dey, L., Wang, A., Mehendale, S., Xie, J.T., Aung, H.H., and Ang-Lee, M.K. (2002). Kavalactones and dihydrokavain modulate GABAergic activity in a rat gastric-brainstem preparation. Planta Med. 68, 1092–1096.10.1055/s-2002-36338Search in Google Scholar
Zhou, L., Chillag, K.L., and Nigro, M.A. (2002). Hyperekplexia: a treatable neurogenetic disease. Brain Dev. 24, 669–674.10.1016/S0387-7604(02)00095-5Search in Google Scholar
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