Piper methysticum is known as kava root, an herb used for anxiety relief that works within an hour or two after ingeston

Piper methysticum is a traditional beverage of various Pacific Basin countries. Piper methysticum has been introduced into the mainstream U.S. market principally as an anti-anxiety preparation. The effects of the long-term consumption of Piper methysticum have not been documented adequately. Preliminary studies suggest Piper methysticum consumption on a regular basis may cause liver harm. See Kava for more information.

Piper methysticum and liver damage
Toxic hepatitis after consumption of traditional kava preparation.
J Travel Med. 2009 Jan-Feb. Christl SU, Seifert A, Seeler D. Department of Gastroenterology, Asklepios Klinik Harburg, Hamburg, Germany.
Liver toxicity from the use of
Piper methysticum dietary supplements has been reported, but little is known about the side effects of traditional Piper methysticum preparations. We present a case study of a tourist who developed serious toxic liver disease after consumption of Piper methysticum beverages in traditional Samoan kava ceremonies.

Piper methysticum and anxiety
Discriminative-stimulus and time-course effects of kava-kava Piper methysticum in rats.
Pharmacol Biochem Behav. 2009 April. Bruner NR, Anderson KG. West Virginia University, Department of Psychology, P.O. Box 6040, Morgantown, WV 26506, United States.
Piper methysticum is a widely available and used herbal medicine. Although there is evidence that kava may possess some anxiolytic properties, the mechanism of action of Piper methysticum and the extent to which it may serve as an alternative to pharmaceutical anxiolytics are not fully known. The current study was designed to evaluate whether Piper methysticum shares discriminative-stimulus properties with the anxiolytic chlordiazepoxide. Our results show partial substitution of Piper methysticum extract for chlordiazepoxide suggests that the herbal compound may share a mechanism of action similar to chlordiazepoxide, but is less potent.

Cosmetics and skin care
Final report on the safety assessment of Piper methysticum leaf/root/stem extract and Piper methysticum root extract.
Int J Toxicol. 2009 Nov-Dec; Robinson V, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr, Shank RC, Slaga TJ, Snyder PW; Cosmetic Ingredient Review Expert Panel, Andersen FA. Cosmetic Ingredient Review, 1101 17th Street, NW, Suite 412, Washington, DC 20036, USA.
Piper methysticum leaf/root/stem extract is the cosmetic ingredient name for a material derived from the leaves, roots, and stems of the Piper methysticum G. Forster plant, commonly known as kava kava. This and other kava-derived ingredients are used as skin-conditioning agents at concentrations from 0.0001% to 0.1%. The Food and Drug Administration issued a consumer advisory in 2002 expressing concern about liver damage in individuals who have ingested kava products. The available oral toxicity data support the concern about liver damage on ingestion but do not resolve the question, for example, whether these ingredients would be substantially absorbed through the skin. Other data needs are described, including toxicology data for yangonin, methysticin, and kavain, which may be present in kava-derived ingredients. Accordingly, the available data are insufficient to support the safety of these ingredients in cosmetics.

Piper methysticum research studies
Efficacy of extracting solvents to chemical components of kava Piper methysticum roots.
Nat Med (Tokyo). 2008 April. Xuan TD, Fukuta M, Wei AC, Elzaawely AA, Khanh TD, Tawata S. Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyus, Okinawa, 903-0213, Japan.
The chemical composition of kava Piper methysticum lactones and various phytochemicals obtained following the sonication of ground Piper methysticum roots extracted in the solvents hexane, chloroform, acetone, ethanol, methanol and water, respectively, was analyzed. Eighteen kava lactones, cinnamic acid bornyl ester and 5,7-dimethoxy-flavanone, known to be present in Piper methysticum roots, were identified, and seven compounds, including 2,5,8-trimethyl-1-naphthol, 5-methyl-1-phenylhexen-3-yn-5-ol, 8,11-octadecadienoic acid-methyl ester, 5,7-(OH)(2)-4'-one-6,8-dimethylflavanone, pinostrobin chalcone and 7-dimethoxyflavanone-5-hydroxy-4', were identified for the first time. Glutathione (26.3 mg/g) was found in the water extract. Dihydro-5,6-dehydrokavain (DDK) was present at a higher level than methysticin and desmethoxyyagonin, indicating that DDK is also a major constituent of Piper methysticum roots. Acetone was the most effective solvent in terms of maximum yield and types of kava lactones isolated, followed by water and chloroform, whereas hexane, methanol, and ethanol were less effective as solvents. Total phenolic and antioxidant activity varied among the extracting solvents, with acetone and chloroform producing the highest effects, followed by water, while methanol, ethanol and hexane were less effective.

Piper species include
Piper longum herb
Piper methysticum
Piper nigrum herb

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