Naphthazarin derivatives (V): formation of glutathione conjugate and cytotoxic activity of 2-or 6-substituted 5,8-dimethoxy-1,4-napthoquinones in the presence of glutathione-S-transferase, in rat liver S-9 fraction and mouse liver perfusate

Kava lactones and the kava-kava controversy

Kava-kava is a traditional beverage of the South Pacific islanders and has had centuries of use without major side effects. Standardised extracts of kava-kava produced in Europe have led to many serious health problems and even to death. The extraction process (aqueous vs. acetone in the two types of preparations) is responsible for the difference in toxicity as extraction of glutathione in addition to the kava lactones is important to provide protection against hepatotoxicity. The Michael reaction between glutathione and kava lactones, resulting in opening of the lactone ring, reduces the side effects of the kava kava extracts. This protective activity was demonstrated using Acanthamoebae castellanii in which 100% cell death occurred with 100 mg ml(-1) kava lactones alone, and 40% cell death with a mixture of 100 mg ml (-1)glutathione and 100 mg ml (-1) kava lactones. A comparison of kava lactone toxicity with other pharmaceutical products is discussed and recommendations made for safe usage of kava-kava products

Kava--the unfolding story: report on a work-in-progress

This paper, originated as a submission (now updated) to the U.K. Medicines Control Agency and Committee of Safety of Medicines (CSM) on January 11, 2002, in response to a report circulated by the German Federal Institute for Drugs and Medical Products (German initials are BfArM), a compilation of which is summarized in Appendix 2. This agency issued notification in late November 2001 of some thirty adverse events associated with the use of concentrated standardized preparations of kava (Piper methysticum, Forst. f.) reported from Germany and Switzerland. An analysis of the summary of the BfArM case reports (see Appendix 2) shows that these contain duplications among the cases cited. The original submission that was sent to the CSM January 2002 has been updated to the version published here. This new version was completed in April 2002. As a result of the alert from BfArM, the evaluation of kava's safety is now occurring on a worldwide basis and, being that this a matter of considerable importance to the public, the health care community, and regulatory authorities as well as to kava farmers throughout Polynesia, it is it important to depict this progress report. As such, this updated report does not provide final answers. The material released by the BfArM is lacking in detail; however, it is hoped that this report will shed light on the kava controversy. It is anticipated that there will be further updates shortly. This report, prepared on behalf of the Traditional Medicines Evaluation Committee, a subcommittee of the European Herbal Practitioners Association, argues that many of the adverse events cited by the BfArM should not be attributed to kava. In addition, the report states that the properties of concentrated standardized kava extracts - as opposed to preparations that closely approximate those created for traditional use - contribute to causing adverse events. This report proposes a number of simple measures that will ensure that safe kava preparations may continue to be available in the United Kingdom.