Kava: an overview.
Singh YN
School of Pure and Applied Sciences, University of the South Pacific, Suva, Fiji.
Since the first significant contact with Europeans in the 18th century, the Oceanic plant, Piper methysticum Forst. (Piperaceae) and the beverage prepared from it, both of which are called kava, have become familiar to much of the outside world through both the written and visual media. The ceremonial preparation and consumption of the beverage are probably its most conspicuous and spectacular features. Kava continues to occupy a central place in everyday life in the islands concerned, although its role has been somewhat diminished by time and outside influences. Despite the large body of literature on kava--about 800 entries are listed in a recent bibliography by Singh (1986)--there has been no comprehensive review on the subject. Earlier contributions by Keller and Klohs (1963) and Shulgin (1973) were selective in treatment and dealt primarily with chemical and pharmacological aspects. The monograph by Steinmetz (1960) remains a standard reference but understandably some of the information in it has become dated. The attention of the reader is also drawn to two excellent additions to the recent kava literature, by Lebot and Cabalion (1988) and Brunton (1989), which are, although somewhat restricted in focus, are very significant contributions to the subject. The present review paper provides an updated and a multidisciplinary overview of the subject. It was prepared on the basis of the author's personal experience--he is a native of Fiji and lived in that country for about 30 years--as well as the relevant literature listed in the Singh (1986) bibliography and some more recent publications.
Eur J Pharmacol 1992 May 14;215(2-3):265-269 Extract of kava (Piper methysticum) and its methysticin constituents protect brain tissue against ischemic damage in rodents. Backhauss C, Krieglstein J Institut fur Pharmakologie und Toxikologie, Philipps-Universitat, Marburg, Germany. The purpose of the present study was to test whether kava extract and its constituents kawain, dihydrokawain, methysticin, dihydromethysticin and yangonin provide protection against ischemic brain damage. To this end, we used a model of focal cerebral ischemia in mice and rats. Ischemia was induced by microbipolar coagulation of the left middle cerebral artery (MCA). To quantify the size of the lesion in mice, the area of the infarct on the brain surface was assessed planimetrically 48 h after MCA occlusion by transcardial perfusion of carbon black. In the rat model infarct volume was determined 48 h after MCA occlusion by planimetric analysis and subsequent integration of the infarct areas on serial coronal slices. Compounds were administered i.p., except the kava extract, which was administered orally. The effects of the kava extract and its constituents were compared with those produced by the typical anticonvulsant, memantine. The kava extract, methysticin and dihydromethysticin produced effects similar to those of the reference substance memantine. The kava extract (150 mg/kg, 1 h before ischemia) diminished the infarct area (P less than 0.05) in mouse brains and the infarct volume (P less than 0.05) in rat brains. Methysticin, dihydromethysticin (both 10 and 30 mg/kg, 15 min before ischemia) and memantine (20 mg/kg, 30 min before ischemia) significantly reduced the infarct area in mouse brains. All other compounds failed to produce a beneficial effect on the infarct area in mouse brains. In conclusion, the kava extract exhibited neuroprotective activity, which was probably mediated by its constituents methysticin and dihydromethysticin.
Eur J Pharmacol 1992 May 14;215(2-3):265-269 Extract of kava (Piper methysticum) and its methysticin constituents protect brain tissue against ischemic damage in rodents. Backhauss C, Krieglstein J Institut fur Pharmakologie und Toxikologie, Philipps-Universitat, Marburg, Germany. The purpose of the present study was to test whether kava extract and its constituents kawain, dihydrokawain, methysticin, dihydromethysticin and yangonin provide protection against ischemic brain damage. To this end, we used a model of focal cerebral ischemia in mice and rats. Ischemia was induced by microbipolar coagulation of the left middle cerebral artery (MCA). To quantify the size of the lesion in mice, the area of the infarct on the brain surface was assessed planimetrically 48 h after MCA occlusion by transcardial perfusion of carbon black. In the rat model infarct volume was determined 48 h after MCA occlusion by planimetric analysis and subsequent integration of the infarct areas on serial coronal slices. Compounds were administered i.p., except the kava extract, which was administered orally. The effects of the kava extract and its constituents were compared with those produced by the typical anticonvulsant, memantine. The kava extract, methysticin and dihydromethysticin produced effects similar to those of the reference substance memantine. The kava extract (150 mg/kg, 1 h before ischemia) diminished the infarct area (P less than 0.05) in mouse brains and the infarct volume (P less than 0.05) in rat brains. Methysticin, dihydromethysticin (both 10 and 30 mg/kg, 15 min before ischemia) and memantine (20 mg/kg, 30 min before ischemia) significantly reduced the infarct area in mouse brains. All other compounds failed to produce a beneficial effect on the infarct area in mouse brains. In conclusion, the kava extract exhibited neuroprotective activity, which was probably mediated by its constituents methysticin and dihydromethysticin.