Comparison of subcritical water and organic solvents for extracting kava lactones from kava root.
Subcritical water extraction of lactones from a kava (Piper metlhysticum) root was compared to a Soxhlet extraction with water, to boiling in water, and to a sonication in acetone. For ground kava (250-500 microm), 2 h of subcritical water extraction were required for a complete extraction at 100 degrees C, while at 175 degrees C, 20 min were sufficient. For a complete extraction of the unground (shredded) kava, the time of extraction was extended to 40 min at 175 degrees C. Boiling for 2 h and extraction with Soxhlet apparatus for 6 h, both of which employed water at atmospheric pressure, produced yields 40-60% lower than those obtained with subcritical water. With unground kava, 40 min of subcritical water extraction yielded essentially the same recoveries of lactones as 18 h of sonication with acetone, methylene chloride, or methanol.
Kubátová
A
A
Energy and Environmental Research Center, University of North Dakota, Grand Forks 58202, USA.
Miller
D J
DJ
Hawthorne
S B
SB
D020901:Kava / Q000737:chemistry*; D007783:Lactones / Q000302:isolation & purification*; D018517:Plant Roots / Q000737:chemistry; D012997:Solvents; D013010:Sonication; D013696:Temperature; D014867:Water
D007783:Lactones; D012997:Solvents; D014867:Water