Examples of Recent Isolation Procedures

The shade-dried sponges were extracted first with -hexane and then with ethyl acetate. The latter extract was evaporated to dryness and chomatographed on silica gel with benzene/ethyl acetate mixtures yielding 0.025% picrotoxinin (1), 0.003% methyl picrotoxate (42), and 0.017% picrotin (2) (7). 

Isolation from the Parasitic Plant Loranthus parasiticus 

The dried leaves (32 kg) of L. parasiticus parasitmg on C. japonica were extracted with ethanol, concentrated, filtered, treated with chloroform, and chromatographed on polyamide. The crystalline eluate was recrystallized yielding 0.02% coriatm (13), 0.035% tutin (11), 0.0085% coriamyrtin (9), and 0.0014% corianin (21) 21). Note the high amount of toxins of the host plant in the parasite A comparison of the main picrotoxanes of L. parasiticus and its host plant Coriaria sinica by TLC-densiometry revealed that the parasite contained 0.012% coriamyrtin (9), 0.075% tutin (11), and 0.05% coriatin (13), and the seeds of the host plant no coriamyrtin, 0.063% tutin (11), and 0.023% coriatin (13) 106). It is known that leaves, stems, and roots of Coriaria spp. contain picrotoxanes in even higher concentration than found for achenes. Thus, it would be desirable to compare the picrotoxane content of the stems and leaves with that of the picrotoxanes of the parasitic plant harvested at the same time. 

Isolation from Toxic Honey and Quantitative Analysis of its Main Picrotoxanes 

Via a plant hopper and honeybees, partly metabolized picrotoxanes from Coriaria spp. growing in New Zealand are found in toxic honey. The rather difficult isolation of picrotoxanes from honey has been described several times 2,3,10,99,100) and even now the procedure seems not entirely satisfactory (700). Originally, the isolation of picrotoxanes was achieved by extraction of honey with acetone. Later, ethyl acetate was the preferred solvent. In the late 1960s, the two main picrotoxanes were identified as tutin (11) and hyenanchin (15). Originally, the detection was governed by the physical properties of crystals obtained, color reactions, and bromoether formation. Palmer—Jones then developed a method 

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