CONCISE MULTIGRAM PURIFICATION OF GUAYULIN-A FROM GUAYULE

An efficient medium-scale isolation of guayulin A is described. The di gestion of defoliated guayule in hot acetone followed by filtration an d concentration yields an extract containing resin, low molecular weig ht guayule rubbers (LGR), and water. Removal of the latter two compone nts affords a transparent green oil. This oil is fractionated by gravi ty chromatography over neutralized silica gel. A nonpolar concentrate of guayulins A (la) and B (1b) first elutes with 10% ethyl acetate in hexane. Further purification by flash chromatography yields pure guayu lin A (1a) in > 98% purity and 0.3% overall yield from the defoliated shrub.