The concentrate (approximately 150 mg) dissolved in H20 was purified by reverse phase HPLC (Waters, ,uBondasphere 5 ,um C18-100A; 19 mm x 15 cm; 100% H20, flow rate 5 mL/min; 214 nm detector). The biological activity was found in fractions with retention times of 5 to 8 min. The eluate was concentrated in vacuo at 350C and further purified by a second HPLC step (YMC Packed Column AQ-324 S-5 120A ODS; YMC Co. Ltd., Kyoto, Japan; 100% H20, 1 mL/min, 214 nm detector). The eluate at retention time 17.0 to 17.8 min showed biological activity and was evaporated to dryness in vacuo at 350C. It gave 6.5 mg of an amorphous powder. We checked whether its occurrence could be ascribed to contamination by microorganisms, but this was not found to be the case. The activity could also be detected in mucilage