Isolation and identification of the toxic peptides from Lophyrotoma zonalis (Pergidae) sawfly larvae

The broad-leaved paper bark tree Melaleuca quinquenervia (Cav) (Myrtaceae) was introduced into Florida (USA) early in this century it has proliferated to such an extent that urgent measures are now required to control it. The sawfly Lophyrotoma zonalis (Pergidae) has been introduced as a possible bi ological control agent due to its ability to defoliate M. quinquenervia. Be cause toxic D-amino acid- containing peptides have been isolated from some sawfly species, L. zonalis larvae were processed using the previously repor ted method for the recovery of these compounds. The toxins lophyrotomin (as the free C-terminal acid) and a mixture of pergidin and Val(4)-pergidin we re isolated at 0.36 and 0.43% yield of the dried larvae, respectively. Both compounds when dosed intraperitoneally to C57/B16 male mice were hepatotox ic with lowest lethal doses of 8 and 32 mg/kg, respectively. The pathology of the liver was different for each compound, with the lophyrotomin free ac id causing a periportal haemorrhagic necrosis and the pergidin causing a pe riacinar coagulative necrosis. (C) 2001 Elsevier Science Ltd. All rights re served.