STUDIES ON THE EFFECT OF PUMPKIN SEED ON EXPERIMENTAL SCHISTOSOMIASIS JAPONICA

1.The suppressive effect.—One hundred albino mice,each infected with 40 cercariae of S. japonicum,were divided into 4 groups and were fed pumpkin seeds in the dosage of 3 gm. per head per day for 1,2,3 and 4 weeks respectively since the day of infection.Two groups of 25 each of similarly infected mice were fed pumpkin seeds in the dosage of 3 gm.per head per day for 4 weeks starting either one week before or after the infection.All groups were sacrificed and examined for worms 5 weeks after the end of treatment.Best results were obtained in the group of mice treated since the day of infection for 4 weeks. 2.The curative effect.—When infected mice were treated with pumpkin seeds 4 weeks after infection in dosages of 3,4 or 5 gm.per head per day for 4 weeks,no curative effect on mature schistosomes was observed,neither was the egg deposition capacity of female worms affected.But when pumpkin seeds were administered per os simultaneously with intraperitoneal injections of tartar emetic in subcurative doses to albino mice habouring mature infection,synergetic therapeutic action of the 2 drugs became evident. 3.The difference in chemotherapeutic action of 2 varieties of pumpkin seeds.—Two ap- parently different kinds of pumpkin seeds were available in the market.They were identified by botanist as belonging to 2 different varieties,viz.,Cucurbita moschata Duch.var.melonaeformis Mark and C.moschata Duch.var.toonas Mark.A comparative study in experimentally infected mice revealed that the former was more potent than the latter in the reduction of worms in the mice,the rates are respectively 90.8% and 60.2%. 4.The active principle of pumpkin seeds.—In collaboration with the Institute of Materia Medica,Academia Sinica and Nanking College of Pharmacy,63 kinds of extracts from pumpkin seeds were tested in experimentally infected mice for activity.The oil-free powder,the aqueous extract and the fraction extracted from acetone were found to be more potent than the rest. 5.The mechanism of the vermicidal effect of pumpkin seeds.—Comparative histopathological studies of artificially infected mice treated with pumpkin seeds and those infected but received no treatment revealed the fact that under the action of pumpkin seeds,the pulmonary stage of young schistosomes lasted much longer than usual,the development of schistosomulae were much retard- ed and they were destroyed during the early stage of their hepatic cycle. 6.During the treatment,glycogen contents in the liver decreased gradually,but the fatty globules were markedly increased.Both became normal after the cessation of treatment.No change was observed in the glycogen contents of the adult worms during the treatment.