There's not much information on pumpkin seeds and how they pertain to Magick. Pumpkin seeds taken from Halloween jackolantern's, however, may be a different story. For example according to the celt's they would make jackolanterns to protect the house from bad spirits on the night of the dead. So extracting pumpkin seeds and saving them can actually be a good thing. I have made up a protection spell using these extracted pumpkin seeds. The goal with this spell though is to protect yourself from people who mean to harm you or do ill will, or even can be a spell to stop gossip. I think its meant to do all of these things though.
First thing to do is make sure the pumpkin seeds are dry. Get a permanent marker and write down the names and or initials of the people who you know or sense mean you harm onto the pumpkin seed(s).
Third step is make a circle out of protection herbs such as Basil, salt, etc.
Fourth step is to Put the pumpkin seeds inside the circle.
Fifth step is to imagine whit light surrounding you blocking out the influences and energies of these people while saying this small incantation.
Goddess/god I pray to you now
Protect me from these people,
Let their tongues be stilled,
No harmful energy can come to me through the barrier,
so that No Harm comes to me through them,
So that no one is harmed,
So mote it be