Apple seeds are actually toxic in high doses.
https://www.medicalnewstoday.com/articles/318706
"Apple seeds, however, contain a plant compound called amygdalin, which can have a toxic effect.
Amygdalin is a part of the seeds’ chemical defenses. It is harmless when a seed is intact, but when a seed is chewed or otherwise damaged, the amygdalin degrades into hydrogen cyanide. This is very poisonous and even lethal in high doses."