Complex sentence: Other compounds may also play a role in St John's wort's antidepressant effects such compounds include: oligomeric procyanidines, flavonoids (quercetin), hypericin, and pseudohypericin.
Split into simpler sentences: Other compounds may also play a role in St John's wort's antidepressant effects. Such compounds include: oligomeric procyanidines, flavonoids (quercetin), hypericin, and pseudohypericin.