Any process that stops, prevents, or reduces the frequency, rate or extent of the chemical reactions and pathways resulting in the formation of prostaglandin.
Synonyms:
exact_synonym:
down regulation of prostaglandin biosynthetic process; downregulation of prostaglandin biosynthetic process; negative regulation of prostaglandin anabolism; negative regulation of prostaglandin biosynthesis; negative regulation of prostaglandin formation; negative regulation of prostaglandin synthesis