Chlorophyll

Chlorophyll was a pigment found in almost all plants.

Tythonians fed upon chlorophyll and mineral salts. Because they were so large, they required great quantities of it. They soon depleted the small amount on their native planet, Tythonus.

Erato was sent as an ambassador to the chlorophyll-rich Chloris. Adrasta imprisoned him for fifteen years, after which he secured a deal in which Tythonus would receive chlorophyll in return for metal. (DW: The Creature from the Pit)

Raspberry leaves contained "natural chlorophyll", as Hade put it. He thought this very healthy. (DW: The Sun Makers)