Chlorophyll is the pigment synthesized with the use of sunlight by plants, and which gives them their green color. Anytime you eat green vegetables, you're consuming chlorophyll.
A similar compound, chlorophyllin is a water-soluble derivative of chlorophyll that is often included in nutritional supplements due to its greater stability in comparison with naturally occurring chlorophyll.
A review published in 2015 noted, "Chlorophyllin has been shown to exhibit potent antigenotoxic, anti-oxidant, and anticancer effects."1