nicotine vs phytotoxin

nicotine and phytotoxin both are nouns.

Word	Noun	Adjective	Verb	Adverb
nicotine	Yes	No	No	No
phytotoxin	Yes	No	No	No

As nouns, phytotoxin is a hypernym of nicotine; that is, phytotoxin is a word with a broader meaning than nicotine:

nicotine: an alkaloid poison that occurs in tobacco; used in medicine and as an insecticide
phytotoxin: any substance produced by plants that is similar in its properties to extracellular bacterial toxin

Other hypernyms of nicotine include pressor, vasoconstrictive, vasoconstrictor, alkaloid, plant toxin.

nicotine (noun)	phytotoxin (noun)
an alkaloid poison that occurs in tobacco; used in medicine and as an insecticide	any substance produced by plants that is similar in its properties to extracellular bacterial toxin