Plants with toxic alkaloids - University of Washington

Phototoxic Plants
Some ancient people thought that some plants harvest more sun than others.
Today we know that some species produce phototoxins = substances that are
activated by the short-wave blue and UV part of the sun’s spectrum. The
plants produce increased phototoxin levels when attacked by fungi or insects.
Giant Upon exposure hoagweed, to ultraviolet the white kernel radiation, turns discoloration violet, then of the skin occurs
(inflammation, lightening or darkening) or rashes, and even blistering.
Blister Bush Peucedanum galbanum with unpleasant cocktail of psoralen,
xanthotoxin, bergapten triggers severe dermmatitis 2-3 days after exposure
Apiaceae like Heracleum (giant hoagweed or cow parsnip), Angelica and
others cause phototoxic blistering
Many toxic plants like Deadly Nightshade Atropa belladonna etc can also
cause dermatitic inflammations
Marigold plant produces the phototoxin alpha-terthienyl, which
functions as a nematicide. When exposed to near ultraviolet light, such as
in sunlight, alpha-terthienyl generates the toxic singlet oxygen.Alphaterthienyl
results in damage to the respiratory, and nervous system of
larvae, resulting in 100% death rates = natural insecticide.