Cimifugin: A linear Furanocoumarin found in Black Cohosh has hypotensive and photosensitizing properties.

Furanocoumarins: Furanocoumarins have sun- or photosensitizing properties and are often used for the treatment of skin conditions sometimes with controlled exposure to the sun.
Other effects of Furanocoumarins reportedly are: hypotensive activity, antiasmatic and antispasmodic.
Furanocoumarins are potentially photo-carcinogenic and may promote a cancer that is initiated by interference with the skins natural ability to protect underlying cells against the carcinogenic effect of harmful ultra violet radiation.
Furanocoumarins are Coumarins with a furan ring

Coumarins: Coumarins are lactones of hydroxycinnamic acids. Coumarins are lactones. There are many variations of coumarins: Furanocoumarins found in Angelica have a spasmolitic effect but must be used with caution as they have a strong phototoxic effect as has many of the Furanocoumarins (Warfarin a blood thinning drug but also virulent rat poison, is a coumarin derivative). In general coumarins have antifungal, hypotensive, anticoagulant and antimicrobial properties.
Many of the Coumarins are phototoxic and skin sensitising.

Lactones: A lactone is an Ester that's functional group has become part of a ring structure with carbon atoms.

Lactones are widely present in the plant kingdom and many are expectorants and febrifuges.