Cucurbitacin

Cucurbitacins are a class of biochemical compounds that some plants – notably members of the pumpkin and gourd family, Cucurbitaceae – produce and which function as a defense against herbivores. Cucurbitacins and their derivatives have also been found in many other plant families (including Brassicaceae, Scrophulariaceae, Begoniaceae, Elaeocarpaceae, Datiscaceae, Desfontainiaceae, Polemoniaceae, Primulaceae, Rubiaceae, Sterculiaceae, Rosaceae, and Thymelaeaceae), in some mushrooms (including Russula and Hebeloma) and even in some marine mollusks. Cucurbitacins may be a taste deterrent in plants foraged by some animals and in some edible plants preferred by humans, such as cucumbers and zucchinis. In laboratory research, cucurbitacins have cytotoxic properties and are under study for their potential biological activity. Cucurbitacins are chemically classified as triterpenes, formally derived from cucurbitane, a triterpene hydrocarbon – specifically, from the unsaturated variant cucurbit-5-ene, or 19(10→9β)-abeo-10α-lanost-5-ene. They often occur as glycosides. Most cucurbitacins are tetracyclic except some have an extra ring due to formal cyclization between C16 and C24 as in cucurbitacin S and cucurbitacin T.